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Microsoft Word Viewer - QTRACW MANUAL 18-8-2008

1. GOTO s can be used within a subroutine IIF Logical expression THEN xxx Execute commands xxx only if Logical expression is true IF Logical expression THEN XXXX yyyy IELSE aaaa bbbb IEND IF Execute commands xxxx and yyyy if Logical expression is true Execute commands aaaa and bbbb if false IRETURN Return to line following last GOSUB PROMPT See below Pop up prompts IMENU See below Pop up menus ISELECT ICHECKLIST See below Pop up checklists ICHECK i ISET Logical variable Logical expression Set Logical variable to True or False depending on evaluation of Logical expression Pop up prompts The operator can be prompted to do something during the execution of a QRP file by writing comment lines starting with and then pausing with PAUSE Two problems with this are a that the operator may not notice the instructions in the comment lines and b they disappear if the text display area is reduced to zero or they may scroll out of sight when other commands are entered To avoid these problems one can create pop up prompts which are unlikely to be missed and are not affected by the size or scrolling of the text area To create a pop up prompt a comment line is preceded by the line PROMPT instead of being followed by PAUSE Many examples will be found in TRONDCM QRP e g Prompt l Use lt Insert gt lt Delete gt to adjust Test stimulus Height for measurable response 58 l As wi
2. N B Data plotted also depends on DP see p I Initialise options QRP files only IF IN IA la II fast sampling Freq 1 2 5 10 20 or 50 kHz R 10 N B this also determines minimum stimulus width Number of points for fast sampling 300 number of pre stimulus A d channels 0 number of post stimulus A d channels 0 slow sampling Interval sec R 1 This is also the minimum inter stimulus interval Unlike most other initialize options it can be changed within QTRACS until writing to file is started IG IC IL IV IS whether to make trace grabbing the default no of channels for fast sampling no of raster Latencies and peaks to save whether to record continuously Variable stimulus intervals max min Stimulator input range 100 stim 5 or 10V R N B The IS setting is remembered by Qtrac INI L N 1 0 L N N B When starting without a QRP script these parameters are set by the Select recording parameters form When starting with a script these parameters are set by the QRP file but reading of the QRP file stops after the last initialize option so that the recording parameters can be overwritten manually when the Select recording parameters form appears K socket options to select A D sockets 0 15 and D A sockets 0 1 KI socket for fast Input 0 to 7 or 15 nl 0 N B When sampling on more than one channel 1st is 0 KO socket for fast Output of stimuli 0 or 1 nl 0 KA first sock
3. PT Trigger Pulse code determines digital outputs 0 Digital outputs 0 PS PE 1 Test stimulus 2 Conditioning stimulus 1 Digital output 0 high during any non zero stim 2 Digital outputs 0 PS PE 1 Ps Pe 2 Conditioning stimulus 3 Digital output 0 PS PE and Ps Pe R Raster options most apply to on line and off line rasters RS Starting time for raster generation RE End time for raster generation RM Maximum no of raster points to display RR Lower and upper voltage limits of on line raster points generated QTRACS only N B Lower limit taken from WH if not set or RRO 0 RD Lower and upper voltage limits of raster points displayed N B Lower limit taken from WH if not set or RDO 0 RC Colour sequence in order highest to lowest point e g RC4 2 5 displays highest peak per trace in blue 2nd highest in red and rest in grey N B If not entered colour is set by channel RR Whether to rank raster points in box by latency QTRACP R Regression options QTracP only To add linear or mono exponential regression lines to User defined plots Only activated when both X and Y data are user defined Fitted equations are shown RT Regression type nl 0 0 None 1 linear y on x 33 1 linear x on y 2 exponential 3 y weighted exponential 4 quadratic RX Limits on X data for regression 0 0 no limits rR 0 0 RY Limits on Y data for regression rR 0 0 RO Y offset to subtract before ex
4. The data that is being recorded or would be following FS to start writing to file is printed in the order of the integer arrays stored in the QZD file Chan Stimulus channel number Stim Test stimulus amplitude Lat n Latency ms of type n see WL command Peak n Peak amplitude V of type n see WP cOnd Conditioning stimulus see CV Delay Conditioning test interval ms see OD Error Percentage error Peak WH WH 100 Frequency Stimulation frequency if variable intervals recorded see IV N B Colour of above determined by stimulus channel N B Latency and Peak are measured from the response and are left blank until stimulation is started AD 1 Amplitude of signal on A D channel 1 V AD 2 j channel 2 etc N B Colour determined by A D channel 3 Time or other incrementing parameter and trace The third box contains the elapsed time or time to beep in the QZD data file plus other rapidly changing parameters T Elapsed time min or T B Elapsed time beep time after OB Advance Amount of stimulus Advance Max Advance ms Average Number of response in average number required Cycles Number of cycles being counted max number Traces Number of last trace grabbed n Rast pts Number of raster latency points max number N B Advance displayed only when stimuli being advanced i e when AA gt 0 and AS gt 0 N B Average displayed only when averaging i e when MV gt 0 N B Cycles displa
5. l These produce a pop up comment entry form with question marks in text boxes Reading the QRP file cannot continue until the operator overwrites all question marks with text strings and hits lt Esc gt or clicks O K For example the following lines in a QRP file require the operator to enter the names of a nerve target muscle and side Enter motor nerve details Nerve Target muscle l Side Left Right The text strings entered are written as comments in the QZD file like those entered with command lines starting with inverted commas and can be displayed with C in the View string Accelerated comment entry with defaults In cases like the above there are only a limited number of possibilities for each of the entries and it might be more convenient for the operator to present a menu of possible answers rather than an open ended question An alternative way of facilitating comment entry is to anticipate possible answers so that only a minimum number of letters need be entered For example the above forced comment commands could be preceded by E1 E1 u Ulnar ADM Left E1 m Median APB Left E1 p Peroneal EDB Left E3 Left E3 Lef Right IE3 r Right The first E1 clears any previous default entries for comment Entry 1 The second specifies that if the entry is u this will be automatically converted to ulnar and ADM will replace the second question mark and Left the third A single characte
6. necessary to change WS 4 When the latency lock is on clicking the left mouse button in a Raw or Modified plot puts a vertical light magenta line at that latency and a corresponding horizontal light magenta line in the latency plot Similarly clicking on the left mouse button in a latency plot also activates the light magenta latency cursor If the latency cursor is already activated clicking on the left mouse button in either a Raw Modified or Latency plot moves it The latency cursor which can also be set by the command Cl is removed by CIO or LLY 5 In QtracP only 4 additional latency cursors Ca to Cd are available in the Raw and Modified plots and when the latency lock is on these also appear as horizontal lines in the Latency plot N B LL does not affect the Stimulus plot which always shows stimuli relative to the time in the sweep N B Raw and Modified plots can start at negative latencies to show events prior to the reference stimulus 6 UNDO REDO OPTIONS The command lt Ctrl Z gt undoes the last command typed in or executed from a program Alternatively and recommended until you are familiar with this operation lt Ctrl U gt displays a list of the last 20 commands and their undo equivalents Clicking on the Undo last button is equivalent to lt Ctrl Z gt and deletes the last Undo command from the list Alternatively you can click on any of the 40 listed commands to execute it When you do so the command
7. all MEM files generated by QtracP from TROND multiple excitability data 4 Having completed this installation but before running QtracS or QtracP you are advised to copy any recent updates which will be found in the same location as the Qtracinstall folder into the appropriate folders Thus updates of QtracP EXE and QtracS EXE should be copied into C Qtrac Programs any QRP files into C Qtrac QRP files and any MES files into C QTRAC MEM data 5 Passwords licence keys Qtrac software licences are now password protected anda password licence key is required to run QtracS for more than 30 days on any PC The 30 days starts the first time QtracP or QtracS is run If you want to get the most out of the free trial period it is therefore important not to run QtracS or QtracP until a data acquisition board is installed and other equipment is available for properly testing the program Uninstalling and reinstalling the program will not extend the 30 day period N B With Windows Vista when you first enter the password you will need administrator privilege which can be obtained by clicking on QtracS EXE with the right mouse button and selecting Run as administrator Otherwise you may get an access denied error message Once the password is accepted normal privilege is sufficient STARTING QTRACS After installing an appropriate data acquisition board and QtracS click on Start Programs QtracW QtracS or preferably on a shortcut
8. and to reset the window height drag the middle of the window line up or down 4 Setting all 3 parameters with right mouse button Whether the window is visible or not the left hand end of the window can be set to the position of the mouse pointer by pressing the right mouse button down and the right hand end of the window is set to the position of the mouse pointer when the right mouse button is released 5 With the arrow keys e g To move the window a bit to the right type lt Altmode gt lt Right arrow gt WS will be increased by 0 5 ms Similarly lt Altmode gt lt Left arrow gt moves the window 0 5 ms to the left lt Altmode gt lt Up arrow gt increases WH by 10 and lt Altmode gt lt Down arrow gt reduces WH by 10 N B The 0 5 ms increment decrement in WS effected by these key presses can be changed with the command WSI 6 Finally the window can be made to track changes in latency automatically by the command WAY Window Autocentre Yes cancelled with WAN Following this command the Window will be centred around the response peak every time the peak exceeds the window height provided the peak falls within the latency limits of the window Plot selection and changing the X and Y axis ranges The red gt gt at the left of the screen is the plot pointer which points to the plot to which all the display commands starting with D apply The plot pointer can be moved up and down by the lt Up arrow gt and lt Down arro
9. axis or calibrations they turn red which means that clicking the mouse will both set the plot pointer to the specified plot and activate the Change parameter range form for specifying new max and or min axis values as if DY lt Enter gt had been typed The X axis range can be set similarly by keyboard and or mouse commands DX followed by minimum and maximum values or mouse clicks specifies the range Additionally start and end times can be specified individually with DS and DE There is no autoscale so there is no double ended arrow in the middle of the X axis Instead single left and right arrows can be used to shift the axis to the left or right by half an axis length Viewing different types of data The View command determines what types of data are displayed their order and relative sizes Up to now we have looked at the Stimulus waveform and Raw and Modified response waveforms selected by the command VSRM If we now want to look for example at Test stimulus amplitudes and the Peak amplitudes of the responses as a function of elapsed time we can add T and P plots either with the command V TP or VSRMTP For the moment only the axes will appear since we haven t started recording data to file which will be dealt with next If stimulating on different channels e g 1 and 2 the responses can be viewed separately by viewing two types of plot of the same type e g VMMTP and then selecting different channels to display for
10. be entered one at a time The new line appears in white rather than yellow In the same way it is possible to edit the QRP file being created during any recording which is listed in the top right dark red panel which may require a right mouse click Lines may be deleted or inserted in the same way as for the green panel and while editing the command and prompt lines have a dark red background Notes on the use of QTRAC 1 COMMENTS NOTES CHANNEL LABELS and EXTRA VARIABLES There are now 5 ways of annotating Qtrac data files Comments eXtended Comments Notes Channel labels and notes and Extra Variables Comments As in DOS Qtrac Comments are brief bits of text used to record when things happen or are done during a recording such as Start treatment A or Subject turning blue These are entered by typing the comment preceded by inverted commas in the command line They are plotted up the screen in grey letters from an arrow that points to the elapsed time when the lt Enter gt key was struck They may also be added to a recording retrospectively in QtracP in which case an Insert Comment form appears with the option to specify exactly the elapsed time at which the comment is to be inserted These Comments are only plotted when the View string see V options contains the letter C They may be added by the command V C and removed by the command V C Some words in Comments have special functio
11. channels 39 SPECIAL KEYS lt Enter gt Terminate and execute instruction a Terminate but don t execute allows 2 or more instructions to be executed at the same time lt Page up gt Move graph text interface up lt Page down gt Move graph text interface down The interface is moved in steps of 10 of the screen height In QTracS the plot height and aspect ratio are changed In QTracP by default the plot height and width in mm and the aspect ratio are unchanged but the screen scaling factor is altered so that the full plot stays on screen Optionally View XY Scaling Fill screen the aspect ratio is changed to fill the screen N B The graph text interface can also be moved by dragging with the mouse lt Up arrow gt Move plot pointer gt gt gt up lt Down arrow gt Move plot pointer down QTracP only lt Left arrow gt Move cursor or beep time 1 to left lt Right arrow gt Move cursor or beep time 1 to right lt Ctrli left right arrows gt Move cursor in 10 bigger steps Cursor movement is also controlled by CC Cl and CL commands The default movement is one sampling interval or one trace if traces have been grabbed CC limits movement to particular channels Cl sets movement interval in minutes CL locks cursor to grabbed traces lt Altmode Left arrow gt Move window 1 4 of its width to left lt Altmode Right arrow gt a right lt Altmode Up arrow gt up by 10 lt Altmode Down arrow gt j down by 10 These
12. clicked 54 whether redo or undo will be performed and added to the list together with its undo equivalent You will find that lt Ctrl Z gt has various uses other than undoing mistakes for example it is more powerful than VX for getting back to an alternative display since it reverses axis settings as well as plot selection N B The command DAA is split up for the purposes of the undo redo table into 1DA 2DA 3DA etc These are saved in such a way that they are all undone by a single lt Ctrl Z gt 7 EDITING AND REMEASURING LATENCY PROFILES In multi unit recordings such as those obtained by microneurography the on line raster display provides a convenient indication of the units present and their changing latencies However it is often wanted to extract the latency profile of a particular unit separated from any others This may be achieved during a recording by latency tracking i e setting a window that only that unit crosses and using the window autocentre AY command to keep the unit within the window Latency profiles recorded in this way may contain erroneous points because of near coincidence of another spike or artifact or the unit in question may be lost for a time as a larger unit crosses its path There are various commands available in QtracP for correcting such faults in a latency profile or measuring the profile of a different unit Retracking or measuring a latency profile If the trace g
13. defined by HX expression binned according to DX and no of bins DN or HN Y value is no of occurrences or if Ymax is set to 1 probability of a hit error gt 0 or peak gt WH if errors not saved or it can be a user defined expression HY W average Waveform plot of modified data from trace grab file X axis determines latency range of data to be averaged If minimum X gt 0 then X value is absolute latency If min X lt 0 then X values are relative to latency L Data is averaged between times set by UT no waveform for UTO 0 Waveforms at different times may be superimposed by US Zan 2271M0O0YFP TIA c Ad Cc 37 Extras C Comments As entered via keyboard with l Instructions Saved automatically B Bars Plotted between consecutive on and off comments also narrower bars from start to stop comments G Grabbed traces indicates times traces were grabbed Other View options X eXchange View string with alternative V redisplay with same format N B For main plot types Optional digit 0 9 after letter determines relative size Repeat letter for more than one plot of same type Repeat in lower case to take scaling from plot above Use DC to limit channels displayed in each plot e g VSRM view Stimuli Raw and Modified data VTCB view Thresholds comments bars VSM2T3 view S M T with axes in proportions 1 2 3 VAAAA 1DC1 2DC2 3DC3 4DC4_ view 4 A D inputs separately and with different scaling VTttt view 4 Threshold plot
14. i e Stimulus Raw response and Modified response waveforms In QTracP several additional features and types of plot are available a If the raw response traces are saved by QTrac then in QTracP latencies and peak amplitudes can be remeasured e g with different filter or window settings and plotted separately or together with the original measurements b Saved traces can be plotted as rasters either of waveforms or of dots at latencies representing peaks above specified thresholds as for the on line raster plot c User defined plots allow simple or complex functions of saved values to be plotted e g the percentage difference between two thresholds The abscissa can also be a user defined expression so that responses can be plotted as a function of stimulus amplitude or conditioning test interval etc d Histogram plots allow data points to be binned in various ways and the ordinate can be either the number of observations the probability of an above threshold response or the mean SE also available of a specified parameter or user defined expression at those points e Waveform plots allow averages of saved traces either between absolute latencies or between times relative to the measured latencies so as to compare mean response Waveforms on different channels or during different parts of an experiment even though the response latencies may have been fluctuating widely Finally data for User defined Histogram and Wa
15. on the desktop QtracW is now password protected and a Password entry form will be presented at this stage unless a valid password has been supplied On clicking on Continue the Select A D board form appears The first time you get this form it is a good idea to click on the checkbox labelled Change A D boards to look for and click on O K This leads to the A D boards enable form where you can click on the checkboxes for one or more installed data acquisition boards On clicking on O K you will be returned to the Select A D board form where the valid options can be selected from a drop down list If no A D boards are installed the only options are Test for which the input waveform is identical to the output waveform and Model motor axon for which the raw response is 100 x the membrane potential of a computer model of a human motor axon i e a resting potential of 83 mV appears as 8 3 V After the A D board is selected you get to the Select recording protocol form The Select recording protocol form enables you to select between any of the last 8 recording protocols in QRP files used or to Browse for another QRP file or to select None in which case you start with all parameters set to their default values On clicking on O K to accept the selected file or O K after browsing for a QRP file or None you will be confronted with the Stimulator sett
16. one The CED units are boxes with convenient BNC connectors but as with the DAQCard 6062E the digital outputs do not function The CED software should be installed in the default directory C 1401 Data transfer to the CED boxes is relatively slow N B A Qtrac driver is supplied for the DAQ2000 loTech PCI board but this is not currently recommended since it can produce occasional extraneous output pulses at the end of a sweep German keyboards with a shift lock rather than a capitals lock are inconvenient for the Qtrac programs The most convenient keyboards have lt Insert gt above lt Delete gt and lt Page Up gt above lt Page Down gt QtracP produces output in various forms Plotted waveforms can be written to disk in Ascll format or transferred directly to an Excel file Nerve excitability data generated by the Trond protocols can be transferred to special text files MEM for analysis by QtracP Plots generated by QtracP can be sent to any Windows printer including the Adobe pdf generator if installed Plots can also be copied to the Windows clipboard as bitmaps or metafiles and hence transferred to programs such as Powerpoint or Word Complete nerve excitability data from a group of MEM files indexed by a MEF file can be plotted or transferred in one go to an excel file Stimulus Stimulation is via one of two 16 bit analogue outputs on the BNC 2110 AOO 1 or alternative device Stimulation and recording are sim
17. require appropriate Modified data plot to be selected or window starts to be locked together with WSLY If latencies or peaks displayed change latency and peak values in QZD file to value remeasured from current trace ad determined by WL WP If delays displayed change delay in QZD according to OD QTracP only lt gt As and move to last or next trace depending on CC QTracP only Enter a comment for saving in QZD file N B will add permanent comments to an existing QZD file which is useful for plotting bars see under View Options lt Backspace gt Deletes last character of current instruction 40 lt Insert gt lt Delete gt Increase TH to next multiple of 5 QtracS only Decrease TH to lower multiple of 5 QtracS only These only work if all the test stimuli are equal see The Increment can be changed with THI lt Pause gt Interrupt program lt Esc gt Continue lt Esc gt both continues after program interruption with lt Pause gt and continues reading from a QRP or QPP file after this has been suspended with PAUSE Qtracs only QtracS only Invert raw data Data inversion off Set test stimulus height on all selected channels to equal height on first selected channel QtracS only In QRP and QPP files Causes a line to be printed in green but not executed allowing comments or instructions to be passed to the operator is also used to indicate a meta command
18. stimuli QtracS Programming with QRP and QPP files Meta commands Pop up prompts Pop up menus Pop up checklists Responding to pop up prompts and menus Logical variables and logical expressions Forced comments Accelerated comment entry with defaults Loading QRP or QPP files 9 Statistical tests in MEF Compare form QtracP Types of test available Approximation of P values Compensation for temperature age etc 10 File structure of QZD and QTG files QZD files QTG files Further information Error reporting PROGRAM INTRODUCTION AND DESCRIPTION QTrac is a flexible stimulus response data acquisition program with averaging and threshold tracking facilities originally written for studies of human nerves in vivo but also suitable for many other preparations It is most appropriate for experiments in which the excitability or response of the preparation varies slowly with time either due to programmed changes in the stimulus or to an externally initiated treatment and the data of primary interest are the changes in selected parameters threshold amplitude latency etc of the response with time All or selected raw response waveforms can also be recorded enabling the time course of additional response parameters to be calculated after the recording is finished QTrac comprises separate stimulation and plotting programs QTracS and QTracP which have the same mode of operation and share many of the same facilities QTrac is a m
19. taken from the script and the effect it has had and a timed record of this information is recorded in a log file QLG Hardware and software requirements QTrac is suitable for use with PCs running Windows software 98 2000 or XP N B Installation under Windows Vista is possible but not at present as convenient as under Windows XP QtracS currently supports the following data acquisition cards units PCI PCI 6221M National Instruments All Qtrac functions PCMCIA DAQCard 6062E National Instruments Digital o p not supported USB USB 6221 USB 6251 NI All Qtrac functions AdWin L16 Ext All Qtrac functions Micro 1401 Cambridge Electronic Design Digital o p not supported Power 1401 j oy 4 The National Instruments devices for which Tim Howells kindly wrote the Qtrac drivers are the best value units and a BNC connector box BNC 2110 or 2120 is available for these devices For counting the cost you will also need a shielded cable SHC68 68 EPM Check for academic discount Recently all in one USB boxes with BNC sockets and DAQ cards such as the USB 6221 BNC have become available It is important to note that NI recommend a Pentium 4 or above processor with at least 256 Mb of memory and that these devices do not work under Windows 98 ME The QtracS driver sets up the NI cards with an input range of 10V and 8 differential inputs AI0 7 If speed is critical the USB boards are not as fast as the PCI
20. the load This is revealed by the output voltage going to the 100V limits and it is convenient therefore to record the peak stimulus voltage as a function of time during the recording The peak output current should normally correspond closely to the commanded test stimulus amplitude and that can also be recorded as a function of time The peak stimulus current and voltage are derived automatically from the relevant stimulus waveforms when these are recorded The values for each stimulus are displayed in the data box and saved in the QZD file Displaying peak values of stimulus current and voltage v elapsed time The monitored peak stimulus current can be displayed with or without the command stimulus current in the Threshold Test stimulus plot VT by using lower case letters for the DP code Thus DPLp displays the command stimuli as lines and the monitored currents as points DPI displays just the monitored current as lines The monitored peak stimulus voltage can be displayed in a Voltage plot Thus VTV displays the time course of changes in test stimulus current and voltage N B The voltages cannot be displayed on their own with VV since that command is already reserved for refreshing the display However voltages can be added with V V or removed with V V QTRACS Running the multiple excitability program TRONDCMW QRP As an example of a QRP program we take the QRP file recording protocol for tracking multiple excitability properties
21. used to control the reading of the QRP or QPP file as indicated in the Notes on programming with QRP and QPP files below e g ICLEAR Clears scrolling part of screen PAUSE Causes suspension of reading a QRP or QPP file allowing the operator to take over Reading from the parameter file is not resumed until lt Esc gt is hit A prompt in light blue appears on the bottom line while lt Esc gt is effective The prompt may be set in the parameter file by including Esc in a comment line See below Notes on using Qtrac 6 Programming with QRP and QPP files lt Ctrl C gt Exit program lt Ctrl N gt Add note lt Ctrl U gt Show undo redo options see section on Undo Redo lt Ctrl X gt Add extended comment lt Ctrl Z gt Undo last command see section on Undo Redo lt F1 gt Stop stimulation immediately QtracS only lt F2 gt to lt F12 gt Programmable function keys edit with Ctrl function key see page 37 41 Deleted N B QTracS and QtracP function keystrings are rememberedseparately in Qtrac INI Formatted Font Italic Deleted also resets data acquisition board Formatted Font Bold Formatted Font Bold PARAMETER TYPES and examples R L T nl nR nL 16l sl nR nL sl Integer Real i e decimal fractions allowed Logical Y or N Text string up to N Integers where N is no of available channels up to N Reals up to N
22. 0 Sets limits relative to start sweep MF No of harmonics of mains frequency to Filter nl 0 N B mains waveform taken from times set by MFT N B mains frequency defined by MFF MFF set mains frequency Hz for MF R 50 MFT set Time limits to fit mains waveform rR 0 0 MD Differentiate Y or N nL N MI whether to Integrate data within window Y N nL N MR Rectification options nl 0 0 no rectification 1 half wave rectification 2 full wave rectification MM Multiply by nR 1 MG Grass cut data within range R 0 M add last trace on channel nl 0 M subtract last trace on channel nl 0 e g 3M 2 subtracts last trace on channel 2 from channel 3 N B M can be used for artefact rejection by adding response to an inverted stimulus whereas M can be used for recording refractory periods by subtracting response to conditioning stimulus alone N B 3M 2 subtracts channel 2 twice from channel 3 MO to specify order of execution of modify options N B V F are always executed first and are unaffected by MO Default order is LHSChDIRMG MO can be used to change this order or to repeat some operations e g MOHHH specifies 3 successive high pass filter operations and no other modifications If no of stimulus channels SN is 1 then MH100 200 1000 would set successive filter frequencies whereas if more than 1 channel is active this command would set filter frequencies on different channels O Other options OS Storage scope o
23. CKLIST option in parentheses is not included in the name of the logical variable 3 The SET meta command defines a new logical variable or resets the value of an existing logical variable N B If a logical variable is created with a name identical to the start of another logical variable they are assumed to be the same and given the name of the shortest Logical expressions which are evaluated to True or False may contain the following elements Logical variable the name of a logical variable within inverted commas AND OR NOT the conventional logical operators parentheses to avoid ambiguity TRUE FALSE N B AND OR NOT TRUE and FALSE can be abbreviated by A O N T F respectively N B Case is disregarded for these as for all other meta commands The following examples of logical variables and expressions are taken from TRONDEM QRP 1 ISET Sensory NOT Motor 2 IIF Sensory THEN TWO 5 ELSE TW1 0 IEND IF 60 3 LHF NOT Short AND Motor THEN 6AQ0 0 2 0 4 0 6 0 8 4 Select recording sequence or single test Singles SR only Singles SD only Singles TE only End_ Finish Singles LHF SR only then Gosub SR HF SD only then Gosub SD IF TE only then Gosub TE Goto MainOptions Forced comment entry The operator can be forced to document a recording by inserting a line in the QRP file starting ENTER and following it with one or more lines starting
24. Logicals up to 16 Integers for input sockets 0 to 15 Selection of Integers Range of Reals SN6 set Number of Stimulus channels to 6 DH3 5 Display Horizontal line at Y 3 5 OSY set trace displays to Storage mode DLStimulus mA sets y axis legend to Stimulus mA N B splits legend into 2 lines MS2 Smooth all channels twice KI1 2 3 4 record 4 channels from corresponding sockets 2MV8 average 8 sweeps for channel 2 13BN4 Burst of 4 stimuli for channels 1 3 TH1 set Height all Test stimuli to 1V TH 5 1 1 5 set Test stimuli 1 3 to Heights 5 1 1 5V 46TW 2 set Width Test stimuli 4 6 to 2ms OTS5 Start Test stimulus 10 at 5 ms MIY Integrate data on all channels MIN Y N Y Integrate channels 2 and 4 SMIY Integrate channel 5 13MIN Don t integrate channels 1 3 SC4 stimulate on channel 4 only SCO stimulate on all available channels C1 3 4 5 stimulate on channels 1 3 4 5 C1 3 5 m DX0 5 10 Display X values from 0 5 to 10 Summary of means of specifying multichannel variables nl nR nL e g TH Prompts for Test stim Height Pop up box 42 TH20 Sets Test stim Height to 20 max on all channels TH10 20 30 Sets Test stim Heights to 10 on channel 1 20 on channel 2 and 30 on remaining channels N B Multichannel commands can be restricted to a single channel by a using the prefixes 1 to 9 0 and a f 2TH30 Sets Test stim Height to 30 on channel 2 only OTH50 Sets Test stim Height to 50 on channel 10 aTH50 Sets Tes
25. QTRACW Version 18 8 2008 USER MANUAL Copyright 2008 Institute of Neurology All rights reserved No part of this specification or the software to which it relates may be reproduced stored in a retrieval system or transmitted in any form or by any means electronic mechanical or otherwise without prior permission of the copyright owner QTRACW Version 18 8 2008 LIST of CONTENTS Program introduction and description Hardware and software requirements Stimulus Response Multiple event recording and on line raster plot Threshold tracking Slow sampling Display and plotting Files Installation Starting QtracS QtracS screen QtracS starting to stimulate and record without a QRP program Changing the stimulus parameters The Window measurement of latencies and peak heights The Window setting starting time width and height Plot selection and changing the X and Y axis ranges Viewing different types of data Recording data to file Starting threshold tracking QtracS running the multiple excitability program TRONDCMW QRP Starting QtracP QtracP screen QtracP menus File View Edit List Zoom MEM MEF LA RCC QPD Display options Print options Metafile options Qtrac options A Automatic stimulus advance options QtracS only B Burst stimuli options C Cursor options QTracP only C Conditioning stimuli options QtracS only D Display options E Extra stimulus options QtracS only F File options G Trace Grab options P
26. ables in QZE file L Latency editing and remeasuring options QtracP only see p selection with right mouse LR Get latencies from selected on line raster points LA Add constant to selected latencies LZ Zero selected latencies LD Latency dehair zero displayed latency outliers limit ms LDR Dehair latency ramp zero latency outliers from ramp LI Interpolate displayed latencies up to max interval min LSL Smooth selected latencies by linear fit over range min LSQ Smooth selected latencies by quadratic fit over range min M Modify options ML Low pass filter frequency Hz O off MH High pass filter frequency Hz 0 off N B Negative frequency for ML or MH gives forward time reverse filtering and avoids time displacement MS number of 1 2 1 Smooths MV number of traces to aVerage see also OV MC baseline Clamp options 30 R R R R R R nR 0 nR 0 nl 0 nl 1 nl 1 0 none 1 clamp start of window and preceding data to zero 2 clamp start and end of window and data outside window to zero 3 clamp to mean value between times set by MCT 4 clamp to best line fit to data within MCT but excluding window 5 clamp 10 pts either side window to zero 6 clamp 10 pts to left of window to zero 7 mean of points displayed N B Asterisks indicate sloping baseline MCT Time limits for baseline Clamp MC3 MC4 rR 0 0 N B MCTO O Sets limits to window MCT 1 1 Sets limits relative to window MCT100 20
27. ad impedance which are updated after every stimulus Depending on the DS5 connections these values are obtained via the USB link from the monitor waveforms not resting current or they can be selected from either source There are preset limits indicated by red lines and when these limits are exceeded the bars turn red as a warning and a red bar with an indication of which limit s were exceeded appears next to the DS5 Mon button on the main form The value for impedance whether obtained from the DS5 or stimulus monitor waveforms is calculated simply as the ratio of peak voltage to peak current Putting a resistor as the DS5 load can provide a check that current and voltage settings are correct Stimulus waveform monitoring It is always important to check that the stimulus current waveform from a constant current stimulator matches the command stimulus waveform generated by Qtrac With the DS5 both current and voltage waveforms are conveniently available on sockets at the back of the stimulator and it is now possible to display these waveforms routinely and to save them with the response waveforms in a QTG file The procedure is to connect the stimulus current monitor output 1V 10mA to input socket 1 assuming that the main response waveform is being recorded on socket 0 and the stimulus voltage monitor output 1V 20V NB This output is incorrectly labelled 1V 10V on some models to input socket 2 and in the Stimulus settings fo
28. age OMNNDDDMDONNAHA H Histogram options QtracP only Initialise options QtracS only K Socket options QtracS only _ L Latency log file and channel label options L Latency editing and remeasuring options QtracP only M Modify options O Other options P Plot options QTracP only P Polarising trigger pulse options QTracS only R Raster options R Regression options QtracP only S Stimulus options QtracS only T Test stimulus and threshold tracking options QtracS only U User defined plot options V View options W Window options Special keys Parameter types and examples Programmable function keys Data display panels Line point options DL DP Index display QRP QPP display Notes on using QTRAC 1 Comments Notes and Extra Variables wo N om O CON Comments Extended comments Notes Channel labels and notes Extra variables Threshold tracking TT TM QtracS Optimising proportional tracking Automatic advance features QtracS Regular advance Irregular advance The TO command The Lock options QtracS Window start lock Window height lock Cursor lock Latency lock and latency cursors Editing and remeasuring latency profiles Retracking or measuring latency profiles Remeasuring latency from an on line raster plot Zeroing selected latency De hairing a latency profile Latency interpolation Add constant to selected latencies Latency smoothing Dummy
29. an appropriate plot can also be set by keyboard and mouse as well as by keyboard alone The Window measurement of latencies and peak heights The Qtrac window is indicated by a horizontal light magenta line in the Modified plot initially from 5 to 15 ms ata height of 2 V The window defines both the part of the response during which the waveform is measured to produce a response peak height and latency and the target response height for threshold tracking The method of measuring the peak height within the window is defined by the command WP and can be discovered by typing WP lt Enter gt while the type of latency measurement is defined by the command LT or WL since latency measured within window The WP and LT methods in use are indicated graphically by light cyan lines on the Modified plot and numerically by the numbers in brackets after Peak and Latency respectively in the data box on the right hand side of the screen Thus initially the latency type is 2 i e latency measured from test stimulus to response peak and a light cyan line is drawn from 1 ms the start of the test stimulus to the highest point of the response within the window at the level of the height of the peak Similarly the peak measurement code is 1 i e baseline to positive peak and a light cyan line is drawn from the baseline to the highest point of the response within the window To record peak to peak heights instead type WP2 lt Enter gt to specify peak mea
30. ate and one letter run code which is incremented automatically from A to Z Additional log files QtracS LOG and QtracP LOG are optionally generated in the Qtrac Programs directory for debugging purposes when QtracSEnable 1 or QtracPEnable 1 are set in the LogFiles section of Qtrac INI QRP files hold the Recording Parameters and may be generated by the FP command while QTracS is running or at the end of a run They hold all the instructions that have been typed in which resulted in parameter changes QRP files therefore specify the experimental protocol and can be used to reset the parameters when QTracS is restarted When a QRP file is called by QTracS and the instructions decoded both the original instructions and their interpretation by the program as they are executed are written to a QRX file with the same name as the QRP file The QRX files are therefore helpful in understanding QRP files During execution of a QRP protocol the forthcoming instructions in the QRP file and the recently executed instructions in the QRX file can be inspected at any time Corresponding QPP and QPxX files are generated by QTracP and specify the parameters required to generate a plot QRP and QPP files are ASCII files which may be edited by a text editor to restart or replot an experiment with altered parameters The QRP and QPP files can be converted into user friendly experimental or plotting programs by the addition of pauses and pop up prompts and menu
31. ax of values per pixel width to plot when number N maxtmin of points exceeds number of pixels R range default is R but others are quicker DP options for plot types T O D E A N L plot lines P plot points radius set by DR for filled circle LP lines and points H plot hit miss if response below target if above size set by DR DP options for plot type L Latency L P LP H as above R on line raster display ie plot latencies of multiple peaks N B R requires rasters to have been enabled e g by IL30 in QRP file 45 N B Range of raster points displayed can be limited by RD N B Maximum number of raster points displayed can be limited by RM N B R can be combined with L or P e g LR plots multiple latencies as points but single latencies recorded within the window as a line DP options for plot type P Peak L P LP H as above R on line raster display ie plot lamplitudes of all peaks as for latencies above W plot window heights in addition N B WHLY to lock WH on different stimulus channels together and plot as single light magenta line QTRACP plot types DP options for plot type S Stimulus S steps only option DP options for plot types R Raw M Modified data L plot lines P plot points radius set by DR for filled circles LP lines and points DP options for plot types T O D E A N L P L LP H W as for QTRACS above DL plot standard dev
32. ch as zero by hitting lt Delete gt 4 times the TH line appears as TH Height test stim 1 10 now 0 20 20 20 20 20 20 20 20 20 i e the test stimulus on channel 1 is now 0 but remains at 20 on channels 2 10 since the lt Insert gt and lt Delete gt commands only work on active channels These fundamental test stimulus properties can be set or changed in 2 ways 1 With keyboard alone e g To reset the test stimulus start from 1 ms to 2 ms type TS2 lt Enter gt Similarly to reset the test stimulus width from 0 1 to 10 ms type TW10 lt Enter gt and to reset the test stimulus height from 20 to 15 type TH15 lt Enter gt 2 With keyboard and mouse e g To reset the test stimulus start type TS and click with mouse at the desired starting point in the Stimulus Raw or Modified plot At the top of the screen you will see e g 11 TS1 4 before clicking the mouse and after clicking the command effected will appear in yellow and the computer s response Start test stimulus 1 10 now 1 4 ms will appear as the last line of the scrolling dialogue Similarly TW and a mouse click at the desired new end of the stimulus pulse or TH at the desired new height will reset TW and TH N B The 1 10 indicates that these changes will apply to all 10 channels Methods of setting different values of multichannel variables for different channels are described in a separate section All other parameters which can be set by clicking on
33. channel 1 16 3 BO 4 iBH i e height burst stimulus as integer 5 iPol i e amplitude polarizing current as integer 6 iCS i e start conditioning stimulus as integer 7 i CS CW i e end conditioning stim as integer 8 iCH 9 iBF 10 iBL 11 BN 12 iBW i e burst stimulus width as integer 13 TF 14 TO 15 iTS 16 i TS TW 17 iTH 18 i TH x TB if TF 1 19 CC 20 iTP 21 iEH 22 iES 23 i ES EW 24 CF 25 iCP 26 iCB 64 The two letters indicate the Qtrac variable value for the particular stimulus channel The i prefix indicates variable is converted to integer In the case of amplitudes this is by multiplying the of maximum output by 200 In the case of times this is by multiplying the value in ms by the sampling rate in kHz ACKNOWLEDGEMENT Although several people have contributed ideas towards improving Qtrac must acknowledge a particular debt to Tim Howells who was responsible for the drivers for the CED1401 and National Instruments devices and for the Excel export functions as well as for various other debugs and improvements FURTHER INFORMATION Further information on any function can be obtained from the author Professor Hugh Bostock Sobell Department of Neurophysiology Institute of Neurology Queen Square London WC1N 3BG Fax U K 020 7813 3107 Int 44 20 7813 3107 email H Bostock ion ucl ac uk ERROR REPORTING Please report any errors to the author If a consistent pr
34. d be obtained by relying on random variation within a group of normal recordings For example compensation for temperature is probably best done by reference to recordings in which the same subjects were recorded over a range of temperatures as is the case for median APB recordings referred to in NCTemp MEF which comprise the data collected by Kiernan Cikurel amp Bostock 2001 11 FILE STRUCTURE OF QZD AND QTG FILES QZD files QZD files consist of a 512 byte header block followed by a two dimensional integer array nArrays x nPoints with the slowly changing parameter nPoints increasing by one for each slow sampling interval corresponding to the minimum interstimulus interval whether or not a stimulus was delivered The 512 bytes of the header block many of which can be edited by the Edit header block menu option in QtracP contain the following parameters and labels Bytes VB6 type Description 1 2 Integer nArrays 3 4 Integer nPoints 5 6 Integer nTraces no of traces saved in QTG file 7 8 Integer 1 if trace grabbing enabled 0 if not 9 10 Integer QZD file format descriptor range 2 255 see below 11 12 Integer nStim number of stimulus channels 13 14 Integer Block size for QTG files 8192 bytes 15 16 Integer nPointsPerTrace as saved in QTG file 17 18 Integer Array offset if nPointsPerTrace lt nSamples 19 27 String 9 Start time 28 29 String 2 Age 30 31 String 2 Sex 32 36 String 5 Temperature 37 50 String 14 Sti
35. display by clicking with the right mouse button QTRACS Starting to stimulate and record without a QRP program As initially loaded the Qtracs white graphics area is split into 3 plots labelled Stimulus Raw and Modified with a data display box on the right described later The stimulus waveform initially a 0 1 ms pulse at 1 ms set to 20 maximum stimulator output is displayed in the top 10 plot but nothing in the Raw response or Modified response plots because stimulation has not yet started The prompt line at the bottom of the screen reads SS to start stimulation Typing SS no shift key required since characters are interpreted by default as upper case overwrites the initial text in the command line Commands keyed in appear here and completing the command with lt Enter gt the Return key executes the command and starts stimulation In the blue scrolling dialogue area above the command line the command typed in appears on the left in yellow and the computer s response STIMULATION STARTED appears in the middle in white Now stimulation starts at the default rate of 1 Hz and the Raw responses from the A D converter appear in the middle plot The Modified response plot at the bottom shows the data after baseline clamping and filtering or other modifying operations The modifications in action are listed in brackets in grey at the bottom of the screen and Initially the only operation is MC6 This means that
36. e Display thresholds as off on overwrite option has to be set to yes OOY Because Qtrac is most often used for TROND recordings TO and OOY are the default settings in QtracP This can cause confusion if a recording was made with TO1 e g the latent addition protocol LA99SD QRP For such recordings it is necessary to set TO1 in QtracP Unfortunately the TO setting is not recorded automatically in the QZD file so if you are not sure which setting to use and it is not obvious by inspection of the thresholds it may be necessary to study the QRX record of what the TO setting was 5 THE LOCK OPTIONS QtracS The commands WSL WHL CL and LL are all Yes Y No N commands which lock one or more parameters or operations together Window Start Lock WSLY or WSLN and Window Height Lock WHLY N WSLY locks the start WS and width WW of the window to the same value on all active channels At start up the lock is on and changing WS or WW on one channel by e g 2WS20 or by dragging the window start with the mouse on a Modified data plot which is not displaying all channels changes it to the same value on all channels N B On earlier versions the lock always held WS and WW to the values on channel 1 When this happens a red warning message reminds you that the lock is on and the other channels have been changed The window height lock is also on at start up and acts similarly to keep WH the sa
37. e T 100 or 5 steps relative T 0 until next SR Starting time recorded for TTA N B If tracking steps absolute T 100 then the stim response step size can be set to a specified fraction of the stimulus on a specific channel e g SR 3 50 sets step size to 1 50th of stimulus on channel 3 SR Starts decremental stimulus response recording SR Stops stimulus response recording see TTA T Test stimulus and Threshold Tracking options QTracS only TS Test stimulus Start time ms nR 1 TW Test stimulus Width ms nR 0 1 34 TH Test stimulus Height V nR 1 see also special keys lt nsert gt lt Delete gt and N B for negative stimuli range must be changed with TR TF Test stimulus waveForm code 0 0 rectangular 1 biphasic TB for ratio 2 triangular TW sets half width 3 sine wave TP for period TW sets duration 4 cosine windowed sinewave peaks at TW 2 5 trapezoidal TP for slope TW for plateau 6 steps TP for step width TW for total TB Biphasic ratio Test stim 2nd phase st nR 1 TP Period step length etc Test stimuli msec nR 1 TT basic step for Tracking with Test stim nR 0 this is the command that activates threshold tracking effect is modified by TM T see also TTA TT TM Tracking Mode determines effect of TT nl 4 0 step proportional to error of stim 100 error in peak 1 fixed step of stim n step incrementing to n times basic step e g TM0 TT10 WH2 if response
38. e QRP file otherwise they will be ignored The characters and at the start of a line in QRP QPP files cause the line not to be treated as ordinary Qtrac commands denotes a line label whereas indicates a prompt or one of a number of meta commands used to control pop up prompts menus and program branching e g Restart Is aline label and not executed GOTO Restart Causes program to continue at line below Restart If an initial 1 is not followed by one of the meta commands below the line becomes a prompt line and is printed in green in the scrolling dialogue area This was the only type of prompt possible in DOS Qtrac Pop up prompts using PROMPT are now generally preferred because of their higher visibility N B Although the meta commands below are all given in upper case they are case insensitive Meta commands ICLEAR Clears scrolling dialogue area IDEFAULTS Rereads default checklist and menu selections from INI file PAUSE Pauses reading of QRP QPP file until Escape key is hit or other form of program advance is encountered ICYCLES n Pauses reading of QRP file for n stimulation cycles where n is an integer oe IENTER See below Forced comments 1E1 See below Accelerated comment entry with defaults GOTO Label Unconditional branch to line starting Label GOSUB Label Branch to subroutine at line starting Label N B Subroutines can be nested to a depth of 20 N B
39. e this after Print start only when you have finished superimposing Exit Quit QtracP View X Y scaling Allows you to choose between filling the screen and maintaining the standard aspect ratio Cm grid Click on this to add a grid corresponding to nominal 1 cm squares on printed output A4 limits Superimposes horizontal or vertical lines corresponding to edges of A4 paper Data boxes Switch on or off the display of data boxes at the right of the screen Cinematic Select to view Modified data in cinematic mode Deselection restores previous display format N B The view cinematic option is equivalent to the following sequence of commands that can be placed in a QPP file Turns Cursor Lock off so that all traces within elapsed time limits are displayed not just the one pointed to by cursor Oso Turns Superimpose off which is turned on by CLN CEY Makes elapsed time displays end at cursor last trace V b Turns off right hand display of Data Box V f Makes display fill available screen irrespective of aspect ratio OF1 Sets fraction of screen for graphics to 1 and removes text Edit Header block Allows header block containing labels and scaling factors to be edited Also allows editing of Notes about the recording and adding Extra variables which are copied into MEM files see below 20 Copy bitmap Copies the display as a bitmap e g to Powerpoint Copy metafile Copies the display as an enhanced metafile e g to Pow
40. e value and then climbs up towards zero Sometimes however it never reaches zero and starts dropping again When this happens there is no point in subjecting the subject to stronger and stronger stimuli and it is best to hit lt Esc gt or click on O K to terminate the RC recording Multitrack This estimates several excitability parameters continuously Strength duration time constant is estimated from the threshold to 1 ms channel 1 and 0 2 ms stimuli channel 6 Threshold electrotonus is monitored at 100 ms intervals for 40 depolarizing channel 2 and 40 hyperpolarizing currents channel 3 Superexcitability at an interstimulus interval of 6 3 ms is monitored with channels 1 control 9 conditioning alone and 10 conditioning test NB TrondCMW is now superseded by TrondH which provides more options 18 STARTING QTRACP QtracP may either be started by clicking on a QZD file in Windows Explorer if QtracP has been set up as the default program for opening QZD files or by clicking on Start Programs Qtrac Qtracp or a shortcut on the desktop Unless you have started by clicking on a QZD file QtracP starts with the Selecty QZD file to display form This lists the 8 most recently opened QZD files which may be opened by selecting one and clicking on O K Alternatively you can click on Browse which opens the Browse for QZD file form This is a full screen form which many items of information about a
41. e within times set by last stimulus response recording Sets TT to optimum tracking step estimated from the slope of the stimulus response relationship e g SC7 SR SR Records stim response on channel 7 then 15TTA 3 Sets WH and TT on channels 1 5 to track 30 of peak response on chan 7 35 N B If peak fraction not specified a fraction between 0 25 and 0 5 is selected where the stim response relation is steepest TT Reduces tracking step by specified factor TT Multiplies tracking step by specified factor TH Divide TH by specified factor TH Multiply TH by specified factor 1 D DDI U User defined plot options UY Define expression to plot separately for each channel U1 Define expression to plot overrides UY for channel 1 U2 to U16 Define additional expressions Select from expressions 1 to 16 for different plots with DC N B UY is plot specific U1 to U16 are not UX define X axis for user defined plots T M UT define Times for user defined plots rR 0 0 if 0 0 times taken from elapsed time plots US to superimpose data at different UT N B UT and US also function for Histogram Waveform plots UC to change Colours of user defined plots nl 1 2 3 etc 4A N B User defined expressions may contain decimal numbers T1 to T16 for Threshold stimulus on specified channel TU for Threshold on channel n corresponding to Un T for Threshold on any channel N B T and TU are equivalent when using UY L1 to L16 LU or L fo
42. ed if desired by setting SkipOutputCheck 1 in the General section in the Qtrac INI file in C Qtrac Progams If multiple fast sampling channels e g waveform monitor channels or slow sampling channels e g for temperature have been specified an Input channel check form appears This is a read only form to show which inputs are expected at which of the input sockets 0 to 7 After these preliminaries are completed control passes to the main QtracS screen QTRACS SCREEN The main part of the screen is divided into a white graphics area and a blue scrolling dialogue area and a line at the bottom provides prompts in pale blue The line above the prompt line is the command line where commands entered from the keyboard appear in yellow This line normally has the focus as indicated by the flashing cursor which is necessary in order to enter keyboard commands The line above the command line which typically contains the last command entered and the computer s response is a protected line and remains visible when the white blue border is moved down as far as possible The white blue border can be moved up and down with the lt Page Up gt and lt Page Down gt keys or the OF command or it can be moved by dragging with the mouse A disadvantage of dragging is that the command line loses the focus which then has to be restored by clicking on the command line the scrolling area or the graphics area The screen is also furthe
43. educed in size or minimized by clicking on the conventional Windows symbols in the top right corner The main graphics display in QtracP is controlled by the V View command which determines what types of data are displayed and the D Display family of commands which determine how the data is displayed and scaled which work as in QtracS Thus Stimulus Raw data and Modified data waveforms can be examined with VSRM for traces that were grabbed and saved in a QTG file The modified data display does not correspond to that originally recorded but is derived afresh from the raw data and the current settings of the window baseline clamp and filter options etc Data normally displayed when viewing Peaks and Latencies e g VPL are the same values as displayed during the recording and saved in the QZD file However it is also possible to remeasure the peaks and latencies from the raw traces saved in the QTG file and the remeasured values can be compared with the original ones and used to replace them The convention is that following the DP Display Plottype command capital letters e g L for lines P for points denote the originally recorded values and lower case letters denote freshly remeasured ones Details of the options available are given in the section on Line Point options on page below In addition to the types of plot that could be viewed with the V command in QtracS i e Stimulus Raw Modified Threshold Latency Peak cOnditioni
44. eful feature is the ability to program changes in a stimulus parameter e g conditioning test stimulus interval so that a variety of excitability curves can be generated automatically Any combination of 4 stimulus parameters can be changed see AA the changes can be made either at regular intervals or conditionally on threshold tracking being satisfactory AC and the parameter s can be changed either in regular steps or following an irregular sequence Al AQ When the program of parameter changes has been completed then a warning beep is sounded and the program is either restarted stopped or reset with the completed channel skipped see Advance End option AE As an example of both regular and irregular advance methods we will take the case of measuring the strength duration relationship for stimulating a nerve i e measuring how the stimulus strength required to excite a single fibre Sa or obtain a standard sub maximal response varies with the stimulus width In either case the parameter to be changed is TW test stimulus width so we select AA8 However to allow for drift in the threshold during the recording it is advisable to always compare threshold for a standard width stimulus with threshold for the variable width stimulus with SN2 AA0 8 so that TW only changes on channel 2 Regular advance Suppose we wish to estimate thresholds for stimulus widths between 50 and 1000 us at 50 us intervals then we could start by se
45. eights instead of times L N N B Only available with AA1 increases CH AA4 TH AA32 WH B Burst stimulus options QTracS only A train of identical stimuli at equal intervals set by BF BL and BN BF start time First Burst stimulus ms R 1 BS same as BF BL time Last Burst stimulus ms R 2 BN Number of stimuli in Burst 1 25 BH Height Burst stimuli R 0 BW Width each stimulus in Burst ms R 0 1 B see C nl 0 BO Burst stim Off 0 On 1 or Overwrite 2 nl 1 e g BN10 BW 1 BH20 BF10 BL100 defines a burst of 10 pulses 0 1 ms long and 20 stimulator output running from 10 to 100 ms i e at a frequency of 100HZz C Cursor options QTracP only CT Cursor Time min R 0 CI Cursor step Interval min R 0 When the Interval 0 min the step is one sampling interval The Cursor step is multiplied by 10 if lt Ctrl gt is held down while hitting the arrow keys CC select Cursor Channels sl 0 Cursor is moved by left and right arrow keys to the next selected channel The data panel displays data for the time indicated CL whether to Lock Cursor to grabbed traces Y N L N With the Cursor Lock on the cursor moves only to times when a trace was grabbed Only the specified trace is displayed if the S R or M View options are selected Also the data n the data panel marked with an asterisk is derived from the trace and therefore depends on Window settings N B CLN sets display to storage mode 2 see OS to su
46. elivered should be kept to a minimum These results can be achieved by measuring one response on stimulus channel 1 in the normal way and making the second measurement on channel 2 after delivering a dummy stimulus on channel 2 i e no stimulus at all with 2SDY or SDN Y The same raw response is then modified and measured in one way on channel 1 and in another way on channel 2 Dummy stimuli reduce the stimulation rate so that if it is desired to deliver a stimulus every second and measure it in 2 ways then the slow sampling interval and stimulus interval must be set to 0 5 s I10 5 SI0 5 9 PROGRAMMING WITH QRP AND QPP FILES QRP and QPP files consist essentially of sequences of Qtrac commands as entered at the keyboard which are executed consecutively when the file is loaded To enable any Qtrac command to be included in a QRP or QPP file all Qtrac operations carried out by the mouse are translated into keyboard equivalents which appear in yellow on the left hand of the scrolling dialogue area and also in the new QRP QPP file being generated where they can be inspected by clicking on the QRP QRX or QPP QPX box in the bottom right of the screen In QtracS the initializing commands starting with I can only be carried out at the start of the program before the Select recording parameters form appears since they set the default recording parameters These initializing commands have to be placed at the very beginning of th
47. erent excitability and extra variables for all the MEM files in a MEF file Repeated measures For waveforms of MEF files which refer to observations on the same set of subjects Provides comparisons of between subject and within subject variation Update extra variables Allows extra variables in a set of MEM files to be updated from QZE files Update Var 35 This updates variable 35 Ted20 peak for all MEM files in a MEF file which had 20 depolarizing threshold electrotonus recorded but not registered as variable 35 LA Create LA file Plots latent addition data created with LASDM QRP or LA99SD QRP etc and saves values in MEM file RCC These options are designed for analysing C fibre and muscle fibre velocity recovery cycle data QPD These options are designed for extracting and analysing parameters measured as a function of time during treatments within a single recording e g responses to ischaemia Display options Dashed lines Option to replace coloured lines by dashed dotted lines Font size Changes the size of all the lettering Bar style Changes bar style for histogram plots Tick spacing Changes minimum tick spacing on axes Label stimuli Clicking this adds labels to Stimulus plot VS t for test stim c for conditioning stim e for extra stim 1 2 etc for burst stims 22 Print options These options enable printout format to differ from displayed format Line width Font size Monochrome Margin Skip cursors Ski
48. erpoint The best quality figures are produced by using Copy metafile then Paste special and Enhanced metafile Copy metafile start Analogous to Print start only for use with Copy metafile finish when superimposition is required List This option allows any combination of Comments i e comments that were typed in during a recording which can be displayed in grey by V C Instructions i e instructions that were typed in during a recording which can be displayed in green by V l and eXtended comments i e comments entered by lt Ctrl X gt to be listed on a form in order of elapsed times to see more easily what happened when in a long recording Zoom Zoom in The mouse pointer becomes a 4 way arrow Place this over a portion of the display to be expanded and click on the mouse to expand X and Y scaling by a factor of 2 This may be repeated This option enables measurements of data from the screen with PM to be made more accurately Zoom out Return to normal scaling MEM Create MEM file This is the first step in automated analysis of multiple excitability data generated by TROND or MEM recording protocols It shows the Options for MEM multiple excitability file form which allows selection between different algorithms for converting the raw stimulus values into threshold estimates It is also possible to select between multiple recordings of the same type e g multiple TE recordings generated by the TRONDC
49. erpreted as U10 to U16 A space after the 1 prevents this N B U lists all user defined expressions as well as options V View options The View string characters following the V defines the types of data plotted one above each other and the relative lengths of the Y axes In addition to a combination of the main plot types the view string can contain one or more extras C I B G Main plot types a Traces refreshed after each stimulus and erased by next trace of same sort unless OS1 0S2 In QtracP these plots requite QTG file to be present in same directory as QZD file Stimulus Raw data Modified data b plots v elapsed data taken from QZD file Thresholds Test stimulus heights Latencies values recorded depend on WL during recording Peaks values recorded depend on WP during recording A D data conditioning test Delay values depend on OD during recording cOnditioning current values depend on CV during recording response Errors stimulation Frequency if variable intervals selected see IV Number of peaks above threshold if multiple peaks recorded itional plots available in QTracP only User defined plot see U options X co ordinates defined by UX expression default M elapsed time Y co ordinates defined by one of 16 expressions U1 to U16 data selected from times specified by UT default times same as main elapsed time plots See also R options for regression options H Histogram plot see H options X data
50. et for slow A D sampling 2 L Latency log file and channel label options LT Latency type determines values saved as Latencies nl 2 29 start test stim to first threshold crossing test stimulus to positive peak conditioning stimulus to test stimulus test stimulus to half peak see also WF width at half peak height see also WF width test stimulus last burst stimulus to test stimulus width conditioning stimulus 9 centre test stim to first threshold crossing 10 centre test stim to peak 11 width at window height NOo ROD 12 latency from start test stimulus to interpolated positive peak 13 latency from start conditioning stim to interpolated peak 14 latency from start extra stim to interpolated peak 15 latency from first burst stim to interpolated peak 16 latency from last burst stim to interpolated peak N B For LT12 16 peak interpolated by fitting quadratic to 3 points N B LT is equivalent to WL LF Fraction of peak for LT4 LT5 e g LF0 1 LT5 measures width at 1 10th peak height LL Latency Lock locks X axes on R M plots to Y axis on L plot N B Since X axis becomes latency it depends on LT WL R 0 5 L N LW Enable writing to QtracS Log or QtracP Log for debugging Toggle on off ns LC Channel labels and notes label notes e g 1LFControl Control threshold to 1 ms stimuli N B The label Control appears in data box the notes after are saved with notes and extra vari
51. ferred AE Advance End code 0 stop 1 skip 2 reset 3 reverse nl 0 i e when advance reaches maximum a beep is sounded and 0 sets advance step to zero leaves advance at maxinum 1 sets advance and advance step to zero this channel is then skipped and requires SC to reselect 2 sets advance to zero leaves advance step unchanged 3 reverses step direction N B Add 4 to AE for automatic stepping through QRP file when advance reaches maximum it is equivalent to lt Esc gt AC Conditional Advance code nl 0 0 Unconditional advance 1 Advance if error acceptable see TE n gt 1 Advance if tracking satisfactory as judged by number of or in row being no more than n ACC Conditional Advance Control channels nl 0 If ACC gt 0 then both the particular stimulus channel and the control channel are tested e g AC1 ACC1 AN4 Advance only occurs after 4 cycles in which the error has been within specified limits on both the channel of interest and channel 1 A set Advance to same as on channel nl 0 AQ irregular Advance Sequence ms 0 e g CS100 AA1 AQ1 2 4 10 causes conditioning stim to be advanced to 101 102 104 110ms CS is not affected AQ resets AM to number of advance steps After an irregular advance sequence has been set by AQ AR AS and AM refer to steps in the sequence not ms AQ can be different for different channels but the longest sequence must be specified first AAQ Add to irregular advance sequence AH Advance H
52. ff on all channels and the colours of MCO and MC1 in the index will be swapped Some of the lines in the index appear in light grey These are options which are unavailable in the current context This might be for example because they are trace grab options and trace grabbing was not enabled for the current file Or they might be DP options to determine how the data points in the current plot are displayed which vary between the different types of plot You will see that as the plot pointer gt gt is moved from plot to plot different lines in the index are 47 enabled Clicking on a command in grey has no effect QRP QPP DISPLAY editing the past and future While running a Qtrac recording program in a QRP file the forthcoming commands can be inspected in the bottom right green panel as already explained A new feature is that it is possible to edit these future commands by inserting or deleting lines To delete lines position the mouse pointer just above the first line to be deleted and click on the mouse A horizontal line will appear the command and prompt lines turn green and the prompt line indicates that the lt Delete gt key now deletes the next line while lt Enter gt stops the editing Similarly to enter new lines click at the site the lines are to be inserted and when the horizontal line appears any line entered in the command line will be inserted at that position Since lt Enter gt stops the editing lines can only
53. ficiently using the slope of the 17 stimulus response curve In each of the other tests the control threshold 1 ms pulse no conditioning stimuli is tracked on channel 1 for comparison with conditioned threshold s on one or more other channels i e SD Control threshold on channel 1 is compared with channel 6 on which the stimulus duration is stepped through the sequence 1 0 0 8 0 6 0 4 0 2 ms The user usually need do nothing during this sequence but check that tracking is satisfactory If the responses show a clear tendency to alternate above and below threshold so that you see a sequence in the tracking box top right then it is advisable to reduce the tracking step on all channels which can be done by the command TT 1 4 i e divide tracking steps by 1 4 TE Control threshold on channel 1 is compared with thresholds measured during and after 100 ms depolarizing and hyperpolarizing currents These are set to defined fractions of the control threshold current i e 40 channel 2 40 channel 3 20 channel 4 and 20 channel 5 If required the 20 levels can be skipped by typing SC1 3 i e select channels 1 3 As with SD the main job for the user is to check that tracking is satisfactory IV Control threshold on channel 1 is compared with thresholds tested at the end of 200 ms polarizing currents set to a fraction of the control threshold that varies in 10 steps from 50 to 100 This part
54. fied threshold The step size can be kept constant or automatically adjusted within limits for improved tracking of rapid changes in excitability Alternatively the step size can be made proportional to the difference between the peak response and the threshold To help optimise the tracking parameters the recent tracking history is displayed separately for each channel The response error i e difference between target and actual peak response is also recorded and may be used to improve threshold estimation Slow sampling Single values may be sampled from up to 8 of the unused A D channels Sampling can be done just before and or just after each stimulus response operation Display and plotting The screen can be split into as many as 8 different plots which can be selected at will from Stimulus waveform Raw response Modified response Threshold Test stimulus amplitude Latency including raster display of multiple peaks Peak amplitude conditioning test Delay cOnditioning current response Error and the slowly sampled A D inputs Traces for the different stimulus channels are normally shown in the same plot distinguished by colour coding but they can also be displayed separately Data values may be plotted as continuous lines or points of specified size axes can be linear or logarithmic with axis limits set manually or automatically Two different Storage scope display modes are available for the plots refreshed after each stimulus
55. generated from the files in a MEF file by the File menu option in MEF Plot Waveforms see below MEF A MEF file contains the filenames without extension of a number of MEM files usually 21 of controls or patients of the same type which allows the group data to be analysed together by the MEF analysis options Create MEF file This option facilitates creation of a MEF file from existing MEM files Edit MEF file Similar to above starting with pre existing MEF file Copy MEF with MEMs This allows all the MEM files in a MEF file to be copied with the MEF file to another directory Export MEF to Excel Transfers all waveform and variable data in all MEM files in a MEF file to an Excel spreadsheet Plot Waveforms This allows waveforms of threshold electrotonus recovery cycle etc to be plotted in various ways each file in a MEF file can be plotted individually or all files superimposed or all files averaged with 95 confidence limits standard deviations or standard errors as dotted lines or error bars etc Compare Waveforms This allows more convenient comparisons of MEF waveform data at the expense of not being able to display single MEM files Compare variables For comparing groups of recordings in up to 8 MEF files at a time using dot plots or bar graphs This option also provides fairly comprehensive statistical tests for comparing all variables between 2 or more MEF files Scatter plots For exploring the relationships between diff
56. iately displayed The second frame sets the fast sampling rate and sweep duration or number of points The third frame determines whether trace grabbing i e recording raw input waveforms is allowed and if input current and or waveform monitoring have been selected whether to save those waveforms to disk NB trace grabbing still has to be started with GS On the right hand side the slow sampling frame sets a the slow sampling interval or minimum interval between sweeps b whether variable intervals are allowed e g non integral multiples of the slow sampling interval c the number of channels of analogue input e g to monitor temperature to sample just before the sweep and d just after the sweep and finally e the number of raster channels to record for recording latencies and amplitudes of multiple peaks Finally the output file frame provides for the setting of a 1 to 3 letter prefix to the data files and the folder where they are to be stored Q the original default is no longer allowed as a prefix to avoid duplicate filenames It is also recommended that data for different projects users be stored in different folders to avoid build up of too many files in the same folder On leaving the Select recording parameters form an Output check message box may appear to provide a check that the output settings were correct N B This message box can be useful when there are multiple Qtrac users but it can be suppress
57. iations as lines if DN large enough LP D lines points SD error bars width set by DR LP E lines points SE s LP C lines points 95 confidence limits for mean l lines remeasured from grabbed traces p points according to WS WH WL WP etc Ip lines and points and to Modify options Additional DP options for plot types L Latency P Peak R on line raster display as for QTRACS r off line raster display i e latencies or amplitudes of peaks remeasured from grabbed traces N B For both types of raster RD sets range of peak amplitudes plotted RM sets maximum number of points within range Additional DP options for L Latency plot when grabbed traces available t plot traces as ladder amplitude scaling set by OL w as t but points restricted to those in last Waveform plot e g DX 10 10 in W plot for 10 ms either side of peak t gt t lt w gt w lt as t or w but with hidden line suppression direction of arrowhead determines line order 46 N B Data from QZD and QTG files can be combined by combining upper and lower case letters e g DPLp plots QZD data as lines and remeasured data from QTG file as points DP options for plot type U User defined L P LP as above L gt plot lines when x increasing only L lt plot lines when x decreasing only DP options for plot type H Histogram L P LP D E C as above S steps B bars F add fitted cumulative Gaussian to probabi
58. illed circle positive radius open circle DM whether to plot dotted line at Y max L N DV Vertical line at X R 1000 Dv 2 Vertical line at X R 1000 27 N B The plot number 1 8 where plot 1 is at the top of the screen can also be determined by an integer prefix which overrides and moves the plot pointer This enables parameters of different plots to be changed at the same time e g 1DC1 2DC2 Display Channel 1 in top plot 2 in 2nd N B The position of the plot pointer gt gt gt can be moved up and down by the up and down arrow keys or Set to a particular plot by clicking on it with the left mouse E Extra conditioning stimulus options QTracS only ES Start Conditioning stimulus ms nR 1 EH Height Conditioning stimulus nR 0 EW Width conditioning stimulus ms nR 0 1 EO Extra stim Off 0 or On 1 nl 1 E set EH to fraction of TH on channel n n to do once nl 0 e g 2E 1 EHO0 5 sets conditioning stimuli on channel 2 to 0 5 future test stimuli on channel 1 E 1 EH 4 sets all EH to 0 4 TH on channel 1 E 0 EH30 sets all EH to 30 max stimulator o p F File options limited file options available at any one time QTracS only FS Start or Stop writing data to File FC Close QZD File and quit program FP write Parameters to QRP or QPP file FL Loads parameters from QRP or QPP file FT Truncate file and lose last data R F start writing data to QZD file F stop writing data G trace Grab options QTracS o
59. ings form The Stimulator settings form is in two parts The right hand part is concerned with settings of the Digitimer DS5 stimulator and is only activated if there is a USB link to a USB enabled DS5 and the DS5 software has been installed The left hand side enables you to set a the stimulator input voltage range the output range of the D A converter if the DS5 link is operating this will also change the DS5 setting normally 10V b the stimulator output range in mA again if the DS5 link is operating this will also change the DS5 setting c whether to monitor the stimulus current waveform e g from DS5 at 1V 10 mA and d whether to monitor the stimulus voltage waveform e g from DS5 at 1V 20V If the DS5 link is not operating it is particularly important to set the stimulator input and output ranges correctly so that 100 maximum output corresponds to the maximum output of the stimulator used From the Stimulator settings form control passes to the Select recording parameters form The Select recording parameters form enables you to override the recording parameters specified in the QRP if you selected a QRP file or to set them for the first time if you selected None The first frame sets the output voltage range of the preamplifier This does not actually change the input voltage range which is fixed at 10V but limits the axes for the Raw and Modified data so that they are appropr
60. l tracking is probably better still as is usually the case in all but single unit preparations Optimising proportional tracking with stimulus response relationship To facilitate setting an optimal step size for proportional tracking it can be automatically calculated from the slope of a stimulus response relationship using the command TTA after recording a stimulus response relationship with SR The procedure is to record a stimulus response relationship with SR terminating it when 3 responses are maximal with SR The times of starting and stopping the stimulus response are then remembered TTA 4 will then estimate the slope of the relationship at the point where the response is 40 of maximal set WH to this level TM to zero and TT to a value to optimise proportional tracking If the stimulus response curve is irregular as can happen with pathology then it is best to track a response where the stimulus response curve is steepest This is done by the command TTA on its own Noise can seriously interfere with threshold tracking In general it is more efficient to allow for a noisy signal by reducing the tracking step than by signal averaging but if the signal is so noisy that noise on its own often exceeds the target response then averaging with MV becomes necessary If TT has been set by TTA it can conveniently be reduced to allow for a noisy signal with e g TT 2 3 AUTOMATIC ADVANCE FEATURE QtracS A very us
61. label and the part after the is the notes for channel 3 The channel labels and notes are saved between Notes and Extra variables in a QZE file They may be inspected in QtracS or QtracP with LC Extra variables Extra variables may be added after Notes at the end of a QZE file either at the end of a recording by clicking on the Add Notes Extra variables button or in QtracP by lt Ctrl N gt Whereas Notes have no particular format and are not used by any program the Extra variables need to be written as parameter value e g Potassium 4 5 The Extra variables are specifically intended for use with multiple excitability Trond data files and are picked up by the MEM Create MEM file menu option which adds them to the list of excitability variables in the MEM file They can then be used to generate statistics and plots with the MEF Compare 49 variables and MEF Scatter plot menu options 2 THRESHOLD TRACKING WITH QTRACS Following the changes in excitability of a preparation by threshold tracking is always a compromise involving a trade off between speed and accuracy The optimum strategy in a particular situation depends not only on the relative importance of these two factors but also on whether the preparation is a single unit one giving an all or none response for stimuli above a certain threshold or whether the responses are graded in which case the threshold to be tracked i
62. lity distribution DP options for plot type W Waveform L P LP DL D E C as above N B SD etc are calculated across traces rather than points INDEX DISPLAY The index facility provides context dependent help and may also be used to select some options without using the keyboard The index is arranged alphabetically with sections and subsections that can be expanded by clicking on or contracted by clicking on Most indexed topics provide a command or partial command in red Clicking on a command in red is equivalent to typing the command in the command line and terminating with lt Enter gt This can be convenient but a possible disadvantage is that any complete commands entered in this way will apply equally to all channels Thus if you start QtracS with the default parameters and want to alter the way the baseline is set you may first look up baseline in the index and find Baseline clamp to zero options MC If you click on MC you will open the Change multichannel variable form for MC which gives the list of baselining options and allows you to set them differently on different channels Alternatively you could click on the and show the options in the index i e Baseline clamp to zero options MC 0 none MCO 1 start window MC1 2 start and end window sloping MC2 Etc MC1 is in green to indicate that that is the currently selected option If you click on MCO baseline adjustment will be turned o
63. ll the QZD files in a folder The default folder is the folder containing the most recently opened file but this can easily be changed The files in the folder can be sorted in ascending or descending order of any of the parameters listed by clicking on the head of the column The files may also be filtered to list only those files with header blocks containing a specific string e g name date recording protocol etc When the required file has been found it can be selected by a single mouse click and opened by clicking on O K or opened directly by a double click After opening and displaying a file you may load and run a pre written plotting protocol QPP file by clicking on the File menu and Load Parameters QPP This opens the Select plotting protocol form which enables you to select between the last 8 most recently opened QPP files Browse for another or Cancel As with the 8 most recently used QZD files the file names are taken from the Qtrac INI file in C Qtrac Programs which is updated automatically QTRACP SCREEN The QtracP screen has the same multipanel structure as the QtracS screen with QPP QPX replacing QRP QRX but differs in two major respects First there is a menu along the top which provides access to printing and copying functions and other options including a suite of programs for analysing multiple excitability data Secondly the display does not have to occupy the full computer screen and can be r
64. me on all channels N B i When the window start or window height are changed by the Automatic Advance feature using AA32 then WSLY and WHLY lock only the root values of WS and WH respectively not the advanced values N B ii If WSLY or WHLY is given when the window settings are different they are set to the values in channel 1 Cursor Lock CLY or CLN QtracP only When data from grabbed traces QTG file are plotted as well as elapsed time data from QZD file the default is that data from a single trace is displayed corresponding to the time of the cursor vertical red line i e at start up the cursor lock is on If the cursor lock is switched off CLN then all the traces within the elapsed time frame are plotted This normally means they are superimposed but if the superimposition is switched off OSO then they are displayed 53 one at a time to produce a cinematic effect This is most conveniently achieved by the View Cinematic menu option see above page Latency Lock LLY or LLN and latency cursors This feature works in both QtracS and QtracP On start up the latency lock is off When it is applied LLY it has 5 effects 1 The X range of Raw and Modified plots is locked to the Y range of the first Latency plot Initially Latency values have priority and it is the Raw and Modified X axis limits that change but once the lock is established changing the start of a Modified plot changes the minimum of the la
65. mpt for adjusting the filtering This is normally not important for CMAP recordings and you can quickly step on to the main menu QRP Option Selection form You are now presented with a menu to choose what excitability tests to perform The 4 excitability tests SD TE IV and RC can be done in the conventional or alternative orders or the tests can be done individually Alternatively you can run a Short Trond protocol which skips the IV and 20 levels of TE uses a faster stimulation rate 2 Hz rather than 1 25 Hz and some other tricks to take only half the time of the full Trond protocol A further option but only to be used after you have done an SR is Multitrack which monitors several excitability parameters continuously e g to monitor the excitability changes during ischaemia The first test to perform is always SR since the stimulus response relationship is required to optimize threshold tracking After clicking on the desired option click on O K or hit the lt Esc gt key to proceed SR The first thing you are asked to do is to step up the stimulus manually to a supramaximal level This is best done by hitting lt Insert gt after each stimulus until the response appears to reach a limit and then immediately hitting lt Esc gt The computer will then generate a more precise stimulus response curve which you terminate by lt Esc gt O K after the 4 maximal response The computer is now ready to track thresholds ef
66. mulation and recording sites 51 58 String 8 Subject or patient type 59 67 String 9 Date 68 90 String 23 Name 91 98 String 8 Recording protocol QRP file 99 122 String 24 Comments 123 126 String 4 Distance 127 128 String 2 Operator 63 129 188 Singles Scaling factors arrays 1 15 189 192 Single Sampling interval ms 193 492 String 20 Units arrays 1 15 493 496 Single Scaling factor stimulus 497 500 Single Scaling factor fast A D 501 502 Integer Disk Offset QTG file 503 504 Integer nSamples no of fast samples per trace 505 506 Integer nRast no of raster points per trace 507 508 Integer lenTrace nPointsPerTrace DiskOffset 509 512 Unused The file format descripto bytes 9 10 currently has the basic value of 39 with the optional additions of 16 If number of latency peak rasters gt 0 64 If variable inter stimulus intervals selected 128 If stimulation frequencies saved QTG files QTG files comprise nTraces bytes 5 6 records of length lenTrace bytes 507 508 integers The first set of integers in each record define the stimulus waveforms and the remaining nPointsPerTrace bytes 15 16 starting after DiskOffset bytes 501 502 comprise the trace itself or part of it if nPointsPerTrace lt nSamples bytes 503 504 The scaling factor to convert these integers to mV or microvolts is found in bytes 497 500 At present Disk Offset 30 and of the 30 integers before each trace 25 are used 2 Stimulus
67. n red rest in grey Plot height mm Plot Width mm e g PH190 PW260 for horizontal plot on A4 paper default PH280 PW180 for vertical plot on A4 Plot measurement options using mouse 1 x y distances 2 baseline corrected slowing and recovery time 3 slowing over 5 sec N B See prompt line for instructions Number of plots side by side superimpose next plot to Right of last superimpose next plot Plot relative elapsed times If Y elapsed times appear to start at 0 even if DS gt 0 If Y labels at top and bottom of screen are skipped vertical Plot Gap mm 0 for auto spacing whether to reverse plot order bottom to top 190 260 AD ee ee P AA r D Zo P Polarising current options QTracS only PH PM Height Polarising output max R 0 1 Polarising mode 0 O off 32 change to Height then hold change to Height and back to zero change to Height then Height then zero 4 change between Height Height 10 change to Height immediately ignore PR PR Rate of change of Polarising output min R 0 1 N B PR prevents rapid changes in Polarisation and provides defined polarising ramps The Polarising current can be monitored by connecting the D A output to a slow sampling A D input or as ipOl OUN a tou a P trigger Pulse digital output options QtracS only PS Start trigger Pulse msec nR 0 Ps Start 2 trigger pulse msec nR 0 PE End trigger Pulse msec nR Pe End 2 trigger Pulse msec nR
68. n to be saved in the INI file and become the default when the QRP file is rerun Pop up checklists The operator can be made to check several True False options by means of pop up checklists These are similar to the pop up menus except that the operator can select more than one option to be true No GOTOs or GOSUBs are generated directly but the checked options become True or False logical variables see below which can be used to control branching with IF meta commands A pop up checklist can be instigated by the CHECKLIST meta command The following comment line then becomes the heading of a pop up checklist This is followed by checklist option lines starting with 7 e g CHECKLIST Check desired options 11 Hz Default 0 5 Hz Sensory Default Motor The checklist specification stops at any line not starting The heading of the pop up checklist often begins with Check as in the case above in which case the CHECKLIST line can be omitted i e Check desired options 11 Hz Default 0 5 Hz Sensory Default Motor Is equivalent to the example above N B An additional checkbox is provided at the top of the screen to allow the chosen selection to be saved in the INI file and become the defaults when the QRP file is rerun 59 Responding to pop up prompts menus and checklists The pop up prompts etc can be moved by dragging or by clicking on one of the pale blue arrows e g to the bottom right corner
69. nd eXtended comment can be added with lt Ctrl X gt In either QtracS or QtracP this brings up the eXtended comment form comprising a small text box in which remarks can be entered the elapsed time at which the comments are to be stored and a button which causes the text to be saved Extended comments are indicated in the plot by an x just below the elapsed time baseline and are made visible be clicking on the x Extended comments and short Comments can be listed in order of elapsed times by the List menu command Notes Notes apply to a recording as a whole and there is only one Notes text area per recording Notes may be edited during a recording or in QtracP with lt Ctrl N gt or at the end of a recording by clicking the Add Notes Extra variables button Channel labels and notes The stimulus channels can be given short labels of up to 8 characters which are displayed next to the channel numbers in the data box to indicate the function of the channel In addition notes can be added to provide more information about the channel The labels and notes are entered by the LC command LC on its own provides access to the Channel label form which has separate text boxes for the label and notes of each channel Alternatively a label with optional notes can be entered e g in a QRP file with a command such as 3LCTE 40 Threshold electrotonus to 100ms current 40 of threshold where the part before the is the
70. ng current Delay Error A D inputs and User defined QtracP allows Histograms to be constructed VH 19 according to the H options and average Waveforms of data in the grabbed traces to be displayed with VW QTRACP MENUS File Load parameters QPP Loads a plotting protocol file and starts carrying out the command in it until a PAUSE is encountered Save parameters Saves all the commands entered since QtracP was loaded excluding menu options in a QPP file Change data QZD Allows the QZD file being displayed to be changed while keeping the display format unchanged The new QZD file can be selected from the 8 last ones accessed or you can browse for it Browse data QZD As above but go straight to browse Write displayed values All the X and Y values of the data points being displayed will be written to disk in Ascll text files so that they can be accessed by other programs You supply a file name and QtracP supplies the extensions according to the type of plot and channel number Thus if you are displaying latencies on channels 1 3 and 4 these will be written to files with extensions L1 L3 and L4 etc Write to Excel file As above except that the data points are written to a single Excel file Print The data displayed on the screen is transferred to a printer subject to the print options selected see below under Options Print start only Use this option if you wish to superimpose multiple plots Print finish Us
71. nly GS Start or Stop Grabbing traces GI Interval between trace Grabs min R 0 GC select Channels to Grab sl 0 GH_ whether to Grab Hits gt threshold only Y N L N When averaging only completed averages are grabbed G start Grabbing traces G stop Grabbing traces H Histogram options QTracP only HX User defined eXpression to histogram Same expression used for all channels If expression contains a U different histograms generated for different channels e g TU test stim on channel n for histogram n N B Yn estimated Y value according to regression for user defined plot of Un e g HXP histograms all peak values 28 HN HW HY HC HG e g HXTU YU 100 histograms stimulus values separately for each channel as of estimated Y values in user defined plots N B HXRL or HXRLU histograms on line raster latencies N B HXRP or HXRPU histograms on line raster peaks No of bins or number can be set indirectly by HW Bin width if negative first bin centred on min X User defined Y expression optional e g HXT HYP plots peaks v test stimulus amplitude averaged within bins Pen no for histogram plots if not separate channels Acceptable limits of gating expression HGX HGX User defined expression for gating out data points to histogram e g HGXP HG3 5 4 Exclude from histogram all data points for which Peak is outside the range 3 5 to 4 N B if Ymax 1 data plotted is probability of hit i e error gt 0
72. normal curve approximation is used for higher values For the Wilcoxon signed ranks matched pairs test exact probabilities are calculated for sample sizes up to 15 anda normal curve approximation used for higher values The Lilliefors test for normality does not give a P value but tests for significance at the 5 level using a table up to a sample size of 30 and an accurate formula for larger samples The Lilliefors test is used by the Auto option to chose between parametric and non parametric tests Compensation for temperature age etc 62 Variables used in the MEF Compare and MEF Scatter forms can be compensated for dependence on other variables such as temperature age or potassium before applying statistical tests provided one or more MEF files are available with suitable data The compensation uses linear or multiple regression depending on whether adjacent variables to be compensated in the Compensation form are taken from the same or different files The advantage of using the same MEF file for compensating two or more variables is that any interaction between the variables e g due to a tendency for older subjects to be colder is taken care of by the multiple regression The advantage of using different MEF files is that you can use data in which the specified variable is altered a lot so that the dependence of excitability parameters on the variable is determined much better and the compensation more accurate than coul
73. ns If a comment beginning with Start is followed in the same display frame by one beginning with Stop case ignored then a bar will appear at the bottom of the plot between the appropriate elapsed times provided the letter B is included in the View string e g by typing V B Similarly on i e on preceded by a space and off in comments in the same display frame produce a broader bar Comments may also be used to record numerical values of a slowly changing variable ae D such as temperature If numbers starting with a digit or are the first characters 48 entered in a comment e g 33 5C then these numbers can be plotted against time in a User defined plot by specifying C as the user defined expression Comments as described above form an integral part of the QZD data file and cannot be separated from it They are limited to short bits of text since only 2 letters can be stored at each slow sampling interval The other forms of annotation which are unlimited in size are put in a QZE Extras file The QZE file is an Ascll text file with the same name as the QZD file which has to be copied with the QZD file for the extra text not to be lost The QZE file can be edited by a text editor such as Notepad or Wordpad as well as by QtracP eXtended comments When more extensive annotation is required than possible with simple Comments a
74. o measure Using the right mouse one can select the upper or lower latencies of a jumping unit and add a positive or negative constant value y ms to bring them into line with the command LAy Latency smoothing LSL LSQ Latency profiles may be irregular for various reasons some biological and some technical There are occasions e g when measuring recovery cycles when it can help to reduce latency fluctuations due to noise in the signal by taking a running average of latency values to smooth the profile The commands LSL and LSQ provide linear and curvilinear quadratic smoothing respectively to the latencies selected by the right mouse only Thus LSLx replaces each latency starting with the point at x 2 minutes from the left with the value given by linear regression of all the points within the range x 2 to x 2 minutes Similarly LSQx substitutes the value for a fitted quadratic Zero latencies and latencies outside the green area are ignored so these functions can also be used to remove outliers However they should only be used for periods when the latency is static or changing smoothly and slowly 8 DUMMY STIMULI Dummy stimuli are used to enable the same responses to be analysed in more than one 56 way e g if 2 stimuli are delivered per trace and it is desirable to measure the responses to each or if it is desirable to measure a rectified and integrated response as well as peak to peak amplitudes and the number of stimuli d
75. of motor axons Note for former DOS users this is broadly equivalent to TRONDXM4 QRP but with new pop up prompts and with a menu to permit greater flexibility There is one change in functionality strength duration time constant is estimated from the strength duration relation for the 40 maximal responses only instead of being estimated at multiple response levels from 2 stimulus response relationships The new method is compatible with single unit recordings compensates for any changes in control 16 threshold during the recording and avoids errors when the stimulator reaches its maximum output It is assumed that TRONDCMW QRP has been selected see above Starting Qtracs the appropriate stimulator has been selected on the Select recording parameters form and the program has started with a rapidly refreshed display of the raw EMG input and a pop up prompt saying Welcome to TRONDCM After reading the contents of the pop up prompt it can be moved out of the way of the input display by clicking on one of the light blue arrows or hidden by clicking on the in the top right corner When it is hidden the last line containing Click on lt Esc gt is retained in the prompt line at the bottom of the screen You will now see clearly the raw input at A D input 0 which should be the amplified EMG normally at a gain of about 1 2 mV V If it is flat get the subject to contract the muscle to check that EMG is being rec
76. of the protocol applies the longest and strongest currents so it is likely to be the most uncomfortable for the subject the most likely to trip a charge overload detector on the stimulator and the most likely to cause the threshold to reach the output limit of the stimulator If in doubt hit lt Esc gt or click on O K and the sequence will be terminated RC To record the recovery cycle after a supramaximal stimulus the control threshold on channel 1 is compared with the the conditioned threshold on channel 10 Because the responses to the conditioning and test stimuli overlap at short intervals channel 9 is used to record the response to the conditioning stimulus alone and the response is subtracted from channel 10 The operator has to ensure that the conditioning stimulus produces a supramaximal response i e that the peak on channel 9 equals the peak of the stimulus response curve on channel 7 which is plotted as a dashed line If peak 9 falls below that level e g because thresholds have drifted upwards during the recording then the conditioning stimuli on channels 9 and 10 should be increased e g from 90CH1 to 90CH1 2 or 9 10 CH1 2 The other thing the operator has to look out for during the recovery cycle recording is that the test stimulus does not get too high At short interstimulus intervals the axons become refractory and the test stimulus will increase As the interval becomes shorter the error first drops to a large negativ
77. of the screen To help differentiate the blue boxes from the blue scrolling dialogue area if they overlap the background to the scrolling dialogue turns grey A prompt or menu box can also be hidden by clicking on the in its top right corner and restored by clicking on the that appears in the bottom right corner of the screen While the pop up prompt or menu is active whether hidden or not text commands can be entered in the command line in the normal way The QRP QPP program continues when the OK button on the box is clicked if the box is visible or the lt Esc gt key is hit whether the box is visible or not Logical variables and Logical expressions Logical variables are text strings which can include spaces which can take the values of True or False They can be defined in 3 different ways 1 Every time a MENU meta command is executed the options displayed become logical variables which are given the value True or False depending on whether or not they are selected Thus in the pop up menu example above the logical variables 1 Hz and 0 5 Hz are created if they don t already exist and if 1 Hz was selected that becomes True and 0 5 Hz becomes False 2 Similarly every time a CHECKLIST meta command is executed each option that is not already a logical variable is created as one and given the value True or False depending on whether or not it was checked N B Any part of a MENU or CHE
78. ogram crash or other malfunction is experienced please email a description of the problem together with copies of the Qtrac INI file and any relevant QLG QZD QRP and QRxX files Most useful for debugging is the QtracS LOG or QtracP LOG file LOG files are only generated if the relevant option is selected in the QTRAC INI file in C Qtrac Programs e g change QtracSEnable 0 to QtracsEnable 1 in the LogFiles section with a simple text editor such as Notepad Alternatively if the error only occurs after the program has been running some time to save generating an unnecessarily long LOG file logging can be toggled on or off during the program with LW The LOG file for the last QtracS and QtracP sessions will be found in C Qtrac Programs Copyright c 2008 Institute of Neurology All Rights Reserved 65
79. olarising stim trig Pulse R Raster S Stimuli T Test stim U User defined plot V View W Window SPECIFIC OPTIONS A Automatic stimulus Advance options QTracS only AA Set stimulus advance code 0 none 1 advance conditioning stim 2 advance burst stimuli 4 advance test stimulus 8 increase width test stimulus 16 increase width conditioning stimulus 32 advance start window 128 period test stimulus 256 period conditioning stimulus 512 start extra stimulus QTracP C Cursor D Display F File H Histogram L Latency log file amp channel labels M Modify data O Others P Plot R Raster and Regression U User defined plot V View W Window Type Default nl 0 CS BS TS TW CW WS TP CP ES These codes may be added so that AA3 advances both conditioning and burst stimuli These codes are calculated automatically if you enter AA lt Enter gt and click on desired advance options AS Advance Step ms 24 nR 0 The Advance Step may be positive or negative to make the specified stimulus occur later or earlier respectively No of steps to advance after AQ AM Maximum Advance ms sign is ignored nR 100 step number after AQ AR Reset Advance to specified interval ms nR 0 Pe specified step after AQ AN No of complete stimulus cycles per advance nl 1 Stimuli can be advanced by a small step each cycle or a larger step every few cycles as pre
80. omatic vertical scaling when plot complete Range Y values is set to max and min plotted values DAA Automatic scaling of All plots DH Display Horizontal line at Y R 1000 Dh Display 2 Horizontal line at Y R 1000 DN Number of points to average 1 For S R and M plots this number may be overridden to keep the number of points displayed to one per pixel DNA No of points to advance Does not apply to S R amp M plots This number is reset to No of points to average by DN DS Display Start time DE Display End time DP set Plot type plot specific see p DG whether Logarithmic Y axis Y N Ignored if axis limits lt 0 DXG whether Logarithmic X axis Y N L DC select Channels to Display sl N B Channel here is normally the stimulus channel but when viewing A D data DC selects A D channel s 1 DDA ro oz zo DXL change X axis Label T DYL change Y axis label T DW set Data Windowing code 0 0 display all data points 1 only use data values within plot limits 2 only use data values in range set by DWL N B Data points are selected before any averaging and before setting the max and min values used by DA DA will only therefore show full range of values after DWO DW1 is the default for R M plots to allow more rapid erasure DWLset Limits of Y data values for DW2 rR 0 0 N B Limits are set to Y axis limits by DW1 DR point Radius mm for DPP etc R N B negative radius gives f
81. orded If there is appreciable spontaneous EMG this is a good time to get the subject to relax facilitated by auditory feedback This is also the time to check that the stimulator is connected to the subject but with the output short circuited On hitting lt Esc gt or clicking on O K if the prompt box is visible the display changes to Stimulus Raw data and is now refreshed after every stimulus at 0 8 sec intervals A new prompt box appears with instructions to adjust the stimulus intensity with the lt Insert gt and lt Delete gt keys for a measurable response Now is the time to release the short circuit on the stimulator to start stimulating the subject The stimulus is initially 3 of the maximum output and is increased and decreased in 3 steps by the lt Insert gt and lt Delete gt keys respectively At this point it is best not to step the stimulus up to a maximal response which may be uncomfortable for the subject but as soon as there is a response of a mV or so to hit lt Esc gt or click on O K This will add a plot of Modified data i e after filtering and baseline correction and the next prompt box has instructions for setting the baseline and the window to measure the peak height of the EMG response appropriately Further information about the window will be found in the sections above on page Once the peak height is being measured to your satisfaction hit lt Esc gt or click on O K to move on to the next pro
82. p databox Channel key Sets line width for printing Sets font size for printing 0 for same as display Prints in monochrome with grey scale in places of colours Sets left hand margin on printout Check to omit time cursors on printout Check to omit data box on printout Check to include channel key above data box Print Print start only Print finish Same as for File menu Metafile options These options enable metafile format to differ from displayed format Line width Font size Monochrome Font weight Skip cursors Skip databox Channel key Sets line width for metafile Sets font size for metafile 0 for same as display Generates monochrome grey scale metafile Increase from 400 to 600 or 800 for bolder lettering Check to omit time cursors in metafile Check to omit data box on printout Check to include channel key above data box Plot latency peak lines Check to include lines on modified plot marking latencies and peaks Plot window line s Check to include window lines on modified plot Transparent Check to omit white background so plots can be superimposed Copy metafile Copy metafile start Copy metafile finish Same as in Edit menu 23 QTrac Options Main Options QTracS A stimulus Advance B Burst stimulus C Conditioning stim D Display E Extra stim F File G trace Grab I Initialise QRP files only K sockets L Latency log file amp channel labels M Modify data O Others P P
83. peak is 3 0 error is 50 so stim is reduced by 10 of 50 i e 5 e g TM1 TT2 stim is always changed by 2 e g TM4 TT2 if peak remains below WH then stim is increased by 2 4 6 8 8 If peak then rises above WH step multiple is halved to 4 etc TR tracking Range Test stimuli and SR rR 0 5 T Test stim step of channel 0 for own nl 0 e g TM2 T 1 TT0 3 TH40 enables tracking on channel 2 with basic step size of 3 of TH on channel 1 i e 3 of 40 or 1 2 of max output incrementing to a maximum of 2 4 TE acceptable Error in response of target WH nR 0 N B if TE gt 0 error limits are displayed in grey TO Off On Overwrite code for Test stimulus nl 1 0 test stimulus off 1 test stimulus on add to conditioning and burst stimuli 2 test stimulus overwrites conditioning and burst stimuli N B Displayed test stimuli altered depending on OO TL Linear series Test stimuli specify min max rR e g SN8 TL10 80 SN8 TH10 20 30 40 50 60 70 80 TJ add Jitter to test stim height range R 0 Jitter range depends on whether tracking steps are absolute T 100 or relative T 0 e g T 100 TH20 TJ10 stimulus varied randomly over 10 absolute range i e from 15 to 25 max output T 0 TH20 TJ100 stimulus varied over 100 relative range i e from 14 14 to 28 28 max output TTA Set auto tracking to defined fraction of peak R Only works after SR SR SR Sets WH to specified fraction of peak respons
84. perimpose traces while CLY turns storage mode to zero off Ca set time ms of cursor a on Mod plot of grabbed data Cb to Cd ditto for cursors b d R 0 C Conditioning stimuli options QTracS only CS Start Conditioning stimulus ms nR 1 CH Height Conditioning stimulus nR 0 CW Width conditioning stimulus ms nR 0 1 CF Conditioning stimulus waveForm code 0 0 rectangular 1 biphasic CB for ratio 2 triangular TW sets half width 3 sine wave CP for period CW sets duration 4 cosine windowed sinewave peaks at CW 2 5 trapezoidal CP for slope CW for plateau 6 steps CP for step width CW for total C set CH to fraction of TH on channel n n to do once nl 0 e g 2C 1 CHO0 5 sets conditioning stimuli on channel 2 to 0 5 future test stimuli on channel 1 C 1 CH 4 sets all CH to 0 4 TH on channel 1 C 0 CH30 sets all CH to 30 max stimulator o p CC Clamp conditioning stimulus after end test stimulus 0 0 no clamp 1 clamp to 1st pt after test stim 26 2 clamp to zero CV Conditioning stimulus value to save 0 0 Value conditioning polarising stimuli at start test stimulus 1 Value conditioning stimulus whenever it occurs 2 Jitter on test stimulus difference from TH see TJ 3 Amplitude extra stimulus 4 Polarizing current D Display options these apply to the plot pointed to by gt gt DX Display X axis values from to rR DY Display Y axis values from to rR DA Aut
85. ponential fit R 0 N B Exponential is fitted by linear fit to log data N B Regression window defined by RX RY is displayed but not printed S Stimulus options QTracS only SS Start or Stop Stimulation see S S SN maximum Number of Stimulus channels 1 16 10 SC select Channels from those set by SN and SF sl 0 SI inter Stimulus Interval sec nR N B Interval set to nearest multiple of cycle time unless variable intervals enabled in which case the interval must be no less than the cycle time N B This is the interval after the specified stimulus SJ Stimulus interval Jitter range sec R 0 e g to randomise intervals for reaction time studies SA Stimulus channel Advance type 1 1 sequential 1 2 2 reverse order 3 hit miss i e select stimulus condition according to number of below threshold stimuli in a row i e 1 if last response above threshold 2 if one response below threshold etc 4 up down e g 1 2 3 4 4 3 2 1 1 2 3 4 6 random 7 pseudo random channels shuffled 8 arbitrary sequence set by SAQ N B If SA is set negative then for those channels engaged in threshold tracking advance is conditional cf AC2 SAQ Set arbitrary advance sequence for SA8 e g 1 3 2 SF First available Stimulus channel 1 S start Stimulation e g to avoid ambiguity in QRP ee S stop Stimulation SR Starts stimulus response recording Stim set to zero then incremented in 1 steps absolut
86. protocols A graphics section of the form displays the results of the conversion When the analysis is satisfactory clicking on O K generates the MEM file which is previewed in the Text in MEM file form In addition to the basic excitability measurements of threshold electrotonus waveforms etc the MEM file lists 32 derived variables e g superexcitability averaged over 3 interstimulus intervals useful for statistics The MEM data can be edited within this form e g to remove spurious data points and to add notes or extra variables such as electrolyte or drug concentrations so that they can be analysed with the excitability data N B If Extra variables have already been entered with QtracS or with the Edit header block option they will appear automatically in the MEM file The MEM file is not actually generated until the O K is clicked on this form A description of the different algorithms for generating the threshold estimates will be found in Appendix Edit MEM file This provides direct access to the text of a MEM file to read it or edit it MEM report This generates a 2 page report with figures and comments by operator Plot Waveforms This provides a changeable list of the last 8 MEM files accessed any combination of which can have their waveforms plotted with full control over colour and symbol if any for the plotted points The MEM file or files can also be compared with 95 confidence limits contained in a MES file
87. ptions for refreshed plots Stim Raw Modified 0 0 normal display 1 display old traces in light cyan 2 display old traces in full colour OB set time for Beep min QTracS R 0 a vertical red line is placed at the beep time the displayed elapsed time is calculated relative to 31 beep time and appears in red rather than black and beeps are sounded from beep time 3 sec OBAwhether to Advance reading QRP script on Beep L N OBT set Beep time relative to current Time min R 0 OBI Interval for regular Beeps R 0 Ol OV oo OD e g OBAY OBI3 advances QRP program at every multiple of 3 min set stimulus Increment for lt Insert gt lt Delete gt R 5 set aVeraging mode 0 0 serial complete average on one channel before advancing to next 1 parallel advances stimuli normally 2 running after accumulating average of n sweeps adds further sweeps in proportion 1 n 1 whether to display test stimuli according to TO L Y scaling factor for ladder plots see DPt R 1 Delay save options determines data viewed by VD 0 save TS CS 1 advancement see A options 2 inter stimulus interval msec 10 for use with SJ P Plot options QTracP only PV PC PH PW PM PN PR PS PE PG PO Vertical plot format L N N to Y sets plot height to 280mm plot width to 180mm Y to N sets plot height to 190mm plot width to 260mm change Colours pens for Plotting nl e g PC2 5 plots channel 1 i
88. r Latencies from QZD file 11 to 116 IU or for latencies measured from QTG file P1 to P16 PU or P for Peaks from QZD file p1 to p16 pU or p for Peaks measured from QTG file D1 to D16 DU or D for Delays O1 to O16 OU or O for cOnditioning currents E1 to E16 EU or E for response Errors A1 to A16 for values from slow A D sampling a1 to a16 aU or a for amplitudes at time of cursor a on Modified plot of Grabbed data only also b c d for arithmetic operations executed from left to right to specify order of operations nestable M the elapsed time in minutes G natural log of expression Je exponentiate expression e g UYTU T1 T1 100 plots difference in threshold from channel one separately for each channel DC2 3 would select channels 2 3 only U1P UXT to combine all channels as stimulus v response 36 N B Additionally when UX is defined as M i e elapsed time the default replacing the user defined expression by C plots numbers derived from Comments starting with a digit or N B When UX is not M DNX averages all consecutive points on the same user channel with same x value DNY averages all consecutive points on the same user channel with same x value DND averages all consecutive points on the same user channel with same delay value DNO averages all consecutive points on the same user channel with same cond stim value N B U1 should not be started with a digit from O to 6 or it will be int
89. r can therefore supply the 3 entries correctly If the muscle was correct but the side wrong then as soon as the operator starts editing Left by deleting the t the program automatically replaces the Lef with Right Loading QRP or QPP files In QtracS a QRP file is usually loaded at the outset whereas in QtracP a QPP file is loaded vial the Menu Files Load QPP file option In either case the loading includes 3 steps First program annotation in the form of a line starting or a part of a line starting lt Tab gt is 61 removed and leading and trailing spaces and tabs stripped Secondly a check is made for duplicate line labels and a red warning printed in the scrolling dialogue area if any are found Thirdly a check is made that for every line label reference e g Goto Restart the line label referred to exists and a warning printed of any illegal references When an illegal reference is encountered while running a QRP or QPP file this causes the program to terminate 10 STATISTICAL TESTS IN MEF COMPARE FORM QtracP Types of test available The statistical tests available for testing differences in 35 standard variables plus any number of extra variables comprise most combinations of a comparison between 2 MEF files A and B or several MEF files as selected from up to 8 b paired or unpaired tests i e comparisons within the same group of subjects or between different groups c pa
90. r subdivided with vertical partitions Clicking on the Index check box bottom left reveals a beige Index panel on the left described in detail below Clicking on the QRP QRX check box bottom right reveals a right hand panel further split into two The bottom right panel in green shows the instructions in an opened QRP file which have not yet been executed starting with the next instruction or remains empty if there is no open QRP file The top right panel has two possible uses and displays two types of text file that are generated by QtracS If no QRP file has been opened then it displays on a dark red background all commands that have been entered which go to form a new QRP file which can be saved with the FP command If however a QRP file is open it displays by default the QRX file being generated which contains all the instructions which have been executed so far in yellow with the computer s response in white on a green background While executing simple QRP programs without branching there is a continuity between the commands executed so far above the split and the commands which are going to be executed next below the split and the line numbers should be consecutive When branching occurs however the line numbers which represent the position of the line in the file are no longer consecutive across the split While executing QRP programs the top panel can be switched between the green QRX display and red QRP
91. rab QTG file is available the latency can be retracked by stepping through the recording e g VML4 filter and baseline the waveforms as required with MH ML MC etc set the cursor at the first time of interest by clicking on the left mouse button in the latency plot and then set the Window to measure the peak of interest and WAY to allow latency tracking The latency lock option LLY see previous section is recommended for this The traces can be stepped through one at a time with the and lt keys In the data boxes the old latency and peak values are displayed in the top section and the new remeasured values in the bottom section marked with an asterisk To substitute the new values for the old ones hit the key To substitute and move one trace to the right or left hit gt or lt If it is impossible to remeasure the values accurately three options are available If for example the values can t be measured because there was no spike then as in QtracS zeros are entered if there is no peak within the window above WH and the latency type set by WL is negative If on the other hand a spike is present and discernible but insufficiently separated from larger spikes or artifacts for automatic measurement then a left mouse click on the spike in the Modified plot will set the latency cursor on it and hitting the key will substitute this latency value Finally if a spike is thought to be present but is too obscured to be able
92. rametric and or non parametric tests There is also a test for comparing variances between two groups The List button lists the individual values of 1 or 4 selected variables in all the MEM files in each selected MEF file If only one variable is selected basic statistical measures of the group mean SD SE median normality test are added Unpaired t test 2 MEF different subjects parametric means Paired t test 2 MEF same subjects parametric means Analysis of variance n MEF different subjects parametric means Repeated measures ANOVA n MEF same subjects parametric means Mann Whitney U test 2MEF different subjects non parametric medians Wilcoxon signed ranks test 2 MEF same subjects non parametric medians Kruskal Wallis n MEF different subjects non parametric medians Friedman test n MEF same subjects non parametric medians F test 2 MEF parametric compare variances Linear correlation Pearson R 1 MEF selected variable v all others Spearman rank correlation coefficient 1 MEF selected variable v all others Approximation of P values Bryc s method is used to approximate the areas under the tails of the normal curve and hence the P values for t tests F tests and chi square tests According to Bryc this gives a maximum absolute error of 1 9x10 and a maximum relative error of slightly less than 0 5 For the Mann Whitney U test exact probability values are calculated for m xn lt 1000 and a
93. red values are replaced by zeros N B The LR command depends on RD and the selected green area but it does not depend on RM or even whether on line rasters are displayed at all To tidy up the remeasured latencies without resorting to remeasuring from the grabbed traces several more latency editing commands are available Zeroing selected latencies LZ Inappropriate latencies separated from a measured profile can be delected by selecting them with the right mouse button see above and entering LZ which sets the values within the green area to zero De hairing a latency profile LD LDR Outlying latencies separated from their neighbours my more than y ms can be removed zeroed by LDy or LDRy LDy removes all values displayed than are more than y ms above or below both neighbours whereas LDRy removes all values that are more than y ms above or below the line joining both neighbours Latency interpolation LI Zeroed latencies can be filled in by linear interpolation with the command LI This applies to all points displayed To interpolate gaps only up to a certain length x minutes use LIx The combination LD or LDR and LI has the effect of multiple operations The use of LZ and LI is both more specific and more powerful since it allows two or more adjacent outliers to be replaced Add constant to latency LA C fibre latency profiles are often complicated by irregular jumps between 2 latencies which makes them difficult t
94. rm ensure that the waveform monitor check boxes are ticked 15 Displaying stimulus current and voltage waveforms The monitored stimulus current waveform can be displayed in QtracS instead of or alongside the command current waveform by changing the DP code Thus DPS displays the stimulus as steps DPC displays the monitored current also as steps DPSC displays both and DPE displays the stimulus error i e the difference between the command and monitor waveforms The scale for all these waveforms is Maximum The voltage waveform can be displayed with DPV where the scale is now 100V Recording stimulus monitor waveforms When stimulus current and or voltage waveform monitoring is activated and the Enable trace grabbing and Grab stimulus monitors boxes are checked on the Select recording parameters form then every time a response waveform is grabbed and saved to disk current and or voltage waveforms are saved as well These are saved as separate traces so it will be observed that if for example current and voltage waveforms are monitored the trace numbers in the databox display increment 1 4 7 etc Trace 2 holds the current waveform for trace 1 and trace 3 the voltage waveform Monitoring peak values of stimulus current and voltage With the DS5 stimulation errors are normally only serious when the stimulator is out of compliance and it takes more than the available 100V to drive the required current through
95. s with GOSUB commands allowing branching and loops INSTALLATION 1 Installation problems can occur with non English versions of Windows Please click on Control Panel Regional Options and set the preferred settings to English United Kingdom 2 If a data acquisition DAQ board is available see above hardware requirements it is recommended that the DAQ software be installed first In the case of NI boards this means running their Measurement and Automation program to confirm that the NI device is recognized and has a device name e g Dev1 3 Copy the Qtracinstall folder onto the computer and then click on SETUP EXE to start installation N B Unless National Instruments software has been installed there may be warnings like nipaui dll not found and an error on registration of DAQmxWrapper dll These errors should be ignored Although other locations are possible by editing Qtrac INl it is recommended that the default folders are accepted namely C QTRAC Programs for all Qtrac system files including QtracS EXE Qtrac Stimulation program QtracP EXE Qtrac Plotting program Qtrac INI Initialization parameters editable QtracS TXT Index of commands used by QtracS QtracP TXT Index of commands used by QtracP C QTRAC Data for newly generated QZD data and QTG trace grab files C QTRAC QRP files for QRP recording protocol files C QTRAC QPP files for QPP plotting protocol files C QTRAC MEM data for
96. s the stimulus that gives a constant sub maximal response For single unit preparations only 1 bit of information is obtainable per stimulus namely whether it was above or below threshold which is determined by whether the peak response was above or below the window height level set by WH and the stimulus is stepped up or down accordingly Recent tracking history is displayed for each channel as a sequence of pluses above threshold and minuses below threshold in the top right corner The simplest strategy is to use a fixed step size TM1 tracking mode 1 although the fixed step size in QTRAC is normally set to a percentage of the last stimulus e g TT2 sets the step size to 2 of the last stimulus The percentage step size is appropriate for most purposes and means that the same figure can be used for low threshold and high threshold preparations There are circumstances however e g when a threshold is reduced to almost zero by a conditioning current when you don t want the step size to get too small This can be avoided in 3 ways firstly the step size never does get vanishingly small because TT2 actually sets the step size to 2 of the last stimulus or of 10 whichever is the greater Secondly you can make the step size a percentage of the last stimulus on a control channel which does not get very small Thus TT2 T 1 sets the step size to 2 of the last stimulus on channel 1 Thirdly you can fix the step size by set
97. s with same scaling N B VR or VM on their own or in combination when not stimulating cause a rapidly refreshed display of raw data QTRACS only The x axis can be made very long in which case the spontaneous activity is displayed as a pseudo continuous time series W Window options WS Window Start time ms nR 2 WW Window Width ms nR 5 WH Window Height V nR 2 i e target response for tracking thresholds WL Latency type determines values saved as Latencies nl 2 See LT WF Fraction of peak for latency types 4 5 see LF R 0 5 WP Peak type nl 1 1 highest positive peak 2 peak to peak height 3 amplitude at end of window W If gt 0 set window height to fraction of peak on specified channel nl 0 e g WH 4 W 6 sets window height to 40 of peak response on channel 6 so window height changes after each stimulus on channel 6 but WH remains 0 4 If lt 0 resets WH permanently to fraction of last peak on specified channel e g WH 4 W 1 if last peak on channel 1 was 3 sets window oe and WH to 1 2 WA Window Autocentre Y N N centres window on peak if above WH WHL Whether to lock window heights together Y N WSL Whether to lock window starts together Y N Y Y rT fT 38 N B If WL is set to a negative number then data is only saved if peak response exceeds target WH N B Remember to enter WSLN before setting WS to different values on different channels or WHLN before setting WH to different heights on different
98. size which is the percentage change in stimulus 50 for a 100 or greater error in the response Proportional tracking can be much more efficient especially when excitability changes abruptly but has the disadvantage that the optimum setting for the maximum step size TT depends on the stimulus response characteristics of the preparation and needs careful tuning for optimal tracking A second disadvantage is that the tracking history does not give a good indication of the quality of threshold tracking as it does for the simpler tracking modes If the excitability of the preparation is changing slowly then a series of responses may fall just short of the target giving a series of minus signs and the erroneous impression that tracking is poor To allow for this you can define an acceptable error for threshold tracking e g TE10 for an acceptable error 10 of target and provided the response is within these limits which are displayed in grey an equals sign is displayed in the tracking history N B For proportional tracking TE does not affect the tracking itself only the tracking history display However for TM gt 1 if the response is acceptable the stimulus is unchanged This provides a further tracking variant 3 way tracking in which a response can have 3 different results stimulus increased decreased or unchanged if 3 way tracking is superior to the normal fixed step or incrementing step modes then proportiona
99. so depends on the tracking mode TM which by default is 4 This means that if the response is repeatedly below target the tracking step will be incremented in multiples of the basic step up to TM i e 2 4 6 8 Once the target response is found the tracking step is halved repeatedly until it reaches the basic step i e 4 2 More options and further details about threshold tracking will be found in the section Threshold tracking with Qtrac QTRACS Links to Digitimer DS5 stimulator and stimulus monitoring DS5 links at startup and from main form If there is a working USB link to a DS5 the same set of DS5 options are available at startup Stimulus settings form and in the main program by clicking on the DS5 button towards the bottom left of the screen The Sound off option stops the DS5 from beeping every time it does something but does not stop the warning sounds The Light off option is useful if stimulus waveform monitoring is activated see below since the DS5 backlight currently causes a high frequency oscillation to appear on the monitor waveforms but not on the stimulus itself Stimulus monitor and impedance check Clicking on the DS5 button see above or Mon button which appears in the same place if there is not USB link to a DS5 but stimulus current and voltage waveforms are being monitored provides access to a panel indicating peak current and voltage outputs resting current level and lo
100. surement code 2 and the single vertical cyan line is joined by a second vertical line from baseline to negative peak and a horizontal line joining the two Also for WP2 a second horizontal light magenta line appears at the level of the negative peak to indicate the level from which the window height target response height is measured The Window setting starting time width and height To ensure that peaks and latencies are measured correctly it is always important to position the window optimally The three key parameters are WS window start WW window width and WH window height Because of their importance these parameters can be set or reset in more ways than others There are 6 different ways 1 With keyboard alone as above with WS for TS etc 2 With keyboard and mouse as above 3 Adjusting separate parameters with mouse alone To reset the window start you can position the mouse pointer over the left end of the window when a light magenta circle will appear You can then drag the start of the 12 window to a new location with the left mouse button down and release it at the new site While dragging the window line doesn t move but a grey line just above it shows that the window is being dragged After it is dropped the WS command duplicated by the drag and drop operation will again appear in the scrolling dialogue Similarly to reset the window width drag the right hand end of the window line to the left or right
101. t stim Height to 50 on channels 11 b using curly brackets which may go before or after the command TH 11 50 Sets Test stim Height to 50 on channels 11 Or multichannel commands can be restricted to specific channels by a using two alphanumeric prefixes for first and last channel 25TH40 Sets Test stim Height to 40 on channels 2 to 5 ObTH20 Sets Test stim Height to 20 on channels 10 12 b using curly brackets with channel numbers separated by commas or hyphens 2 4 6 TH70 Sets Test stim Height to 70 on channels 2 4 and 6 TH 2 4 6 70 Sets Test stim Height to 70 on channels 2 4 and 6 TH 11 14 50 Sets Test stim Height to 50 on channels 11 14 PROGRAMMABLE FUNCTION KEYS The function keys lt F2 gt to lt F12 gt can be programmed to execute either a single command or a short sequence of Qtrac commands separate by colons For compatiblity with DOS Qtrac lt F1 gt is an emergency stop stimulation key equivalent to S lt Enter gt used by QtracS only and is not programmable To program the key lt Fn gt hit lt Ctrl gt lt Fn gt and enter or edit the text string as if you were entering a single Qtrac command or series of commands separated by colons Examples of the use of the function keys might be a to save keystrokes for frequently performed commands e g to refresh the display normally requires 3 keystrokes V V lt Enter gt but if programmed into a function key only one key stroke is required b frequentl
102. te on a user defined plot and all consecutive measurements with the same X co ordinate can be averaged together with DN1000 4 THE TO COMMAND Should the test stimulus overwrite or add to conditioning stimuli The TO command determines whether the test stimulus is off 0 added to the 52 conditioning stimulus 1 or overwrites the conditioning stimulus 2 The TO2 option is used in TROND protocols for recording threshold electrotonus and current voltage relationships The reason for this is to save time and facilitate tracking the threshold changes at the onset and offset of the conditioning stimuli For example at the start of a 40 of threshold conditioning stimulus the threshold is expected to fall by 40 To avoid having to track this anticipated threshold change the test stimulus overwrites the conditioning stimulus instead of being added to it which effectively reduces it by 40 for the duration of overlap with the conditioning stimulus To compensate for this the amplitude of the conditioning stimulus is added to the test stimulus before displaying or analysing the results This automatic correction of test stimulus amplitude can be suppressed by the command OON As a result of this device tracking of the onset and offset of conditioning stimuli appears to be instantaneous To display thresholds recorded with TO1 or TO2 correctly TO must be set to the corresponding value in QtracP and th
103. tency plot or vice versa etc 2 The X axis of the Raw and Modified plots becomes a latency axis so that the X values at which data points are plotted normally correspond to the time after the test stimulus rather than the time in the sweep Thus if the test simulus is applied at 201 ms a peak in the response waveform at 209 ms appears at the latency of 8 ms when the latency lock is on Moreover to maintain the correspondence between the Latency plot and the R and M plots the X values of the R and M plots depend on the type of latency measurement selected for the particular channel set by WL Thus if latencies are measured relative to the start of the conditioning stimulus WL13 then the X values of the R and M plots correspond to the time after the start of the conditioning stimulus set by CS Similarly WL14 displays latencies relative to an extra stimulus ES while WL15 and WL16 display latencies relative to the first and last burst stimuli N B If stimulus start times are altered by the automatic advance feature e g conditioning stimulus advance with AA1 then the display is locked to the time of the advanced stimulus not the root value set by TS CS etc 3 For the convenience of measuring latencies when the latency lock is on WS sets the latency at which the window starts not the absolute time in the sweep WS can be set by the mouse in the usual way Therefore if the latency lock is applied while running QtracS it will in general be
104. th PAUSE execution of the QRP pauses after a prompt and control returns to the Command line so that the operator may then change the display or stimulation or recording parameters as if the QRP file was not running Pop up menus The operator can be made to select between several branch options by means of pop up menus These are similar to the pop up prompts except that the operator can click on one of several option buttons and the program executes a GOTO the relevant line label A pop up menu can be instigated by the MENU meta command The following comment line then becomes the heading of a pop up menu This is followed by menu choice lines starting with 1 e g MENU Select stimulation rate option Set1Hz 1 Hz Set0 5Hz 0 5 Hz which are interpreted as GOTO Set1Hz etc The rest of the line 1 Hz becomes the description of the option in the menu The menu specification stops at any line not starting The heading of the pop up menu often begins with Select or contains the word option as in the case above and if either of these conditions is met the MENU line can be omitted i e Select stimulation rate option Set1Hz 1 Hz Set0 5Hz 0 5 Hz is equivalent to the example above N B There is no menu equivalent to GOSUB so the lines of program following a menu are never executed without a line label N B A checkbox is provided at the top of the screen to allow the selected optio
105. the baseline is clamped to the mean value during the last 10 points i e 1 ms before the start of the window indicated by the magenta line from 5 to 15 ms The points used for setting the baseline are marked by a green line at the level of the baseline in the Raw and Modified plots Other methods of setting the baseline can be found by typing MC lt Enter gt Other methods of modifying the data can be found by typing M lt Enter gt Changing the stimulus parameters QtracS can generate several different types of stimulus Test Conditioning Burst and Extra The most versatile is the Test stimulus which is the only one initially active All the commands that change the Test stimulus begin with T except for the useful lt Insert gt which increments the Test stimulus by 5 and lt Delete gt which reduces the Test stimulus by 5 This test stimulus height increment can be changed e g to 3 with THI3 lt Enter gt The remaining test stimulus parameters can be inspected by typing T lt Enter gt This produces a long list of test tracking stimulus options For the present we will just note that these include initial settings TH Height test stim 1 10 now 20 TS Start test stim 1 10 now 1 ms TW Width test stim 1 10 now 0 1 ms i e the test stimulus on channels 1 10 has height 20 of maximum stimulator output it starts at 1 ms and has width 0 1 ms N B If the test stimulus on channel 1 has been set to a different height su
106. the different plots Thus the first Modified response plot can be selected by clicking in the plot area or by moving the pointer with the lt Up arrow gt lt Down arrow gt keys and then DC1 selects that only Channel 1 will be displayed in it Alternatively plot and channel can be selected at the same time by 2DC1 and channel 2 can be displayed in the 2 Modified plot by 3DC2 Scaling of multiple plots of the same type can be set independently or repeat plots can have the same scaling as the previous one by use of small letters VSMmTP Recording data to file The command FS starts recording data to File Since FS also stops recording to file the alternatives F and F can be used to avoid ambiguity An elapsed time counter is started and a set of variables Test stimulus amplitude Latency Peak response amplitude Delay cOnditioning stimulus amplitude percentage Error etc is recorded in the QZD file every time a stimulus is delivered Starting threshold tracking 14 To start threshold tracking all that is required is to specify a tracking step e g TT2 This means that every time the response is less than the target i e WH the stimulus will be increased by 2 and every time it is greater than the target the stimulus will be decreased by 2 By default the 2 refers to 2 of the maximum stimulus amplitude However following the command T 0 the 2 will refer to the current stimulus amplitude on the same channel Tracking al
107. ther channel can be added or subtracted Clamping is with respect to a time Window which is also used to determine the section of the response to be measured The response can optionally be Clamped to zero either at the start of the window or both at the start and end of the window to produce a sloping baseline correction or the mean value within specified times can be set to zero or a baseline fitted between specified times by linear regression Within the Window the Peak height is either measured from the baseline to the maximum value or from the minimum to the maximum or may be defined as the amplitude at a specified time Latencies can be measured e g from the stimulus to the positive peak half peak or an arbitrary threshold or the width at half peak height can be recorded Lines on the display indicate which latencies and peaks have been measured Multiple event recording and on line raster plot The latencies and amplitudes of up to n peaks above a threshold where n is specified on starting the program can also be recorded for each stimulus and displayed on line in raster format with each peak represented by a dot at the appropriate latency This facility has proved particularly useful for microneurography Threshold tracking The amplitude of the Test stimulus can be increased or decreased by a specified percentage step after each response depending on whether the peak or peak to peak value within the window exceeded the speci
108. ting it to a percentage of the last stimulus on an unused channel Thus SN3 TT2 T 9 9TH50 sets the step size for stimulus channels 1 3 to 2 of stimulus 9 which is set to 50 i e the step is fixed at 1 of maximum output Tracking mode 1 has the merit of simplicity and avoids the dangers of overshoot inherent in the other methods but for most purposes a much better combination of tracking speed and accuracy of threshold determination can be achieved by using an incrementing step size TMn where n is the maximum step size as a multiple of the basic step size set by TT For example the default setting is TM4 which means that if successive peak responses fall the same side of the target response then the step size is incremented from the basic step size to 2 3 and 4 times that value Once the threshold is crossed the step size is halved and if the threshold is crossed again it is halved again to a minimum of the basic step size The incrementing step reduces the time taken to follow large changes in excitability for the same steady state accuracy but produces an overshoot if the changes in excitability are too fast If the responses are graded rather than all or none then extra information is available from the amount by which the response differs from the target response i e the error and in proportional tracking TMO tracking mode 0 the step size is made proportional to the error In this mode TT determines the maximum step
109. to point to hitting will interpolate latency and peak values from the points on either side also replaces the peak by the mean of the adjacent peaks N B If more than one channel is in use the channel or channels used by gt gt lt and can be limited by the CC cursor channels command Remeasuring latencies from an on line raster plot LR Whether or not a QTG file is available all the peaks for a particular unit may be available in the on line raster plot displayed by selecting DPR for the latency display and it may be apparent in the raster display which points belong to the unit of interest In this case the latencies can be selected from the on line raster points by selecting an arbitrary shaped area on the latency plot with the right mouse button Hold the right mouse button down and then moving it to the right sets the lower limit while moving it to the left sets the upper latency limit The area selected appears in light green This area can be refined by redrawing the upper or J9 lower limits but is lost when the data is replotted While a green latency elapsed time area is visible the command LR substitutes for the recorded latencies and peaks the largest on line raster peaks within each selected trace and latency range If the range of peak amplitudes of the raster points displayed is limited by RD then only peaks within this range are selected by LR If no on line raster peaks are within the range the measu
110. tting the width on both channels to 50 us TW 05 the maximum advance to 950 us AM 95 ensure the advancement was reset to zero ARO and once the thresholds were stable start increasing the stimulus width in 50 us steps by AS 05 N B for 50 us intervals it is necessary to have selected a sampling rate of 20 kHz or 100 kHz but not 50 kHz To make sure each threshold was estimated accurately we could require each stimulus width to be repeated 10 times AN10 However since the changes in stimulus strength with each step will initially be large and become small it is usually more efficient to make the number of repetitions conditional on the tracking e g AC2 ANS After AC2 trials only count towards the 5 repetitions specified which meet the criterion on both the test channel and channel 1 that either the response is within the acceptable error limits see TE or that no more than 2 responses in a row have been the same side of the target response Some trial and error will be needed to find the appropriate conditions for a particular preparation i e depending on whether a single unit whether proportional tracking is used what the tracking step size is what the signal to noise ratio is etc Irregular advance Because the strength duration relationship is very non linear using regular changes in stimulus width may be inefficient The alternative is to specify irregular advancement by entering a complete seq
111. uence up to 50 of advances with AQ For example to set up a sequence of stimulus durations of 40 60 80 100 140 180 240 300 360 420 500 600 700 800 900 1000 us we could start with TW40 and set up the advances with AQ 02 04 06 1 14 2 26 32 38 46 56 66 76 86 96 With the irregular advance the function of AS AR and AM are somewhat changed ASO stops advancing and ARO resets the advancement to zero and stops advancing as before but AS1 starts advancing according to the prescribed sequence while ARn resets the advancement to the nth value Note that AQ determines the difference in the parameter from its starting value set in this case by TW not its absolute value AM is set by AQ to the number of advance steps and should not be changed N B In the case of strength duration data it is not wise to use the shortest stimulus duration for the control channel since if the thresholds are unusually high the stimulator may not be able to generate an adequate stimulus of the shortest duration It may therefore be preferable to advance the stimulus duration backwards from 1 ms to 40 us using negative values for the AQ series Whether advancement is regular or irregular the absolute value of the parameter should be saved for subsequent analysis by appropriate choice of WL or by choosing to record the conditioning test delay during initialisation The latency or delay can then be selected as the X co ordina
112. ultaneous and may use an arbitrary number of points presented sampled at 1 2 5 10 20 50 or 100 kHz The minimum stimulus width is therefore 10 us The stimulus waveform is made up of a Test stimulus whose height can be varied depending on the response to effect threshold tracking with an optional Conditioning stimulus Burst of conditioning stimuli at equal time intervals and or an Extra stimulus Heights of the Conditioning Burst and Extra stimuli can be set to a fraction of the test stimulus height on another channel To help study the time course of the effects or after effects of conditioning stimuli any combination of the four types of stimulus Test Conditioning Burst and Extra can be advanced or retarded in regular or irregular steps and the conditioning test intervals recorded A trigger pulse is provided on digital output zero NB Not available on all devices This normally goes high throughout the stimulus response period but the start and end times can be specified and can be different for different channels Alternatively digital outputs 0 2 can be used to trigger auxiliary stimulators Response The response is sampled from one of 8 16 bit A D inputs at one of the above rates The Raw response can be Modified by filtering High pass Low pass Mains frequency and its harmonics or Smooth Differentiated Rectified Integrated aVeraged baseline Clamped Multiplied by a constant Grass cut and or the last response on ano
113. ulti channel program in which the channels up to 16 may be associated with different physical inputs and outputs or with different stimulation parameters or different operations on the response waveform Flexibility comes from the ability to associate any combination of physical or operational parameters with any channel QTrac also has a versatile display facility which enables any combination of stimulus waveform response waveform raw or after modification or measured parameters to be selected for display and rescaled at any time during a recording The combination of colour coded fast and slow time base displays obviates the need for oscilloscopes storage scopes chart recorders or other ancillary display devices QTrac can be operated by entering commands at the keyboard or by running scripts QRP or QPP Qtrac recording or plotting protocols which enable complex sequences of commands to be stepped through manually or automatically For example the nerve excitability testing protocol TrondCM allows a fully automated sequence of tests stimulus response strength duration threshold electrotonus current threshold relationship recovery cycle to be carried out with a minimum of key strokes or mouse clicks The script being run is viewable and can be varied either by entering commands manually at any point or by editing the next part of the script A scrolling dialogue portion of the screen records every command entered manually or
114. veform plots can be gated in or out depending on the value of a specified parameter or expression Files QTrac generates and uses seven types of files with extensions QZD QRP QRX QPP QPX QLG and QTG QTracP also generates MEM files with the results of the TROND multiple excitability testing protocols MEF files which refer to a group of MEM files and other ASCII files for exporting plotted data to other programs The QZD files are data files which store as integers the following values for each stimulus response the channel number threshold i e test stimulus amplitude measured peak height and latency of the response conditioning test delay conditioning polarizing current response error up to 50 latencies and amplitudes of multiple peaks and up to 8 sampled A D inputs Typed in comments and parameter changes are also saved at their proper time points and a header block holds scaling factors etc specified when the file is closed Individual raw response traces or averages are saved in a separate QTG file with the same name but the QZD and QTG files are fully cross referenced and appear to the user as a single file A log file QLG keeps a record with times corresponding to the clock as well as the QZD file of all significant events and parameter changes during the recording The file name for QZD QTG and QLG files is generated automatically by QTracS and is made up of an arbitrary prefix of up to 3 letters 6 digit d
115. w gt keys or a plot can be selected by pointing the mouse anywhere within the plot area and clicking the left mouse button The Y axis range can be set or reset in 4 ways 1 With keyboard alone DY5 15 lt Enter gt sets the Y axis range from 5 to 15 DA lt Enter gt autoscales the Y axis range to the minimum and maximum values displayed N B You may need to enter DA twice to match the current data range amp With keyboard and mouse DY followed by mouse clicks at the minimum and maximum values to be displayed but only if they are within the plot area 3 With mouse alone There are 5 mouse active areas just to the right of each Y axis which are revealed by the appearance of a red arrow when the mouse points within them i Just above the maximum an upwards arrow indicates that clicking will increase the maximum value to double the range 13 ii Just below the maximum a downwards arrow indicates that clicking will reduce the maximum value to halve the range iii In the middle a double ended arrow indicates that clicking will perform an autoscale operation equivalent to DA iv Just above the minimum an upwards arrow indicates that clicking will increase the minimum value to halve the range v Just below the minimum a downwards arrow indicates that clicking will reduce the minimum value to double the range 4 With mouse and keyboard The Y axis itself is another mouse active area and when the mouse points to the
116. y used filter settings can be conveniently kept as function keys e g for C fibre microneurography recordings typical filter settings are MH 300 ML 2000 MC7 c to estimate strength duration time constant from thresholds on channel 2 tracking a 0 1 ms stimulus and channel 3 tracking a 1 ms stimulus a user defined channel 1 can be generated as U1T2 T3 0 1 T3 T2 0 1 and this instruction can be remembered by programming a function key N B To check on how function keys have been programmed simply hit lt Enter gt three times to bring up first Main Options then Special Key Options and then Programmable Function Keys To select a function key option either click on the red lt Fn gt or cancel and then hit the appropriate function key _ N B Function key strings are remembered in Qtrac INI shared by QtracS and_QtracP 43 DATA DISPLAY PANELS In QTracS three panels appear to the right of the data plots 1 Tracking history For each stimulus channel a sequence of and characters record whether the last few responses were above or below threshold The last active stimulus channel is indicated by the pointer gt in black if stimulating light green if not Stimulus channels not currently selected i e following SC are displayed in light cyan Following the TE instruction an appears in place of a or if the response is within the specified acceptable error limits 2 Data being recorded
117. yed only when counting cycles i e after Cycles in QRP file N B Traces displayed only when trace grabbing enabled e g IGY G N B Trace no initially displayed in the channel colour but when it is no longer the last 44 trace recorded it fades to light cyan N B Raster points displayed only if enabled e g by IL20 In QtracP up to 4 panels appear to the right of the data plots 1 Colour key to channels and any user defined traces These colours can be changed by PC and UC respectively 2 Recorded data as for QTracS at the time pointed to by the cursor 3 Time and trace numbers CT Cursor Time min Tr Time of trace or times of 1st and last traces displayed If grabbed traces are available and the Cursor Lock is applied CLY then latency and peak are also measured from the traces and indicated by L n and Pk n 4 If n on line raster points saved a box with n latencies and peaks or 30 if n gt 30 Order depends on RR LINE POINT OPTIONS DL or DP The line point display options e g whether to display data as lines or points available depend on the type of plot and in some cases also differ between QtracS and QtracP The line options available at any time can be seen in the Index under Display Line Point options or by typing DP return QTRACS plot types DP options for plot type S Stimulus S Steps only option DP options for plot types R Raw data M Modified data M mean X m

Microsoft Word Viewer - QTRACW MANUAL 18-8-2008

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