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Acquisition InterfacesNational Instruments USB-6341-BNCHEKA LIH 8+8 Data Acquisition SystemAmplifiersNeuroLog SystemD360 8-Ch. EP/EEG/EMGD360R 4 Channel Isolated Research Amplifier/FilterD440 2/4 Ch. EMG/EPHEKA EPC10 Patch ClampHEKA EPC10 2/3/4 Ch. Patch ClampHEKA EPC800 Patch ClampAnti-vibration SystemsThorLabs Science DesksNarishige ITS Anti-vibrationNarishige Double MagnetNarishige SBP-2 BaseplateCell InjectorsPLI-100A Pico-injectorPLI-10 Pico-injectorNarishige IM-11-2Narishige IMS-20Narishige IM-21Narishige IM-400Injection Accessories
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Signal GeneratorsTG315 Function GeneratorSoftwareQtracW Threshold TrackingAutoMate EasycodeHEKA Chartmaster SoftwareHEKA Patchmaster SoftwareHEKA Fitmaster SoftwareStimulatorsDS2A Constant VoltageDS3 Constant CurrentDS4 Biphasic Constant CurrentDS5 Bipolar Constant CurrentDS7A/DS7AH Constant CurrentDS7R Constant Current ResearchDS8R Biphasic ResearchD121-11 Mounting FrameD185 Transcranial MultiPulseD330 MultiStim SystemNL800A Current Stimulus Isolator
A/D Interface ModulesNL201 – Spike TriggerNL601 – Pulse IntegratorAmplifier ModulesNL100AK – HeadstageNL100RK (NL100AKS & NL100C)NL102G – DC PreamplifierNL104A – AC PreamplifierNL106 – AC/DC AmplifierNL108A – Pressure AmplifierNL109 – Bridge AmplifierNL120S – Audio AmplifierNL820A – 4-Ch. IsolatorNL844 – 4-Ch. AC PreamplifierAnalogue ModulesNL254 – RatemeterNL506 – Analogue SwitchNL703 – EMG Integrator
Digital ModulesNL405 – Width/DelayNL501 – Logic GateNL505 – Flip FlopNL603 – CounterNL730 – Pulse ShiftFilter & Conditioner ModulesNL125/6 – Band-Pass FilterNL134/5/6 – 4-Ch. Low Pass FiltersNL143 – 3-Ch. Difference AmplifierNL144 – 4-Ch. High Pass FilterNL530 – Signal ConditionerNL540 – Inverting Attenuator (Alt. Gain)Generator ModulesNL301 – Pulse GeneratorNL304 – Period GeneratorNL412 – Pulse
NeuroLog AccessoriesAccessory KitsAdaptors & Adaptor CablesSockets (for cable mounting)Sockets (for panel mounting)Plugs (for cable mounting)Extension CablesCablesElectrode HoldersMiscellaneous AccessoriesNeuroLog System CasesNL900D – NeuroLog System CaseNL905 – Compact NeuroLog System Case
Pressure Transducers & AccelerometersPressure TransducersForce TransducersAccelerometersStimulator ModulesNL510 – Pulse BufferNL512 – Biphasic BufferNL800A Constant Current Stimulus Isolator
Application NotesSignal AmplificationTriggering & Pulse GenerationSignal Conditioning Filtering & ProcessingElectrical Stimulation
Isolated Amplifiers for EMG/EEG/EP D440 2/4-Ch. EMG AmplifierD360 8-Ch. Patient Amplifier D360R 4-Ch. Research AmplifierAmplifier Accessories D175 Electrode Impedance Meter D179 Performance Checker D360 Audio Interface D360 USB to Serial Adaptor D177 Bio-Feedback Unit
Peripheral Stimulators DS5 Isolated Bipolar Constant Current Stimulator DS7A & DS7AH HV Constant Current Stimulator DS7R HV Constant Current Research Stimulator DS8R Biphasic Constant Current Stimulator
Transcranial Cortical StimulatorsD185 MultiPulse Cortical Electrical StimulatorStimulator AccessoriesD188 Remote Electrode SelectorElectrode Connection HeadboxesTrigger CablesElectrode HandlesMiscellaneous Items
Neurodiagnostic AccessoriesIntraoperative Neuromonitoring (IONM) Electroecephalography (EEG) Electromyography (EMG)Nerve Conduction Study (NCS) Evoked Potential (EP)Axelgaard Stimulation ElectrodesTouch Proof Plugs Adaptors & Electrode Linkers
Cath SecureCATH-SECURE – OriginalCATH-SECURE – ExtendedCATH-SECURE PlusCATH-SECURE – Dual TabCATH-SECURE For KidsNG SECURE
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Urodynamic ConsumablesUrodynamics CathetersPump Infusion SetsTransducer Pressure DomesFemale Voiding AdaptorDuckbill ValvesSetguards3-Way Taps
Introduction to QtracW Threshold Tracking Software
QtracW Threshold Tracking Software is a flexible, stimulus-response data acquisition program with averaging, threshold-tracking and latency-tracking facilities, originally written for studies of human nerves in vivo, but also used for microneurography, muscle excitability testing and cortical excitability testing with transcranial magnetic stimulation. 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 (which became QtracW when adapted for Windows) comprises separate stimulation and plotting programs, QTracS and QTracP, both written in Visual Basic 6.0, which have the same mode of operation and share many of the same facilities.
The Digitimer DS5 Bipolar Constant Current Stimulator was specifically designed to work with QtracW software for human studies of nerve excitability. The major components of a human nerve excitability setup include a PC running QtracW software, a nerve stimulator (e.g. Digitimer DS5), an isolated EMG amplifier (e.g. Digitimer D440-2) and a compatible DAQ interface. We also strongly recommend the Quest Scientific Humbug Noise Eliminator to remove mains interference, as many QtracW systems are mobile and used in electrically noisy hospital environments. For animal-based studies, our DS4 Biphasic Stimulator is compatible with QtracW.
For those unfamiliar with the application of QtracW software in studies of nerve excitabiltiy, we recommend the recent article by Prof. Matthew Kiernan and colleagues (Kiernan et al. 2020), which provides guidelines for the measurement of axonal excitability and provides a state of the art review of axonal excitability research.
Compatible DAQ Hardware
National Instruments DAQ interfaces are recommended for use with QtracW software (see below). Please consult the QtracW users manual for the latest details on specific models.
The most recent version of QtracW software can be freely downloaded from the QtracW FTP site (login details available from Digitimer upon request). After 50 days evaluation QtracW will only function through use of a USB hardware dongle/key which is provided once a licence has been purchased from Digitimer. All new licences are activated for 3 years.
All the necessary files and installation instructions are available from the QtracW FTP site.
A series of highly successful nerve excitability workshops have been held between 2009 and 2016. Further workshops may be organised in the future if there is adequate demand. Please contact us if you are interested in attending a workshop and we can put you in touch with the organisers if any are planned.
New QtracW users need to purchase a 3 year licence pack from Digitimer, with non-commercial academic and clinical users receiving a 50% discount from the full price. This initial pack consists of one QtracSP dongle (stimulation and analysis/plotting) and two QtracP (analysis/plotting only) dongles. Once a user becomes a registered QtracW licencee, further dongles can be purchased individually with variable lifetimes (one to five years) and capabilities (either QtracP or QtracSP). It is also possible to extend the lifetime of a dongle by paying the appropriate licence fee. Existing QtracW users can also transfer remaining licence time from a password on their computer to up to three USB dongles (only one QtracS) using “DongleExtend” software. Please contact Digitimer for further details.
Hardware & Software Requirements
QTrac can be used with PCs running Windows XP, Vista, 7, 8 or 10. (Qtrac may also be used on a Mac, if Parallels is used to install Windows and a Windows keyboard is added.)
QtracS currently supports the following data acquisition cards/units:
Muscle Excitability (MScanFit)
MScanFit is a freeware program which is described in the paper ‘Estimating motor unit numbers from a CMAP scan’ (Bostock, 2015). The program works by generating a motor unit model to account for a detailed stimulus-response curve or CMAP scan. Full details of the assumptions, the generation of a preliminary model, and the method of refining the model to improve the fit to the recorded CMAP scan can be found in that paper.
Typical Equipment Setup for DS5/QtracW Installation
QtracW Operator’s Manual
Publications which cite use of QtracW can be found on Google Scholar.
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