Advanced Examples
The standard examples that ship with BioSigRZ cover the most common use case of one recording channel and one stimulation channel (tone or click).
The examples below are for custom experiments requiring more acquisition channels and/or more stimulus channels. Choose an appropriate template based on your electrode channels and stimulation needs. Use the tables below to guide you.
The templates are described in detail, and include a link to the BioSigRZ
experiment (*.acf) that is used. Copy the ACF file into the
C:\TDT\BioSigRZ\Configs\ABR folder so it is available in BioSigRZ.
Standard Examples for Higher Channel Count
Tone
Click
* You must have an RZ6-A-P1 with serial number > 2400 or TDT must have applied ECNs newer than ECN9322
† Use of the BioSigRZ individual traces is supported with this file.
Fish ABR with Hydrophone
When using the RZ6 with fish, customers generally want lower frequencies and slower presentation rates than commonly found with other animals like rodents. Additionally customers typically want to record the stimulus with a Hydrophone at the same time they record the ABR.
These examples use FishFixedPhase.sig for presenting typical frequencies used for fish. Users can make changes to the frequencies if desired. It disables the phase variable so that the stimulus does not alternate, allowing the hydrophone to record the stimulus.
The modified RCX file allows recording from the preamp and the BNC input at the same time. The hydrophone (connected to In-A on the RZ6) is recorded on channel 1 and the ABR (from the preamp) is recorded on channel 2 in BioSigRZ.
Note
Users must now manually average the ABR results after the recordings are obtained. This can be done in the Worksheet or in post-processing. Each frequency will be presented in two consecutive SGIs, once with a positive phase stimulus, and once with a negative phase.
Calibration can be done with BioSigRZ, however, you must first convert the hydrophone output to mV/Pa. To determine the mV/Pa output of your hydrophone, please see the equation in Tech Note TN0828.
Find a closely matching TCF file to your sensitivity in C:\TDT\BioSigRZ\TCF.
For example, if you determine the sensitivity of your hydrophone is 3.1mV/Pa,
use 3.0mV.tcf as your acquisition TCF during calibration. If your sensitivity
does not closely match any of the stock TCF files provided by TDT please
contact support@tdt.com and a custom file can be made for you.
Once setup is complete, you can follow the standard steps in the BioSigRZ manual for a typical ABR. The remaining variables (Filters, Acquisition duration, and similar) can be modified as needed. These modified files will allow you to record both the stimulus and the ABR at the same time. You will need to manually average the positive and negative responses from each frequency tested using the calculator functions. From there you can export the data from your Worksheet if desired.
Mismatch Negativity (MMN or Oddball)
This experiment records one channel of ABR but presents two different stimuli in a user-defined order and saves the responses in separate channels.
This experiment presents two different stimuli (Oddball1.sig and Oddball2.sig)
from Out-A on the RZ6 based on the order specified in Random_1_2_2000.txt. It
records one channel of ABR data from the preamp, but organizes the averaged responses
into two different channels based on the stimulation that was presented - one for
the standard and one for the odd or deviant.
If you want to change the percentage of Standard vs Odd presentations,
change the ratio of 1s and 2s in the Random_1_2_2000.txt file. To change
the presentation file, open the RCX file and navigate to the Stim-2 sheet.
Change the 'Name' field in the SourceFile component to point to a different .txt file.
Note
The file path must be under 33 characters and avoid special characters.
Contralateral Stim with ABR
BioSigRZ can generate stimuli on the contralateral (Out-B) side of the subject during the ABR recording. These files are designed to generate continuous Tones, Noise, or Filtered Noise from the contralateral speaker as long as BioSigRZ is actively runnin an experiment. Once BioSigRZ stops recording, the Contralateral stimulation will stop five seconds later.
Note
This five second delay is adjustable. Contact TDT Tech Support support@tdt.com if you need help with this.
There are three examples for this experiment. Examples 1 and 2 below will run on RZ6 units with three DSPs. Example 3 requires four DSPs.
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Contralateral Tones
Users have control of the Frequency and Intensity of the contralateral tone during the experiment.
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Contralateral Noise
Users have control of the Intensity of the contralateral noise during the experiment.
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Contralateral Filtered Noise
Users have control of the Intensity and the Low Pass Fc (filter cutoff) and the High Pass Fc of the contralateral noise.