Biosemi for recording motor-evoked potentials
Posted: Wed Mar 27, 2013 1:49 pm
Hi,
I have been using a Biosemi system to record motor-evoked potentials (MEPs) using TMS. Active electrodes on the FDI muscle of the right hand record the MEPs. I have been recording at 2048Hz sampling rate (speed mode 4).
Could I ask what the hardware filter settings are set at with this kind of sampling - particularly the high end of the bandpass?
The MEPs currently recorded look a little strange. If you look at the attachment of what a normal MEP should look like (normal_MEP.jpg) and compare it to the MEPs I have been getting (myMEP.jpg), there are some differences. For example, the waves that should be present just after the MEP are entirely absent in my MEP. This seems like it might be an issue with filtering.
Finally, after some TMS pulses in the raw data, the signal also struggles to return to baseline following the TMS pulse artefact. I wonder if this is also likely to be a product of amplifier settings, or some kind of interaction between the TMS pulse and the amplifier?
Any help would be enormously appreciated.
Thank you,
Erman
I have been using a Biosemi system to record motor-evoked potentials (MEPs) using TMS. Active electrodes on the FDI muscle of the right hand record the MEPs. I have been recording at 2048Hz sampling rate (speed mode 4).
Could I ask what the hardware filter settings are set at with this kind of sampling - particularly the high end of the bandpass?
The MEPs currently recorded look a little strange. If you look at the attachment of what a normal MEP should look like (normal_MEP.jpg) and compare it to the MEPs I have been getting (myMEP.jpg), there are some differences. For example, the waves that should be present just after the MEP are entirely absent in my MEP. This seems like it might be an issue with filtering.
Finally, after some TMS pulses in the raw data, the signal also struggles to return to baseline following the TMS pulse artefact. I wonder if this is also likely to be a product of amplifier settings, or some kind of interaction between the TMS pulse and the amplifier?
Any help would be enormously appreciated.
Thank you,
Erman