Abstract
There is described a 60-channel EEG acquisition system designed for the recording of scalp-potential distributions starting just 2.5ms after individual transcranial magnetic stimulation (TMS) pulses. The amplifier comprises gain-control and sample-and-hold circuits to prevent large artefacts from magnetically induced voltages in the leads. The maximum amplitude of the stimulus artefact during the 2.5ms gating period is 1.7 μV, and 5 ms after the TMS pulse it is only 0.9 μV. It is also shown that mechanical forces to the electrodes under the stimulator coil are a potential source of artefacts, even though, with chlorided silver wire and Ag/AgCl-pellet electrodes, the artefact is smaller than 1 μV. The TMS-compatible multichannel EEG system makes it possible to locate TMS-evoked electric activity in the brain.
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Virtanen, J., Ruohonen, J., Näätänen, R. et al. Instrumentation for the measurement of electric brain responses to transcranial magnetic stimulation. Med. Biol. Eng. Comput. 37, 322–326 (1999). https://doi.org/10.1007/BF02513307
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DOI: https://doi.org/10.1007/BF02513307