Dependence of Induced Electric Fields in Human Brain onWorking Frequency in Transcranial Magnetic Stimulation

摘要

Transcranial magnetic stimulation could provide new,non-invasive therapeutic options for various psychiatric and neurological disorders.In this work,we study the dependence of induced electric fields on working frequency in real human brain by usage the conventional figure-of-eight and round coils.The induced electric fields in brain tissues were calculated by using impedance method.The thresholds for motor neural activation at different frequencies were calculated by considering the motor strength-duration curve.Comparison of the induced electric fields at 3.6 kHz,18 kHz and 36 kHz have been performed.Numerical results show that the induced electric fields can be distributed in the deep brain regions by increasing the working frequency.Since the threshold for motor neural activation increases dramatically with the increase of working frequency,we suggest the TMS application with higher frequency should work at a frequency less than 40 kHz.