EEG PECULIARTITIES AND KINDLED SEIZURES UNDER CONDITION OF TRANSCRANIAL MAGNETIC STIMULATION

Transcranial magnetic stimulation (TMS) at low frequency (2/s for 10 s, 0.1 Tl at the heightof the impulse peak) induced an increase in delta bandwidth power and a marked reduction intheta and alpha rhythms in the basal EEG in rats kindled via amygdalar electrical stimulation(ES). A marked reduction in beta and gamma bandwidth power was also seen. All effects wereseen within half an hour of TMS and were brain structure-dependent. Amygdalar ES did notinduce generalized clonic-tonic fits when applied to kindled rats after TMS. The duration ofgeneralized epileptoform activity was also shorter after TMS. A reduction in theta, beta, andgamma rhythms and an increase in delta rhythm at the moment of cessation of epileptiform discharge (ED) (last 16 s of discharge) in TMS-kindled rats were observed. Thus, a suppressiveantiseizure effect can be seen when relatively low intensity TMS is used, and the effects might be mediated through delta rhythmogenesis activation.