Frequency-dependent effects of contralateral repetitive transcranial magnetic stimulation on penicillin-induced seizures.

Transcranial magnetic stimulation (TMS) has been shown to modulate multiple brain functions, warranting further exploration in clinical applications. TMS treatment for epilepsy is particularly promising because of its anti-convulsive capabilities. However, TMS has been found to both inhibit and facilitate various experimental and clinical seizures, depending on the TMS parameters used. Repetitive TMS (rTMS) pulse frequency is recognized as one of the most influential parameters and thus was investigated in this study at 1, 5 and 10 Hz for its effects on a rat model of penicillin-induced seizures. High-dose penicillin-induced seizures were characterized by a combination of myoclonic and tonic-clonic (GTC) seizures. rTMS effects were analyzed with intracranial electroencephalographic (iEEG) data and video-captured behaviors. Animals treated with 1 and 5 Hz consistently showed evidence of anti-convulsive properties in their iEEG-based seizure profiles when compared to sham rTMS treatment. In contrast, data from 10 Hz rTMS suggested facilitative characteristics. Our results showed that 5 Hz rTMS consistently outperformed 1 Hz rTMS in seizure suppression. This re-emphasizes the importance in accurately characterizing TMS effects on seizure suppression due to the heterogeneous nature of seizures. Thus, finely tuned TMS treatment has great potential to become a powerful asset in combating epilepsy.