"Optimization of Transcranial Magnetic Stimulation (TMS) Parameters using concurrent TMS-EEG and TMS-fMRI"

Transcranial magnetic stimulation (TMS) is a non-invasive brain stimulation method that has shown diagnostic, therapeutic and research potential in the central nervous system (CNS), with research and clinical uses still evolving. Efficient TMS involves finding an optimal target location, i.e., coil position and orientation over a target brain region. Despite being an important procedure, there are no standard guidelines addressing the optimal procedure for TMS hotspot search. We used TMS evoked EEG potentials (TEPs) measured using concurrent TMS-EEG to propose a TMS hotspot search procedure. We also proposed the means to validate the TMS hotspot search procedure using TMS evoked BOLD response measured using concurrent TMS-fMRI. Although the presented TEPs evidence to characterize a genuine TMS hotspot is convincing, the TMS-fMRI-based evidence is insufficient and limited to claim any generalized validation of the proposed procedure. It reflects that future studies are needed to conduct further research validations.