Corominas-Teruel, X.; Mutanen, T.; Leto, C.; Colomina, M. T.; Gallea, C.; Bracco, M.; Cabre, A. V.

Background: The concurrent use of Transcranial magnetic stimulation (TMS) with electroencephalography (EEG) is increasingly integrated in research and clinical protocols to provide proof of effect by magnetic pulses. However, a reliable identification of evoked local EEG activity over TMS targeted cortical sites remains still challenging. Methods: Here we present EPICURUS, a novel EEG spatial filtering approach, by which, individual MRI based simulations of TMS- electrical fields (E-fields) guide the reconstruction of TMS evoked o EEG signals originated in the primary motor cortex, minimizing crosstalk from non relevant more distant sources. Results: A reduction of late Transcranial Evoked-Potentials (TEPs) components (>100 ms post pulse onset) suggest our E-field-based spatial filter approach efficiently reduced intrusion of non-locally relevant distant sources engaged by TMS, particularly when combined with a suppression of auditory entries. Conclusion: The individually customized E-field-based spatial filtering procedure here developed for TMS-EEG datasets shows promise improving the spatio-temporal mapping of primary sources activated by magnetic pulses.