Noninvasive transcranial brain stimulation (NTBS) techniques, such as transcranial magnetic stimulation (TMS) and transcranial direct or alternating current stimulation (TDCS/TACS) can be combined with electroencephalography (EEG) and magnetoencephalography (MEG). The combination of NTBS and EEG/MEG can 1) inform brain stimulation (where, when, and how to stimulate), and 2) reveal aftereffects of stimulation induced changes in cortical activity, and interregional connectivity (offline approach), as well as the immediate neuronal response to the stimulation (online approach). While offline approaches allow to separate NTBS and EEG/MEG in space and time, online approaches require concurrent stimulation and recording. While TMS and MEG cannot be combined online, concurrent TMS-EEG as well as TDCS/TACS-MEG/EEG are feasible but pose a range of methodological challenges at the technical and conceptual level. This chapter provides an introduction into the principal experimental approaches and research questions that can be tackled by the combination of transcranial brain stimulation and EEG/MEG. We review the technical challenges arising from concurrent recordings as well as measures to avoid or remove stimulation artefacts. We also discuss the conceptual caveats and required control conditions.
Transcranial Magnetic Stimulation-induced Changes in Scalp-recorded EEG and Evoked Responses in Patients with Cerebrovascular Disease.