Applications of TMS to Study Brain Connectivity

This chapter focuses on studying brain connectivity by employing two coils in a paired pulse protocol. It describes the evidence of known corticocortical interactions modulating the output of M1 including homologous M1, dorsal premotor cortex (PMd), ventral premotor cortex (PMv), posterior parietal cortex (PPC), presupplementary motor area and supplementary motor area (preSMA/SMA), cerebellum, and the peripheral nervous system (PNS). The chapter addresses how these connections are affected in various cognitive and motor processes in both health and disease, as well as how these paired pulse protocols themselves can be used to elicit plasticity changes. In addition, transcranial magnetic stimulation (TMS) has also been used in combination with other techniques such as fMRI, PET, and EEG to incorporate causality into correlation-based functional imaging and to provide information on functional connectivity between the site of TMS stimulation and more remote brain regions.