Neurophysiological Bases and Mechanisms of Action of Transcranial Magnetic Stimulation

Abstract

Transcranial Magnetic Stimulation (TMS) is a neurophysiological technique based on the Faraday’s principle of electromagnetic induction, which allows a noninvasive, painless stimulation of the human brain through the intact scalp. TMS is a very versatile tool that can be used alone or in combination with other techniques to test different brain functions. Furthermore, protocols of repetitive TMS (rTMS) have been shown to induce effects that outlast the period of stimulation, opening new scenarios in which rTMS is used for neuromodulatory and therapeutic purposes. About 35 years after its introduction, TMS still has a prominent role in the clinical and research settings. In this chapter, we will introduce the neurophysiological bases and the mechanisms of action of different TMS protocols, focusing on TMS application to the primary motor cortex.