Transcranial Magnetic Stimulation – TMS
TMS is based on the principle of electromagnetic induction. A magnetic field is applied over the head of a subjects by means of a coil placed above a cortical target of interest. The magnetic field passes through the skull and reaches the cortical brain tissue where induces an electric field, which interferes transiently with the cortical activity. TMS can be used in many different paradigms to study neural correlates of cognitive functions and brain plasticity with experimental or clinical applications. It can be applied in single-pulse modality to interfere with a target area during a cognitive task. Otherwise, multiple stimuli can be delivered in repetitive TMS (rTMS) protocols, which can modulate the cortical excitability with lasting inhibitory or excitatory effects depending on the frequency of stimulation.