This lecture covers the application of Transcranial Magnetic Stimulation (TMS) to determine brain functioning, focusing on electrophysiological evaluation, virtual lesion approaches, and neuromodulation. It explores physiological measures, TMS coil technology, intracortical neurotransmitter systems, and cortical brain mapping tools. The lecture delves into the technical evolution of TMS, neuronavigated and robotized TMS, closed-loop protocols, and the use of TMS in mapping visual hallucinations.