Professor Ugawa is interested in clinical neurophysiology and one of the pioneers of transcranial magnetic stimulation (TMS). He started to study pathophysiological mechanisms underlying various involuntary movements, especially myoclonus, using EEGs, evoked potentials and MEGs. After the invention of TMS and neuroimaging techniques, he also used those newly developed methods for this purpose. He extended the target disorders to Parkinson’s disease and related disorders. After the invention of repetitive TMS (rTMS), he studied neuroplasticity in humans and developed a new plasticity induction method [quadripulse stimulation (QPS)]. In addition to studies of normal plasticity, he applied the plasticity induction method to the treatment of neurological disorders, and he is now developing new treatments using rTMS for movement disorders, especially Parkinson’s disease.