Two stimulation approaches developed for selectively exciting descending motor pathways are, transcranial electrical (TES) and transcranial magnetic (TMS) stimulation. This article highlights the comparison between electrical and magnetic transcranial stimulation. Magnetic stimulation is relatively painless; therefore it is the more preferred technique. The article reviews the use of TMS for monitoring the functional integrity of the descending motor systems during surgery and discusses the potential role of TMS in the preoperative period for conscious patients planning to undergo neurosurgical procedures involving the cerebral cortex. Selective monitoring of spinal cord motor function involves acquisition of TMS-induced epidural and/or myogenic responses. As patients are generally given anesthesia before spinal cord surgeries, this article discusses the effect of general anesthetic agents on the myogenic responses.