Intraoperative Neurophysiology and the Motor-evoked Potentials Methodology

Abstract

The revolutionary discovery of transcranial electrical stimulation (TES) by Merton and Morton1 became a well recognized method for corticospinal tract (CT) activation and has been used in the clinical setting for the last 25 years. Due to the painless method of brain stimulation and other advantages after introducing transcranial magnetic stimulation of the brain, TES is mostly used during intraoperative monitoring of the functional integrity of the CT in comatose patients, and as a research tool in clinical neurophysiology. We will describe the use of TES during surgery in anesthetized patients and highlight the underling physiology of the motor-evoked potentials (MEPs) elicited by this method.