Motor Cortex

Abstract

The term motor cortex refers either to a single cortical area, the primary motor cortex, or to a group of motor areas in the frontal lobe. This article uses the narrow definition. It is commonly held that the motor cortex functions mainly to permit the independent control of muscle groups that usually work in concert. More generally, the motor cortex controls voluntary actions and plays a role in motor learning and memory, including skill acquisition. The activity of neurons in motor cortex reflects the direction and speed of voluntary movements, properties consistent with a role in motor control. Some of these cells control movement through their outputs to the brain stem and spinal cord, including direct projections to motor neurons. Motor cortex has a rough topographical organization, meaning that separate parts of it control movements of the foot, hand, and face, respectively. Nearly one in every hundred people has a motor disability caused by damage to motor cortex, usually resulting from strokes, and recovery often remains incomplete. However, the fine organization of the motor cortex can change as people practice motor skills, and such plasticity may enhance the recovery of function after strokes.