The motor cortex is the region of the frontal lobe that controls voluntary movement. It lies immediately anterior to the central sulcus and is organized as a map of the body.

Neurons in the primary motor cortex send axons down the corticospinal tract to the spinal cord, where they influence the motor neurons that drive muscles. The map is distorted: regions that control fine movements of the hands, fingers, and face occupy disproportionately large areas. Stimulation of a given spot produces movement in the corresponding body part. Premotor and supplementary motor areas, located just in front of the primary motor cortex, are involved in planning, sequencing, and coordinating movements.

Damage to the motor cortex produces weakness or paralysis on the opposite side of the body. Plasticity allows some recovery, especially when rehabilitation encourages the use of remaining pathways. The motor cortex is active not only during movement but also during motor imagery and the observation of others’ actions.

When you decide to reach for a cup and then do so, the motor cortex is translating intention into muscle commands.