Brain
Motor Cortex
Master controller of voluntary movement
Overview
The primary motor cortex (M1) occupies the precentral gyrus of the frontal lobe. It generates neural signals that travel down the corticospinal tract to control voluntary skeletal muscle movement throughout the body. Adjacent areas—the premotor cortex and supplementary motor area—plan and coordinate movements.
Function
- Executes voluntary muscle contractions
- Encodes movement speed, direction, and force
- Coordinates multi-joint movements
- Adapts movements through motor learning
- Sends commands via the corticospinal and corticobulbar tracts
Key Facts
- The motor homunculus maps body parts: the hand and face have the largest areas
- Contralateral control: left M1 moves the right side of the body
- Mirror neurons (also found here) fire when observing others' movements
- Motor cortex stimulation can evoke involuntary movements even in anesthesia