Summary

The motor cortex is responsible for controlling movements. In this process, different neurons respond to specific movements. When there is damage to this area, it can lead to local paralysis.

Function

This area is responsible for performing body movements. Among other things, it receives information about the current position of the body from receptors on "stretch-and-flex" muscles, and projects to motor nerve cells in the spinal cord. This area contains a special type of neurons found nowhere else in the brain: Betz neurons. These neurons have an extremely long axon, which is probably useful for sending information from this area to the spinal cord, so that muscles receive commands.

In the motor cortex, the different body parts are represented in a motor homunculus. This is a kind of map of the body: each body part is represented in a different part of the brain. Body parts that are used a lot, such as your hand and arm, occupy larger areas of the brain than body parts you don't use as often.

Location

The primary motor cortex is located at the back of the frontal lobe, on the anterior part of the central sulcus. The central sulcus is a prominent groove in everyone's brain that separates the frontal cortex from the parietal cortex.

Fact

The motor cortex is organized contralaterally. This means that the right side of your brain, controls the left side of your body. Your left motor cortex controls the right side of your body.

Patients

With damage to the motor cortex, it becomes difficult to move the body part associated with that piece of cortex. Severe damage can even lead to paralysis of a body part.

Author: Myrthe Princen (translated by Melanie Smekal)

Image: Marcel Loeffen