In this video, I describe the location and functions of the primary motor cortex and the nonprimary motor cortex, which is often divided into the supplementary motor cortex and premotor cortex. I also describe the main pathways by which motor information travels away from the motor cortex: the corticospinal tract, which carries motor information to the spinal cord to cause movement of the body, and the corticobulbar tract, which carries motor information to the brainstem to cause movement of the head, neck, and face.

For an article (on my website) that explains the motor cortex more in-depth, click this link: https://neuroscientificallychallenged.com/posts/know-your-brain-motor-cortex

TRANSCRIPT:

Welcome to 2 minute neuroscience, where I simplistically explain neuroscience topics in 2 minutes or less. In this installment I will discuss the motor cortex.

The motor cortex is a region of cortex in the frontal lobe that is involved with voluntary movement. It is located anterior to a large sulcus called the central sulcus and is often divided into two major regions: the primary motor cortex and the nonprimary motor cortex.

The primary motor cortex is found in the strip of cortex known as the precentral gyrus, which is located just anterior to the central sulcus. The primary motor cortex is arranged such that different parts of the region are associated with motor control of different parts of the body and thus is said to contain a motor map of the body.

Most of the neurons that travel from the primary motor cortex carrying signals regarding movement will enter one of two major motor pathways: the corticospinal or corticobulbar tract. The corticospinal tract carries movement-related signals to the spinal cord to cause movement of the body, while the corticobulbar tract carries signals to the brainstem to cause movement of the head, neck, and face.

The nonprimary motor cortex is often divided into two main regions: the supplementary motor cortex and the premotor cortex. Although the functions of these areas are not well understood, it is thought the supplementary motor cortex may be involved with the execution of sequences of movement, the attainment of motor skills, and the selection of movements based on incoming sensory information. The premotor cortex contributes about 30% of the neurons that enter the corticospinal tract, but seems to be more active during the planning of, rather than the execution of, movements.

REFERENCE:

Nolte J. The Human Brain: An Introduction to its Functional Anatomy. 6th ed. Philadelphia, PA. Elsevier; 2009.