Areas of motor cortex: the primary motor cortex, the premotor cortex and the supplementary motor area, their localization.functions. Motor homunculus.

The motor cortex is a region of the cerebral cortex involved in the planning, control, and execution of voluntary movements. It is located in the frontal lobe of the brain, just anterior to the central sulcus. The motor cortex is divided into several areas, each with its own specific functions:1. Primary motor cortex (M1): This is the most anterior part of the motor cortex and is responsible for generating neural impulses that control the execution of movement. It is organized in a somatotopic manner, with different regions of the primary motor cortex corresponding to different parts of the body. This organization is known as the motor homunculus. The primary motor cortex sends signals to the muscles of the body, causing them to contract and produce movement.2. Premotor cortex: This area is located anterior to the primary motor cortex and is involved in the planning and preparation of movement. It helps to coordinate and integrate sensory information with motor commands, allowing for smooth and coordinated movements. The premotor cortex is also involved in the learning of new motor skills and the adaptation of existing ones.3. Supplementary motor area: This area is located medial to the primary motor cortex and is involved in the planning and coordination of complex movements, such as those requiring bilateral coordination or those that involve sequencing of multiple actions. It is also involved in the control of posture and bilateral coordination of movements.The motor homunculus is a visual representation of the body within the primary motor cortex. It shows the relative size of different body parts in terms of their motor control. For example, the fingers and face are represented as larger than other body parts, reflecting the greater degree of motor control required for these areas. The motor homunculus is used to understand the organization of the motor cortex and how different body parts are controlled by different regions of the motor cortex.