Primary motor cortex (M1)

The **primary motor cortex** is a region of the cerebral cortex located in the precentral gyrus of the frontal lobe (Brodmann area 4). It is responsible for executing voluntary movements that are planned by other brain regions. The primary motor cortex contains large neurons called Betz cells, which send long axons down to synapse with spinal cord interneurons and directly onto alpha motor neurons controlling skeletal muscles. Its organization is somatotopic, meaning different areas correspond to control over specific body parts—this arrangement forms a "motor homunculus," with disproportionately large areas devoted to hands and face due to their need for fine control. Each hemisphere's primary motor cortex controls movements on the opposite side of the body[1][4][5][6][7]. **Note:** The primary motor cortex is not a molecular target such as a receptor, enzyme, transporter, or ion channel; it is an anatomical brain region composed of many cell types and circuits. Therefore, it does not fit standard definitions for therapeutic targets at the molecular level (such as those targeted by drugs), making "is_target" false and "is_incorrect" true in this context[1][4].

Other names

Precentral gyrusBrodmann area 4Somatomotor area