The primary motor cortex, located in the frontal lobe of the brain, is primarily responsible for initiating voluntary commands to skeletal muscles. This region is situated just anterior to the central sulcus and is organized in a way that corresponds to various body parts, a concept known as the motor homunculus.
When we decide to move, the primary motor cortex sends electrical signals down the spinal cord through upper motor neurons, which then connect to lower motor neurons in the spinal cord that directly innervate the skeletal muscles. This pathway allows us to execute voluntary movements, whether it’s waving a hand or walking across a room.
In addition to the primary motor cortex, other areas like the premotor cortex and supplementary motor area also contribute to planning and coordinating movements, but the initiation point for those voluntary commands starts in the primary motor cortex.