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Primary motor cortex is defined anatomically as the region of cortex that contains large neurons known as Betz cells, which, along with other cortical neurons, send long axons down the spinal cord to synapse onto the interneuron circuitry of the spinal cord and also directly onto the alpha motor neurons in the spinal cord which connect to the ...
The motor cortex is the region of the cerebral cortex involved in the planning, control, and execution of voluntary movements.The motor cortex is an area of the frontal lobe located in the posterior precentral gyrus immediately anterior to the central sulcus.
For example, Brodmann areas 1, 2 and 3 are the primary somatosensory cortex; area 4 is the primary motor cortex; area 17 is the primary visual cortex; and areas 41 and 42 correspond closely to primary auditory cortex.
The right half of the motor area controls the left side of the body, and vice versa. Two areas of the cortex are commonly referred to as motor: Primary motor cortex, which executes voluntary movements [69] Supplementary motor areas and premotor cortex, which select voluntary movements. [70] In addition, motor functions have been described for:
There is a precise somatotopic representation of the different body parts in the primary motor cortex, with the leg area located medially (close to the midline), and the head and face area located laterally on the convex side of the cerebral hemisphere (cortical homunculus). The arm and hand motor area is the largest and occupies the part of ...
That is, the legs and trunk fold over the midline; the arms and hands are along the middle of the area shown here; and the face is near the bottom of the figure. Because Brodmann area 4 is in the same general location as primary motor cortex, the homunculus here is called the motor homunculus.
The corticospinal tract is a white matter motor pathway starting at the cerebral cortex that terminates on lower motor neurons and interneurons in the spinal cord, controlling movements of the limbs and trunk. [1] There are more than one million neurons in the corticospinal tract, and they become myelinated usually in the first two years of life.
Fibres arise from the primary motor cortex (about 30%), supplementary motor area and the premotor cortex (together also about 30%), and the somatosensory cortex, parietal lobe, and cingulate gyrus supplies the rest. [2] The cells have their bodies in the cerebral cortex, and the axons form the bulk of the pyramidal tracts. [4]