Answer
The postcentral gyrus is a fold of the cerebral cortex that is situated caudal the central sulcus . It forms forward border of the parietal lobe and comprises the primary somatosensory cortex. It is in a position adjacent to the somatosensory association cortex which is in the roof of the lateral sulcus , caudal to the postcentral gyrus.
The cortex of the postcentral gyrus is the primary somatosensory cortex; this lies adjacent to the somatosensory association cortex The primary somatosensory cortex functions to make us aware of stimuli. The function o the somatosensory association cortex is to convert perception ito knowledge.
Work Step by Step
Because of decussation of ascending and descending sensory fibers to the contralateral thalamus, the right postcentral gyrus receives input from the left side of the body, and the left postcentral gyrus receives input from the right side of the body.
Honuculus;
This is the name given the cortical representations of the parts of the body in the cerebral cortex. The sensory homunculus is formed by projections of sensory neurons that carry sensory stimuli from various parts of the body:
Receptors in the lower limbs project to the superior and medial parts of the postcentral gyrus. But receptors from the face project to the inferior and lateral parts of the gyrus. The parts of the body are not represented in proportion to size in the somatotopy. This is so because the amount of cerebral tissue devoted to a body area depends on the degree of innervation and sensitivity of an area. Thus hands and faces get disproportionately large representation compared with the trunk which has fewer receptors, and is less sensitive.
