The postcentral gyrus is a prominent structure in the parietal lobe of the human brain and an important landmark. It is almost the same as Brodmann areas 3, 1 and 2.
It is the location of primary somatosensory cortex, the main sensory receptive area for the sense of touch. Like other sensory areas, there is a map of sensory space called a homunculus in this location. For the primary somatosensory cortex, this is called the sensory homunculus. See a somewhat fanciful and highly schematic representation of the sensory homunculus at lower right.
Brodmann Areas 3, 1 and 2
Brodmann areas 3, 1 and 2 of human brain. Brodmann area 3 is in red, area 1 in green, and area 2 in yellow.
Brodmann areas 3, 1 and 2 comprise the primary somatosensorycortex of the human brain. Because Brodmann sliced the brain somewhat obliquely, he encountered area 1 first; however, from rostral to caudal the Brodmann designations are 3, 1 and 2, respectively.
Sensory homunculus of the human brain.
This area of cortex, as shown by Wilder Penfield and others, has the pattern of a homunculus. 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. While it is not well-shown here, the lips and hands are enlarged on a proper homunculus, since a large number of neurons in the cerebral cortex are devoted to processing information from these areas.
Because Brodmann sliced the brain somewhat obliquely, he encountered area1 first; however, from rostral to caudal the Brodmann designations are 3, 1 and 2, respectively.
Brodmannsareas3, 2,1 (on the postcentral gyrus) is the primary somatosensorycortex; area 17 (cuneus and lingual gyri) receives visual input; area 41 (transverse temporal gyrus) is for auditory sense.
Areas 5 and 7 are secondary to somatosensoryareas 3,2,1; areas 18 and 19 are secondary to visual area 17; areas 42 and 22 are secondary to auditory area 41; area 28 is secondary to olfactory area 34.
Parietal areas 39 and 40, i.e., the angular and supramarginal gyri, lie at the junction of the parietal, occipital, and temporal lobes and integrate tactile-kinesthetic, visual, and auditory association areas at the highest level.
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