Postcentral gyrus Edit
The lateral postcentral gyrus is bounded by:
- medial longitudinal fissure medially (to the middle)
- central sulcus rostrally (in front)
- postcentral sulcus caudally (in back)
- lateral sulcus inferiorly (underneath)
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 Edit
Brodmann areas 3, 1 and 2 comprise the primary somatosensory cortex 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.
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.
These areas contain cells that project to the secondary somatosensory cortex.
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|Telencephalon (cerebrum, cerebral cortex, cerebral hemispheres) - edit|
frontal lobe: precentral gyrus (primary motor cortex, 4), precentral sulcus, superior frontal gyrus (6, 8), middle frontal gyrus (46), inferior frontal gyrus (Broca's area, 44-pars opercularis, 45-pars triangularis), prefrontal cortex (orbitofrontal cortex, 9, 10, 11, 12, 47)
temporal lobe: transverse temporal gyrus (41-42-primary auditory cortex), superior temporal gyrus (38, 22-Wernicke's area), middle temporal gyrus (21), inferior temporal gyrus (20), fusiform gyrus (36, 37)
limbic lobe/fornicate gyrus: cingulate cortex/cingulate gyrus, anterior cingulate (24, 32, 33), posterior cingulate (23, 31),
Some categorizations are approximations, and some Brodmann areas span gyri.