Postcentral gyrus

Postcentral gyrus

Infobox Brain
Name = Postcentral gyrus
Latin = gyrus postcentralis
GraySubject = 189
GrayPage = 823


Caption = Postcentral gyrus of the human brain.


Caption2 = Brodmann areas 3, 1 and 2 of human brain. Brodmann area 3 is in red, area 1 in green, and area 2 in yellow.
IsPartOf =
Components =
Artery =
Vein =
BrainInfoType = hier
BrainInfoNumber = 87
MeshName =
MeshNumber =
DorlandsPre = g_13
DorlandsSuf = 12405446
The lateral postcentral gyrus is a prominent structure in the parietal lobe of the human brain and an important landmark. It was initially defined from surface stimulation studies of Penfield, and parallel surface potential studies of Bard, Woolsey, and Marshall. Although initially defined to be roughly the same as Brodmann areas 3, 1 and 2, more recent work by Kaas has suggested that for homogeny with other sensory fields only area 3 should be referred to as "primary somatosensory cortex", as it received the bulk of the thalamocortical projection from the sensory input fields.

Postcentral gyrus

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 below.

Brodmann areas 3, 1 and 2

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.

Clinical significance

Lesions affecting the primary somatosensory cortex produce characteristic symptoms including: agraphesthesia, astereognosia, loss of vibration, proprioception and fine touch (because the third-order neuron of the medial-lemniscal pathway cannot synapse in the cortex). It can also produce hemineglect, if it affects the non-dominant hemisphere.

It could also reduce nociception, thermoception and crude touch, but since information from the spinothalamic tract is interpreted mainly by other areas of the brain (see insular cortex and cingulate gyrus), it is not as relevant as the other symptoms.

ee also

* Brodmann area
* List of regions in the human brain


=Additional

External links

* - area 1
* - area 2
* - area 3


Wikimedia Foundation. 2010.

Игры ⚽ Нужна курсовая?

Look at other dictionaries:

  • postcentral gyrus — n a gyrus of the parietal lobe located just posterior to the central sulcus, lying parallel to the precentral gyrus of the temporal lobe, and comprising the somatosensory cortex …   Medical dictionary

  • postcentral gyrus — noun the convolution of parietal lobe that is bounded in front by the central sulcus • Hypernyms: ↑central gyrus • Part Holonyms: ↑parietal lobe, ↑parietal cortex …   Useful english dictionary

  • Gyrus postcentral — Le gyrus postcentral est un gyrus du lobe pariétal du cortex cérébral, limité en avant par le sillon central et en arrière par le sillon postcentral. C est un ruban vertical qui suit les sinuosités de la scissure de Rolando (ou sillon central),… …   Wikipédia en Français

  • Gyrus — A gyrus (pl. gyri ) is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci.Notable gyri* Fornicate gyrus * Superior frontal gyrus, lat . gyrus frontalis superior * Middle frontal gyrus, lat . gyrus frontalis medius *… …   Wikipedia

  • Postcentral sulcus — Infobox Brain Name = PAGENAME Latin = sulcus postcentralis GraySubject = 189 GrayPage = 822 Caption = Postcentral sulcus of the human brain. Caption2 = Lateral surface of left cerebral hemisphere, viewed from the side. IsPartOf = Components =… …   Wikipedia

  • postcentral — (ˈ) ̷ ̷+ adjective Etymology: post + central : located behind a center or central structure; especially : located behind the central sulcus of the cerebral cortex the postcentral gyrus the postcentral sulcus * * * adj. * * * postcentral centrally …   Useful english dictionary

  • postcentral — Referring to the cerebral convolution forming the posterior bank of the central sulcus : the p. gyrus. * * * post·cen·tral pōst sen trəl adj located behind a center or central structure esp located behind the central sulcus of the cerebral cortex …   Medical dictionary

  • gyrus postcentralis — [TA] postcentral gyrus: the convolution of the parietal lobe lying between the central and postcentral sulci; the primary sensory area of the cerebral cortex for the face, upper extremity, trunk, and hip. Called also posterior central g. and… …   Medical dictionary

  • gyrus paracentralis posterior — [TA] posterior paracentral gyrus: the posterior portion of the paracentral lobule, medial to and continuous with the postcentral gyrus; it is the primary somatosensory cortex for the lower extremities and genitalia …   Medical dictionary

  • postcentral sulcus of cerebrum — sulcus postcentralis cerebri [TA] a sulcus on the superolateral surface of the cerebrum, separating the postcentral gyrus from the remainder of the parietal lobe …   Medical dictionary

Share the article and excerpts

Direct link
Do a right-click on the link above
and select “Copy Link”