Parietal operculum
Encyclopedia
The parietal operculum is the portion of the parietal lobe
on the outside surface of the brain bordering the lateral sulcus
, and the extension of this cortex which forms the posterior ceiling of the lateral sulcus. It contains the secondary somatosensory cortex
(region S2).
40
and 43
.
Areas PV and S2 both map the body surface. Functional neuroimaging
in humans has revealed that in areas PV and S2 the face is represented nearest the entrance to the lateral sulcus, and the hands and feet deeper in the fissure, nearer the border with VS. Individual neurons in areas PV and S2 receive input from wide areas of the body surface (they have large "receptive field
s"), and respond readily to stimuli such as wiping a sponge over a large area of skin.
Areas S2 in the left and right hemispheres
are densely interconnected, and stimulation on one side of the body will activate area S2 in both hemispheres. Area S2 is interconnected with Brodmann area
(BA) 1, and densely so with BA 3b, and projects to PV, BA 7b
, insular cortex
, amygdala
and hippocampus
. PV connects densely with BA 5
and the premotor cortex
.
Parietal lobe
The parietal lobe is a part of the Brain positioned above the occipital lobe and behind the frontal lobe.The parietal lobe integrates sensory information from different modalities, particularly determining spatial sense and navigation. For example, it comprises somatosensory cortex and the...
on the outside surface of the brain bordering the lateral sulcus
Lateral sulcus
-External links:* * * http://www.uams.edu/radiology/education/residency/diagnostic/pdf/sylvian_cistern_RSNA2003.pdf...
, and the extension of this cortex which forms the posterior ceiling of the lateral sulcus. It contains the secondary somatosensory cortex
Secondary somatosensory cortex
The human secondary somatosensory cortex is a region of cerebral cortex lying mostly on the parietal operculum.Region S2 was first described by Adrian in 1940, who found that feeling in cats' feet was not only represented in the previously described primary somatosensory cortex but also in a...
(region S2).
Secondary somatosensory cortex
In monkeys, apes and hominids region S2 is divided into several "areas". In humans, the area adjoining the primary somatosensory cortex (S1) is called the parietal ventral area (PV). Adjacent to PV, but towards the posterior of the parietal operculum, is area S2 - which must not be confused with region S2 (which designates the entire secondary somatosensory cortex, of which area S2 is a part). Deeper in the lateral sulcus, bordering areas PV and S2, lies the ventral somatosensory area (VS). In humans, the parietal operculum includes parts of Brodmann areasBrodmann area
A Brodmann area is a region of the cerebral cortex defined based on its cytoarchitectonics, or structure and organization of cells.-History:...
40
Brodmann area 40
Brodmann area 40, or BA40, is part of the parietal cortex in the human brain. The inferior part of BA40 is in the area of the supramarginal gyrus, which lies at the posterior end of the lateral fissure, in the inferior lateral part of the parietal lobe....
and 43
Brodmann area 43
Brodmann area 43 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It was described on the map of cortical areas in Brodmann-1909, and it was regarded as cytoarchitecturally homologous to area 30 of Mauss in 1908 in the guenon and subcentral area 43 of...
.
Areas PV and S2 both map the body surface. Functional neuroimaging
Functional neuroimaging
Functional neuroimaging is the use of neuroimaging technology to measure an aspect of brain function, often with a view to understanding the relationship between activity in certain brain areas and specific mental functions...
in humans has revealed that in areas PV and S2 the face is represented nearest the entrance to the lateral sulcus, and the hands and feet deeper in the fissure, nearer the border with VS. Individual neurons in areas PV and S2 receive input from wide areas of the body surface (they have large "receptive field
Receptive field
The receptive field of a sensory neuron is a region of space in which the presence of a stimulus will alter the firing of that neuron. Receptive fields have been identified for neurons of the auditory system, the somatosensory system, and the visual system....
s"), and respond readily to stimuli such as wiping a sponge over a large area of skin.
Areas S2 in the left and right hemispheres
Cerebral hemisphere
A cerebral hemisphere is one of the two regions of the eutherian brain that are delineated by the median plane, . The brain can thus be described as being divided into left and right cerebral hemispheres. Each of these hemispheres has an outer layer of grey matter called the cerebral cortex that is...
are densely interconnected, and stimulation on one side of the body will activate area S2 in both hemispheres. Area S2 is interconnected with Brodmann area
Brodmann area
A Brodmann area is a region of the cerebral cortex defined based on its cytoarchitectonics, or structure and organization of cells.-History:...
(BA) 1, and densely so with BA 3b, and projects to PV, BA 7b
Brodmann area 7
Brodmann area 7 is one of Brodmann's cytologically defined regions of the brain. It is involved in locating objects in space. It serves as a point of convergence between vision and proprioception to determine where objects are in relation to parts of the body....
, insular cortex
Insular cortex
In each hemisphere of the mammalian brain the insular cortex is a portion of the cerebral cortex folded deep within the lateral sulcus between the temporal lobe and the frontal lobe. The cortical area overlying it towards the lateral surface of the brain is the operculum...
, amygdala
Amygdala
The ' are almond-shaped groups of nuclei located deep within the medial temporal lobes of the brain in complex vertebrates, including humans. Shown in research to perform a primary role in the processing and memory of emotional reactions, the amygdalae are considered part of the limbic system.-...
and hippocampus
Hippocampus
The hippocampus is a major component of the brains of humans and other vertebrates. It belongs to the limbic system and plays important roles in the consolidation of information from short-term memory to long-term memory and spatial navigation. Humans and other mammals have two hippocampi, one in...
. PV connects densely with BA 5
Brodmann area 5
Brodmann area 5 is one of Brodmann's cytologically defined regions of the brain. It is involved in somatosensory processing and association.-Human:Brodmann area 5 is part of the parietal cortex in the human brain...
and the premotor cortex
Premotor cortex
The premotor cortex is an area of motor cortex lying within the frontal lobe of the brain. It extends 3 mm anterior to the primary motor cortex, near the Sylvian fissure, before narrowing to approximately 1 mm near the medial longitudinal fissure, which serves as the posterior border for...
.