| Brodmann area 8 | |
|---|---|
 Image of brain with Brodmann area 8 shown in red | |
 Image of brain with Brodmann area 8 shown in orange | |
| Details | |
| Identifiers | |
| Latin | area frontalis intermedia |
| NeuroNames | 1034 |
| NeuroLex ID | birnlex_1739 |
| FMA | 68605 |
| Anatomical terms of neuroanatomy | |
Brodmann area 8 is one of Brodmann's cytologically defined regions of the brain. It is involved in planning complex movements.[ citation needed ]
Brodmann area 8, or BA8, is part of the frontal cortex in the human brain. Situated just anterior to the premotor cortex (BA6), it includes the frontal eye fields (so-named because they are believed to play an important role in the control of eye movements). Damage to this area, by stroke, trauma or infection, causes tonic deviation of the eyes towards the side of the injury. This finding occurs during the first few hours of an acute event such as cerebrovascular infarct (stroke) or hemorrhage (bleeding).
The term Brodmann area 8 refers to a cytoarchitecturally defined portion of the frontal lobe of the guenon. Located rostral to the arcuate sulcus, it was not considered by Brodmann-1909 to be topographically homologous to the intermediate frontal area 8 of the human.
Distinctive features (Brodmann-1905): compared to Brodmann area 6-1909, area 8 has a diffuse but clearly present internal granular layer (IV); sublayer 3b of the external pyramidal layer (III) has densely distributed medium-sized pyramidal cells; the internal pyramidal layer (V) has larger ganglion cells densely distributed with some granule cells interspersed; the external granular layer (II) is denser and broader; cell layers are more distinct; the abundance of cells is somewhat greater. [1]
The area is involved in eye movements and possibly in the management of uncertainty. A functional magnetic resonance imaging study demonstrated that Brodmann area 8 activation occurs when test subjects experience uncertainty, and that with increasing uncertainty there is increasing activation. [2]
An alternative interpretation is that this activation in the frontal cortex encodes hope, a higher-order expectation positively correlated with uncertainty. [3]
The cerebral cortex, also known as the cerebral mantle, is the outer layer of neural tissue of the cerebrum of the brain in humans and other mammals. The cerebral cortex mostly consists of the six-layered neocortex, with just 10% consisting of the allocortex. It is separated into two cortices, by the longitudinal fissure that divides the cerebrum into the left and right cerebral hemispheres. The two hemispheres are joined beneath the cortex by the corpus callosum. The cerebral cortex is the largest site of neural integration in the central nervous system. It plays a key role in attention, perception, awareness, thought, memory, language, and consciousness. The cerebral cortex is part of the brain responsible for cognition.
A Brodmann area is a region of the cerebral cortex, in the human or other primate brain, defined by its cytoarchitecture, or histological structure and organization of cells. The concept was first introduced by the German anatomist Korbinian Brodmann in the early 20th century. Brodmann mapped the human brain based on the varied cellular structure across the cortex and identified 52 distinct regions, which he numbered 1 to 52. These regions, or Brodmann areas, correspond with diverse functions including sensation, motor control, and cognition.
Brodmann area 23 (BA23) is a region in the brain that lies inside the posterior cingulate cortex. It lies between Brodmann area 30 and Brodmann area 31 and is located on the medial wall of the cingulate gyrus between the callosal sulcus and the cingulate sulcus.
Brodmann area 6 (BA6) is part of the frontal cortex in the human brain. Situated just anterior to the primary motor cortex (BA4), it is composed of the premotor cortex and, medially, the supplementary motor area (SMA). This large area of the frontal cortex is believed to play a role in planning complex, coordinated movements.
Brodmann area 9, or BA9, refers to a cytoarchitecturally defined portion of the frontal cortex in the brain of humans and other primates. It contributes to the dorsolateral and medial prefrontal cortex.
Brodmann area 10 is the anterior-most portion of the prefrontal cortex in the human brain. BA10 was originally defined broadly in terms of its cytoarchitectonic traits as they were observed in the brains of cadavers, but because modern functional imaging cannot precisely identify these boundaries, the terms anterior prefrontal cortex, rostral prefrontal cortex and frontopolar prefrontal cortex are used to refer to the area in the most anterior part of the frontal cortex that approximately covers BA10—simply to emphasize the fact that BA10 does not include all parts of the prefrontal cortex.
Brodmann area 5 is one of Brodmann's cytoarchitectural defined regions of the brain. It is involved in somatosensory processing, movement and association, and is part of the posterior parietal cortex.
Brodmann area 19, or BA 19, is part of the occipital lobe cortex in the human brain. Along with area 18, it comprises the extrastriate cortex. In humans with normal sight, extrastriate cortex is a visual association area, with feature-extracting, shape recognition, attentional, and multimodal integrating functions.
Brodmann area 20, or BA20, is part of the temporal cortex in the human brain. The region encompasses most of the ventral temporal cortex, a region believed to play a part in high-level visual processing and recognition memory.
Brodmann area 21, or BA21, is part of the temporal cortex in the human brain. The region encompasses most of the lateral temporal cortex and is also known as middle temporal area 21. In the human it corresponds approximately to the middle temporal gyrus.
Brodmann area 11 is one of Brodmann's cytologically defined regions of the brain. It is in the orbitofrontal cortex which is above the eye sockets (orbitae). It is involved in decision making, processing rewards, and encoding new information into long-term memory.
Brodmann area 4 refers to the primary motor cortex of the human brain. It is located in the posterior portion of the frontal lobe.
Brodmann area 24 is part of the anterior cingulate in the human brain.
The Brodmann area 32, also known in the human brain as the dorsal anterior cingulate area 32, refers to a subdivision of the cytoarchitecturally defined cingulate cortex. In the human it forms an outer arc around the anterior cingulate gyrus. The cingulate sulcus defines approximately its inner boundary and the superior rostral sulcus (H) its ventral boundary; rostrally it extends almost to the margin of the frontal lobe. Cytoarchitecturally it is bounded internally by the ventral anterior cingulate area 24, externally by medial margins of the agranular frontal area 6, intermediate frontal area 8, granular frontal area 9, frontopolar area 10, and prefrontal area 11-1909. (Brodmann19-09).
Brodmann Area 14 is one of Brodmann's subdivisions of the cerebral cortex in the brain. It was defined by Brodmann in the guenon monkey . While Brodmann, writing in 1909, argued that no equivalent structure existed in humans, later work demonstrated that area 14 has a clear homologue in the human ventromedial prefrontal cortex.
Brodmann area 12 is a subdivision of the cerebral cortex of the guenon defined on the basis of cytoarchitecture. It occupies the most rostral portion of the frontal lobe. Brodmann-1909 did not regard it as homologous, either topographically or cytoarchitecturally, to rostral area 12 of the human. Distinctive features (Brodmann-1905): a quite distinct internal granular layer (IV) separates slender pyramidal cells of the external pyramidal layer (III) and the internal pyramidal layer (V); the multiform layer (VI) is expanded, contains widely dispersed spindle cells and merges gradually with the underlying cortical white matter; all cells, including the pyramidal cells of the external and internal pyramidal layers are inordinately small; the internal pyramidal layer (V) also contains spindle cells in groups of two to five located close to its border with the internal granular layer (IV).
Brodmann Area 15 is one of Brodmann's subdivisions of the cerebral cortex in the brain.
Brodmann area 28 is a subdivision of the cerebral cortex defined on the basis of cytoarchitecture. It is located on the medial aspect of the temporal lobe and is part of the entorhinal cortex (Brodmann-1909).
The external granular layer of the cerebral cortex is commonly known as layer II. It is different from the internal granular layer of the cerebral cortex.
This article incorporates text available under the CC BY 3.0 license. "BrainInfo". Archived from the original on December 7, 2013. Retrieved December 3, 2013.{{cite web}}: CS1 maint: bot: original URL status unknown (link)