Brodmann area

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Brodmann area
Brodmann areas 3D.png
3D representation of Brodmann areas
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Part of Cerebrum
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NeuroNames 427
FMA 68596
Anatomical terms of neuroanatomy

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. [1]

Contents

History

Brodmann areas were originally defined and numbered by the German anatomist Korbinian Brodmann based on the cytoarchitectural organization of neurons he observed in the cerebral cortex using the Nissl method of cell staining. Brodmann published his maps of cortical areas in humans, monkeys, and other species in 1909, [2] along with many other findings and observations regarding the general cell types and laminar organization of the mammalian cortex. The same Brodmann area number in different species does not necessarily indicate homologous areas. [3] A similar, but more detailed cortical map was published by Constantin von Economo and Georg N. Koskinas in 1925. [4]

Present importance

Brodmann areas have been discussed, debated, refined, and renamed exhaustively for nearly a century and remain the most widely known and frequently cited cytoarchitectural organization of the human cortex.

Many of the areas Brodmann defined based solely on their neuronal organization have since been correlated closely to diverse cortical functions. For example, Brodmann areas 1, 2 and 3 are the primary somatosensory cortex; area 4 is the primary motor cortex; area 17 is the primary visual cortex; and areas 41 and 42 correspond closely to primary auditory cortex. Higher order functions of the association cortical areas are also consistently localized to the same Brodmann areas by neurophysiological, functional imaging, and other methods (e.g., the consistent localization of Broca's speech and language area to the left Brodmann areas 44 and 45). However, functional imaging can only identify the approximate localization of brain activations in terms of Brodmann areas since their actual boundaries in any individual brain require its histological examination.

Overview

Brodmann's classification of areas of the cortex Vergleichende Lokalisationslehre der Grosshirnrinde in ihren Prinzipien dargestellt auf Grund des Zellenbaues.pdf
Brodmann's classification of areas of the cortex

Different parts of the cerebral cortex are involved in different cognitive and behavioral functions. The differences show up in a number of ways: the effects of localized brain damage, regional activity patterns exposed when the brain is examined using functional imaging techniques, connectivity with subcortical areas, and regional differences in the cellular architecture of the cortex. Neuroscientists describe most of the cortex—the part they call the neocortex—as having six layers, but not all layers are apparent in all areas, and even when a layer is present, its thickness and cellular organization may vary. Scientists have constructed maps of cortical areas on the basis of variations in the appearance of the layers as seen with a microscope. One of the most widely used schemes came from Korbinian Brodmann, who split the cortex into 52 different areas and assigned each a number (many of these Brodmann areas have since been subdivided). For example, Brodmann area 1 is the primary somatosensory cortex, Brodmann area 17 is the primary visual cortex, and Brodmann area 25 is the anterior cingulate cortex. [5]

Topography of the primary motor cortex, showing which zone controls each body part Human motor cortex topography.png
Topography of the primary motor cortex, showing which zone controls each body part

Many of the brain areas defined by Brodmann have their own complex internal structures. In a number of cases, brain areas are organized into topographic maps, where adjoining bits of the cortex correspond to adjoining parts of the body, or of some more abstract entity. A simple example of this type of correspondence is the primary motor cortex, a strip of tissue running along the anterior edge of the central sulcus. Motor areas innervating each part of the body arise from a distinct zone, with neighboring body parts represented by neighboring zones. Electrical stimulation of the cortex at any point causes a muscle-contraction in the represented body part. This "somatotopic" representation is not evenly distributed, however; the head, for example, is represented by a region about three times as large as the zone for the entire back and trunk. The size of any zone correlates to the precision of motor control and sensory discrimination possible. The areas for the lips, fingers, and tongue are particularly large, considering the proportional size of their represented body parts.

The maps for visual areas are retinotopic, meaning that they reflect the topography of the retina: the layer of light-activated neurons lining the back of the eye. In this case too, the representation is uneven: the fovea—the area at the center of the visual field—is greatly overrepresented compared to the periphery. The visual circuitry in the human cerebral cortex contains several dozen distinct retinotopic maps, each devoted to analyzing the visual input stream in a particular way. The primary visual cortex (Brodmann area 17), which is the main recipient of direct input from the visual part of the thalamus, contains many neurons that are most easily activated by edges with a particular orientation moving across a particular point in the visual field. Visual areas farther downstream extract features such as color, motion, and shape.

In auditory areas, the primary map is tonotopic. Sounds are parsed according to frequency (i.e., high pitch vs. low pitch) by subcortical auditory areas, and this parsing is reflected by the primary auditory zone of the cortex. As with the visual system, there are a number of tonotopic cortical maps, each devoted to analyzing sound in a particular way.

Within a topographic map there can sometimes be finer levels of spatial structure. In the primary visual cortex, for example, where the main organization is retinotopic and the main responses are to moving edges, cells that respond to different edge-orientations are spatially segregated from one another.

For humans and other primates

(*) Area only found in non-human primates.

Some of the original Brodmann areas have been subdivided further, e.g., "23a" and "23b". [7]

Clickable map: lateral surface

Note: the lateral view, or side view, of the brain is denoted the 'lateral surface'
Image mapped Brodmann Areas. Clicking on an area in the picture causes the browser to load the appropriate article. Gray726-Brodman.pngAreas 3, 1 & 2 – Primary Somatosensory CortexArea 4 – Primary Motor CortexArea 5 – Somatosensory Association CortexArea 6 – Premotor cortex and Supplementary Motor Cortex (Secondary Motor Cortex)(Supplementary motor areaArea 7 – Somatosensory Association CortexArea 8 – Includes Frontal eye fieldsArea 9 – Dorsolateral prefrontal cortexArea 10 – Anterior prefrontal cortexArea 11 – Orbitofrontal areaArea 17 – Primary visual cortex (V1)Area 18 – Secondary visual cortex (V2)Area 19 – Associative visual cortex (V3)Area 20 – Inferior temporal gyrusArea 21 – Middle temporal gyrusArea 22 – Superior temporal gyrusArea 37 – Fusiform gyrusArea 38 – PULAArea 39 – Angular gyrusArea 40 – Supramarginal gyrusArea 41 – Primary and Auditory Association CortexArea 42 – Primary and Auditory Association CortexArea 43 – Primary gustatory cortexArea 44 – pars opercularis, part of Broca's areaArea 45 – pars triangularis, Broca's areaArea 46 – Dorsolateral prefrontal cortexArea 47 – Inferior prefrontal gyrusImage Map
Image mapped Brodmann Areas. Clicking on an area in the picture causes the browser to load the appropriate article.

Clickable map: medial surface

Note: the view of the section between the right and left hemispheres of the brain is denoted the 'medial surface'
Image mapped Brodmann Areas. Clicking on an area in the picture causes the browser to load the appropriate article. Gray727-Brodman.pngAreas 3, 1 & 2 – Primary Somatosensory Cortexarea 4 – primary motor cortexArea 5 – Somatosensory Association CortexArea 6 – Premotor cortex and Supplementary Motor Cortex (Secondary Motor Cortex)(Supplementary motor areaArea 7 – Somatosensory Association CortexArea 8 – Includes Frontal eye fieldsArea 9 – Dorsolateral prefrontal cortexArea 10 – Anterior prefrontal cortexArea 11 – Orbitofrontal areaArea 12 – Orbitofrontal areaArea 17 – Primary visual cortex (V1)Area 18 – Secondary visual cortex (V2)Area 19 – Associative visual cortex (V3)Area 19 – Associative visual cortex (V3)Area 18 – Secondary visual cortex (V2)Area 23 – Ventral Posterior cingulate cortexArea 24 – Ventral Anterior cingulate cortexArea 25 – Subgenual cortex (part of the Ventromedial prefrontal cortex)Area 26 – Ectosplenial portion of the retrosplenial region of the cerebral cortexArea 27 – Piriform cortexArea 28 – Posterior Entorhinal CortexArea 29 – Retrosplenial cingulate cortexArea 30 – Part of cingulate cortexArea 31 – Dorsal Posterior cingulate cortexArea 32 – Dorsal anterior cingulate cortexArea 33 – Part of anterior cingulate cortexArea 34 – Anterior Entorhinal Cortex (on the Parahippocampal gyrus)Area 35 – Perirhinal cortex (on the Parahippocampal gyrus)Area 20 – Inferior temporal gyrusArea 37 – Fusiform gyrusArea 38 – Temporopolar areaImage Map
Image mapped Brodmann Areas. Clicking on an area in the picture causes the browser to load the appropriate article.

Criticism

When von Bonin and Bailey constructed a brain map for the macaque monkey, they found the description of Brodmann inadequate and wrote: "Brodmann (1907), it is true, prepared a map of the human brain which has been widely reproduced, but, unfortunately, the data on which it was based was never published" [8] They instead used the cytoarchitectonic scheme of Constantin von Economo and Georg N. Koskinas published in 1925 [4] which had the "only acceptable detailed description of the human cortex".

See also

Related Research Articles

<span class="mw-page-title-main">Cerebral cortex</span> Outer layer of the cerebrum of the mammalian brain

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. It is the largest site of neural integration in the central nervous system, and plays a key role in attention, perception, awareness, thought, memory, language, and consciousness. The cerebral cortex is the part of the brain responsible for cognition.

<span class="mw-page-title-main">Cingulate cortex</span> Part of the limbic lobe of the brain cortex

The cingulate cortex is a part of the brain situated in the medial aspect of the cerebral cortex. The cingulate cortex includes the entire cingulate gyrus, which lies immediately above the corpus callosum, and the continuation of this in the cingulate sulcus. The cingulate cortex is usually considered part of the limbic lobe.

<span class="mw-page-title-main">Brodmann area 23</span>

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.

<span class="mw-page-title-main">Precuneus</span> Region of the parietal lobe of the brain

In neuroanatomy, the precuneus is the portion of the superior parietal lobule on the medial surface of each brain hemisphere. It is located in front of the cuneus. The precuneus is bounded in front by the marginal branch of the cingulate sulcus, at the rear by the parieto-occipital sulcus, and underneath by the subparietal sulcus. It is involved with episodic memory, visuospatial processing, reflections upon self, and aspects of consciousness.

<span class="mw-page-title-main">Frontal lobe</span> Part of the brain

The frontal lobe is the largest of the four major lobes of the brain in mammals, and is located at the front of each cerebral hemisphere. It is parted from the parietal lobe by a groove between tissues called the central sulcus and from the temporal lobe by a deeper groove called the lateral sulcus. The most anterior rounded part of the frontal lobe is known as the frontal pole, one of the three poles of the cerebrum.

The primary sensory areas are the primary cortical regions of the five sensory systems in the brain. Except for the olfactory system, they receive sensory information from thalamic nerve projections. The term primary comes from the fact that these cortical areas are the first level in a hierarchy of sensory information processing in the brain. This should not be confused with the function of the primary motor cortex, which is the last site in the cortex for processing motor commands.

<span class="mw-page-title-main">Brodmann area 6</span>

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.

<span class="mw-page-title-main">Brodmann area 10</span> Brain area

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.

<span class="mw-page-title-main">Brodmann area 44</span> Brain area

Brodmann area 44, or BA44, is part of the frontal cortex in the human brain. Situated just anterior to premotor cortex (BA6) and on the lateral surface, inferior to BA9.

<span class="mw-page-title-main">Brodmann area 11</span> Brain area

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.

<span class="mw-page-title-main">Inferior frontal gyrus</span> Part of the brains prefrontal cortex

The inferior frontal gyrus is the lowest positioned gyrus of the frontal gyri, of the frontal lobe, and is part of the prefrontal cortex.

<span class="mw-page-title-main">Brodmann areas 41 and 42</span> Parts of the primary auditory cortex

Brodmann areas 41 and 42 are parts of the primary auditory cortex.

<span class="mw-page-title-main">Transverse temporal gyrus</span> Gyrus of the primary auditory cortex of the brain

The transverse temporal gyrus, also called Heschl's gyrus or Heschl's convolutions, is a gyrus found in the area of each primary auditory cortex buried within the lateral sulcus of the human brain, occupying Brodmann areas 41 and 42. Transverse temporal gyri are superior to and separated from the planum temporale by Heschl's sulcus. Transverse temporal gyri are found in varying numbers in both the right and left hemispheres of the brain and one study found that this number is not related to the hemisphere or dominance of hemisphere studied in subjects. Transverse temporal gyri can be viewed in the sagittal plane as either an omega shape or a heart shape.

<span class="mw-page-title-main">Gyrus</span> Ridge on the cerebral cortex of the brain

In neuroanatomy, a gyrus is a ridge on the cerebral cortex. It is generally surrounded by one or more sulci. Gyri and sulci create the folded appearance of the brain in humans and other mammals.

<span class="mw-page-title-main">Lobes of the brain</span> Parts of the cerebrum

The lobes of the brain are the four major identifiable regions of the human cerebral cortex, and they comprise the surface of each hemisphere of the cerebrum. The two hemispheres are roughly symmetrical in structure, and are connected by the corpus callosum. Some sources include the insula and limbic lobe but the limbic lobe incorporates parts of the other lobes. The lobes are large areas that are anatomically distinguishable, and are also functionally distinct. Each lobe of the brain has numerous ridges, or gyri, and furrows, sulci that constitute further subzones of the cortex. The expression "lobes of the brain" usually refers only to those of the cerebrum, not to the distinct areas of the cerebellum.

<span class="mw-page-title-main">Brodmann area 32</span> Brain area

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).

<span class="mw-page-title-main">Brodmann area 43</span> Brain area

Brodmann area 43, the subcentral area, is a structurally distinct area of the cerebral cortex defined on the basis of cytoarchitecture. Along with Brodmann Area 1, 2, and 3, Brodmann area 43 is a subdivision of the postcentral region of the brain, suggesting a somatosensory function. The histological structure of Area 43 was initially described by Korbinian Brodmann, but it was not labeled on his map of cortical areas.

<span class="mw-page-title-main">Superior longitudinal fasciculus</span> Association fiber tract of the brain

The superior longitudinal fasciculus (SLF) is an association tract in the brain that is composed of three separate components. It is present in both hemispheres and can be found lateral to the centrum semiovale and connects the frontal, occipital, parietal, and temporal lobes. This bundle of tracts (fasciculus) passes from the frontal lobe through the operculum to the posterior end of the lateral sulcus where they either radiate to and synapse on neurons in the occipital lobe, or turn downward and forward around the putamen and then radiate to and synapse on neurons in anterior portions of the temporal lobe.

Nonprimary motor cortex is a functionally defined portion of the frontal lobe. It includes two subdivisions, the premotor cortex and the supplementary motor cortex. Largely coincident with the cytoarchitecturally defined area 6 of Brodmann (human), it is located primarily in the rostral portion of the precentral gyrus and caudal portions of the superior frontal gyrus and the middle frontal gyrus, It aids in cerebral control of movement. Anatomically speaking, several nonprimary areas exist, and make direct connections with the spinal cord.

References

  1. ↑ Creative Commons by small.svg  This article incorporates text available under the CC BY 4.0 license.Betts, J Gordon; Desaix, Peter; Johnson, Eddie; Johnson, Jody E; Korol, Oksana; Kruse, Dean; Poe, Brandon; Wise, James; Womble, Mark D; Young, Kelly A (May 14, 2023). Anatomy & Physiology. Houston: OpenStax CNX. 16.2 Mental status exam. ISBN   978-1-947172-04-3.
  2. ↑ Brodmann K (1909). Vergleichende Lokalisationslehre der Grosshirnrinde (in German). Leipzig: Johann Ambrosius Barth.[ page needed ]
  3. ↑ Garey LJ. (2006). Brodmann's Localisation in the Cerebral Cortex. New York: Springer. ISBN   978-0387-26917-7.[ page needed ]
  4. 1 2 Economo, C.; Koskinas, G.N. (1925). Die Cytoarchitektonik der Hirnrinde des erwachsenen Menschen (in German). Wien & Berlin: Springer. LCCN   31025948. OCLC   14723058.[ page needed ]
  5. ↑ Principles of Anatomy and Physiology 12th Edition - Tortora, Page 519-fig. (14.15)
  6. ↑ Fales CL, Barch DM, Rundle MM, Mintun MA, Snyder AZ, Cohen JD, Mathews J, Sheline YI (February 2008). "Altered emotional interference processing in affective and cognitive-control brain circuitry in major depression". Biol. Psychiatry. 63 (4): 377–84. doi:10.1016/j.biopsych.2007.06.012. PMC   2268639 . PMID   17719567.
  7. ↑ Brent A. Vogt; Deepak N. Pandya; Douglas L. Rosene (August 1987). "Cingulate Cortex of the Rhesus Monkey: I. Cytoarchitecture and Thalamic Afferents". The Journal of Comparative Neurology. 262 (2): 256–270. doi:10.1002/cne.902620207. PMID   3624554. S2CID   6099000.
  8. ↑ Gerhardt von Bonin & Percival Bailey (1925). "The Neocortex of Macaca Mulatta". Journal of Anatomy. 82 (Pt 4). Urbana, Illinois: The University of Illinois Press: 271. PMC   1273070 .
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