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. Brodmann areas were 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 and other species in 1909, 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 indicate homologous areas. A similar, but more detailed cortical map was published by Constantin von Economo and Georg N. Koskinas in 1925. Brodmann areas have been discussed, debated and renamed exhaustively for nearly a century and remain the most known and cited cytoarchitectural organization of the human cortex. Many of the areas Brodmann defined based on their neuronal organization have since been correlated to diverse cortical functions.
For example, Brodmann areas 3, 1 and 2 are the primary somatosensory cortex. Higher order functions of the association cortical areas are consistently localized to the same Brodmann areas by neurophysiological, functional imaging, other methods. 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 requires its histological examination. 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, 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, 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 used schemes came from Korbinian Brodmann, who split the cortex into 52 different areas and assigned each a number. For example, Brodmann area 1 is the primary somatosensory cortex, Brodmann area 17 is the primary visual cortex, Brodmann area 25 is the anterior cingulate cortex. Many of those 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 and tongue are large, considering the proportional size of their represented body parts. In visual areas, the maps are retinotopic. In this case too, the representation is uneven: the fovea—the area at the center of the visual field—is 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, the main recipient of direct input from the visual part of the thalamus, contains many neurons that are most 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 and shape.
In auditory areas, the primary map is tonotopic. Sounds are parsed according to frequency by subcortical auditory areas, 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. Areas 3, 1 and 2 – Primary somatosensory cortex in the postcentral gyrus Area 4– Primary motor cortex Area 5 – Superior parietal lobule Area 6 – Premotor cortex and Supplementary Motor Cortex Area 7 – Visuo-Motor Coordination Area 8 – Includes Frontal eye fields
The indusium griseum, consists of a thin membranous layer of grey matter in contact with the upper surface of the corpus callosum and continuous laterally with the grey matter of the cingulate cortex. On either side of the midline of the induseum griseum are two ridges formed by bands of longitudinally directed fibres known as the medial and lateral longitudinal striae; the indium griseum is prolonged around the splenium of the corpus callosum as a delicate layer, the fasciolar gyrus, continuous below with the surface of the dentate gyrus. Toward the genu of the corpus callosum it curves down along the rostrum to form the subcallosal gyrus; this article incorporates text in the public domain from page 827 of the 20th edition of Gray's Anatomy Atlas image: n1a5p10 at the University of Michigan Health System
Brodmann area 11
Brodmann area 11 is one of Brodmann's cytologically defined regions of the brain. It is in the orbitofrontal cortex, above the eye sockets, it is involved in decision making and processing rewards, encoding new information into long-term memory, reasoning. Brodmann area 11, or BA11, is part of the frontal cortex in the human brain. BA11 is the part of the orbitofrontal cortex that covers the medial portion of the ventral surface of the frontal lobe. Prefrontal area 11 of Brodmann-1909 is a subdivision of the frontal lobe in the human defined on the basis of cytoarchitecture. Defined and illustrated in Brodmann-1909, it included the areas subsequently illustrated in Brodmann-10 as prefrontal area 11 and rostral area 12. Area 11 is a subdivision of the cytoarchitecturally defined frontal region of cerebral cortex of the human; as illustrated in Brodmann-10, It constitutes most of the orbital gyri, gyrus rectus and the most rostral portion of the superior frontal gyrus. It is bounded medially by the inferior rostral sulcus and laterally by the frontomarginal sulcus.
Cytoarchitecturally it is bounded on the rostral and lateral aspects of the hemisphere by the frontopolar area 10, the orbital area 47, the triangular area 45. In an earlier map, the area labeled i.e. prefrontal area 11 of Brodmann-1909, was larger. Brodmann area 11 is a subdivision of the frontal lobe of the guenon monkey defined on the basis of cytoarchitecture. Distinctive features: area 11 lacks an internal granular layer. Brodmann area List of regions in the human brain For Neuroanatomy of this area in guenon see BrainInfo For Neuroanatomy of this area in human see BrainInfo
Brodmann area 5
Brodmann area 5 is one of Brodmann's cytoarchitectural defined regions of the brain. It is involved in somatosensory association. Brodmann area 5 is a subdivision of part of the cortex in the human brain. BA5 is the superior parietal part of the postcentral gyrus, it is situated posterior to the primary somatosensory cortex. It is bounded cytoarchitecturally by Brodmann area 2, Brodmann area 7, Brodmann area 4, Brodmann area 31. In guenon Brodmann area 5 is a subdivision of the parietal lobe defined on the basis of cytoarchitecture, it occupies the superior parietal lobule. Brodmann-1909 considered it topologically and cytoarchitecturally homologous to the preparietal area 5 of the human. Distinctive features: compared to area 4 of Brodmann-1909 area 5 has a thick self-contained internal granular layer. In the macaque monkey the area PE corresponds to BA5. Brodmann area List of regions in the human brain Visit BrainInfo for Neuroanatomy of this area Brodmann area 5 in the Brede Database at the Technical University of Denmark
Anterior cingulate cortex
The anterior cingulate cortex is the frontal part of the cingulate cortex that resembles a "collar" surrounding the frontal part of the corpus callosum. It consists of Brodmann areas 24, 32, 33, it appears to play a role in a wide variety of autonomic functions, such as regulating blood pressure and heart rate. It is involved in certain higher-level functions, such as attention allocation, reward anticipation, decision-making and morality, impulse control, emotion; the anterior cingulate cortex can be divided anatomically based on cognitive, emotional components. The dorsal part of the ACC is connected with the prefrontal cortex and parietal cortex, as well as the motor system and the frontal eye fields, making it a central station for processing top-down and bottom-up stimuli and assigning appropriate control to other areas in the brain. By contrast, the ventral part of the ACC is connected with the amygdala, nucleus accumbens, hypothalamus and anterior insula, is involved in assessing the salience of emotion and motivational information.
The ACC seems to be involved when effort is needed to carry out a task, such as in early learning and problem-solving. On a cellular level, the ACC is unique in its abundance of specialized neurons called spindle cells, or von Economo neurons; these cells are a recent occurrence in evolutionary terms and contribute to this brain region's emphasis on addressing difficult problems, as well as the pathologies related to the ACC. A typical task that activates the ACC involves eliciting some form of conflict within the participant that can result in an error. One such task is called the Eriksen flanker task and consists of an arrow pointing to the left or right, flanked by two distractor arrows creating either compatible or incompatible trials. Another common conflict-inducing stimulus that activates the ACC is the Stroop task, which involves naming the color ink of words that are either congruent or incongruent. Conflict occurs because people’s reading abilities interfere with their attempt to name the word’s ink color.
A variation of this task is the Counting-Stroop, during which people count either neutral stimuli or interfering stimuli by pressing a button. Another version of the Stroop task named the Emotional Counting Stroop is identical to the Counting Stroop test, except that it uses segmented or repeated emotional words such as "murder" during the interference part of the task. Many studies attribute specific functions such as error detection, anticipation of tasks, attention and modulation of emotional responses to the ACC; the most basic form of ACC theory states that the ACC is involved with error detection. Evidence has been derived from studies involving a Stroop task. However, ACC is active during correct response, this has been shown using a letter task, whereby participants had to respond to the letter X after an A was presented and ignore all other letter combinations with some letters more competitive than others, they found that for more competitive stimuli ACC activation was greater. A similar theory poses that the ACC’s primary function is the monitoring of conflict.
In Eriksen flanker task, incompatible trials produce the most conflict and the most activation by the ACC. Upon detection of a conflict, the ACC provides cues to other areas in the brain to cope with the conflicting control systems. Evidence from electrical studiesEvidence for ACC as having an error detection function comes from observations of error-related negativity uniquely generated within the ACC upon error occurrences. A distinction has been made between an ERP following incorrect responses and a signal after subjects receive feedback after erroneous responses. No-one has demonstrated that the ERN comes from the ACC, but patients with lateral PFC damage do show reduced ERNs. Reinforcement learning ERN theory poses that there is a mismatch between actual response execution and appropriate response execution, which results in an ERN discharge. Furthermore, this theory predicts that, when the ACC receives conflicting input from control areas in the brain, it determines and allocates which area should be given control over the motor system.
Varying levels of dopamine are believed to influence the optimization of this filter system by providing expectations about the outcomes of an event. The ERN serves as a beacon to highlight the violation of an expectation. Research on the occurrence of the feedback ERN shows evidence that this potential has larger amplitudes when violations of expectancy are large. In other words, if an event is not to happen, the feedback ERN will be larger if no error is detected. Other studies have examined whether the ERN is elicited by varying the cost of an error and the evaluation of a response. In these trials, feedback is given about whether the participant has gained or lost money after a response. Amplitudes of ERN responses with small gains and small losses were similar. No ERN was elicited for any losses as opposed to an ERN for no wins though both outcomes are the same; the finding in this paradigm suggests that monitoring for wins and losses is based on the relative expected gains and losses. If you get a different outcome than expected, the ERN will be larger than for expected outcomes.
ERN studies have localized specific functions of the ACC. The rostral ACC seems to be active after an error commission, indicating an error response function, whereas the dorsal ACC is active after bot
Brodmann area 32
The Brodmann area 32 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 its inner boundary and the superior rostral sulcus its ventral boundary. 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, prefrontal area 11-1909.. The dorsal region of the anterior cingulate gyrus is associated with rational thought processes, most notably active during the Stroop task. In the guenon, Brodmann area 32 is a subdivision of the cytoarchitecturally defined cingulate region of cerebral cortex; this area was named 25 in Brodmann-1905 and labeled 25 in a figure contributed by Brodmann in Mauss-1908. In Brodmann-1909, the area was labeled 32 and the name "area 25" was attached to the area that has since been the accepted area 25 of Brodmann-1909.
Distinguishing features according to Brodmann-1905: in contrast with area 6 of Brodmann-1909 the cortex of area 32 is thick. Brodmann-1909 regarded area 32 as topologically, but not cytoarchitecturally, homologous to the human dorsal anterior cingulate area 32. Brodmann area See BrainInfo for Brodmann area 32 3D representation
Brodmann area 13
Brodmann area 13 is a subdivision of the cerebral cortex as defined on the guenon monkey and on the basis of cytoarchitecture. Brodmann area 13 is found in humans as part of the insula; this structure lies between the medial layers of the brain. Thus it is sometimes misidentified as not being a Brodmann area. Located in the anterior part of the insular cortex, Brodmann area 13 shares with other parts of the insular cortex a wide molecular layer and wide multiform layer; the external granular layer is dense. The external lamina pyramidalis externa has a central stripe of less cellular density that separates two sublayers, IIIa and IIIb; the internal granular layer is sufficiently wide and dense to separate sublayer IIIb from layer V. The boundary between layers V and VI is defined by larger ganglion cells, more pyramidal in shape, in layer V giving way to smaller, more spindle-shaped cells that become denser and more homogeneous deeper in layer VI; the spindle cells are arrayed horizontally as in the claustrum, which Brodmann considered a extension of layer VI beyond the extreme capsule.
Brodmann areas List of regions in the human brain BrainInfo - Brodmann Area 13 Brodmannarea.info