Cingulate cortex
Encyclopedia
The cingulate cortex is a part of the brain
Brain
The brain is the center of the nervous system in all vertebrate and most invertebrate animals—only a few primitive invertebrates such as sponges, jellyfish, sea squirts and starfishes do not have one. It is located in the head, usually close to primary sensory apparatus such as vision, hearing,...

 situated in the medial aspect of the cortex
Cerebral cortex
The cerebral cortex is a sheet of neural tissue that is outermost to the cerebrum of the mammalian brain. It plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness. It is constituted of up to six horizontal layers, each of which has a different...

. It includes the cortex of the 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
Limbic lobe
The limbic lobe is an arc-shaped region of cortex on the medial surface of each cerebral hemisphere of the mammalian brain, consisting of parts of the frontal, parietal and temporal lobes...

, separate from the adjacent frontal
Frontal lobe
The frontal lobe is an area in the brain of humans and other mammals, located at the front of each cerebral hemisphere and positioned anterior to the parietal lobe and superior and anterior to the temporal lobes...

 and parietal
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...

 lobes.

It receives inputs from the thalamus
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

 and the neocortex
Neocortex
The neocortex , also called the neopallium and isocortex , is a part of the brain of mammals. It is the outer layer of the cerebral hemispheres, and made up of six layers, labelled I to VI...

, and projects to the entorhinal cortex
Entorhinal cortex
The entorhinal cortex is located in the medial temporal lobe and functions as a hub in a widespread network for memory and navigation. The EC is the main interface between the hippocampus and neocortex...

 via the cingulum. It is an integral part of the limbic system
Limbic system
The limbic system is a set of brain structures including the hippocampus, amygdala, anterior thalamic nuclei, septum, limbic cortex and fornix, which seemingly support a variety of functions including emotion, behavior, long term memory, and olfaction. The term "limbic" comes from the Latin...

, which is involved with emotion formation and processing, learning, and memory, and is also important for executive function and respiratory control.

History

Cingulum means belt in Latin. The name was likely chosen because this cortex, in great part, surrounds the corpus callosum
Corpus callosum
The corpus callosum , also known as the colossal commissure, is a wide, flat bundle of neural fibers beneath the cortex in the eutherian brain at the longitudinal fissure. It connects the left and right cerebral hemispheres and facilitates interhemispheric communication...

. Cingulate is an adjective (cingularis or cingulatus).
The cingulate cortex is a part of the "grand lobe limbique" of Broca (1898)
Paul Broca
Pierre Paul Broca was a French physician, surgeon, anatomist, and anthropologist. He was born in Sainte-Foy-la-Grande, Gironde. He is best known for his research on Broca's area, a region of the frontal lobe that has been named after him. Broca’s Area is responsible for articulated language...

 that consisted (in addition to the olfactory part, which is no more considered there today) of a superior cingulate part, supracallosal; and an inferior hippocampic part, infracallosal. The limbic lobe
Limbic lobe
The limbic lobe is an arc-shaped region of cortex on the medial surface of each cerebral hemisphere of the mammalian brain, consisting of parts of the frontal, parietal and temporal lobes...

 was separated from the remainder of the cortex by Broca for two reasons: first that it is not convoluted, and second that the gyri are directed parasagittally (contrary to the transverse gyrification). Since the parasagittal gyrification is observed in non-primate species, the limbic lobe was thus declared to be "bestial". As with other parts of the cortex, there have been and continue to be discrepancies concerning boundaries and naming. Brodmann (1909)
Korbinian Brodmann
Korbinian Brodmann was a German neurologist who became famous for his definition of the cerebral cortex into 52 distinct regions from their cytoarchitectonic characteristics.-Life:...

, a student of Cécile Vogt-Mugnier
Cécile Vogt-Mugnier
Cecile Vogt-Mugnier was a French neurologist from Haute-Savoie.-Family:She obtained her medical doctorate in Paris and was the student of Pierre Marie. There she met her future husband, Oskar Vogt, when he came to Paris to work with Joseph Jules Déjérine...

 and Oskar Vogt
Oskar Vogt
Oskar Vogt was a German physician and neurologist. He was born in Husum - Schleswig-Holstein...

, who worked on cercopithecus (and not much in human (Bailey and von Bonin)), elaborated a system of numeration that had unfortunately no typological logics (1, 2 and 3 are sensory, 4 is motor, 5 is parietal, 6 is premotor and 7 is again parietal!). Area 25 was even not placed by him in the same place in the human brain. Area 24 (anterior) was distinguished from 23 (posterior) on the basis that it was agranular. More recently, the typographical von Economo's system was adopted by Bailey and von Bonin. Simple typographical naming should be preferred, for evident heuristic purposes.

Subdivisions

Based on cerebral cytoarchitectonics
Cytoarchitectonics of the cerebral cortex
The cytoarchitectonics of the cerebral cortex is the study of neuronal cell bodies cytoarchitecture in the cerebral cortex of the brain.-History:...

 it has been divided into the 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:...

s 23
Brodmann area 23
Brodmann area 23 is a region in the brain corresponding to some portion of 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.-Human:This area is also...

, 24
Brodmann area 24
-Human:In the human this area is known as ventral anterior cingulate area 24, and it refers to a subdivision of the cytoarchitecturally defined cingulate cortex region of cerebral cortex . It occupies most of the anterior cingulate gyrus in an arc around the genu of corpus callosum. Its outer...

, 26
Brodmann area 26
-Human:In the human this area is called ectosplenial area 26. It is a cytoarchitecturally defined portion of the retrosplenial region of the cerebral cortex. It is a narrow band located in the isthmus of cingulate gyrus adjacent to the fasciolar gyrus internally...

, 29
Brodmann area 29
Brodmann area 29, also known as granular retrolimbic area 29, is a cytoarchitecturally defined portion of the retrosplenial region of the cerebral cortex. In the human it is a narrow band located in the isthmus of cingulate gyrus. Cytoarchitecturally it is bounded internally by the ectosplenial...

, 30
Brodmann area 30
Brodmann area 30, also known as agranular retrolimbic area 30, is a subdivision of the cytoarchitecturally defined retrosplenial region of the cerebral cortex. In the human it is located in the isthmus of cingulate gyrus...

, 31
Brodmann area 31
Brodmann area 31, also known as dorsal posterior cingulate area 31, is a subdivision of the cytoarchitecturally defined cingulate region of the cerebral cortex. In the human it occupies portions of the posterior cingulate gyrus and medial aspect of the parietal lobe. Approximate boundaries are the...

 and 32
Brodmann area 32
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 region of cerebral cortex. In the human it forms an outer arc around the anterior cingulate gyrus...

. The areas 26
Brodmann area 26
-Human:In the human this area is called ectosplenial area 26. It is a cytoarchitecturally defined portion of the retrosplenial region of the cerebral cortex. It is a narrow band located in the isthmus of cingulate gyrus adjacent to the fasciolar gyrus internally...

, 29
Brodmann area 29
Brodmann area 29, also known as granular retrolimbic area 29, is a cytoarchitecturally defined portion of the retrosplenial region of the cerebral cortex. In the human it is a narrow band located in the isthmus of cingulate gyrus. Cytoarchitecturally it is bounded internally by the ectosplenial...

 and 30
Brodmann area 30
Brodmann area 30, also known as agranular retrolimbic area 30, is a subdivision of the cytoarchitecturally defined retrosplenial region of the cerebral cortex. In the human it is located in the isthmus of cingulate gyrus...

 are usually referred to as the retrosplenial areas.

Anterior cingulate cortex

This corresponds to area 24 of Brodmann and LA of Constantin von Economo
Constantin von Economo
Constantin Freiherr von Economo was a Romanian psychiatrist and neurologist of Greek origin. He is mostly known for his discovery of encephalitis lethargica and his atlas of cytoarchitectonics.- Youth and schooling :Constantin Freiherr Economo von San Serff was born in Brăila, Romania, to Greek...

 and Bailey and von Bonin.
It is continued anteriorly by the subgenual cortex (area 25).
It is cytoarchitectonically agranular.
It has a gyral part on the surface and a sulcal part.
Anterior cingulate cortex
Anterior cingulate cortex
The anterior cingulate cortex is the frontal part of the cingulate cortex, that resembles a "collar" form around the corpus callosum, the fibrous bundle that relays neural signals between the right and left cerebral hemispheres of the brain...

 can further be divided in the perigenual anterior cingulate cortex and midcingulate cortex. The anterior cingulate cortex receives primarily its afferent axons from the intralaminar and midline thalamic nuclei (intralaminar and midline of the thalamus, see thalamus
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

).
The nucleus anterior receives mamillo-thalamic afferences. The mamillary neurons receive axons from the subiculum
Subiculum
The subiculum is the most inferior component of the hippocampal formation. It lies between the entorhinal cortex and the CA1 subfield of the hippocampus proper.-Paths:...

.
The whole forms a part of Papez' circuit
Papez circuit
Described by James Papez in 1937, the Papez circuit of the brain is one of the major pathways of the limbic system and is chiefly involved in the cortical control of emotion. The Papez circuit plays a role in storing memory....

.
The anterior cingulate cortex sends axons to the anterior nucleus and through the cingulum to other Broca's limbic areas.
The ACC is involved in error and conflict detection processes, such as in the go/no-go task.

Posterior cingulate cortex

This corresponds to area 23 of Brodmann LP of von Economo and Bailey and von Bonin. Its cellular structure is granular. It is followed posteriorly by the retrosplenial cortex (area 29).
Dorsally is the granular area 31. The posterior cingulate cortex receives a great part of its afferent axons from the superficial nucleus (or nucleus superior- falsely LD-) of the thalamus (see thalamus
Thalamus
The thalamus is a midline paired symmetrical structure within the brains of vertebrates, including humans. It is situated between the cerebral cortex and midbrain, both in terms of location and neurological connections...

), which itself receives axons from the subiculum. To some extent it thus duplicates Papez' circuit. It receives also direct afferents from the subiculum of the hippocampus.

Inputs of the Anterior Cingulate Gyrus

A retrograde tracing experiment on macaque monkeys revealed that ventral anterior (VA) and ventral lateral (VL) nuclei of the thalamus are connected with motor areas of cingulate sulcus (McFarland and Haber, 2000).
Retrosplenial region (Brodmann’s area 26, 29 and 30) part of cingulate gyrus can be divided into three parts retrosplenial granular cortex A, the retrosplenial granular cortex B and the retrosplenial dysgranular cortex. The hippocampal formation sends dense projections to the retrosplenial granular cortex A and B and fewer projections to the retrosplenial dysgranular cortex. Postsubiculum sends projections to the retrosplenial granular cortex A and B and to the retrosplenial dysgranular cortex. Dorsal subiculum sends projections to the retrosplenial granular cortex B, while ventral subiculum sends projections to the retrosplenial granular cortex A. Etnorhinal cortex – caudal parts – sends projections to the retrosplenial dysgranular cortex (Wyss & Groen, 1999).

Outputs of the Anterior Cingulate Gyrus

Rostral cingulate gyrus (Brodmanns’s area 32) projects to rostral superior temporal gyrus, midorbitofrontal cortex and lateral prefrontal cortex (Pandya, Van Hoesen & Mesulam, 1981).
Ventral anterior cingulate (Brodmann’s area 24) sends projections to the anterior insular cortex, premotor cortex (Brodmann’s area 6), Brodmann’s area 8, the perirhinal area, the orbitofrontal cortex (Brodmann’s area 12), the laterobasal nucleus of amygdala, and the rostral part of the inferior parietal lobule (Pandya, Van Hoesen & Mesulam, 1981). Injecting wheat germ agglutinin
Wheat germ agglutinin
Wheat germ agglutinin or WGA is a lectin that protects wheat from insects, yeast and bacteria. An agglutinin protein, it binds to N-acetyl-D-glucosamine and Sialic acid. N-acetyl-D-glucosamine in the natural environment of wheat is found in the chitin of insects, and the cell membrane of yeast &...

 and horseradish peroxidase
Horseradish peroxidase
The enzyme horseradish peroxidase , found in horseradish, is used extensively in biochemistry applications primarily for its ability to amplify a weak signal and increase detectability of a target molecule.-Applications:...

 conjugate into anterior cingulate gyrus of cats, revealed that anterior cingulate gyrus has reciprocal connections with rostral part of the thalamic posterior lateral nucleus and rostral end of the pulvinar (Fuji, 1983).
Postsubiculum receives projections from the retrospleinal dysgranular cortex and the retrosplenial granular cortex A and B. Parasubiculum receives projections from the retrosplenial dysgranular cortex and retrosplenial granular cortex A. Caudal and lateral parts of the entorhinal cortex get projections from the retrosplenial dysgranular cortex, while caudal medial entorhinal cortex receives projections from the retrosplenial granular cortex A. The retrosplenial dysgranular cortex sends projections to the perirhinal cortex. The retrospleinal granular cortex A sends projection to the rostral presubiculum (Wyss & Groen, 1999).

Outputs of the Posterior Cingulate Gyrus

The posterior cingulate cortex (Brodmann’s area 23) sends projections to dorsolateral prefrontal cortex (Brodmann’s area 9), anterior prefrontal cortex (Brodmann’s area 10), orbitofrontal cortex (Brodmanns’ area 11), the parahippocampal gyrus, posterior part of the inferior parietal lobule, the presubiculum, the superior temporal sulcus and the retrosplenial region (Pandya, Van Hoesen & Mesulam, 1981).
The retrosplenial cortex and caudal part of the cingulate cortex are connected with rostral prefrontal cortex via cingulate fascicule in macaque monkeys (Petrides and Pandya, 2007). Ventral posterior cingulate cortex was found to be reciprocally connected with the caudal part of the posterior parietal lobe in rhesus monkeys (Cavada and Goldman-Raiuc, 1989). Also the medial posterior parietal cortex is connected with posterior ventral bank of the cingulate sulcus (Cavada and Goldman-Raiuc, 1989).

Other Connections

The anterior cingulate is connected to the posterior cingulate at least in rabbits. Posterior cingulate gyrus is connected with retrosplenial cortex and this connection is part of the dorsal splenium of the corpus callosum. The anterior and posterior cingulate gyrus and retrosplenial cortex send projections to subiculum and presubiculum (Adey, 1951).

Cingulate Gyrus and Schizophrenia

Using a three-dimensional magnetic resonance imaging procedure to measure the volume of the rostral anterior cingulate gyrus (perigenual cingulate gyrus) Takahashi et. all (2003) found that the rostral anterior cingulate gyrus is larger in control – healthy – females than males, but this sex difference was not found in schizophrenic patients. Schizophrenic patients also had a smaller volume of perigenual cingulate gyrus than control subjects.
Haznedar et. all (2004) studied metabolic rate of glucose in anterior and posterior cingulate gyrus in patients with schizophrenia, schizotypal personality disorder (SPD) and compared them with a control group. The metabolic rate of glucose was found to be lower in the left anterior cingulate gyrus and the right posterior cingulate gyrus in patients with schizophrenia relative to controls. Although SPD patients were expected to show a glucose metabolic rate somewhere between the schizophrenic and controls, they actually had higher metabolic glucose rate in the left posterior cingulate gyrus ( Haznedar et all, 2004). The volume of the left anteriror cingulate gyrus was reduced in schizophrenic patients as compared with controls, but there was not any difference between SPD patients and schizophrenic patients. From these results it appears that the schizophrenia and SPD are two different disorders.
A study of the volume of the gray and white matter in the anterior cingulate gyrus in patients with schizophrenia and their healthy first and second degree relatives revealed no significant difference in the volume of the white matter in the schizophrenic patients and their healthy relatives (Costain et. all, 2010). Nonethless a significant difference in the volume of gray matter was detected, schizophrenic patients had smaller volume of gray matter than their second degree relatives, but not relative to their first degree relatives. Both schizophrenic and their first degree healthy relatives have smaller gray matter volume than the second degree healthy relatives. It appears that genes are responsible for the decreased volume of gray matter in schizophrenic patients (Costain et. all, 2010).
Fujiwara et. all (2007) did an experiment in which they correlated the size of anterior cingulate gyrus in schizophrenic patients with their functioning on social cognition, psychopathology and emotions with control group. The smaller the size of anterior cingulate gyrus, the lower was the level of social functioning and the higher was the psychopathology in schizophrenic patient. The anterior cingulate gyrus was found to be bilaterally smaller in patients with schizophrenia as compared with control group. No difference in IQ tests and basic visuoperceptual ability with facial stimuli was found between schizophrenia patients and the control.

Summary

Schizophrenic patients have differences in the anterior cingulate gyrus when compared with controls. Anterior cingulate gyrus was found to be smaller in schizophrenic patients (Fujiwara et. all, 2007). The volume of the white and gray matter in the anterior cingulate gyrus was found to be lower in schizophrenic patients (Haznedar et. all 2004). Healthy females have larger rostral anterior cingulate gyrus than males, this sex difference in size is absent in schizophrenic patients (Takahashi et. all, 2003). Metabolic rate of glucose was lower in the left anterior cingulate gyrus and in the right posterior cingulate gyrus (Haznedar et. all, 2004).
In addition to changes in the cingulate cortex more brain structures show changes in schizophrenic patients as compared to controls. The hippocampus in schizophrenic patients was found to decrease in size when compared with controls of the same age group (Koolschijn et. all, 2010). The caudate and putamen was found to decrease in volume in a longitudinal study of schizophrenic patients (Mitelman et. all, 2009). While the volume of gray matter decreases, the size of the ventricles increases in schizophrenic patients, both lateral ventricles and third ventricle (Kempton et. all, 2010).

External links

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