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Circumvolution of the cingulum: structure and functions

Circumvolution of the cingulum: structure and functions

The cingulum gyrus It is found in the limbic system. Specifically, it extends over the corpus callosum forming a large arch. It lies deep in the longitudinal fissure and separates from the frontal and parietal cortices on the cingulate groove.

The first studies on the brain divided the circumvolution of the cingulate or cingulate gyrus into two parts, anterior and posterior. Currently, scientists opt for a four-party division.

Circumvolution of the cingulum: structure and functions

As we have said, it is divided into four parts, namely:

Anterior cingulate cortex (CCA)

It consists of the cortex of the cingulate gyrus that is anterior and inferior to the anterior end of the corpus callosum. The CCA receives the entrance of the thalamic nuclei and has connection with the medial and lateral prefrontal cortex.

It stands out compared to the rest of the structure by the massive entrance from the amygdala. It is affected by major depression, since "filters" and controls the relationship between the emotional limbic system and the autonomous parts of the nervous system, being in connection, in turn, with the basal ganglia and the prefrontal cortex.

Another characteristic of the CEC is its role in attentional control, as well as in short and long term memory and in decision making. The anterior cingulate cortex is divided into a pregenual region (CCAp) and a subgenual region (CCAs)

Limbic system

Pregenual anterior cingulate cortex (CCAp)

The pregenual anterior cingulate cortex (CCAp) is found in the anterior part of the corpus callosum. Participates in emotional sensations and is responsible for storing memories of this class.

It is activated by self-generated emotions and is important in the recovery of fear memories. It is also activated during decision-making based on rewards and is very sensitive to pleasure.

Subgenual anterior cingulate cortex (CCAs)

This part is located under the knee of the corpus callosum and is recognized as an autonomous control center. Responds to one's own and others' emotions and determines the autonomous expressions of emotion.

It has projections with the amygdala, parabrachial nucleus and periacueductal gray matter, which send signals for autonomous tone expression. At the same time, projections to the solitary nucleus, the dorsal nucleus of the vagus and the spinal cord provide a route for the direct control of emotion expression.

Mediocingulate cortex (CMC)

It is found in the middle third of the gyrus gyrus. As with the pregenual anterior cingulate cortex, receive the entrance of the tonsil and record emotional sensations. However, instead of having a connection with the autonomous centers, sends projections to the motor areas of the motor cortex, forgive the redundancy.

Anterior mediocingulate cortex (CMCa)

The most previous part participates in the detection of errors (conflict monitoring). That is to say, detects conflicts in information processing and points out the incidence of other areas where motor responses are possibly given.

Posterior mediocingulate cortex (CMCp)

This part of the structure contains two motor areas. It is important in the planning of skeletal motor reactions to emotional sensations.

In summary, CMC intervenes in certain motor behaviors, such as paying attention to a specific external stimulus. Specifically, it is involved in what is called the orientation reflex, which implies the orientation movement of the head and eyes towards said stimulus, while focusing all attention on it (even for a few moments).

The same role plays in the orientation response inhibition, when we want to focus attention on a specific task. CMC is very involved in obsessive-compulsive disorder.

Posterior cingulate cortex (CCP)

It is the back of the gyrus gyrus. It consists of:

  • Dorsal posterior cingulate cortex
  • Ventral posterior cingulate cortex
  • Retrospinal cortex

These three structures form what is called the "posterior cingulate area".

The CCP receives connections from the anterior thalamic nucleus and the frontal, occipital and posterior parietal cortices, as well as from the hippocampal formation. Both the CCP and the retrospinal cortex have connections with the superior temporal gyrus, so they most likely have a important function for the spatial location of surrounding sounds.

Incredibly, scientists have demonstrated a strong activation of this structure during the successful recovery of memories caused by the facilitation of names of friends or family (Maddock et al. 2001). Dysfunction of this specific area may be related to Alzheimer's disease.

Dysfunctions of the gyrus gyrus

Previously, we have briefly examined both the structure and some of the functions of the cingulate gyrus. However, What can happen when this structure is immersed in a pathological or degenerative process?

The researchers point out that the dysfunctions of the gyrus gyrus, could carry the following pathologies:

  • Disorders in pain perception
  • Problems in social interaction
  • Social inhibition or inability to recognize emotions
  • Schizophrenia
  • Depression and bipolar disorder
  • Obsessive-compulsive disorder
  • Posttraumatic Stress Disorder
  • Tourette syndrome
  • Kinetic mutism

References

  • Bouckoms, A.J. (1994). Limbic surgery for pain. In: P.D. Wall, and R. Melzack (eds.). Textbook of Pain. Edinburgh: Churchill Livingstone.
  • Jenike, M.A. (1992). Obsessional disorders. Psychiatric Clinics of North America (vol. 15). Philadelphia: Elsevier.
  • Maddock, R.J., Garrett, A.S., and Buonocore, M.H. (2001). Remembering familiar people: The posterior cingulate cortex and autobiographical memory retrieval. Neuroscience 104:667-676.
  • Rodgers, J.E. (1992). Psychosurgery: Damaging the Brain to Save the Mind. New York: Harper Collins.
  • Vogt, B.A. (2009). Cingulate Neurobiology and Disease. New York: Oxford University Press.