Neuroanatomy of affective disorders

The prefrontal cortex is the anterior part of the frontal lobes of the cerebral cortex. It is conditionally subdivided into dorsal areas responsible for cognitive functions (memory, attention, speech) and ventral areas that regulate decision making, response to external stimuli, social behavior, individuality ( Matsuo K. et al ., 2007; Prado J. with et al ., 2007).

Hypofunction of the dorsal regions, due to which there is a cognitive deficit and hyperfunction of the ventral prefrontal regions, leads to depression. Treatment with antidepressants evens out this imbalance.

Affective disorders are associated with the activity of two large parts of the ventral region – the ventromedial prefrontal cortex and the amygdala, which belong to the limbic system. They are closely related to each other.

Genetic predisposition to post-stress disorders and depression indicates that these two areas are combined into one functional apparatus ( Pezawas L. et al . 2005).

Affective processes depend on the functioning of the amygdala, therefore, if its function is disturbed, perception, expression of emotions, and experience suffer. The amygdala consists of more than twelve subnuclei . With the help of neuroimaging, it was possible to display this area only as a single system. The activity of each of the twelve subnuclei cannot be determined ( Adolphs R., 2003).

The manifestations of the functional activity of the amygdala have been studied. This is induction:

  • a well-founded fear;
  • feelings of fear;
  • learned helplessness;
  • destruction of the “mother-infant bond”.

Disruption of the “maternal-infant connection” at an early age in a child contributes to a decrease in the expression of guanylate cyclase in the lateral and basal sub-nuclei of the amygdala ( Sabatini M., et Al ., 2007).

Disgusting ( aversive ) olfactory and auditory stimuli promote activation of the amygdala and associative-sensory cortex, altering regional blood flow by more than 10%. The degree of change in blood flow in the amygdala depends on the degree of aversive stimulus.

A detailed study of the ventral prefrontal cortex revealed that it consists of the ventromedial prefrontal cortex and the orbitofrontal cortex.

The ventromedial prefrontal cortex is functionally connected with the amygdala and covers the fields according to Brodmann : 24a, 10m, 10r, 10o, 32m, 14r, 14c, 13a, 13b, 11m, 1ai, 47 / 12s, 25.

It also interacts with the hypothalamus, which has a connection with the amygdala, but does not receive direct sensory impulses from it.

The hypothalamus receives processed sensory information from the anterior temporal regions of the brain.

The orbitoprefrontal cortex is associated with the sensory associative cortex.

The ventromedial prefrontal cortex performs the function of comparing information from sensory introreceptors located in the orbitofrontal cortex and separates volitional manifestations from natural reflex activity ( Aupperle R., Paulus M., 2010).

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