Biochemical disorders at the cellular level also lead to changes in the electrical activity of the brain.
It was found that patients with the so-called “melancholy depression” have electrophysiological signs of an increased tone of the parasympathetic system. Outwardly, this manifests itself in dilated pupils, decreased activity of the cardiovascular system, narrowing of the bronchi, increased intestinal activity, the appearance of red spots on the skin and watery sweat. According to many scientists, depression of this type is associated with the predominance of the activity of systems that are sensitive to serotonin.
But in patients with anxious depression, electrophysiological studies reveal the opposite picture, namely, an increase in the tone of the sympathetic part of the autonomic system. Moreover, this type of depression is associated with a lack of both serotonin (to a greater extent) and norepinephrine.
The electrical activity of the brain is studied using the method of electroencephalography , which at one time made it possible to discover special rhythms in the work of the brain both during wakefulness and sleep. In depression, specific changes in these rhythms are revealed. A mismatch in bioelectric activity is characteristic of a decreased mood with signs of irritability, anxiety and melancholy.
Depression often occurs when there are disorders in certain areas of the cerebral hemispheres. Thus, the “dreary depression” with sleep disorders observed in lesions of the temporal lobe of the right hemisphere and “anxious depression” with the reduction or disappearance of Dreamers Nij – with the defeat of the left hemisphere. In general , with depression, sleep time is reduced, while its latent (“preparatory”) phase increases. Note that the study of the structure of sleep is now considered the most accurate method for diagnosing depression. The internal structure of sleep and its phases also change (the third and fourth phases of sleep are reduced ). Observed with depression and disturbances in the interaction of the cerebral hemispheres.