Russian scientists have presented new arguments in favor of the hypothesis that people with depression are more active in neural networks that are responsible for thinking about themselves and their close environment. The study was supported by a grant from the Russian Science Foundation, and its findings were published in the Journal of Affective Disorders .
Depression is one of the most serious and common mental disorders. Despite this, science knows little about the physiological causes of depression, since the condition of patients is very heterogeneous, and disorders affect many mental processes. There is a hypothesis that in depression, a certain part of the brain is extremely active, the so-called network of the passive mode of the brain, which is associated with thoughts about oneself and about loved ones (in a healthy state it is most active when a person is not busy with anything). Scientists from the Research Institute of Physiology and Fundamental Medicine of the Russian Academy of Sciences proposed diagnostics to test this hypothesis and thus provided new evidence.
The activity of the passive mode of the brain in depression means that a person is fixated on his own problems, and sees his situation as hopeless and presents his image in the eyes of others in the most negative colors. At the same time, the connections that are responsible for performing tasks related to the outside world and information processing are weakening. The hypothesis that this region of the brain is associated with depression has previously been confirmed using functional magnetic resonance imaging, measuring the saturation of blood with oxygen in specific areas of the brain. This method does not allow making unambiguous conclusions, since the work of the cardiovascular system significantly affects the saturation of blood with oxygen.
Scientists decided to test the same hypothesis using a second method – electroencephalography. In this case, using the connected electrodes, the electromagnetic activity of different areas of the brain is examined. Scientists recruited two groups of patients: healthy and suffering from clinical depression. The results obtained in each group of patients were then compared with the results of functional magnetic resonance imaging. As a result, the researchers confirmed the increased activity of the network of the passive mode of the brain in patients with depression. Both methods localized the effect of “dominance” in the anterior regions of the left hemisphere, which was previously shown to be associated with the genesis of depression.
The authors of the study hope that the proven hypothesis will soon be applied in clinical practice. The results of the study, according to scientists, will help to better understand how to work with patients with depression. For example, with the help of methods of cognitive-behavioral therapy, they need to be more focused on the outside world.