Link has been identified between depression and changes in the motor and visual areas

Scientists from the Washington University School of Medicine conducted one of the largest studies in this field. They analyzed over 22,000 brain scans, combining data from six large datasets covering different age groups. The main goal was to use whole‑brain assessment and large data sets to find more robust evidence of changes associated with depression. Each dataset, ranging from 185 to 11,000 participants, was analyzed separately, comparing generalized indicators of brain structure and function with indicators of depression severity and personality risk factors. Then the results from all six datasets were combined to identify common patterns.

As in earlier studies, the researchers confirmed the link between depression and a reduction in gray matter volume in a number of key areas: in the frontal cortex, anterior cingulate cortex, and insular lobe. These areas are involved in regulating emotions, making decisions, forming motivation, and processing internal bodily sensations—that is, in the functions that are directly affected in depressive disorder.

However, the main surprise was the discovery of a link between more pronounced manifestations of depression and a reduction in the size of areas in the motor and visual regions of the brain. According to the study’s senior author, Janine Bysterbosch, this result was unexpected: traditionally, symptoms of depression are associated with emotional regulation and cognitive processes, rather than with the processing of sensory information or the organization of movements. That is precisely why such changes in unusual areas have not previously come into focus.

At the same time, almost no evidence was found of changes in the deep structures of the brain, in particular in the amygdala and hippocampus, which have often been associated with depression in previous studies. This is likely due to the characteristics of the samples used, as they mainly include people with subclinical manifestations or moderate symptoms, rather than patients with severe forms of depression.

The importance of the work lies not only in confirming already known connections but also in expanding our understanding of which brain networks are involved in the development of depressive disorder. The identified changes affect a wide range of areas responsible for various mental functions and indicate that depression is not an isolated disorder of the emotional center but a systemic change in the functioning of many interconnected brain regions.

Experts intend to investigate whether changes in the visual and motor areas can reflect specific symptoms of depression. If this connection is confirmed, it will help to more accurately correlate individual manifestations of the disorder with specific neural mechanisms, and in the long term, it may form the basis for more personalized approaches to diagnosis and treatment.