The area of the brain within which depression most commonly occurs has been identified as the lateral orbitofrontal cortex. This is the region of the brain that regulates non-reward.
It would seem, from the analysis, that this area of the brain is efficient at processing actions that produce ‘reward’ (which translates as feeling ‘good’). The same region of the brain regulates the sense of self and personal worth. If this region of the brain fails to signal a reward, the reverse happens and instead feelings of loss and sadness are manifest. In more extreme cases this leads to longer-term feelings of low self-esteem that the symptoms of depression.
It also transpires that those who experience clinical depression have reduced connectivity in the reward brain area (the medial orbitofrontal region) when this region interacts with the parts of the brain that store memories. It is thought this interactions explains why depressed patients from struggle to recall happier times, which also reinforces the depression and causes it to last for an extended period of time.
The finding has been made by researchers based at the University of Warwick, in the U.K., and China’s Fudan University. For the study the researchers examined 1000 subjects in China. The subjects agreed to undergo magnetic resonance imaging scans.
The scans focused on the medial and lateral oribitofrontal cortex of the brain. When information was overlaid about the subjects and their mental health, variances in activity in these brain areas correlated with depression.
It is hoped the findings will lead to explorations of new treatments for patients. Speaking with Laboratory Roots, one of the lead researchers, Professor Jianfeng Feng explained: “Our finding, with the combination of big data we collected around the world and our novel methods, enables us to locate the roots of depression which should open up new avenues for better therapeutic treatments in the near future for this horrible disease.”
The findings are published in the journal Brain. The research is titled “Medial reward and lateral non-reward orbitofrontal cortex circuits change in opposite directions in depression”.
