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Changes to some of the star-shaped brain cells called astrocytes may play a role in depression, a new study finds. The findings are based on the postmortem examination of brains of depressed individuals who committed suicide.
The researchers focused on a part of the brain involved in mood regulation and decision making, called the anterior cingulate cortex. In depressed people, some astrocytes were larger and more branched than those of people with no history of psychiatric illness who died suddenly, the researchers said.
The study adds to a growing body of research linking changes in white matter to depression. It is the first study to "zoom in" and observe changes occurring at a cellular level, said study researcher Naguib Mechawar of McGill University in Quebec. The researchers said they don't know whether these alterations are a cause or effect of depression and can only speculate on how the changes would contribute to the mood disorder. It's likely they would affect communication between the anterior cingulate cortex and other parts of the brain, Mechawar added.
The researchers said the astrocytes may have changed in reaction to a change in their environment – specifically, inflammation in the brain. Chronically high levels of inflammation have been linked to stress and are known to be bad for health. The immune system produces inflammation as a reaction to foreign invaders, but it also can occur independent of infection. Astrocytes are known to swell up when they sense inflammation.