Brain cells and depression/bipolar disorder

Professor Wayne Drevets explains that specific glial cells known as oligodendrocytes may be decreased in the brains of individuals who have bipolar disorder or major depressive disorder.

The post-mortem studies of depression – these would be studies of people who’ve had depression or bipolar disorder and then have died and then the changes in cells and cell processes are studied – one of the things that they have commonly shown has been that glial cells are decreased. Glial cells don’t get much attention in neurobiology textbooks because neurons get all the press, even though glial cells are about 10 times more common than neurons, but this would be like on a football team where the quarterback gets all the publicity and the linemen are there and important but don’t get any publicity. Glial cells are like the linemen; they have vital roles in brain function. One of the roles that they specifically engage in are supporting a network across brain systems. The type of glial cell that has been most implicated in major depressive disorder and bipolar disorder is called the oligodendrocyte, and that cell does a couple of things. One is that it makes the myelin. Myelin is that sheath that surrounds neurons and then supports the long processes and the connections between brain regions, and the myelin, the basic protein that makes the myelin and the oligodendrocytes themselves have all been shown to be decreased in the brains of individuals who have bipolar disorder or major depressive disorder and then have died. We think that may be one of the biological changes in the brain that interferes with the function of circuits in the brain, and the circuits that would get involved in maintaining the balance between the normal responses to stressful events, to anxiety provoking events, to rewarding stimuli and so forth. We think it’s the network that works across multiple structures that’s affected. It might be the cellular elements that are giving rise to the impaired communication and balance between these different structures.