Brain Circuitry Trouble May Explain Depression

Mar. 23 -- THURSDAY, July 5 (HealthDay News) -- Depression may be triggered by changes within a single circuit in a part of the brain known as the hippocampus, a new U.S. study suggests.

Researchers at Stanford University School of Medicine used a new brain imaging technique called voltage-sensitive dye imaging to observe the effects of antidepressant medications on slices of rats' brains in real-time. Fluorescent dye in the brain tissues lights up in response to electrical activity. The changing patterns of light and dark can be captured on camera.

The tissues were from the hippocampus, which is thought to play a role in depression.

When the Stanford team examined the activity in the hippocampus tissues -- with and without antidepressants -- they found that in depressed rats certain electrical signals spread more slowly or not at all. Human antidepressants corrected the lack of activity, they noted.

The results were published July 5 in Science Express, the online edition of the journal Science.

"I think this will help us make sense of how there can be so many different causes and treatments of depression," senior author Dr. Karl Deisseroth, assistant professor of bioengineering and of psychiatry and behavioral sciences at the Stanford University School of Medicine, said in a prepared statement. "You can use that common pathway as the most efficient, most direct targeted way to find truly specific treatments."

The researchers also found that the growth of new neurons in the hippocampus tissues reduced the effects of depression, although it was not true that fewer neurons increased depression risk.

More information

To learn about depression, visit the U.S. National Institute of Mental Health.

SOURCE: Stanford University, news release, July 5, 2007