Scientists home in one part of the brain.
Many of us find ourselves swimming along in the tranquil sea of life when suddenly a crisis hits — a death in the family, the loss of a job, a bad breakup. Some power through and find calm waters again, while others drown in depression.
Scientists continue to search for the underlying genes and neurobiology that dictate our reactions to stress. Now, a study using mice has found a switch-like mechanism between resilience and defeat in an area of the brain that plays an important role in regulating emotions and has been linked with mood and anxiety disorders.
After artificially enhancing the activity of neurons in that part of the brain — the medial prefrontal cortex — mice that previously fought to avoid electric shocks started to act helpless. Rather than leaping for an open escape route, they sat in a corner taking the pain — presumably out of a belief that nothing they could do would change their circumstances.
“This helpless behavior is quite similar to what clinicians see in depressed individuals — an inability to take action to avoid or correct a difficult situation,” said study author and neuroscientist Bo Li of the Cold Spring Harbor Laboratory in New York. The results were published online May 27 in the Journal of Neuroscience.
Because there is no true animal equivalent to the depression that affects humans, researchers instead model certain symptoms of the disorder, such as despair and, in this case, helplessness.
For the rest of the story: http://www.washingtonpost.com/national/health-science/why-are-some-depressed-others-resilient-scientists-home-in-one-part-of-the-brain/2014/06/05/db638498-e83f-11e3-a86b-362fd5443d19_story.html?wprss=rss_national