Most people handle stress well, but some find it difficult to cope and as a result develop depression and other mood disorders. Researchers have previously been able to identify the part of the brain that controls this response, but not exactly how it does so. Now, a study in mice identifies a small group of neurons that could be responsible.
How an animal deals with stress is controlled by a part of the brain known as the prefrontal cortex, and the neurons in this part of the brain are known to change in structure and function in response to stressful situations. To look at the cellular basis of the responses, neuroscientist Bo Li of Cold Spring Harbor Laboratory in New York and his colleagues subjected mice to small electric shocks at random intervals to produce stress. Most of the mice tried to avoid the shocks, but just over one-fifth did not. They also started to avoid other animals or failed to choose tasty foods over plain ones — typical signs of depressive behavior.
The researchers then looked at the animals' brains and found that a specific set of neurons in the prefrontal cortex were easily excitable in depressed mice, but much harder to excite in those resilient to the stress. Furthermore, artificially increasing the activity of these neurons caused mice that were once resilient to become susceptible to depressive behaviors. "We were surprised that we were able to see a difference between depressed and resilient animals at the level of synaptic transmission," says Li.
Category(s):Depression
Source material from Scientific American
