Light-emitting medical devices could hold the key to to managing the symptoms of mental illness, according to a study in the Journal of Neuroscience. Researchers at the University of Pennsylvania discovered that neurons correlated with social anxiety could be "turned off" by exposure to a specialized light.

Some neurons in the mammalian brain inhibited the release of serotonin, a neurotransmitter. When a mammal has a serotonin deficiency, this condition may manifest itself through social disorders.

In the study, researchers exposed 54 laboratory mice to an unpleasant social experience. By placing these mice in an apparatus with very aggressive mice, researchers were able to induce anxiety. In response to this environmental condition, mouse neurons correlated with the emission of serotonin were less responsive.

Researchers discovered that GABA neurons were often located next to brain neurons that helped control the release of serotonin. Through optogenetics, a technique that can make neurons in a mammalian brain respond to light waves, researchers were able to inhibit the action of GABA neurons. In turn, this reduced the GABA-correlated inhibition of serotonin.

Once GABA neurons were turned off, mice responded to social threats in a less-anxious way. Extrapolating these results to humans could shed light on depression, anxiety and other debilitating mental illnesses.

"Though exciting to imagine, whether such manipulations will ever be available or practical for use to treat human psychiatric diseases in the future, remains to be seen," noted a researcher.