Brains show physical reaction to the stress of depression

By Staff Writer

Researchers studying stressed-out mice have tracked physical changes in the brain that are caused by mental states like threat and depression.

The discovery shows that social stress can increase inflammation among brain cells, and may help scientists to develop better drugs for treating human depression and anxiety.

Scientists at Ohio State University added aggressive animals to colonies of mellow mice, disrupting the groups' social hierarchy.

After just three conflict sessions with the mean mice, subordinate subjects began to display anxiety-like behaviors because of the social disruption. Being defeated in mice fights caused the subjects to develop a mouse condition called "learned helplessness," which is comparable to the human states of psychological stress and depression.

When they studied the animals after the experiment, scientists found that an immune cell usually found only in physical infection or injury had entered the circulatory system and migrated to the brain. The number of myeloid progenitor cells (MPCs) more than tripled in the meek mice's brains following their torment, the authors reported in the Journal of Neuroscience.

Future studies may use the finding to help fight the crippling depression in humans that sometimes requires treatment in therapeutic schools.