In response to stress, some people cope easily while others succumb to depression or other mood disorders. While depression can develop from a wide variety of biological and genetic factors, stressful events are often a major trigger. But why does stress make some people develop mood disorders while others remain resilient?
Learning more about the changes in the brain following stress could help answer this question and lead to better methods and treatments. Recently, researchers at Cold Spring Harbor Laboratory in New York did just that, using a mouse model of human depression to ask questions about the effects of stress on depression and the brain.
What they found was that in “depressed” mice, neurons fire differently than they do in resilient mice. In addition, these neurons can turn a resilient mouse into a depressed mouse when activated.
To figure this out, the researchers’ first step was to separate the mice into two groups: those that get depressed when facing stress and those that are more resilient. Much like humans, some mice are more prone to depression than others, so the researchers simply used random electric shocks to figure out how stress produces these differences in mouse behavior. Resilient mice persisted in avoiding the repeated shocks, while depressed mice gave up and failed to move away from the shocks.