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Neuroscience & Depression

The neuroscience of depression is still a relatively new field shrouded in mystery. Many neuroscientists point to an imbalance of brain chemicals as a cause for depression. This theory is supported by the fact that anti-depressant medications that target specific neurotransmitters are effective for some people. The amygdala, an area of the brain that shows increased activity in depressed patients, is currently being studied for its role in depression. New research suggests that another brain region, area 25, could also be involved.

  1. The Amygdala

    • The amygdala, a region of the brain associated with a wide range of behaviors and disorders, appears to be implicated in depression. Researchers at San Diego State University found the amygdala showed increased metabolic activity in the brains of depressed individuals. They also found the increased amygdala metabolism corresponded with raised cortisol levels, a stress hormone associated with depression and anxiety.

    Serotonin

    • A lack of the neurotransmitter serotonin has long been linked to depression. Neurotransmitters help relay electrical signals from one part of the brain to another. According to WebMD, researchers believe that many cases of depression are the result of low levels of serotonin or a lack of receptor sites for the neurotransmitter. Unfortunately, there is currently no way to measure levels of serotonin in the living brain. Anti-depressant medications like Prozac and Paxil prevent re-absorption of serotonin, thus increasing its levels in the brain.

    Norepinephrine

    • The neurotransmitter norepinephrine is also associated with depression and could be affecting men's moods more than women's, according to an article in Scientific American Mind. Selective serotonin re-uptake inhibitors (SSRIs) tend to work better in women than in men, and researchers think this might be due to the gender differences in brain chemistry.

    Dopamine

    • The neurotransmitter dopamine may also play a role in depression. According to WebMD, researchers have linked prolonged exposure to dopamine with depression and drug addiction. Current anti-depressant medications target deficiencies of neurotransmitters; however, as more is learned about the role of excess dopamine in depression, future medications could aim for the opposite effect.

    Area 25

    • Researchers at Emory University have identified a part of the brain, called area 25, that is overactive in people suffering from depression. Area 25 is a hub, linking the frontal cortex and the limbic system. While the frontal cortex is associated with logic and problem solving, the limbic region is associated with emotional processing. The researchers posit that a "short circuit" between these two regions could be responsible for mood disorders, like depression.

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