Columbia study finds neurogenesis stalls in adults with major depression
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Neurogenesis, the production of new neurons, stalls in the hippocampus of adults with major depressive disorder, according to a Columbia University study. The findings provide the first evidence that this process is impaired in depression. Researchers also identified molecular programs controlling neurogenesis, offering potential targets for new treatments.
Key Facts
- The adult hippocampus continues to generate a small number of new neurons, and this process is impaired in major depressive disorder.
- Researchers identified molecular programs involved in controlling neurogenesis, offering potential clues for developing new treatments.
- Pattern separation, the ability to distinguish similar memories and separate their emotional connotations, depends on adult neurogenesis.
- A study of brain tumor patients whose hippocampal neurogenesis was eliminated by radiation therapy suggests the same relationship exists in humans.
Neurogenesis and Depression
Most of the brain's roughly 100 billion neurons are produced before birth, but a small number continue to form in the adult hippocampus. The new Columbia University study provides the first evidence that neurogenesis stalls in the brains of adults with major depressive disorder. Maura Dupont, professor of psychiatry who led the research, said depression was historically viewed as a neurotransmitter deficiency, especially serotonin. Dupont stated that depression now appears to stem from multiple issues affecting neurons' ability to adapt to stress and changing environments.
Hippocampus and Pattern Separation
The hippocampus plays a major role in episodic memory and emotional responses to the environment, and is one of the few adult brain regions that continues to generate new neurons. Researchers believe changes in the hippocampus may contribute to the tendency of people with depression to interpret experiences more negatively. Pattern separation is the ability to distinguish between similar but different memories and separate the emotional connotation of past memories and current events. When pattern separation is impaired, individual memories and the emotions attached to them may become less distinct, allowing separate experiences to blend together. Dupont gave an example: a lunch with a tired, quiet friend could be remembered as a unique event with intact pattern separation, but with impairment it becomes mixed with previous memories of feeling rejected.
Evidence from Animal and Human Studies
Research in mice has shown that adult neurogenesis is necessary for pattern separation. A recent study involving patients with brain tumors, in whom neurogenesis was eliminated by radiation therapy directed at the hippocampus, suggests that the same relationship may exist in humans.
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Columbia study finds neurogenesis stalls in adults with major depression
