Editors' ChoiceEarly Life Stress

Can't Get Next to You

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Science Translational Medicine  20 Jan 2010:
Vol. 2, Issue 15, pp. 15ec10
DOI: 10.1126/scitranslmed.3000825

Social attachment to caregivers during early development is a profound experience for each of us, and inexorably shapes our capacity to regulate our emotions and behavior. Now, Moriceau and colleagues link the neural circuitry of early attachment learning (which promotes attachment to the mother through maternal odor) with the central stress-response system. These investigators compared rat pups reared by either normal or stressed mothers with both groups of pups exposed to the maternal odor paired with a mild electrical shock. Compared with pups with normal mothers, the pups with stressed mothers exhibited elevated levels of the stress hormone corticosterone, avoidance of rather than approach to maternal odor, and abnormally enhanced metabolism in both the olfactory bulb and amygdala, regions of the brain that are involved in odor memory and fear responses, respectively. These effects were normalized by the administration of a corticosterone antagonist and were also mimicked by systemic corticosterone administration to pups with normal mothers. Furthermore, corticosterone injected into the amygdala or corticotropin-releasing hormone injected into the locus coeruleus (the brain’s alarm system) both enhanced aversion learning, and the injections into the locus coeruleus increased olfactory bulb norepinephrine (the substance used by the locus coeruleus to signal to other brain cells). These results suggest that altered early-life rearing disrupts infant attachment learning via effects on the central stress-response system. In humans, these types of early attachment disruptions are strong predictors of adult psychiatric disorders, future parental dysfunction, disturbed health-related behavior, and even impulsive behavior, such as suicide and criminal behavior. With the present findings, these investigators point the way toward a mechanistic account of these widespread effects, and toward potential treatment targets, which may be pharmacological or psychological in nature.

S. Moriceau et al., Early-life stress disrupts attachment learning: The role of amygdala corticosterone, locus ceruleus corticotropin releasing hormone, and olfactory bulb norepinephrine. J. Neurosci. 29, 15745–15755 (2010). [Abstract]

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