Neural plasticity and emotional memory

Posttraumatic stress disorder is the pathological replay of emotional memor y formed in response to painful, life-threatening, or horrifying events. In contrast, depression is often precipitated by more social context-related stressors. New data suggest that different types of life experiences can di fferentially impact biochemistry, physiology, anatomy, and behavior at the level of changes in gene expression. Repeated separation of neonatal rat pu ps from their mother results in many long-lasting alterations in biology an d behavior paralleling that in depression, including hypercortisolism. The role of the amygdala in modulating emotional memory is highlighted, as well as some of its unique properties such as metaplasticity (i.e., the differe ntial direction of long-term adaptation, either potentiation or depression) in response to the same input as a function of the prior history of stimul ation. The implications of these emerging data on the physiological and mol ecular mechanisms underlying emotional memory emphasize the particular impo rtance of prevention and early intervention.