The neurobiology of emotionally influenced memory. Implications for understanding traumatic memory.

Substantial evidence from animal and human subject studies converges on the view that memory for emotionally arousing events is modulated by an endogenous memory-modulating system consisting, at minimum, of stress hormones and the amygdaloid complex. Within the normal range of emotions experienced, this system is viewed as an evolutionarily adaptive method of creating memory strength that is, in general, proportional to memory importance. In conditions of extreme emotional stress, the operation of this normally adaptive system may underly the formation of strong, "intrusive" memories characteristic of PTSD. An improved understanding of the neurobiology of memory modulation should lead to an improved ability to treat or prevent traumatic memories.