Situations surrounding emotional events are better remembered than others that accompany neutral events. However, in severe pathological states such as posttraumatic stress disorder (PTSD), exposure to threatening situations can also result in memory impairment. In this case, a hypermnesia for a salient trauma-related cue is associated with loss of memory for important aspects of the traumatic event. The memory for the core traumatic event is enhanced, but the capacity to place it in the right place and in response to the right cues is reduced. Kaouane et al. associated a high-intensity threat with the infusion of corticosterone in the hippocampus to induce PTSD-like memory impairments in mice. The animals became unable to identify the threat context as the right predictor of the threat, and they showed a fear response for discrete salient cues normally identified as safe. The neural activation patterns in the amygdala and hippocampal regions of these mice were similar to those observed in human PTSD.
N. Kaouane, Y. Porte, M. Vallée, L. Brayda-Bruno, N. Mons, L. Calandreau, A. Marighetto, P. V. Piazza, A. Desmedt, Glucocorticoids can induce PTSD-like memory impairments in mice. Science 335, 1510–1513 (2012). [Abstract] [Full Text]