Neurobiology of disrupted contextual odor discrimination in an animal model of PTSD

Neurobiological basis of stress-induced disruption of contextual odor discrimination in an animal model of posttraumatic stress disorder (PTSD) Animal models are a useful tool for delineating neurobiological factors involved in post traumatic stress disorder (PTSD), because manipulation of experimental parameters is possible and causality can be tested. Clinically, PTSD is characterized by extreme and over-generalized responses to contextual cues. Animal models of PTSD traditionally focus on conditioning, anxiety or arousal and the processing of contextual cues has not been studied in sufficient detail.

We have recently developed a behavioral paradigm which addresses contextualization and trauma - differential contextual odor conditioning (DCOC) to address this gap. Preliminary results appear to support the notion that exposure to severe traumatic stress interferes with processes related to subsequent adequate and flexible application of contextualization. Traumatized animals were unable to acquire the ability to accurately evaluate the contextual relevance of an odor-stimulus or lost this ability after having effectively acquired it.

This study examined the validity of the DCOC as an animal model of contextualization in PTSD, examining the neurobiological basis of the extreme "emergency response" of PTSD patients to contextual cues. We examined behavioral, molecular and neurobiological processes and brain plasticity functions in mPFC, amygdala and the hippocampus, associated with acquisition of differential contextual odor conditioning, and the alterations in these processes induced by severe stress/trauma.