Acute early life stress alters threat processing in adult rats

Abstract

Individuals diagnosed with stress-related psychiatric disorders in adulthood are likely to have experienced early life stress, suggesting that early adversity is an important vulnerability factor in subsequent development of trauma- and anxiety-related psychiatric illness. It is important to develop animal models of psychiatric dysfunction to determine evident vulnerability considerations, potential biomarkers, and novel treatment avenues to improve the human condition. In our model of acute early life stress (aELS), 15 footshocks are delivered in a single session on postnatal day (PND) 17. The following experiments investigated the persistent impacts of our aELS procedure on stress-enhanced fear learning, anxiety-related behaviors, maintenance of fear, and resistance to extinction in adult male and female rats. The findings from these experiments demonstrate that our aELS procedure yields enhanced fear learning and increased anxiety. This enhanced fear is maintained over time, yet it extinguishes normally. Taken together, these results demonstrate that exposure to 15-footshocks during a single session early in life (PND 17) recapitulates a number of important features of trauma- and anxiety-related disorder symptomatology, but not others. Future studies are needed to determine the persistent physiological phenotypes resulting from aELS, and the neurobiological mechanisms that mediate these long-term changes.