Acute stress increases behaviors that optimize safety and decreases the exploration of aversive areas

Abstract

The avoidance-approach conflict has been proposed as the main drive of spontaneous exploration in rodents. Given this assumption, exploratory behavior has been interpreted as an anxiety index that can be measured in several paradigms. Although pharmacological manipulations predominate in anxiety and exploratory behavior studies, exposure to real stressful situations could be considered a more ecological approach. In the present study, we evaluated the immediate effect of 1-hour restraint stress on Wistars rats’ exploratory behavior in the following models of anxiety: the light/dark box (L/D box), the elevated plus-maze (EPM), and the elevated gradient of aversion (EGA). Results showed that animals avoid risky areas according to the complexity of each apparatus and that acute stress increases that tendency. We propose that subjects tend to search and remain in safer areas when exposed to novel environments and that a single exposure to stress by motor restriction increases these behaviors which could be associated with a response related to anxiety but also to the optimization of a more complex survival system.