Abstract
An experiment was conducted with the goal of exploring strain differences between female inbred Roman High and Low Avoidance rats (RHA-I, and RLA-I, respectively) on acquisition and extinction of a food-rewarded running response in a straight alley. Acquisition proceeded faster in the less emotional RHA-I and Wistar rats (used as controls) than in the more emotional RLA-I rats. However, extinction proceeded slower in RHA-I rats than in RLA-I and Wistar rats. This strain-based asymmetry on instrumental performance between acquisition and extinction is discussed in terms of strain differences in locomotor activity, associative flexibility and emotional reactivity.