The relationship between plasma corticosterone levels and leverpress avoidance vs. escape behaviors in rats

Abstract

Groups of rats were exposed to training procedures that produce leverpress avoidance (Experiment 1) or escape (Experiment 2) behaviors. Plasma samples were obtained by decapitation after 30 sessions, and corticosterone concentrations were determined and compared with those of corresponding yoked and nonshocked (time-in-box) groups. The mean corticosterone level of the “avoiders” was lower than that of their yoked mates and not different from that of their non-shocked mates. This indicated a reduction in their arousal level with mastery of the avoidance response, which could not be accounted for by the reduction in numbers of shocks received. The mean corticosterone level of the “escapers” was as high as that of their yoked mates, and both levels were higher than that of the nonshocked group. © 1981, Psychonomic Society, Inc.. All rights reserved.