DISSOCIATION BETWEEN BEHAVIORAL AND CORTICOSTERONE RESPONSES ON REPEATED EXPOSURES TO CAT ODOR

Rats exposed for 5 min to a phobic stimulus (the odor of a cat) had pl asma corticosterone concentrations significantly higher than those exp osed to a neutral odor and than a group remaining undisturbed in the a nimal house. During the first exposure to cat odor the increased corti costerone was related to the avoidance behavior, measured as the time spent sheltering. After five exposures to cat odor the rats continued to avoid the odor cloth, but no longer responded with raised corticost erone levels. The results are discussed with reference to the two comp onents of a phobic response (avoidance and disturbance), and it is sug gested that the latter, reflected by changes in corticosterone, habitu ates more readily than the former.