CORRELATIONAL RELATIONSHIP BETWEEN SHOCK-INTENSITY AND CORTICOSTERONESECRETION ON THE ESTABLISHMENT AND SUBSEQUENT EXPRESSION OF CONTEXTUAL FEAR CONDITIONING

A role for corticosterone in the consolidation of contextual fear cond itioning has previously been proposed. In this study, physiological ev idence was found to support this view. The extent of conditioned fear and the levels of plasma corticosterone in rats, after context exposur e at training and at different posttraining times (24 hr and 7 days), depended on the intensity of the unconditional stimulus (footshock). I n each experimental session, a positive correlation was found between the magnitude of corticosterone levels and the fear-related behavioral inhibition exhibited in the context. Results support the involvement of corticosterone on the processes that occur during consolidation in determining the strength at which the contextual fear conditioning is stored as a long-term memory.