Effects of dexamethasone on discriminative fear conditioning in pigs

Eight pigs were trained in a shuttle-box to avoid electric shocks according to a continuous avoidance schedule. After stabilisation of the response rate they were submitted to a discriminative Pavlovian fear conditioning. In a subsequent test session, presentation of the CS+ increased the avoidance response rat at a greater extent than the CS-. Dexamethasone (0.2 mg/kg) administered before Pavlovian conditioning and before test sessions enhanced the increase in avoidance response rate to both CS presentation, irrespective of its type. Results are interpreted in terms of DX effects on response inhibition processes.