Acquisition of an avoidance response in rats during conditioned suppression

Wistar rats were trained to suppress completely a lever response for food reward during 60 sec of light (CS). After suppression was acquired, deflection of an omnidirectional bar would terminate the CS and prevent shock. An FR schedule to omnidirectional bar pressing to CS termination was acquired by three of nine experimental Ss. Control animals (N = 3), without conditioned suppression and avoidance training, never acquired an FR to terminate the CS.