Abstract

A punishment discrimination was conditioned in laboratory rats by simultaneously rewarding with food and punishing with shock all lever responses made in the presence of a discriminative stimulus (tone). Appropriate setting of the shock intensity resulted in low and stable output of responses during the tone periods. A series of central nervous system depressants was administered in order to determine degrees of attenuation of the punishment discrimination relative to the side effects of nonspecific depression. Meprobamate, a di-urethan, produced the maximum attenuation at a dose that produced a minimum of side effects. The mono-urethans hedonal, emylcamate, and urethan produced the least attenuation. Pentobarbital and phenobarbital produced intermediate attenuating effects upon the punishment discrimination.