Latent inhibition.

Latent inhibition (LI) refers to the deleterious effects of nonreinforced stimulus preexposure on its subsequent conditioning. LI is considered to index an organism's ability to ignore inconsequential stimuli and as such provides a useful tool to measure attentional processes as well as their disruption and enhancement by various pharmacological, physiological and behavioral manipulations. During the last decade, LI has received increasing interest as an animal model of schizophrenia and of antipsychotic drug action. This unit describes the measurement of LI in the conditioned emotional response and two-way active avoidance procedures, including parametric variations which allow the demonstration of the disruption and the potentiation of this phenomenon.