A SINGLE ADMINISTRATION OF D-AMPHETAMINE PRIOR TO STIMULUS PRE EXPOSURE AND CONDITIONING ATTENUATES LATENT INHIBITION

The effect of a single administration of d-amphetamine (0.32 mg/kg, SC ) upon latent inhibition (LI) in a one-session pre-exposure and condit ioning procedure was investigated in rats in a conditioned emotional r esponse paradigm. It was found that amphetamine attenuated LI. The eff ects could not be attributed to differences in unconditioned suppressi on nor to differences in response rates between the experimental group s. These results support the observations of Dunn and suggest that the disruption of LI may not depend upon a complex interaction between ch anges in neuronal processes consequent upon repetitive amphetamine adm inistration and the schedule with which the drug is administered durin g the experimental procedure.