Abolition of latent inhibition by a single 5 mg dose ofd-amphetamine in man

The performance of healthy volunteer subjects on an auditory latent inhibition (LI) paradigm was assessed following administration of a single oral dose ofd-amphetamine or placebo. It was predicted that a low (5 mg), but not a high (10 mg), dose ofd-amphetamine would disrupt LI. The prediction was supported with left ear presentation of the preexposed stimulus only. When the preexposed stimulus was presented to the right ear the predicted pattern of findings was not obtained. It is concluded that the dopaminergic system is involved in the mediation of LI in man and it is speculated that the interaction between amphetamine dose and ear of presentation of the preexposed stimulus may reflect normally occurring dopaminergic hemisphere asymmetry.