Kumari V, Corr P J, Mulligan O F, Cotter P A, Checkley S A, Gray J A
Department of Psychology, Institute of Psychiatry, University of London, UK.
Psychopharmacology (Berl). 1997 Feb;129(3):271-6. doi: 10.1007/s002130050190.
The effects of an indirect dopamine-agonist, d-amphetamine, and a non-selective dopamine receptor antagonist, haloperidol, were investigated in normal male volunteers using a between-subjects double-blind design in a procedural learning task, thought mainly to involve unconscious/automatic learning. The results showed: (1) d-amphetamine facilitated response speed, whereas haloperidol inhibited it, in comparison to placebo; (2) the linear increase in procedural learning corresponded with pharmacological manipulation of degree of dopaminergic activity, i.e. subjects given haloperidol showed the least, and subjects given d-amphetamine the greatest, procedural learning. The implications of these findings are discussed in relation to investigation of abnormalities of procedural learning processes in schizophrenia.
