DOPAMINE AND THE MECHANISMS OF COGNITION - PART-II - D-AMPHETAMINE EFFECTS IN HUMAN-SUBJECTS PERFORMING A SELECTIVE ATTENTION TASK

Background: A neural network computer model described in a companion p aper predicted the effects of increased dopamine transmission on selec tive attention under two different hypotheses. Methods: To evaluate th ese predictions we conducted an empirical study in human subjects of D -amphetamine effects on performance of the Eriksen response competitio n task. Ten healthy volunteers were rested before and after placebo or D-amphetamine in a double-blind crossover design. Results: D-amphetam ine induced a speeding of reaction time overall and an improvement of accuracy at fast reaction times but only in the task condition requiri ng selective attention. Conclusions: This pattern of results conforms to the prediction of the model under the hypothesis that D-amphetamine primarily affects dopamine transmission in cognitive rather than moto r networks. This suggests that the principles embodied in parallel dis tributed processing models of task performance may be sufficient to pr edict and explain specific behavioral effects of some drug actions in the central nervous system. (C) 1998 Society of Biological Psychiatry. .