THE EFFECT OF DECREASED CATECHOLAMINE TRANSMISSION ON ERP INDEXES OF SELECTIVE ATTENTION

This study examines the effect of decreased catecholamine transmission on event-related potential (ERP) indices of selective attention. Intr avenous clonidine (1.5 mu g/kg Catapres), droperidol (15 mu g/kg Drole ptan), or placebo were administered to healthy adult males prior to pe rformance of a multidimensional auditory selective attention task (SAT ) in which dichotically presented sequences of tone pips varied on dim ensions of location (left or right ear), pitch (high or low), and dura tion (short or long). Subjects were required to make a button press re sponse to infrequent ''target'' stimuli that matched a prespecified st imulus on three dimensions. ERPs were recorded during the task. Clonid ine led to a significant increase of processing negativity (PN) over 2 00-400 ms at the irrelevant location. Droperidol led to a significant increase in reaction time (RT), a significant decrease in the hit rate , and an attenuation of PN over the 200- to 400-ms and 400- to 700-ms epochs. Neither substance led to a significant change in P3 amplitude. The role of catecholamines in the selective attention subprocesses of ''tuning'' and ''switching'' is discussed. (C) 1997 American College of Neuropsychopharmacology.