DOPAMINERGIC MODULATION OF SEMANTIC NETWORK ACTIVATION

In order to examine the effect of dopamine on semantic processing, we performed a double-blind, placebo-controlled study. Healthy volunteers (n = 31) were tested in a lexical decision paradigm after ingestion o f either L-dopa 100 mg with benserazide 25 mg or placebo. While direct semantic priming was influenced only marginally by L-dopa, the indire ct priming effect was reduced significantly. These data support the hy pothesis that dopamine increases the signal-to-noise ratio in semantic networks by reducing the spread of semantic processing, thereby leadi ng to a focussing of activation. Copyright (C) 1996 Elsevier Science L td.