Lack of dopaminergic modulation of cognitive flexibility

OBJECTIVE: To evaluate performance on a cognitive flexibility task after administration of a dopaminergic agonist. BACKGROUND: L-3,4- dihydroxyphenylalanine, which is converted into dopamine and norepinephrine, results in a restriction of the semantic network in priming experiments. Recent evidence suggests that flexibility of access to semantic networks in problem solving is mediated by the noradrenergic system. We wished to determine if dopaminergic agonists also affect this type of cognitive flexibility. METHODS: Eighty-four subjects were tested twice on an anagram task, once 1 hour after bromocriptine (dopamine agonist) and once 1 hour after placebo administration. RESULTS: No difference was detected between placebo and bromocriptine on anagram performance. CONCLUSIONS: Therefore, modulation of this type of cognitive flexibility does not seem to be mediated by the dopaminergic system. This suggests that the noradrenergic modulation of cognitive flexibility previously reported does not seem to extend to the dopaminergic system among catecholamines.