Noradrenergic modulation of cognitive flexibility in problem solving

STRESS causes impaired performance on tests of creativity. Drugs that block beta-adrenergic receptors improve test performance in patients with test a nxiety. Furthermore, catecholamine precursors (L-DOPA) reduce the flexibili ty of semantic networks. Our study investigated the effect of noradrenergic system modulation on cognitive flexibility in problem solving. Eighteen no rmal subjects undertook three problem solving tasks (number series, shape m anipulation and anagrams) 45 min after propranolol, placebo and ephedrine. On the task that appeared to rely most heavily on cognitive flexibility (an agrams), subjects who were most able to serve these problems demonstrated s ignificantly shorter solution times (logarithmic scores) after propranolol than after ephedrine. This suggested that the noradrenergic system exerts a modulatory effect on cognitive flexibility in problem solving. (C) 1999 Li ppincott Williams & Wilkins.