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Abstract:
Stress is known to cause impaired performance on tests of
creativity. Drugs that block b-adrenergic receptors are known to
improve test performance in patients with test anxiety.
Furthermore, catecholamines (specifically L-DOPA, which is
converted into both dopamine and norepinephrine) are known to
reduce the flexibility of semantic networks. The purpose of our
study was to test the effect of the noradrenergic system on
cognitive flexibility in problem solving. Eighteen normal subjects
participated in three types of problem solving 45 minutes after
taking propranolol (b-adrenergic blocker), placebo, and ephedrine
(b-adrenergic agonist). The problem solving tasks included number
series, matchstick shape manipulation, and word unscrambling, in
which the correct solution must emerge from a range of possible
solutions. On the task that appeared to rely most heavily on
cognitive flexibility (word unscrambling), those subjects who were
most able to solve these problems demonstrated significant
differences in solution times (logarithmic scores) as a function of
treatment. It took these subjects a shorter time to complete these
problems while medicated with propranolol than ephedrine (p=0.026).
This result suggests that the noradrenergic system exerts a
modulatory effect on cognitive flexibility in problem
solving.
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