Independent contributions of noradrenaline to behavioural flexibility and motivation

Abstract

15Among neuromodulatory systems, the noradrenergic system remains one of the least 16 understood. Several theories have pointed out its implication in behavioural flexibility 17 and more recently in motivation, with a strong role in effort processing. Here, we 18 designed a sequential cost/benefit decision task to test the causal role of 19 noradrenaline in these two functions. We manipulated noradrenaline using clonidine, 20 an alpha-2 noradrenergic receptor agonist, which reduces central noradrenaline 21 levels. Clonidine had two distinct effects: it decreased choice volatility (without 22 affecting the cost/benefit trade off) and reduced force production. Because the effects 23 were independent, they cannot be accounted for by a non-specific effect on arousal. 24Altogether, these results support the global implication of noradrenaline in facing 25 challenging situations in two complementary ways: by modulating behavioural 26 volatility, which would facilitate adaptation depending on the lability of the 27 environment, and by modulating the mobilization of resources to face immediate 28 challenges.

Catecholaminergic modulation of the avoidance of cognitive control.

“…Recent empirical evidence indeed indicates that blocking noradrenaline selectively, by propranolol, increases participants' confidence in good performance on a dot-motion task relative to placebo (Hauser et al, 2017). In addition, the injection of clonidine, a selective noradrenergic agonist which reduces central noradrenaline levels, has been sown to reduce choice volatility in a cost/benefit decision task in monkeys (Jahn et al, 2017). Monkeys were inclined to make the same decision when faced with the same type of choice.…”