Thesis defense Monja Froböse (Donders series 399)

31 October 2019

The mental couch potato. Neurochemistry of cognitive control

Cognitive control is an umbrella term that refers to the set of cognitive functions that allow to stabilize goals by resisting impulses, temptation and distraction. Yet it seems that people do not always recruit maximal cognitive control and that the true performance is a mixture of (at least) the capacity to perform a certain task and the motivation to do so. In this dissertation I studied the basis of such motivated cognition by quantifying the willingness to recruit cognitive control in the healthy population. The overarching goal was to characterize the role of catecholamines (dopamine and noradrenaline) in shaping the motivation for cognitively demanding processes. We demonstrated in two independent studies that a pharmacological challenge of the catecholamine system altered cognitive demand avoidance as a function of trait impulsivity; in more relative to less impulsive participants, the administration of methylphenidate as well as tyrosine reduced the motivation to conduct difficult tasks. In addition, the studies indicate that cognitive processes that require distractor inhibition are accompanied by a greater effort cost than flexible control and that the administration of tyrosine to older adults impaired the ability to inhibit distractors. In sum, the studies presented in this thesis demonstrate that task execution with a high demand for cognitive control is perceived as subjectively costly and that catecholaminergic drugs do not just alter the ability to perform a task but also the motivation to do so.