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Cogn Affect Behav Neurosci. 2019 Jan 18. doi: 10.3758/s13415-019-00691-6. [Epub ahead of print]

Task context load induces reactive cognitive control: An fMRI study on cortical and brain stem activity.

Author information

1
Department of Psychology, University of Oslo, Postbox 1094, 0317, Oslo, Norway. makimarttunen.veronica@gmail.com.
2
Department of Psychology, University of Oslo, Postbox 1094, 0317, Oslo, Norway.
3
Norwegian Centre for Mental Disorders Research (NORMENT), KG Jebsen Centre for Psychosis Research, Division of Mental Health and Addiction, Ullevål Hospital, Building 49, Kirkeveien 166, Postbox 4956, 0424, Oslo, Norway.

Abstract

Cognitive control is a highly dynamic process that relies on flexible engagement of prefrontal areas and of neuromodulatory systems in order to adapt to changing demands. A range of internal and external factors come into play when individuals engage in a task requiring cognitive control. Here we investigated whether increased working memory (WM) demands would induce a flexible change in cognitive control mode in young healthy individuals. We developed a novel variant of the well-known AX-continuous performance task (AX-CPT). We manipulated the cognitive demands of maintaining task-relevant contextual information and studied the impact of this manipulation on behavior and brain activity. We expected that low WM load would allow for a more effortful, proactive strategy, while high WM load would induce a strategy of less effortful, stimulus-driven reactive control. In line with our hypothesis, a web-based experiment revealed that increased load was associated with more reactive behavioral responses, and this finding was independently replicated in behavioral data acquired in the MRI scanner. The results from brain activity showed that the right dorsolateral prefrontal cortex was activated by cues in the proactive mode and by probes in the reactive mode. The analysis of task-induced brain stem activity indicated that both the dopaminergic and noradrenergic systems are involved in updating context representations, and that, respectively, these systems mediate a gating signal to the control network and are involved in the dynamic regulation of task engagement.

KEYWORDS:

AX–continuous performance task; Attention; Cognitive control; Locus coeruleus; Ventral tegmental area/substantia nigra; fMRI

PMID:
30659515
DOI:
10.3758/s13415-019-00691-6

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