Dorsal striatum mediates cognitive control, not cognitive effort per se, in decision-making: An event-related fMRI study

Brian D Robertson; Nole M Hiebert; Ken N Seergobin; Adrian M Owen; Penny A MacDonald

doi:10.1016/j.neuroimage.2015.03.082

Dorsal striatum mediates cognitive control, not cognitive effort per se, in decision-making: An event-related fMRI study

Neuroimage. 2015 Jul 1:114:170-84. doi: 10.1016/j.neuroimage.2015.03.082. Epub 2015 Apr 8.

Authors

Brian D Robertson¹, Nole M Hiebert¹, Ken N Seergobin², Adrian M Owen¹, Penny A MacDonald³

Affiliations

¹ Brain and Mind Institute, The Natural Sciences Centre, University of Western Ontario, London, Ontario, Canada N6A 5B7; Department of Physiology and Pharmacology, Medical Sciences Building, Room 216, University of Western Ontario, London, Ontario, Canada N6A 5C1.
² Brain and Mind Institute, The Natural Sciences Centre, University of Western Ontario, London, Ontario, Canada N6A 5B7.
³ Brain and Mind Institute, The Natural Sciences Centre, University of Western Ontario, London, Ontario, Canada N6A 5B7; Department of Physiology and Pharmacology, Medical Sciences Building, Room 216, University of Western Ontario, London, Ontario, Canada N6A 5C1; Clinical Neurological Sciences, London Health Sciences Centre, University Hospital, 339 Windermere Road, London, Ontario, Canada N6A 5A5. Electronic address: penny.macdonald@gmail.com.

PMID: 25862263
DOI: 10.1016/j.neuroimage.2015.03.082

Abstract

Objective: Whether the dorsal striatum (DS) mediates cognitive control or cognitive effort per se in decision-making is unclear given that these effects are highly correlated. As the cognitive control requirements of a neuropsychological task intensify, cognitive effort increases proportionately. We implemented a task that disentangled cognitive control and cognitive effort to specify the particular function DS mediates in decision-making.

Methods: Sixteen healthy young adults completed a number Stroop task with simultaneous blood-oxygenation-level-dependent response (BOLD) measurement using functional magnetic resonance imaging. Participants selected the physically larger number of a pair of single-digit integers. Discriminating smaller versus larger physical size differences between a number pair requires greater cognitive effort, but does not require greater cognitive control. We also investigated the effect of conflict between the physical and numerical dimensions of targets (e.g., 2 6). Selections in this incongruent case are more cognitively effortful and require greater cognitive control to suppress responding to the irrelevant dimension. Enhancing cognitive effort or cognitive control demands increases errors and response times. Despite similar behavioural profiles, our aim was to determine whether DS mediates cognitive control or simply indexes cognitive effort, using the same data set.

Results: As expected, behavioural interference effects occurred for both enhanced cognitive control and/or cognitive effort conditions. Despite similar degrees of behavioural interference, DS BOLD signal only correlated with interference arising due to increased cognitive control demands in the incongruent case. DS was not preferentially activated for discriminations of smaller relative to larger physical size differences between number pairs, even when using liberal statistical criteria. However, our incongruent and physical size effects conjointly activated regions related to effortful processing (e.g., anterior cingulate cortex).

Interpretation: We interpret these findings as support for the increasingly accepted notion that DS mediates cognitive control specifically and does not simply index cognitive effort per se.

Keywords: Cognitive control; Cognitive effort; Striatum; Stroop; fMRI.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Adult
Brain Mapping
Cognition / physiology*
Decision Making / physiology*
Executive Function / physiology*
Female
Humans
Magnetic Resonance Imaging
Male
Neostriatum / physiology*
Reaction Time
Stroop Test
Young Adult