A neuro-metabolic account of why daylong cognitive work alters the control of economic decisions

Antonius Wiehler, Francesca Branzoli, Isaac Adanyeguh, Fanny Mochel, Mathias Pessiglione

Research output: Contribution to journalArticlepeer-review

5 Scopus citations

Abstract

Behavioral activities that require control over automatic routines typically feel effortful and result in cognitive fatigue. Beyond subjective report, cognitive fatigue has been conceived as an inflated cost of cognitive control, objectified by more impulsive decisions. However, the origins of such control cost inflation with cognitive work are heavily debated. Here, we suggest a neuro-metabolic account: the cost would relate to the necessity of recycling potentially toxic substances accumulated during cognitive control exertion. We validated this account using magnetic resonance spectroscopy (MRS) to monitor brain metabolites throughout an approximate workday, during which two groups of participants performed either high-demand or low-demand cognitive control tasks, interleaved with economic decisions. Choice-related fatigue markers were only present in the high-demand group, with a reduction of pupil dilation during decision-making and a preference shift toward short-delay and little-effort options (a low-cost bias captured using computational modeling). At the end of the day, high-demand cognitive work resulted in higher glutamate concentration and glutamate/glutamine diffusion in a cognitive control brain region (lateral prefrontal cortex [lPFC]), relative to low-demand cognitive work and to a reference brain region (primary visual cortex [V1]). Taken together with previous fMRI data, these results support a neuro-metabolic model in which glutamate accumulation triggers a regulation mechanism that makes lPFC activation more costly, explaining why cognitive control is harder to mobilize after a strenuous workday.

Original languageEnglish (US)
Pages (from-to)3564-3575.e5
JournalCurrent Biology
Volume32
Issue number16
DOIs
StatePublished - Aug 22 2022
Externally publishedYes

Bibliographical note

Funding Information:
The work was supported by a Labex “ Bio-Psy ” ( http://www.biopsy.fr/index.php/fr/ ) research grant and by the “Big Brain Theory” program of the Paris Brain Institute . The MRS package was developed by Gülin Öz, Ivan Tkac, Dinesh Deelchand (semi-LASER sequence), Edward J. Auerbach, and Małgorzata Marjańska (diffusion-weighted semi-LASER sequence) and was provided by the University of Minnesota under a C2P agreement. We would like to thank Jean Daunizeau and Gerhard Jocham for their insightful comments.

Funding Information:
The work was supported by a Labex “Bio-Psy” (http://www.biopsy.fr/index.php/fr/) research grant and by the “Big Brain Theory” program of the Paris Brain Institute. The MRS package was developed by Gülin Öz, Ivan Tkac, Dinesh Deelchand (semi-LASER sequence), Edward J. Auerbach, and Małgorzata Marjańska (diffusion-weighted semi-LASER sequence) and was provided by the University of Minnesota under a C2P agreement. We would like to thank Jean Daunizeau and Gerhard Jocham for their insightful comments. A.W. F.M. and M.P. designed research. A.W. conducted experiments and collected data. A.W. F.B. I.A. and M.P. conceived behavioral and neural analyses. A.W. analyzed data. A.W. and M.P. wrote the paper and all authors provided feedback on the manuscript. The authors declare no competing interests.

Publisher Copyright:
© 2022 Elsevier Inc.

Keywords

  • cognitive control
  • computational modeling
  • decision-making
  • delay
  • effort
  • fatigue
  • glutamate
  • prefrontal cortex
  • reward
  • spectroscopy

PubMed: MeSH publication types

  • Journal Article
  • Research Support, Non-U.S. Gov't

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