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Transl Psychiatry. 2015 Oct 13;5:e659. doi: 10.1038/tp.2015.139.

Lateral prefrontal model-based signatures are reduced in healthy individuals with high trait impulsivity.

Author information

1
Max Planck Fellow Group 'Cognitive and Affective Control of Behavioral Adaptation', Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
2
Department of Psychiatry and Psychotherapy, Campus Charité Mitte, Charité-Universitätsmedizin Berlin, Berlin, Germany.
3
Department of Neurology, Otto-von-Guericke University, Magdeburg, Germany.
4
International Max Planck Research School on the Neuroscience of Communication, Leipzig, Germany.
5
Department of Cognitive Neurology, Max Planck Institute for Human Cognitive and Brain Sciences, Leipzig, Germany.
6
IFB AdiposityDiseases, University of Leipzig, Leipzig, Germany.
7
Clinic for Cognitive Neurology, University Hospital Leipzig, Leipzig, Germany.
8
Berlin School of Mind and Brain, Mind and Brain Institute, Humboldt University, Berlin, Germany.
9
Department of Behavioral Neurology, Leibniz Institute for Neurobiology, Magdeburg, Germany.

Abstract

High impulsivity is an important risk factor for addiction with evidence from endophenotype studies. In addiction, behavioral control is shifted toward the habitual end. Habitual control can be described by retrospective updating of reward expectations in 'model-free' temporal-difference algorithms. Goal-directed control relies on the prospective consideration of actions and their outcomes, which can be captured by forward-planning 'model-based' algorithms. So far, no studies have examined behavioral and neural signatures of model-free and model-based control in healthy high-impulsive individuals. Fifty healthy participants were drawn from the upper and lower ends of 452 individuals, completing the Barratt Impulsiveness Scale. All participants performed a sequential decision-making task during functional magnetic resonance imaging (fMRI) and underwent structural MRI. Behavioral and fMRI data were analyzed by means of computational algorithms reflecting model-free and model-based control. Both groups did not differ regarding the balance of model-free and model-based control, but high-impulsive individuals showed a subtle but significant accentuation of model-free control alone. Right lateral prefrontal model-based signatures were reduced in high-impulsive individuals. Effects of smoking, drinking, general cognition or gray matter density did not account for the findings. Irrespectively of impulsivity, gray matter density in the left dorsolateral prefrontal cortex was positively associated with model-based control. The present study supports the idea that high levels of impulsivity are accompanied by behavioral and neural signatures in favor of model-free behavioral control. Behavioral results in healthy high-impulsive individuals were qualitatively different to findings in patients with the same task. The predictive relevance of these results remains an important target for future longitudinal studies.

PMID:
26460483
PMCID:
PMC4930122
DOI:
10.1038/tp.2015.139
[Indexed for MEDLINE]
Free PMC Article

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