Abstract
Decision-makers often arrive at different choices when faced with repeated presentations of the same evidence. Variability of behavior is commonly attributed to noise in the brain’s decision-making machinery. We hypothesized that phasic responses of brainstem arousal systems are a significant source of this variability. We tracked pupil responses (a proxy of phasic arousal) during sensory-motor decisions in humans, across different sensory modalities and task protocols. Large pupil responses generally predicted a reduction in decision bias. Using fMRI, we showed that the pupil-linked bias reduction was (i) accompanied by a modulation of choice-encoding pattern signals in parietal and prefrontal cortex and (ii) predicted by phasic, pupil-linked responses of a number of neuromodulatory brainstem centers involved in the control of cortical arousal state, including the noradrenergic locus coeruleus. We conclude that phasic arousal suppresses decision bias on a trial-by-trial basis, thus accounting for a significant component of the variability of choice behavior.
Original language | English |
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Article number | e23232 |
Journal | eLife |
Volume | 6 |
DOIs | |
Publication status | Published - 11 Apr 2017 |
Funding
We thank Daniel Lindh for help with the data collection of the main experiment. We thank Matthew McGinley for providing the stimuli, and Dani?lle Rijkmans, Guusje Boomgaard and Christopher David Riddell for help with the data collection for the auditory detection task. We thank Konstantinos Tsetsos, Angela Yu, David J Heeger, Birte U Forstmann and Todd Hare for discussion. This research was supported by the German Research Foundation (DFG, SFB 936/Z1 and DO 1240/3?1, to THD), the European Union Seventh Framework Programme (FP7/2007-2013) under grant agreement no. 604102 (Human Brain Project, to THD), and the European Research Council (ERC) under grant agreement no. 283314-NOREPI (to SN).
Funders | Funder number |
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Seventh Framework Programme | 283314, 604102 |
European Research Council | |
Deutsche Forschungsgemeinschaft | DO 1240/3–1, SFB 936/Z1 |
Seventh Framework Programme |