Dynamic modulation of decision biases by brainstem arousal systems.
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.
['de Gee|Jan Willem|JW|0000-0002-5875-8282', 'Colizoli|Olympia|O|0000-0001-5288-2437', 'Kloosterman|Niels A|NA|0000-0002-1134-7996', 'Knapen|Tomas|T|0000-0001-5863-8689', 'Nieuwenhuis|Sander|S|0000-0003-2418-3879', 'Donner|Tobias H|TH|0000-0002-7559-6019']
D000328:Adult D001143:Arousal D001933:Brain Stem D003657:Decision Making D005260:Female D064368:Healthy Volunteers D006801:Humans D008279:Magnetic Resonance Imaging D008297:Male D008959:Models, Neurological D055815:Young Adult
Decision-making human fMRI Locus Coeruleus Accumulator model Neuromodulation Trial-to-trial variability neuroscience