title: The µ-opioid system promotes visual attention to faces and eyes.
abstract: Paying attention to others' faces and eyes is a cornerstone of human social behavior. The µ-opioid receptor (MOR) system, central to social reward-processing in rodents and primates, has been proposed to mediate the capacity for affiliative reward in humans. We assessed the role of the human MOR system in visual exploration of faces and eyes of conspecifics. Thirty healthy males received a novel, bidirectional battery of psychopharmacological treatment (an MOR agonist, a non-selective opioid antagonist, or placebo, on three separate days). Eye-movements were recorded while participants viewed facial photographs. We predicted that the MOR system would promote visual exploration of faces, and hypothesized that MOR agonism would increase, whereas antagonism decrease overt attention to the information-rich eye region. The expected linear effect of MOR manipulation on visual attention to the stimuli was observed, such that MOR agonism increased while antagonism decreased visual exploration of faces and overt attention to the eyes. The observed effects suggest that the human MOR system promotes overt visual attention to socially significant cues, in line with theories linking reward value to gaze control and target selection. Enhanced attention to others' faces and eyes represents a putative behavioral mechanism through which the human MOR system promotes social interest.
authors.affiliation: Department of Psychology, University of Oslo, Oslo N-0317, Norway siri.leknes@psykologi.uio.no.
authors.forename: Olga
authors.initials: O
authors.lastname: Chelnokova
authors.affiliation: Department of Psychology, University of Oslo, Oslo N-0317, Norway.
authors.forename: Bruno
authors.initials: B
authors.lastname: Laeng
authors.affiliation: Department of Psychology, University of Oslo, Oslo N-0317, Norway.
authors.forename: Guro
authors.initials: G
authors.lastname: Løseth
authors.affiliation: Department of Psychology, University of Oslo, Oslo N-0317, Norway.|Norwegian Center for Addiction Research, University of Oslo, Oslo N-0318, Norway.|Division of Mental Health and Addiction, Oslo University Hospital, Oslo N-0318, Norway.
authors.forename: Marie
authors.initials: M
authors.lastname: Eikemo
authors.affiliation: Department of Medicine, University of Oslo, Oslo N-0316, Norway.
authors.forename: Frode
authors.initials: F
authors.lastname: Willoch
authors.affiliation: Department of Psychology, University of Oslo, Oslo N-0317, Norway.|Department of Medicine, University of Oslo, Oslo N-0316, Norway.|The Intervention Centre, Oslo University Hospital, Oslo N-0424, Norway.
authors.forename: Siri
authors.initials: S
authors.lastname: Leknes
mesh_terms: D000328:Adult; D000701:Analgesics, Opioid / Q000494:pharmacology*; D001288:Attention / Q000187:drug effects*; D003463:Cues; D005133:Eye Movements / Q000187:drug effects; D005145:Face; D006801:Humans; D008297:Male; D009020:Morphine / Q000494:pharmacology; D009271:Naltrexone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology*; D017450:Receptors, Opioid, mu / Q000819:agonists*; D012201:Reward; D012919:Social Behavior; D014796:Visual Perception / Q000187:drug effects*; D055815:Young Adult
chemical_list: D000701:Analgesics, Opioid; D009292:Narcotic Antagonists; D017450:Receptors, Opioid, mu; D009271:Naltrexone; D009020:Morphine
keywords: eye region; eye-movements; human µ-opioid receptor system; social motivation