title: Learning affective values for faces is expressed in amygdala and fusiform gyrus.
abstract: To monitor the environment for social threat humans must build affective evaluations of others. These evaluations are malleable and to a high degree shaped by responses engendered by specific social encounters. The precise neuronal mechanism by which these evaluations are constructed is poorly understood. We tested a hypothesis that conjoint activity in amygdala and fusiform gyrus would correlate with acquisition of social stimulus value. We tested this using a reinforcement learning algorithm, Q-learning, that assigned values to faces as a function of a history of pairing, or not pairing, with aversive shocks. Behaviourally, we observed a correlation between conditioning induced changes in skin conductance response (SCR) and subjective ratings for likeability of faces. Activity in both amygdala and fusiform gyrus (FG) correlated with the output of the reinforcement learning algorithm parameterized by these ratings. In amygdala, this effect was greater for averted than direct gaze faces. Furthermore, learning-related activity change in these regions correlated with SCR and subjective ratings. We conclude that amygdala and fusiform encode affective value in a manner that closely approximates a standard computational solution to learning.
authors.affiliation: Wellcome Trust Centre for Neuroimaging, University College of London, 12 Queen Square, London, WC1N 3BG, UK. predrag.petrovic@ki.se
authors.forename: Predrag
authors.initials: P
authors.lastname: Petrovic
authors.forename: Raffael
authors.initials: R
authors.lastname: Kalisch
authors.forename: Mathias
authors.initials: M
authors.lastname: Pessiglione
authors.forename: Tania
authors.initials: T
authors.lastname: Singer
authors.forename: Raymond J
authors.initials: RJ
authors.lastname: Dolan
mesh_terms: D000293:Adolescent; D000328:Adult; D000679:Amygdala / Q000502:physiology*; D001245:Association Learning / Q000502:physiology*; D003214:Conditioning, Classical / Q000502:physiology; D004644:Emotions; D005149:Facial Expression; D005239:Fear / Q000502:physiology; D005712:Galvanic Skin Response / Q000502:physiology; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008959:Models, Neurological; D021641:Recognition, Psychology / Q000502:physiology; D012016:Reference Values; D012938:Social Perception; D013702:Temporal Lobe / Q000502:physiology*; D055815:Young Adult