Altered face scanning and arousal after orbitofrontal cortex lesion in adult rhesus monkeys.

To further assess orbitofrontal cortex (OFC) contribution to the processing of socioemotional signals, spontaneous scanning patterns and pupil diameter variations were measured while adult rhesus macaques with either bilateral lesions of OFC areas 11 and 13 (Group O-asp) or sham-operations (Group C) freely viewed pictures of neutral and expressive faces of conspecifics, of other nonhuman primates and humans, and of objects with and without facial features. As compared to Group C, Group O-asp displayed (a) increased overall spontaneous visual exploration and increased scanning of primate neutral faces regardless of species and face orientation (upright/inverted), (b) longer gazes at the eyes of faces and of objects with facial features, and (c) intact ability to discriminate emotional from neutral faces, but (d) altered scanning patterns at emotional macaque faces coupled with (e) increased pupil dilation for conspecific faces according to face emotion and orientation (profile/stare). Thus, the primate OFC appears essential in the attention to and processing of faces, especially attention to the eyes and arousal self-regulation. (PsycINFO Database Record (c) 2020 APA, all rights reserved).