title: A shared neural network for emotional expression and perception: an anatomical study in the macaque monkey.
abstract: Over the past two decades, the insula has been described as the sensory "interoceptive cortex". As a consequence, human brain imaging studies have focused on its role in the sensory perception of emotions. However, evidence from neurophysiological studies in non-human primates have shown that the insula is also involved in generating emotional and communicative facial expressions. In particular, a recent study demonstrated that electrical stimulation of the mid-ventral sector of the insula evoked affiliative facial expressions. The present study aimed to describe the cortical connections of this "affiliative field". To this aim, we identified the region with electrical stimulation and injected neural tracers to label incoming and outgoing projections. Our results show that the insular field underlying emotional expression is part of a network involving specific frontal, cingulate, temporal, and parietal areas, as well as the amygdala, the basal ganglia, and thalamus, indicating that this sector of the insula is a site of integration of motor, emotional, sensory and social information. Together with our previous functional studies, this result challenges the classic view of the insula as a multisensory area merely reflecting bodily and internal visceral states. In contrast, it supports an alternative perspective; that the emotional responses classically attributed to the insular cortex are endowed with an enactive component intrinsic to each social and emotional behavior.
authors.affiliation: Department of Anatomy and Neurobiology, Washington University in St. Louis St. Louis, MO, USA.
authors.forename: Ahmad
authors.initials: A
authors.lastname: Jezzini
authors.affiliation: Department of Neuroscience, University of Parma Parma, Italy.
authors.forename: Stefano
authors.initials: S
authors.lastname: Rozzi
authors.affiliation: Department of Neuroscience, University of Parma Parma, Italy.
authors.forename: Elena
authors.initials: E
authors.lastname: Borra
authors.affiliation: Department of Neuroscience, University of Parma Parma, Italy.
authors.forename: Vittorio
authors.initials: V
authors.lastname: Gallese
authors.affiliation: Department of Neuroscience, University of Parma Parma, Italy ; Brain Center for Social and Motor Cognition, Istituto Italiano di Tecnologia Parma, Italy.
authors.forename: Fausto
authors.initials: F
authors.lastname: Caruana
authors.affiliation: Department of Neuroscience, University of Parma Parma, Italy.
authors.forename: Marzio
authors.initials: M
authors.lastname: Gerbella
keywords: affiliative field; emotion expression; emotion perception; insula; interoception; lip-smacking