Face-selective and auditory neurons in the primate orbitofrontal cortex

Abstract

Neurons with responses selective for faces are described in the macaque orbitofrontal cortex. The neurons typically respond 2-13 times more to the best face than to the best non-face stimulus, and have response latencies which are typically in the range of 130-220 ms. Some of these face-selective neurons respond to identity, and others to facial expression. Some of the neurons do not have different responses to different views of a face, which is a useful property of neurons responding to face identity. Other neurons have view-dependent responses, and some respond to moving but not still heads. The neurons with face expression, face movement, or face view-dependent responses would all be useful as part of a system decoding and representing signals important in social interactions. The representation of face identity is also important in social interactions, for it provides some of the information needed in order to make different responses to different individuals. In addition, some orbitofrontal cortex neurons were shown to be tuned to auditory stimuli, including for some neurons, the sound of vocalizations. The findings are relevant to understanding the functions of the primate including human orbitofrontal cortex in normal behaviour, and to understanding the effects of damage to this region in humans.

Electrophysiological correlates of spatial orienting towards angry faces: A source localization study

“…The pattern of activity in this region seen here, and for validly cued versus invalidly cued angry probes, is consistent with work demonstrating a role for the orbitofrontal cortex and adjacent prefrontal areas in social and emotional responses to faces (Rolls, Critchley, Browning, & Inoue, 2006; Wilson, O'Scalaidhe, & Goldman-Rackic, 1993). These areas are not only implicated in decoding the social information and social reinforcement conveyed in emotional expressions but also in using this information to guide social interactions (for review see Rolls, 2007).…”

Invariant Representations of Objects in Natural Scenes in the Temporal Cortex Visual Areas

“…Anatomically, there does not appear to be a whole further set of visual processing areas present in the brain; and outputs from the temporal lobe visual areas such as those described, are taken to limbic and related regions such as the amygdala and orbitofrontal cortex, and via the entorhinal cortex to the hippocampus, where associations between the visual stimuli and other sensory representations are formed Rolls 2005). Indeed, tracing this pathway onward, we have found a population of neurons with face-selective responses in the amygdala Rolls 2000b) and orbitofrontal cortex (Rolls et al 2006a), and in the majority of these neurons, different responses occur to different faces, with ensemble (not local) coding still being present. The amygdala in turn projects to another structure that may be important in other behavioral responses to faces, the ventral striatum, and comparable neurons have also been found in the ventral striatum (Williams et al 1993).…”

“…In humans, bilateral dysfunction of the amygdala can impair face expression identifi cation, although primarily of fear (Adolphs et al 1995;Adolphs et al 2002), so that the impairment seems much less severe than that produced by orbitofrontal cortex damage. Rolls et al (2006a) have found a number of face-responsive neurons in the orbitofrontal cortex, and they are also present in adjacent prefrontal cortical areas (Wilson et al 1993). The orbitofrontal cortex face-responsive neurons, fi rst observed by Thorpe et al (1983), then by Rolls et al (2006a), tend to respond with longer latencies than temporal lobe neurons (140-200 ms typically, compared with 80-100 ms); they also convey information about which face is being seen, by having different responses to different faces (Fig.…”

“…Rolls et al (2006a) have found a number of face-responsive neurons in the orbitofrontal cortex, and they are also present in adjacent prefrontal cortical areas (Wilson et al 1993). The orbitofrontal cortex face-responsive neurons, fi rst observed by Thorpe et al (1983), then by Rolls et al (2006a), tend to respond with longer latencies than temporal lobe neurons (140-200 ms typically, compared with 80-100 ms); they also convey information about which face is being seen, by having different responses to different faces (Fig. 19), and are typically rather harder to activate strongly than temporal cortical face-selective neurons, in that many of them respond much better to real faces than to 2-D images of faces on a video monitor (Rolls and Baylis 1986).…”

“…The fi ndings are consistent with the likelihood that these neurons are activated via the inputs from the temporal cortical visual areas in which face-selective neurons are found. The signifi cance of the neurons is likely to be related to the fact that faces convey information that is important in social reinforcement, both by conveying face expression , which can indicate reinforcement, and by encoding information about which individual is present, also important in evaluating and utilizing reinforcing inputs in social situations (Rolls et al 2006a). We have also been able to obtain evidence that nonreward used as a signal to reverse behavioral choice is represented in the human orbitofrontal cortex (for background, see Rolls 2005).…”