Visual Information Routes in the Posterior Dorsal and Ventral Face Network Studied with Intracranial Neurophysiology and White Matter Tract Endpoints.

M Babo-Rebelo,A Puce,K Lehongre,F Pestilli,V Lambrecq,N George,C Adam,D Bullock,L Hugueville,V Dinkelacker

doi:10.1093/cercor/bhab212

Abstract

Occipitotemporal regions within the face network process perceptual and socioemotional information, but the dynamics and information flow between different nodes of this network are still debated. Here, we analyzed intracerebral EEG from 11 epileptic patients viewing a stimulus sequence beginning with a neutral face with direct gaze. The gaze could avert or remain direct, while the emotion changed to fearful or happy. N200 field potential peak latencies indicated that face processing begins in inferior occipital cortex and proceeds anteroventrally to fusiform and inferior temporal cortices, in parallel. The superior temporal sulcus responded preferentially to gaze changes with augmented field potential amplitudes for averted versus direct gaze, and large effect sizes relative to other network regions. An overlap analysis of posterior white matter tractography endpoints (from 1066 healthy brains) relative to active intracerebral electrodes in the 11 patients showed likely involvement of both dorsal and ventral posterior white matter pathways. Overall, our data provide new insight into the timing of face and social cue processing in the occipitotemporal brain and anchor the superior temporal cortex in dynamic gaze processing.

Highlights

Faces are critical social stimuli as they provide unique information about identity, emotional and mental states, and as such they are the primary focus of social attention
Event-Related Potentials (ERPs) data: Response profile to face onset and social cue change Here, we answer the first questions that we posed in the introduction: Where are the predominant sites that respond to face onset and changes in gaze and emotion across the face network? How does waveform morphology, amplitude and latency alter as a function of these facial attributes? For this, we compared responses to ‘Face 1’ and ‘Face 2’ stimuli
We focused our analyses on four regions of interest (ROI): the Inferior Occipital Cortex (IOC), the Fusiform Cortex (FC), and the Superior Temporal Cortex (STC), and the Inferior Temporal Cortex (ITC)

Summary

Introduction

Faces are critical social stimuli as they provide unique information about identity, emotional and mental states, and as such they are the primary focus of social attention. This social information is gleaned quickly, typically within a fraction of a second of seeing the face, as in a fleeting glance. There is a wealth of neuroimaging and neuropsychological research on the core and extended network for face processing (see Figure 4 of (Gobbini and Haxby 2007)), with information channeled along two main functional pathways, one based on identity and the other on the changeable aspects of faces such as gaze and emotional expression, consistent with the pioneering neuropsychological model of Bruce and Young (Bruce and Young 1986). The time course and nature of the interactions within the core face network remain unknown (e.g., Kennedy and Adolphs 2012; Stanley and Adolphs 2013)

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Discussion

Conclusion