title: Early Left Parietal Activity Elicited by Direct Gaze: A High-Density EEG Study.
abstract: Gaze is one of the most important cues for human communication and social interaction. In particular, gaze contact is the most primary form of social contact and it is thought to capture attention. A very early-differentiated brain response to direct versus averted gaze has been hypothesized. Here, we used high-density electroencephalography to test this hypothesis. Topographical analysis allowed us to uncover a very early topographic modulation (40-80 ms) of event-related responses to faces with direct as compared to averted gaze. This modulation was obtained only in the condition where intact broadband faces-as opposed to high-pass or low-pas filtered faces-were presented. Source estimation indicated that this early modulation involved the posterior parietal region, encompassing the left precuneus and inferior parietal lobule. This supports the idea that it reflected an early orienting response to direct versus averted gaze. Accordingly, in a follow-up behavioural experiment, we found faster response times to the direct gaze than to the averted gaze broadband faces. In addition, classical evoked potential analysis showed that the N170 peak amplitude was larger for averted gaze than for direct gaze. Taken together, these results suggest that direct gaze may be detected at a very early processing stage, involving a parallel route to the ventral occipito-temporal route of face perceptual analysis.
authors.affiliation: Institut du Cerveau et de la Moelle Epinière, ICM, Social and Affective Neuroscience (SAN) Laboratory and Centre MEG-EEG, Paris, France.|Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1127 and Centre MEG-EEG, Paris, France.|CNRS, UMR 7225 and Centre MEG-EEG, Paris, France.|Inserm, U 1127 and Centre MEG-EEG, Paris, France.|Faculté de Psychologie et des Sciences de l'Education, Université de Genève, Geneva, Switzerland.
authors.forename: Nicolas
authors.initials: N
authors.lastname: Burra
authors.affiliation: Faculté de Psychologie et des Sciences de l'Education, Université de Genève, Geneva, Switzerland.
authors.forename: Dirk
authors.initials: D
authors.lastname: Kerzel
authors.affiliation: Institut du Cerveau et de la Moelle Epinière, ICM, Social and Affective Neuroscience (SAN) Laboratory and Centre MEG-EEG, Paris, France.|Sorbonne Universités, UPMC Univ Paris 06, UMR_S 1127 and Centre MEG-EEG, Paris, France.|CNRS, UMR 7225 and Centre MEG-EEG, Paris, France.|Inserm, U 1127 and Centre MEG-EEG, Paris, France.|ENS, Centre MEG-EEG, Paris, France.
authors.forename: Nathalie
authors.initials: N
authors.lastname: George
mesh_terms: D000328:Adult; D001519:Behavior; D001921:Brain / Q000000981:diagnostic imaging*; D004569:Electroencephalography; D005071:Evoked Potentials / Q000502:physiology; D005260:Female; D006801:Humans; D008297:Male; D010775:Photic Stimulation; D055815:Young Adult