title: Parieto-occipital cortex shows early target selection to faces in a reflexive orienting task.
abstract: It is well established that human faces induce stronger involuntary orienting responses than other visual objects. Yet, the timing of this preferential orienting response at the neural level is still unknown. Here, we used an antisaccade paradigm to investigate the neural dynamics preceding the onset of reflexive and voluntary saccades elicited by human faces and nonface visual objects, normalized for their global low-level visual properties. High-density event-related potentials (ERPs) were recorded in observers as they performed interleaved pro- and antisaccades toward a lateralized target. For reflexive saccades, we report an ERP modulation specific to faces as early as 40-60 ms following stimulus onset over parieto-occipital sites, further predicting the speed of saccade execution. This was not linked to differences in the programming of the saccadic eye movements, as it occurred early in time. For the first time, we present electrophysiological evidence of early target selection to faces in reflexive orienting responses over parieto-occipital cortex that facilitates the triggering of saccades toward faces. We argue for a 2-stage process in the representation of a face in involuntary spatial orienting with an initial, rapid implicit processing of the visual properties of a face, followed by subsequent stimulus categorization depicted by the N170 component.
authors.affiliation: Institute of Neuroscience and Psychology and.
authors.forename: Stéphanie M
authors.initials: SM
authors.lastname: Morand
authors.forename: Monika
authors.initials: M
authors.lastname: Harvey
authors.forename: Marie-Hélène
authors.initials: MH
authors.lastname: Grosbras
mesh_terms: D000328:Adult; D000704:Analysis of Variance; D001931:Brain Mapping; D004569:Electroencephalography; D005074:Evoked Potentials, Visual; D005145:Face; D005260:Female; D006801:Humans; D008297:Male; D009778:Occipital Lobe / Q000502:physiology*; D009949:Orientation / Q000502:physiology*; D010296:Parietal Lobe / Q000502:physiology*; D010364:Pattern Recognition, Visual / Q000502:physiology*; D010775:Photic Stimulation; D012438:Saccades / Q000502:physiology; D055815:Young Adult