Revealing the neural time-course of direct gaze processing via spatial frequency manipulation of faces

Direct gaze is a powerful social cue signalling the attention of another person toward oneself. Here we investigated the relevance of low spatial frequency (LSF) and high spatial frequency (HSF) in facial cues for direct gaze processing. We identified two distinct peaks in the ERP response, the N170 and N240 components. These two components were related to different stimulus conditions and influenced by different spatial frequencies. In particular, larger N170 and N240 amplitudes were observed for direct gaze than for averted gaze, but only in the N240 component was this effect modulated by spatial frequency, where it was reliant in LSF information. By contrast, larger N170 and N240 components were observed for faces than for non-facial stimuli, but this effect was only modulated by spatial frequency in the N170 component, where it relied on HSF information. The present study highlights the existence of two functionally distinct components related to direct gaze processing.