Stepwise emergence of the face-sensitive N170 event-related potential component

TLDR

The study aimed to characterize early ERPs to face stimuli across varying noise levels. A parametric design embedded face stimuli in gradually decreasing random noise to elicit these ERPs. N170 and VPP amplitudes increased and latencies decreased linearly with reduced noise, whereas P1 remained stable, revealing a functional dissociation between low‑ and high‑level face processing and supporting that N170 and VPP reflect the same integrative processes.

Abstract

The present study used a parametric design to characterize early event-related potentials (ERP) to face stimuli embedded in gradually decreasing random noise levels. For both N170 and the vertex positive potential (VPP) there was a linear increase in amplitude and decrease in latency with decreasing levels of noise. In contrast, the earlier visual P1 component was stable across noise levels. The P1/N170 dissociation suggests not only a functional dissociation between low and high-level visual processing of faces but also that the N170 reflects the integration of sensorial information into a unitary representation. In addition, the N170/VPP association supports the view that they reflect the same processes operating when viewing faces.