The early visual encoding of a face (N170) is viewpoint-dependent: A parametric ERP-adaptation study

Visual representations of faces are extracted shortly after 100 ms in the human brain, leading to an occipito-temporal cortex N170 event-related potential (ERP). To understand the nature of this early visual representation, a full-front adapting face preceded a different or identical target face identity. The target face varied parametrically in head orientation from the adapting face (0-90 degrees, 15 degrees steps). The N170 elicited by the target face increased progressively from 0 degrees up to 30 degrees head orientation, with no further increase until 90 degrees. The N170 decreased for repeated face identities, this effect being stable between 0 degrees and 30 degrees changes of viewpoint, and no effect beyond that angle. These observations suggest that a face is encoded in a view-dependent manner, being matched to either a full-front or a profile face view. Yet, individual face representations activated as early as the peak of the N170 generalize partially across views. (C) 2015 Elsevier B.V. All rights reserved.