Abstract
The N170 is a component measured with event-related potentials (ERP) that typically shows a higher amplitude to faces than to non-face objects and is delayed when faces are inverted. Of the acquired prosopagnosics that have been studied, only one has shown evidence for normal face-selectivity in the N170 (Rossion et al., 2004), and none have demonstrated a normal N170 delay in response to inverted faces. Thus, the functional significance of the N170 is still very much an open question. LR is a prosopagnosic who, after suffering damage to his right anterior temporal lobe, can no longer recognize faces, familiar or otherwise. Behavioral testing reveals that LR has a remarkably preserved ability to make local fine-level discriminations and shows some holistic processing of coarse-grain information. LR's impairment appears to disrupt his ability to integrate multiple fine-grained features into a more complex representation (Bukach et al., 2006). Interestingly, LR does seem to retain the ability to process fine-grained details in a limited region around the mouth. Here, we present evidence that LR shows a normal N170 to faces, and a delayed N170 to inverted faces. These findings are consistent with the idea that the N170 is a marker for the preprocessing of faces rather than their recognition and that LR's impairments have left early visual processing relatively preserved.
Supported by a grant from the James S. McDonnell Foundation to the Perceptual Expertise Network, and by the National Science Foundation (BCS 0339122).