• Bruno Rossion, Chun-Chia Kung, and Michael J Tarr.
• Unite de Neurosciences Cognitives and Laboratoire de Neurophysiologie, Université Catholique de Louvain, 10 place du Cardinal Mercier, 1348 Louvain-la-Neuve, Belgium. bruno.rossion@psp.ucl.ac.be
• Proc. Natl. Acad. Sci. U.S.A. 2004 Oct 5;101(40):14521-6.

AbstractHuman electrophysiological studies have found that the processing of faces and other objects differs reliably at approximately 150 ms after stimulus onset, faces giving rise to a larger occipitotemporal field potential on the scalp, termed the N170. We hypothesize that visual expertise with nonface objects leads to the recruitment of early face-related categorization processes in the occipitotemporal cortex, as reflected by the N170. To test this hypothesis, the N170 in response to laterally presented faces was measured while subjects concurrently viewed centrally presented, novel, nonface objects (asymmetric "Greebles"). The task was simply to report the side of the screen on which each face was presented. Five subjects were tested during three event-related potential sessions interspersed throughout a training protocol during which they became experts with Greebles. After expertise training, the N170 in response to faces was substantially decreased ( approximately 20% decrease in signal relative to that when subjects were novices) when concurrently processing a nonface object in the domain of expertise, but not when processing untrained objects of similar complexity. Thus, faces and nonface objects in a domain of expertise compete for early visual categorization processes in the occipitotemporal cortex.

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