The N170 event related brain potential (ERP) is used as a physiological index to assess face-specific neural processing. Research indicates that the N170 may by atypical in autism.
To examine the N170 in children with high-functioning autism. To examine the relation between the N170 and social behavior and autistic symptomology.
27 children with high-functioning autism and 22 children with typical development participated in the study. Participants were fitted with a 128-lead Geodesic sensor net and viewed a slideshow of upright faces, inverted faces, upright vehicles, and inverted vehicles. Six electrodes over the left lateral posterior scalp and over the right lateral posterior scalp were used to identify N170 amplitude and latency.
There was a significant interaction between diagnostic group and stimulus orientation, F(1, 45) = 6.46, p = 0.015, and a marginal interaction between diagnostic group and stimulus type, F(1, 45) = 3.50, p = 0.068, on N170 amplitude. Children with typical development differentiated between stimulus orientation and type to a greater extent than children with autism. There was a main effect of diagnostic group on N170 latency,F(1, 45) = 6.16, p = 0.017, such that children with autism had longer N170 latencies than children with typical development. For both groups, there was no relation between N170 and social behavior and autistic symptomology.
Children with autism seem to approach all stimuli with a steady level of interest and mental processing, while children with typical development almost immediately adjust their level of interest and mental processing to match stimulus meaning. The delayed N170 latency in autism may be caused by cortical underconnectivity. Finally, the lack of a relation between N170 and social behavior and autistic symptomology was surprising, given that face processing has been hypothesized to be a primary deficit in autism.