Reduced neural sensitivity for implicit individual face discrimination in autism

Abstract

Fluently recognizing faces is crucial for social interactions. Impaired and atypical face processing have often been postulated as key deficits in autism spectrum disorders (ASD). Despite the great amount of research on face processing in ASD it is still unclear which processes are impaired. This is partly due to overreliance on explicit face processing tasks, which may give an incomplete estimate of spontaneous face processing abilities in ASD. To address this limitation, we apply an innovative scalp electroencephalography approach combined with fast periodic visual stimulation (FPVS). Groups of typically developing (TD) boys (N=23) and boys with ASD (N=23) were presented with images at the fast periodic rate of 6 Hz. In experiment 1, face images were inserted every 5^th stimulus (i.e. at 6/5 = 1.2 Hz, reflecting face categorization) among non-face object images. In experiment 2, the same face identity is presented at 6 Hz and a different identity appears every 1.2 Hz (reflecting face identity discrimination). Amplitude and scalp distribution of the base response to visual stimulation (6 Hz) were similar for boys with ASD and TD boys, indicating equal attention to the images presented on the screen. Furthermore, both groups show similar face-categorization responses (1.2 Hz in experiment 1) indicating that both groups fluently detect brief and periodic appearances of faces within a range of widely variable objects. However, in experiment 2 responses to brief changes in identity were much smaller for ASD than TD boys when faces were presented upright, while no group difference was found when faces were inverted. This demonstrates reduced sensitivity to individual faces in boys with ASD. We conclude that within a few minutes of recording time, we are able to pinpoint and quantify a specific impairment in implicit individualization of faces in individuals with ASD

Meeting abstract presented at VSS 2018