Response to familiar faces, newly familiar faces, and novel faces as assessed by ERPs is intact in adults with autism spectrum disorders

Abstract

Individuals with autism spectrum disorders (ASD) have pervasive impairments in social functioning, which may include problems with processing and remembering faces. In this study, we examined whether posterior ERP components associated with identity processing (P2, N250 and face-N400) and components associated with early-stage face processing (P1 and N170) are atypical in ASD. We collected ERP responses to a familiar repeated face (Familiar), an unfamiliar repeated face (Other) and novel faces (Novels) in 29 high-functioning adults with ASD and matched controls. For both groups, the P2 and N250 were sensitive to repetition (Other vs. Novels) and personal familiarity (Familiar vs. Other), and the face-N400 was sensitive to repetition. Adults with ASD did not show significantly atypical processing of facial familiarity and repetition in an ERP paradigm, despite showing significantly poorer performance than controls on a behavioral test of face memory. This study found no evidence that early-stage facial identity processing is a primary contributor to the face recognition deficit in high-functioning ASD.

Figure 1

GSN 128 sensor layout. 10/20 ROI electrodes are labeled by text. Webb ROIs include the medial right and left (black boxes) and lateral right and left (grey boxes) posterior electrodes. Tanaka leads are represented by grey filled posterior electrodes.

Figure 2

Grand average waveform across Webb ROIs for ASD (top) and Controls (bottom), (a) mean across left lateral electrode groups with the N250 shaded in light grey and the face-N400 shaded in dark grey; (b) mean across left medial electrode groups; (c) mean across right medial electrode groups; (d) ASD (top) and Controls (bottom), mean across right lateral electrode groups;

Figure 3

Mean amplitude of the (a) P2, (b) N250a, (c) N250b, (d) face-N400a, and (e) face-N400b for Familiar, Other (repeated unfamiliar face) and Novels by group collapsed across lead and hemisphere for the Webb ROIs.

Figure 4

Topography of the Familiarity effect (Familiar minus Other), showing on the left a topographical amplitude plot for the ERP difference wave (red is positive amplitude and blue is negative amplitude) and on the right the mean amplitude of the difference over left and right Webb ROIs, collapsed across lead for: (a) the P2, (b) N250a, (c) N250b, (d) face-N400a, and (e) face-N400b. An asterix over a bar indicates a significant difference between responses to Familiar and Other; an ampersand (&) between two bars indicates a significant difference in the Familiarity effect across hemispheres (all p < 0.05).

Figure 5

Topography of the Repetition effect (Other minus Novels), showing on the left a topographical amplitude plot for the ERP difference wave (red is positive amplitude and blue is negative amplitude) and on the right the mean amplitude of the difference over left and right Webb ROIs, collapsed across lead for: (a) the P2, (b) N250a, (c) N250b, (d) face-N400a, and (e) face-N400b. An asterix over an individual bar indicates a significant difference between responses to Other and Novel; an ampersand (&) indicates a main effect of Repetition across both groups and hemispheres (all p < 0.05).

Figure 6

Relations between behavior and ERP responses to faces over Webb ROIs in the ASD group: (a) More negative-going N250 amplitude correlates with higher verbal IQ for Familiar, Other (repeated unfamiliar face) and Novels, and with (b) lower ADOS total scores (fewer symptoms) for Familiar and Other only; (c) Greater right-lateralization of the N250 Familiarity effect (Familiar minus Other) correlates with lower total ADOS scores, and (d) Greater right-lateralization of the P2 Familiarity effect correlates with lower total ADOS scores. Of note, the N250 was averaged across both a and b time windows for the correlation analyses.