A neural marker of eye contact highly impaired in autism spectrum disorder

Abstract

Attention to faces and eye contact are key behaviors for establishing social bonds in humans. Autism Spectrum Disorders (ASD) is characterized by poor communication skills, impaired face processing and gaze avoidance. The biological alterations underlying these impairments are still unclear. Using electroencephalography, multi-variate pattern classification and blind source separation methods we searched for face and face components related neural signals that could best discriminate neurotypicals and ASD visual processing. We isolated a face-specific neural signal in the superior temporal sulcus peaking at 240ms after stimulus onset. A machine learning algorithm applied on the extracted neural component reached 74% decoding accuracy at the same latencies, dissociating neurotypicals from ASD subjects in whom this signal was weak. By manipulating attention to face parts we found that the signal-evoked power in neurotypicals varied as a function of the distance of the eyes in the face stimulus with respect to the viewers' fovea. Such selective face and face-components neural modulations were not found in ASD individuals although they showed early face related P100 and N170 signals. These findings show that dedicated cortical mechanisms related to face perception set neural priority for attention to eyes and that these mechanisms are altered in individuals with ASD.

Dissociation of early and late face-related processes in Autism Spectrum Disorder and Williams syndrome

“…Then, for each participant, a map was generated indicating the level of evoked activity as a function of each viewed face area. We expected that, unlike what was found in ASD patients by Lio et al 1 , face parts that carry a rich amount of social information, such as the eyes, will yield selective STS responses in WS patients, just as was found.…”

“…We recruited 14 neurotypical participants (5 men and 9 women, mean age = 11.6, range = 6-21) and 14 WS patients (5 men and 9 women, mean age=11.6, range= 6-21) from 2018-2019 matched for age and gender. The number of participants in each group was selected to provide a balanced designed across groups, therefore we matched the size of groups to that acquired by Lio et al 1 . We compared the present dataset with the EEG data of subjects both participated in a short neuropsychological evaluation to assess visuospatial reasoning, logical thinking and verbal skills (matrix and similarities subtest, WISC-V, 37 ) and visuospatial and auditory attention (Arrows and auditory attention subtest, NEPSY, 38 ).…”

“…In the present study, using a face perception task developed by Lio et al 1 , we investigated whether a neural signature can be identified that reflects the behavioral dissociation between the two neurodevelopmental disorders.…”

“…In this task, we could control the face area focus on by subjects and link it to the cortical response. We examined the EEG brain activity of WS patients compared with data from a group of neurotypical subjects and a group of patients with ASD previously reported by Lio et al 1 . Two sets of EEG analysis were performed.…”

“…Two sets of EEG analysis were performed. First, in a spatio-temporal a priori analysis we built a spatial filter from the STS source identified at 240ms by Lio et al 1 and used it to extract evoked single-trial activity. Then, for each participant, a map was generated indicating the level of evoked activity as a function of each viewed face area.…”