Neural Correlates of Eye Contact and Social Function in Autism Spectrum Disorder

Abstract

Reluctant eye contact and reduced social interactions characteristic of autism spectrum disorder (ASD) are consistent with deficits in oculomotor and face processing systems. We test the hypothesis that these deficits are interrelated ASD. Eye-tracking and hyperscanning with functional near-infrared spectroscopy (fNIRS) were used to acquire neuroimaging data during live, dynamic eye-to-eye contacts in 17 ASD and 19 typically-developed (TD) adults. Real eye contact conditions were contrasted with conditions where eye gaze was directed at a comparable dynamic face video. These findings were regressed with eye-contact dwell-time, i.e., times when gaze of both partners was in the eye-box of the other, to confirm the relationship between visual sensing and neural coding. Visual fixations and positional variance were also determined. Average gaze dwell-times in the "eye-box" did not vary between ASD and TD participants but were longer for the Real Eye than Video Eye condition for both groups. However, positional gaze variability, "jitter", was higher for ASD in both conditions. Neural findings for TD [Real Eye > Video Eye] were consistent with previous findings for interactive face-gaze with activity in right temporal and dorsal parietal regions. However, in ASD ventral temporal regions were observed for this contrast without evidence for dorsal parietal activity. This neural difference was enhanced when regressed by eye-contact dwell-times. Together findings are consistent with the hypothesis that unstable bottom-up oculomotor signals contribute to deficits in live face processing and reduced dorsal stream activity in ASD.

No evidence for differential saccadic adaptation in children and adults with an autism spectrum diagnosis

“…Considering our current findings and the lack of consistent evidence for saccade differences in the literature, it seems highly unlikely that there is a fundamental sensorymotor processing deficit in the oculomotor system in Autism. Of course, gaze and fixation differences have been widely observed and reported in Autism (Klin et al, 2002;Hirsch et al, 2022), leaving open the question as to what drives them. Although not tested here, it may well be the case that the alternate hypothesis, that these differences are related to social motivational factors, for instance a reluctance or difficulty in engaging with peers, is the more parsimonious explanation.…”

“…In the context of Autism, eye-movements have been of substantial interest to clinicians and researchers because of the long-noted atypicalities that autistic individuals show in making or maintaining eye-contact in social settings (Hirsch et al, 2022).…”

Individual Symptom Severity in Adult Autism Spectrum Disorder Predicts Reduction in Right Dorsal Stream Neural Activity During Live Eye-to-Eye Contact

“…Methods and materials are similar to those reported in a separate study currently under review (Hirsch et al, 2021). Hemodynamic signals were acquired for TD and ASD adults during live and interactive gaze at the eyes of a confederate and the eyes of a comparable dynamic video-face.…”