Autistic Traits Modulate Gaze and Neural Activity in Constrained Versus Unconstrained Conditions

Background: Individuals affected by autism spectrum disorder (ASD) often display differences in cognitive control and flexibility which are measured reliably via electroencephalography (EEG) from frontal brain areas. Despite the ostensible ease of resting EEG paradigms, the cognitive demand to maintain fixation on a computer screen elicits differential brain activity in individuals with varying levels of cognitive control and behavioral rigidity. Brain activity via EEG, and gaze patterns, acquired via eye-tracking (ET), can provide information about relationships between behavioral measures, cognitive rigidity and biological states of visual hyposensitivity.

Objectives: Using concurrent ET and EEG recordings, we compared gaze behavior and spectral power between resting experiments where participants were free to look anywhere on a screen (unconstrained) and were required to maintain gaze on a fixation point (constrained). We explored the differential impact of how maintaining fixation affects its relationship with gaze, neural response and autistic traits.

Methods: Resting EEG data was recorded from 10 TD adults (data collection is ongoing) using a 128-channel sensor net. ET was acquired with an EyeLink-1000 camera system. Participants completed: (1) a 2-minute non-constrained viewing task in which they viewed a blank, gray colored screen; (2) a 2-minute constrained viewing task in which they were prompted to maintain gaze for 2 minutes within a dark square in the center of a light background. Self-report measures of behavioral rigidity and other autistic traits included (Broad Autism Phenotype Questionnaire; BAPQ) and sensory behavior (Glasgow Sensory Questionnaire; GSQ).

Results: Constrained vs. unconstrained viewing conditions demonstrated an overall reduction of delta power by 20%. Lateralized posterior beta power positively correlated with rigidity as measured by the BAPQ (left: r=.658, p=.039; right: r=.642, p=.045). Fixation duration in unconstrained contexts correlated negatively with visual hyposensitivity (r=-.646, p<0.05). Central and midline gamma during unconstrained viewing correlated with elevated levels of visual hyposensitivity (central: r=.723, p=.018; midline: r=.719, p=.019). Pupil diameter in unconstrained viewing correlated positively with visual hyposensitivity (r=.655, p<0.05).

Conclusions: Our data shows that differing relationships between brain activity, attention and autistic traits are revealed and dependent upon task demands in a resting context. Additionally, observations of pupil diameter during constrained conditions suggested that increased arousal is reflective of higher behavioral rigidity when instructed to maintain gaze. Increased fixation duration in unconstrained contexts indicates higher levels of attention amongst individuals with self-reports of high behavioral rigidity. This study highlights the importance in understanding the relationship of some observable behaviors and brain activity. By exploring the connections between gaze behaviors, brain activity and the clinical phenotype of ASD under differing task demands, we elucidate the extent to which brain and behavior differences reflect stable individual differences (trait) versus task dependent effect (state). These findings will guide the development of novel and appropriate methods for measuring brain activity in individuals with ASD.