Abstract
Intro: Bistable perception is known to rely in part on the balance of inhibitory/excitatory neurotransmission in the brain, and therefore may provide a behavioral index of alterations in inhibition that are thought to characterize autism. Indeed, we recently demonstrated a striking reduction in perceptual suppression during binocular rivalry in autism, which linked to reduced GABAergic action in the autistic brain (Robertson et al., 2013, 2016). Here, we test whether this behavioral difference generalizes to another class of bistable stimuli, motion-induced blindness, which is known to tax competitive interactions in different regions of the brain than rivalry (Donner et al., 2008, 2013). Methods: 38 adults (18 ASD, matched for age and IQ) participated in a simple motion-induced blindness study (Bonneh et al., 2001). On each of the 24 16-second long trials (2 practice and 22 experimental), participants reported the duration and frequency of target disappearances using a button press. Half of the trials included "catch trials" in which a target was physically removed from the display at a random timepoint during the trial (duration: 1.75s). Results: The frequency of target disappearances was significantly lower for participants with ASC than for controls (t(37)=2.70, p=0.01), while the average duration of each target disappearance was equivalent across groups (t(36)=0.43, p=0.63). The frequency of MIB inversely predicted autism symptom severity (ADOS scores): individuals with reduced perceptual suppression exhibited higher autistic symptomatology (rho=-0.51, p=0.03). Critically, the two groups were matched on their accuracy and RTs to detect catch trials (both p>0.53). Conclusions: Individuals with autism demonstrate a reduced frequency of motion-induced blindness. These results cannot be explained by group differences in motor latencies, and are predictive of autistic symptom severity. Together with our previous findings in binocular rivalry, these results suggest that reduced perceptual suppression may be a generalizable characteristic of autistic vision.
Meeting abstract presented at VSS 2017