A Substantial and Unexpected Enhancement of Motion Perception in Autism
Open Access
- 8 May 2013
- journal article
- Published by Society for Neuroscience in Journal of Neuroscience
- Vol. 33 (19), 8243-8249
- https://doi.org/10.1523/jneurosci.1608-12.2013
Abstract
Atypical perceptual processing in autism spectrum disorder (ASD) is well documented. In addition, growing evidence supports the hypothesis that an excitatory/inhibitory neurochemical imbalance might underlie ASD. Here we investigated putative behavioral consequences of the excitatory/inhibitory imbalance in the context of visual motion perception. As stimulus size increases, typical observers exhibit marked impairments in perceiving motion of high-contrast stimuli. This result, termed “spatial suppression,” is believed to reflect inhibitory motion-processing mechanisms. Motion processing is also affected by gain control, an inhibitory mechanism that underlies saturation of neural responses at high contrast. Motivated by these behavioral correlates of inhibitory function, we investigated motion perception in human children with ASD (n= 20) and typical development (n= 26). At high contrast, both groups exhibited similar impairments in motion perception with increasing stimulus size, revealing no apparent differences in spatial suppression. However, there was a substantial enhancement of motion perception in ASD: children with ASD exhibited a consistent twofold improvement in perceiving motion. Hypothesizing that this enhancement might indicate abnormal weakening of response gain control, we repeated our measurements at low contrast, where the effects of gain control should be negligible. At low contrast, we indeed found no group differences in motion discrimination thresholds. These low-contrast results, however, revealed weaker spatial suppression in ASD, suggesting the possibility that gain control abnormalities in ASD might have masked spatial suppression differences at high contrast. Overall, we report a pattern of motion perception abnormalities in ASD that includes substantial enhancements at high contrast and is consistent with an underlying excitatory/inhibitory imbalance.Keywords
This publication has 59 references indexed in Scilit:
- Contrast gain control abnormalities in idiopathic generalized epilepsyAnnals of Neurology, 2011
- GABAAInhibition Controls Response Gain in Visual CortexJournal of Neuroscience, 2011
- Improved Motion Perception and Impaired Spatial Suppression following Disruption of Cortical Area MT/V5Journal of Neuroscience, 2011
- Decreased GABAB receptors in the cingulate cortex and fusiform gyrus in AutismJournal of Neurochemistry, 2010
- Stimulus onset quenches neural variability: a widespread cortical phenomenonNature Neuroscience, 2010
- Enhanced Visual Motion Perception in Major Depressive DisorderJournal of Neuroscience, 2009
- Enhanced and diminished visuo-spatial information processing in autism depends on stimulus complexityBrain, 2005
- High “intelligence,” low “IQ”? Speed of processing and measured IQ in children with autismDevelopment and Psychopathology, 2000
- Spatial summation properties of directionally selective mechanisms in human visionJournal of the Optical Society of America A, 1991
- Quest: A Bayesian adaptive psychometric methodPerception & Psychophysics, 1983