Magnocellular Impairments in Autism Spectrum Disorders as Assesses by Visual Evoked Potentials
AdvisorHutsler, Jeffrey J
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Motion perception in Autism Spectrum Disorders (ASD) has become a salient topic in the past few years. Several studies have found links between abnormal motion processing and symptomatology in ASDs, suggesting that impaired magnocellular function may underlie some of the various symptoms and outcomes in individuals with ASD. The following study explored achromatic motion perception processing differences in high-functioning adolescents with Autism Spectrum Disorder (ASD). Previous studies have shown abnormalities in the way that individuals with ASD perceive motion, including biological and coherent motion, but few studies have examined pattern-reversal and expanding and contracting motion. Abnormalities can have implications for ASD symptomatology, including emotional/facial expression processing, and difficulty with integration of visual information with other cognitive information, such as social cues and communication systems. Two motion stimuli, a reversing checkerboard and an expanding and contracting dartboard, were displayed for ASD male participants and male and female neurotypical control groups. Visual-evoked potentials (VEPs) were used to examine differences in time-to-peak amplitude, area amplitude, and latency of the VEP in participants. Results showed that there are magnocellular impairments in ASD. There were several main effects for check size and contrast and significant 3-way interactions for contrast, check size and diagnosis in P1 area amplitude and N1 fractional area latency for all three groups, and P1 peak amplitude for ASD males and neurotypical males. Results imply that contrast and size in environment have an effect on how individuals with ASD process visual stimuli, which can explain some of their symptomatology and difficulty with other forms of processing that follow the magnocellular process. Future research can focus on successful interventions that aim to correct these deficits in visual-motion processing and as a result, help treat the individuals with innovative therapies that improve quality of life. These results can also have implications for early diagnosis and treatment, and possibly prevention.