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Sabrina Censi, Mathieu Simard, Laurent Mottron, Dave Saint-Amour, Armando Bertone; Assessing lateral interactions within the early visual areas of adults with autism.. Journal of Vision 2013;13(9):837. doi: 10.1167/13.9.837.
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© ARVO (1962-2015); The Authors (2016-present)
Background. Although atypical performance on visuo-spatial tasks targeting early, non-social perception is a defining characteristic of autism, few biologically plausible hypotheses are available to explain them. Some authors have theorized that persons with autism may have atypical local connectivity resulting in altered response properties of early visual feature detectors. The goal of this study is to use steady-state visual evoked potentials (ssVEPs) to measure and define local neural activity originating from lateral interactions between neurons within early visual areas elicited by windmill-dartboard stimuli (Zemon & Ratcliff, 1982). Methods. Eight participants with autism and 9 typically developing participants, matched for full-scale IQ and age (18-30 years), were asked to passively view the windmill-dartboard stimuli while ssVEPs from four electrodes over the occipital cortex (Oz, POz, O1 and O2) were collected. Windmill-dartboard stimuli consisted of a radial pattern comprised of concentric contrast reversing zones with contiguous static zones. EEGs were analyzed using a Fast Fourier Transform. First- and second-harmonic components of the steady-state responses were used to calculate indices reflecting facilitatory (FI) and inhibitory (SI) cortical interactions, which were compared between groups. Results. Preliminary results demonstrate that there are no group-differences for either FI or SI cortical interactions. Conclusions. To date, our results suggest that cortical lateral connections within early visual brain areas whether defined by facilitatory (FI) and inhibitory (SI) indices, are similar in autism and control participants. However, given the small sample size, we have yet to draw a strong conclusion from the results; data collection (and analysis) is ongoing. In a complimentary study, we are also presently analyzing ssVEP data collected for the same group of participants while viewing low-contrast Gabor patches presented ether in isolation (target), or flanked by collinear/orthogonal Gabors at different contrasts (8, 16, 30%) at target-flanker distances (1.5λ, 3 λ, 6 λ).
Meeting abstract presented at VSS 2013
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