Assessing Lateral Interactions in Autism Spectrum Disorder Using Visual Evoked Potentials

Poster Presentation
Saturday, May 4, 2019: 11:30 AM-1:30 PM
Room: 710 (Palais des congres de Montreal)
S. M. Lurie1, M. A. Rowe2, J. George-Jones3, V. Zemon1, J. Buxbaum4, A. Kolevzon2 and P. M. Siper2, (1)Ferkauf Graduate School of Psychology, Yeshiva University, Bronx, NY, (2)Seaver Autism Center, Department of Psychiatry, Icahn School of Medicine at Mount Sinai Hospital, New York, NY, (3)Psychology, University of Texas at Austin, Austin, TX, (4)Department of Psychiatry, Icahn School of Medicine at Mount Sinai, New York, NY
Background: Excitatory/inhibitory (E/I) imbalance is one hypothesis of autism spectrum disorder (ASD) which can be tested objectively using electrophysiological methods such as visual evoked potentials (VEPs). VEPs reflect the sum of excitatory and inhibitory postsynaptic potentials, and provide a rapid, noninvasive, and reliable technique to assess the functional integrity of visual pathways in the brain. Previously, our group identified weaker excitatory input and a consequential reduction in an inhibitory component of the transient VEP in children with ASD.

Objectives: The aim of the current study was to use steady-state VEPs (ssVEPs) with two radial stimulus conditions, partial-windmill (PW) and windmill-dartboard (WD), to assess short- and long-range lateral inhibitory interactions in children with ASD.

Methods: ssVEPs were obtained from 47 children with ASD and 33 typically developing (TD) controls between the ages of 2 and 12 years old. PW and WD patterns were contrast-reversed in time at 4.29 Hz (peak contrast = 32%). Fourier analysis extracted amplitude and phase measures of frequency components of the response, and a magnitude-squared coherence (MSC) statistic was used to quantify the relative response power at each frequency. Facilitation (short-range lateral interaction) and suppression (long-range lateral interaction) indices were computed based on 1st and 2nd harmonic amplitude measures.

Results: There were no significant differences between groups for measures of amplitude, MSC, facilitation or suppression indices. Significant differences in combined PW and WD amplitude and phase measures, equivalently expressed as sine and cosine coefficients, were observed for diagnostic group (p < .001), age (p = .034) and Diagnosis x Age (p = .001) interactions. Sine-cosine plots for 1st and 2nd harmonics for both conditions indicate that responses change with age for each diagnostic group.

Conclusions: There were no significant differences in short-range or long-range lateral inhibitory interactions between groups, which is consistent with previous findings from tVEP studies demonstrating intact inhibitory activity, on average, in ASD. However, results indicate that global measures of lateral inhibitory interactions significantly differ between groups when age is included as a developmental factor. Further research is needed with larger samples within specific age cohorts to explore these findings in greater detail.