August 2012
Volume 12, Issue 9
Free
Vision Sciences Society Annual Meeting Abstract  |   August 2012
Contrast response functions for visual evoked nonlinearities demonstrate differences in magnocellular but not parvocellular components as a function of autistic tendency.
Author Affiliations
  • David Crewther
    FLSS, Swinburne University of Technology
  • Brianna Jackson
    FLSS, Swinburne University of Technology
  • Ellie Blackwood
    FLSS, Swinburne University of Technology
  • Julieanne Blum
    FLSS, Swinburne University of Technology
  • Sean Carruthers
    FLSS, Swinburne University of Technology
  • Sabrina Nemorin
    FLSS, Swinburne University of Technology
  • Brett Pryor
    FLSS, Swinburne University of Technology
  • Shannon Sceneay
    FLSS, Swinburne University of Technology
  • Stephanie Bevan
    FLSS, Swinburne University of Technology
  • Reneta Slikboer
    FLSS, Swinburne University of Technology
Journal of Vision August 2012, Vol.12, 1356. doi:10.1167/12.9.1356
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      David Crewther, Brianna Jackson, Ellie Blackwood, Julieanne Blum, Sean Carruthers, Sabrina Nemorin, Brett Pryor, Shannon Sceneay, Stephanie Bevan, Reneta Slikboer; Contrast response functions for visual evoked nonlinearities demonstrate differences in magnocellular but not parvocellular components as a function of autistic tendency.. Journal of Vision 2012;12(9):1356. doi: 10.1167/12.9.1356.

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      © ARVO (1962-2015); The Authors (2016-present)

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Abstract

Autistic tendency has often been associated with impaired visual motion sensitivity, global/local perception and visual discrimination of facial emotion. However, the neurophysiological mechanisms underlying this impaired visual perception have yet to be established. Nonlinear multifocal visual evoked potentials (Sutherland and Crewther, 2010) have demonstrated delayed magnocellular processing for high stimulus contrast in populations scoring high on Baron-Cohen’s autism spectrum quotient (AQ). Here we investigated the contrast response functions of the main peaks of the first order and first two slices of the second order multifocal VEP with (central unstructured patch subtending 4°) with temporal contrasts of 10%, 25%, 50%, 70% and 96% in 29 normal participants (8 High AQ, 12 Middle AQ, 9 Low AQ) showing no group differences in non-verbal IQ (Raven’s Advanced Progressive Matrices). Motion coherence sensitivity was also assessed. The contrast response function (CRF) for the first slice 2nd order (K2.1) showed high contrast gain and response saturation, while the second slice K2.2 showed lower contrast gain and little saturation – giving support for generation by the magno- and parvocellular systems respectively. As a function of participant AQ score, the High AQ group showed greater CRF amplitudes for the N60-P85 K2.1 response than Middle or Low AQ groups, while the CRFs for the N95-P125 K2.2 were similar across AQ groups. Tests of within-subject effects revealed a significant Contrast * AQ interaction between High and Low AQ groups. Also High AQ showed a significant delay in the K2.1 positivity at high contrast. An expected impairment in motion sensitivity was only observed in the High AQ group for limited lifetime low contrast (10%) coherent motion. The data suggest that the magnocellular system in High AQ individuals has more difficulty recovering after stimulation.

Meeting abstract presented at VSS 2012

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