August 2009
Volume 9, Issue 8
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Vision Sciences Society Annual Meeting Abstract  |   August 2009
Magnocellular VEP delay in high Autism Quotient individuals: Absence of the magnocellular advantage may explain poor global identification of locally salient Navon figures
Author Affiliations
  • David Crewther
    Brain Sciences Institute, Swinburne University of Technology
  • Alexandra Sutherland
    Brain Sciences Institute, Swinburne University of Technology
Journal of Vision August 2009, Vol.9, 87. doi:10.1167/9.8.87
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      David Crewther, Alexandra Sutherland; Magnocellular VEP delay in high Autism Quotient individuals: Absence of the magnocellular advantage may explain poor global identification of locally salient Navon figures. Journal of Vision 2009;9(8):87. doi: 10.1167/9.8.87.

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

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Abstract

Many individuals in normal life exhibit certain characteristics of Autism Spectrum Disorder. We were interested whether differences in early visual processing (grouping, motion) shown by autistic children (Dakin and Frith, 2005) would be demonstrated by adults of normal intelligence with high versus low AQ (autism quotient scale; Baron-Cohen, 2001), and whether such differences would be reflected in the electrophysiology of the magnocellular and parvocellular pathways.

129 participants completed an online questionnaire and 15 low AQ (20) were selected for further testing. Participants identified (reaction time/accuracy) the global or local form of locally or globally salient (and congruent or incongruent) Navon figures. In addition, infinite and limited (100 ms) dot lifetime motion coherence thresholds were measured. First and second order kernels of the visual evoked potential (VEP; VERIS multifocal system) using achromatic stimuli of low (24%) and high (96%) contrast, indicative of magno and parvocellular function (Klistorner et al 1997), were recorded.

A mixed design ANOVA with AQ score (high versus low), target identity (global versus local), congruency (congruent versus incongruent) and saliency (globally salient versus locally salient) demonstrated a significant Score*Target Identity*Saliency interaction (F(1, 27) = 9.20, p=.005) on the Navon figures task. Non-linear VEP grand mean average waves for first order and for the first slice of the second order kernel (K2.1) showed significant departures, with the magnocellular generated K2.1 showing manifest delay at high contrast in high AQ participants.

The delayed magnocellular VEP observed at high contrast for the high AQ group would negate the magnocellular advantage (Laycock et al 2007) seen in normals, preventing any assistance from retroinjection of dorsal stream grouping information to area V1 in the recognition of global forms.

Crewther, D. Sutherland, A. (2009). Magnocellular VEP delay in high Autism Quotient individuals: Absence of the magnocellular advantage may explain poor global identification of locally salient Navon figures [Abstract]. Journal of Vision, 9(8):87, 87a, http://journalofvision.org/9/8/87/, doi:10.1167/9.8.87. [CrossRef]
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