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Open Access Short report

Spatial localisation in autism: evidence for differences in early cortical visual processing

Keziah Latham12*, Susana TL Chung23, Peter M Allen12, Teresa Tavassoli45 and Simon Baron-Cohen4

Author Affiliations

1 Department of Vision & Hearing Sciences, Anglia Ruskin University, Cambridge, UK

2 Vision and Eye Research Unit, Anglia Ruskin University, Cambridge, UK

3 School of Optometry, University of California, Berkeley, CA, USA

4 Department of Psychiatry, Autism Research Centre, Cambridge University, Cambridge, UK

5 Department of Psychiatry, Seaver Autism Centre, Mount Sinai School of Medicine, New York, NY, USA

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Molecular Autism 2013, 4:4  doi:10.1186/2040-2392-4-4

Published: 19 February 2013

Abstract

Background

Vision in people with autism spectrum conditions (ASC) is reported to be different from people without ASC, but the neural level at which the differences begin to occur is not yet known. Here we examine two variants of a vernier acuity task to determine if differences are evident in early visual processing.

Findings

Abutting and separated vernier acuity was assessed in 16 people with ASC and 14 matched controls. In controls, abutting and separated thresholds were unrelated (r = 0.13, p = 0.65), suggesting thresholds are determined by two separate mechanisms. In contrast, the abutting and separated thresholds of ASC observers were strongly correlated (r = 0.88, p < 0.0001), with separated thresholds tending towards being superior to those of controls [t(28) = −2.46, p = 0.02].

Conclusions

The findings suggest the mechanisms employed by ASC observers in separated vernier tasks are different to those of controls. This psychophysical evidence suggests that visual differences in ASC may begin at an early cortical stage of visual processing.

Keywords:
Autism spectrum conditions; Spatial vision; Vernier acuity; Hyperacuity; Psychophysics; Visual processing