RT Journal Article
SR Electronic
T1 Larger Extrastriate Population Receptive Fields in Autism Spectrum Disorders
JF The Journal of Neuroscience
JO J. Neurosci.
FD Society for Neuroscience
SP 2713
OP 2724
DO 10.1523/JNEUROSCI.4416-13.2014
VO 34
IS 7
A1 Schwarzkopf, D. Samuel
A1 Anderson, Elaine J.
A1 de Haas, Benjamin
A1 White, Sarah J.
A1 Rees, Geraint
YR 2014
UL http://www.jneurosci.org/content/34/7/2713.abstract
AB Previous behavioral research suggests enhanced local visual processing in individuals with autism spectrum disorders (ASDs). Here we used functional MRI and population receptive field (pRF) analysis to test whether the response selectivity of human visual cortex is atypical in individuals with high-functioning ASDs compared with neurotypical, demographically matched controls. For each voxel, we fitted a pRF model to fMRI signals measured while participants viewed flickering bar stimuli traversing the visual field. In most extrastriate regions, perifoveal pRFs were larger in the ASD group than in controls. We observed no differences in V1 or V3A. Differences in the hemodynamic response function, eye movements, or increased measurement noise could not account for these results; individuals with ASDs showed stronger, more reliable responses to visual stimulation. Interestingly, pRF sizes also correlated with individual differences in autistic traits but there were no correlations with behavioral measures of visual processing. Our findings thus suggest that visual cortex in ASDs is not characterized by sharper spatial selectivity. Instead, we speculate that visual cortical function in ASDs may be characterized by extrastriate cortical hyperexcitability or differential attentional deployment.