Purchase this article with an account.
Janine V. Spencer, Justin M. O'Brien; Imaging visual deficits in autistic spectrum disorder. Journal of Vision 2005;5(8):288. doi: 10.1167/5.8.288.
Download citation file:
© ARVO (1962-2015); The Authors (2016-present)
Previous studies of autism have identified deficits in motion processing (Spencer et al, 2000 Neuroreport 11 2765–2767) and spatial form processing (O'Brien & Spencer, 2004 Perception 33 S28) which may contribute to widely reported deficits in visuomotor control and object recognition or central coherence. To examine the neural bases of these visual deficits we conducted an event-related fMRI study of form and motion coherence processing on a group of adults with autism; a group with Asperger syndrome, and a group comprising matched controls. We measured responses to form and motion stimuli using a Glass stimulus of varying coherence in a field of random dots. A coherent visual patch was depicted by dots separated by a rotational transformation in space (form coherence) or space-time (motion coherence). Five fixed coherence levels were used (0.0, 0.125, 0.25, 0.5, 1.0). Stimuli were presented for 250ms. Participants responded according to the location (left or right of fixation) of the coherent patch. The order of events was pseudo-randomly permuted. The regions of interest in our analysis were based on those previously identified as responding differentially to coherent motion and coherent form (Braddick et al, 2000 Current Biology 10 731–734). The BOLD response in all 4 form ROIs and all 4 motion ROIs was significantly lower in autism than controls, though this finding cannot at this stage be attributed specifically to visual deficits over non-perceptual experimental factors such as attention. A non-linear relationship between the change in BOLD signal and motion coherence was found for autism in V5/MT compared to a linear relationship for controls. Participants with Asperger syndrome did not show results significantly different from the control group.
This PDF is available to Subscribers Only