Abstract
Williams Syndrome (WS) is a rare neurodevelopmental disorder, which stems from a genetic deletion on chromosome 7. WS causes a distinct cognitive profile: a relative strength in language, but a profound weakness in visuospatial cognition. Our current study explores how orientation perception may contribute to the visuospatial deficits in WS. In Experiment 1, we found that WS individuals and normal 3–4 year olds had similar orientation discrimination thresholds that were three times higher than thresholds of normal adults. We also found that WS individuals and normal 3–4 year olds had mirror reversal errors for diagonal targets (±45 deg), which did not occur in normal adults. In Experiment 2, we found that sensitivities of WS individuals for detecting orientation defined contours were higher than sensitivities of normal 3–4 year olds, and were not significantly different from sensitivities of normal adults. Together, these results suggest that orientation discrimination in WS is impaired due to delayed or arrested functions at the level of normal 3–4 year olds, while integration of neighboring orientation information is functionally normal.
An NIH fellowship (F31-NS047979) to MP, NSF (0117744), March of Dimes (04-4601-87), and NIH (RO1-NS050876) grants to BL funded this research.