Roles of the Dorsal and Ventral Visual Streams in Fluent Reading
Abstract
Despite the current emphasis in the reading literature on phonological awareness, visual deficits have also been observed in disabled readers. Visual processing has been shown to be abnormal in individuals with dyslexia (e.g., Eden et al., 1996), specifically in the dorsal visual stream of the brain, which processes motion. It is unclear, however, whether or not there is a significant relationship between visual processing in the dorsal stream and reading ability in typically developing children. Furthermore, few studies have examined performance on tasks purported to measure the ventral visual stream, which processes form. The current study examined the correlations between detection thresholds for coherent motion detection (CMD) and coherent form detection (static Glass patterns) tasks, designed to measure dorsal and ventral stream functioning, respectively, and scores on a standardized measure of reading fluency in 25 typically developing children. Results indicated that in typically developing children, reading fluency is significantly correlated with thresholds for coherent form detection but not coherent motion detection when controlling for nonverbal IQ (NVIQ) and age. This suggests that reading fluency is related to ventral, rather than dorsal, visual processing in typically developing children. Though the current results were not expected based on previous studies, ventral