Visual motion processing in typical development and developmental coordination disorder

• Main Author: Corbett, Fleur Phaedra
• Published: University College London (University of London) 2017
• Online Access: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.747092

This thesis is concerned with the maturation of global motion coherence sensitivity in typical development and in Developmental Coordination Disorder (DCD), in relation to the dorsal stream vulnerability hypothesis. Dorsal stream vulnerability, indicated by poorer coherence sensitivity to motion relative to form, has been reported in many neurodevelopmental disorders. As dorsal stream networks underpin a cluster of visuomotor, visuospatial and oculomotor functions, in addition to motion perception, both visuomotor ability and motion coherence sensitivity were examined. Coherence sensitivity to rotational, radial and translational motions was compared with behavioural and electrophysiological techniques. Results indicated that typical adults show greatest coherence sensitivity to rotational motion, followed by radial and translational motions, and distinct patterns of coherence-sensitive visual event-related potentials for each motion. Discrimination of motion direction was better than coherent motion detection, consistent with models of the neural representation of motion coherence. In typical 6-14 year olds, coherence sensitivity to form matured earlier than to motion, with developmental trajectories converging in adulthood. Children’s coherence sensitivity matured earlier for radial motion than rotational or translational motions. These studies provide the first normative data for the maturation of coherence sensitivity to radial, rotational and translational motions and form, demonstrating asynchronous development and differential coherence sensitivity to each motion. In adults with DCD, coherence sensitivity to both motion and form was impaired relative to typical adults but adults with DCD were not selectively disadvantaged in using motion information in a visuomotor context. Young children with DCD showed a specific deficit in coherence sensitivity to motion relative to form, concordant with the dorsal stream vulnerability concept. Motor impairment correlated with motion coherence sensitivity in children with DCD. These studies showed that dorsal stream impairments could have a role in the early development of DCD, even when not evident in later development, when poor motor competency persists.