The ability to perceive visual motion is one of the most fundamental and essential facets of vision. While much has been learned over the years about the psychophysics and neurophysiology of motion processing in adults, little is known about its development in infants. The long-term objective of this research is to characterize the development of visual motion perception in human infants, and to understand how underlying neural mechanisms can account for the progression from an immature to an adult-like state. To this end, visual psychophysical experiments are conducted in infants 1-6 months of age, and the results are modeled in terms of known or hypothetical neural mechanisms. Data are collected from infants using simple observational techniques that rely on the fact that infants preferentially state at a patterned stimulus rather than a blank field and that infants exhibit directionally-appropriate eye movements in response to moving targets. Together, we use these techniques to ask questions regarding the development of 1) direction and speed discrimination 2) motion integration across visual space and 3) chromatic (red/green) input to motion processing. The study of infant motion processing is particularly appealing as much is known about the neural basis of motion processing in adults. Thus, discovering the time course of development for different aspects of motion processing will improve our understanding of the neural development of specific visual areas known to be involved in motion processing. From the clinical standpoint, assessment of motion processing capacities could potentially be used to diagnose damage to motion processing areas during development. For example, there are recent claims that the reading disorder """"""""dyslexia"""""""" is correlated with damage to specific motion-related areas of the brain. In virtue of such findings, it is quite possible that early detection of dyslexia could be aided by simple tests of motion processing capabilities. In addition, development of motion mechanisms may be particularly susceptible to environmental factors as suggested from studies (in animals) demonstrating abnormal development of motion processing as a result of altered early visual experience. Thus, assessment of the normal development of visual functions, such as motion processing, is likely to play an important role in clinical diagnosis and in monitoring the effects of treatment in infants and children with visual disabilities.
