Development of spatiotemporal mechanisms in infant vision.

In adult spatiotemporal vision information is processed in parallel by a number of mechanisms tuned for orientation and spatial frequency. An examination of infant neuroanatomical data suggests that three major factors are involved in the development of these mechanisms: (1) Growth of foveal cone outer segments causes an increase in mechanism sensitivity. (2) Migration of foveal cones produces a change in spatial scale and a progressive shift of mechanism tuning towards higher spatial frequencies. (3) Development of cortical inhibition transforms low-pass into bandpass spatial frequency and orientation tuning. These changes are developed into a quantitative model which is shown to provide a coherent interpretation of many of the psychophysical data on infant vision.