Retinotopic organization of visual cortex in human infants

Vision develops rapidly during infancy, yet how visual cortex is organized
during this period is unclear. In particular, it is unknown whether
functional maps that organize the mature adult visual cortex are present
in the infant striate and extrastriate cortex. Here we test the functional
maturity of infant visual cortex by performing retinotopic mapping with
fMRI. Infants aged 5–23 months had retinotopic maps, with alternating
preferences for vertical and horizontal meridians indicative of area
boundaries from V1 to V4, and an orthogonal gradient of preferences from
high to low spatial frequencies. The presence of multiple visual maps
throughout visual cortex in infants indicates a greater maturity of
extrastriate cortex than previously appreciated. The areas showed subtle
age-related fine-tuning, suggesting that early maturation undergoes
continued refinement. This early maturation of area boundaries and tuning
may scaffold subsequent developmental changes.