Postnatal development of the human lateral geniculate nucleus: relationship to a critical period for the visual system.

The cross-sectional areas of 31,800 dorsal lateral geniculate nucleus cells were measured in 53 human brains ranging in age from newborn to 40 years. Geniculate cells increase in size rapidly during the first 6 to 12 months of postnatal life, with cells in the parvocellular layers developing faster than cells in the magnocellular layers. At least 2 years are required before all cells have reached their adult size.