Visual deprivation induced by monocular eyelid suture, a laboratory model for congenital cataract, results in shrinkage of ocular dominance columns serving the closed eye. We performed monocular suture in macaques at ages 1, 3, 5, 7, and 12 weeks to define the critical period for plasticity of ocular dominance columns. After a minimum survival of 8 months, complete montages of [3H]proline-label...