It is of long-standing interest about how early experiences sculpt the structure and function of cortical circuits during a brief postnatal development period.One of classic paradigms for this critical-period plasticity is experience-induced ocular dominance plasticity of primary visual cortex (V1), in which brief visual deprivation of one eye in a short period after the eye-opening often results in persistent changes of V1 ocular dominance in rodents and higher mammals.Accumulating evidence has suggested that postnatal maturation of cortical inhibition, primarily mediated by a parvalbumin-positive (PV+) type of GABAergic interneurons, is important in regulating the critical period onset.