ABSTRACT
Neuronal activity is necessary for the normal development of mammalian sensory systems; sensory stimulation appears to be an important source of this activity. For example, the cat’s visual system, which has been very extensively studied, is immature at birth and undergoes substantial postnatal development. The course of this development is affected by neuronal activity. For more peripheral structures (e.g., the visual thalamus), the necessary neuronal activity is generated mainly by spontaneous firing of nerve cells in the retina, but for more central structures (e.g., the primary visual cortex), much of the necessary activity results from patterned visual stimulation. The developmental impact of neuronal activity in visual cortex is greatest during a brief critical period, at a time when large numbers of synaptic contacts are being formed within this structure.
