Rapid, experience-dependent expression of synaptic NMDA receptors in visual cortex in vivo.

Sensory experience is crucial in the refinement of synaptic connections in the brain during development. It has been suggested that some forms of experience-dependent synaptic plasticity in vivo are associated with changes in the complement of postsynaptic glutamate receptors, although direct evidence has been lacking. Here we show that visual experience triggers the rapid synaptic insertion of new NMDA receptors in visual cortex. The new receptors have a higher proportion of NR2A subunits and, as a consequence, different functional properties. This effect of experience requires NMDA receptor activation and protein synthesis. Thus, rapid regulation of postsynaptic glutamate receptors is one mechanism for developmental plasticity in the brain. Changes in NMDA receptor expression provide a mechanism by which brief sensory experience can regulate the properties of NMDA receptor-dependent plasticity in visual cortex.