Controlling the Ups and Downs of Synaptic Strength

Abstract
Neuroscientists have long been puzzled by the fact that N -methyl--aspartate (NMDA) receptors can both boost and dampen synaptic efficiency in the brain. In their Perspective, Bliss and Schoepfer reveal specific roles for NMDA receptor subtypes. According to new work ( Liu et al.), the NMDA receptor supports either long-term potentiation or long-term depression, depending on whether the receptor contains NR2A or NR2B subunits, respectively.