The NMDA receptors are responsible for breeding super-smart mice. When glutamate binds to these receptors and activates them, they become responsible for memory function. They form associations between stimuli that take place, even at relatively widespread timeframes. In addition, enhancing the NR2B gene (and providing extra copies of it) allowed the mice to form memories even as they aged, which was something that did not occur in mice without these extra copies.
