space. Olney and Sharpe (1969) initially observed that exposure
of the brains of rhesus monkeys to excess glutamate
causes toxicity and neuronal cell death. Subsequent studies
established that excess glutamate results in overstimulation
of glutamate receptors, including the N-methyl-d-aspartate
(NMDA) receptors and the non-NMDA receptors (Ozawa
et al., 1998).