APP and Alzheimer disease: In addition, in mouse transgenic models of Alzheimer’s disease with overexpression of various APP mutations in the brain, abnormalities in glutamatergic signaling affecting learning and memory are suggested, as Aβ-induced oxidative stress deregulates the glutamatergic neurotransmission system and increases the accumulation of extracellular glutamate and activation of NMDA receptors, leading to excitotoxicity [178].