ARC and Alzheimer disease: Intriguingly, memantine, an NMDA antagonist widely used to treat symptoms of mild to moderate AD (Folch et al., 2018), reverses the disruptions of behaviorally-induced Arc in chronic inflammation, which appear to be mediated via NMDAR-related mechanisms, perhaps adding another layer to Arc's proposed neuronal functions in AD (Rosi et al., 2005, 2006).