RBFOX3 and Alzheimer disease: Since neuronal loss is correlated with memory deficits in AD, we next examined neuronal survival in the hippocampal CA1 and CA3 regions, areas crucial for learning and memory.42,43 Immunofluorescence staining revealed that AR@ENV-treated mice had significantly more NeuN+ neurons than saline-treated AD mice did (Fig. 7g; Supplementary Fig. 27), indicating substantial neuroprotection and reduced neuronal loss.