RBFOX3 and Alzheimer disease: To further determine the in vivo protective mechanism of CRB‐2131, we asked whether it could prevent neuronal‐cell death: Aβ is well known to drive neuronal‐cell death in AD.[34, 35] Thus, 5XFAD mice were treated with prophylactic CRB‐2131 treatment (3.5‐month‐old mice, 1, 3, or 10 mpk, q.d., P.O., and 10 weeks), after which the brain was subjected to immunohistochemistry with anti‐NeuN+ as a marker of mature neuron.