Little is known about the role of ErbBs in PD and AD; however,ErbB activation improves neuronal survival and synaptic function inAD models,13,17,24 and ErbB4 is highly phosphorylated in the neurons of the AD humanbrain and of APP/PS1 mice, a model of early onset AD.25 Furthermore, oligomeric amyloid beta (Aβ)—amajor inducer of neurotoxicity in AD—binds to ErbB4,26 presumably increasing Aβ insertion intoneuronal membranes. Here, APP is linked to Alzheimer disease.