To test whether HCQ may rescue impaired hippocampal synaptic plasticity in AD, we studied its effects on late long-term potentiation (LTP), a form of activity-induced synaptic plasticity that has been shown to be impaired prior to significant accumulation of amyloid plaques and neurodegeneration in the APP/PS1 transgenic AD mouse model [33]. The gene discussed is APP; the disease is Alzheimer disease.