PSEN1 and early-onset autosomal dominant Alzheimer disease: Moreover, the introduction of the CDNF protein or a CDNF transgene into the hippocampus in APP/PS1 mice (transgenic mice expressing a chimeric mouse/human amyloid precursor protein (AßPP) and a mutant human presenilin 1 (PS1); this is an experimental model of Alzheimer’s disease) improves long-term memory [41].