PSEN1 and Cognitive impairment: In PSAPP (SweAPP, PSEN1dE9) AD mice, which carry human Swedish mutant amyloid precursor protein (SweAPP) and mutant presenilin 1 (PS1) genes, a single controlled cortical impact (CCI) injury precipitated cognitive impairment and extracellular Aβ deposits between two and six weeks post- injury [10].