PSEN1 and memory impairment: In contrast, Yue et al. demonstrated that IH (14.3% O2 4 h/day for 14 d or 28 d) alleviates memory impairment and reduces Aβ accumulation and inflammation in the brain of double transgenic mice expressing a chimeric mouse/human APP (Mo/HuAPP695swe) and a mutant human presenilin 1 (PS1-dE9) with the reduction of IL-1β, IL-6, and β-secretase levels [166].