PSEN1 and Alzheimer disease: Then, we evaluated the newborn oligodendrocyte lineage cells (BrdU+/Olig2+) in the hippocampi of 10-month-old APP/PS1 mice, but did not observe significant differences in the densities of BrdU+/Olig2+ cells in the hippocampal subregions between the AD mice and the non-transgenic littermates.