PSEN1 and Alzheimer disease: In a study by Li et al. [25],4-month-old and 12-month-old APP/PS1 mice were used to simulate the mild and the moderate stages of AD, EA was found to be more effective in mild AD mice than in moderate AD mice by suppressing microglial polarization to the M1 phenotype and promoting microglial M2 polarization, they also found changes specifically in the number of Aβ-positive plaques, but not in the area fraction in moderate AD mice.