After analyzing the waveform of hippocampal CA1 pyramidal neurons (Fig. 5H), we found an increase in half-width (Fig. 5I, P < 0.05) and a decrease in membrane potential (Fig. 5J, P < 0.05) and frequency (Fig. 5K, P < 0.01) of action potentials in the AD + saline group compared to the WT mice, whereas EVs treatment significantly reversed (Fig. 6I-K, P < 0.05) these potential changes, suggesting that MSC-EVs treatment restores the excitability of hippocampal CA1 pyramidal neurons in APP / PS1 mice. Here, APP is linked to Alzheimer disease.