PPP1R9B and Mental deterioration: The present study found decreased gene expressions of several neurodegenerative biomarkers in the hippocampus of aged mice, including Sirt1 and FoxO3, which have been revealed to modulate cognitive decline [30], and reduced expressions of synapse-related genes PSD95 and Spinophilin, which play crucial roles in synaptic plasticity modulation [21,31].