SYP and Alzheimer disease: We found that 12 weeks of treadmill exercise prevented a decline in spatial learning and memory in six-month-old 3×Tg-AD mice and that treadmill exercise led to enhanced structural synaptic plasticity by increasing synapse numbers and synaptic structural parameters, the expression of synaptophysin (Syn), the axon length, dendritic complexity, and the dendritic spine numbers.