Objective To investigate the age-dependent modulatory effects of treadmill exercise on spatial learning and memory in mice and to elucidate the potential neurobiological mechanisms underlying these effects.Methods Male C57BL/6J mice at three distinct developmental stages were subjected to a controlled treadmill training protocol for a duration of four weeks.Cognitive performance was assessed in terms of spatial learning and memoryusing a series of behavioral tests.To examine exercise-induced neurogenesis,proliferating adult neural stem cells in the hippocampal region were labeled via intraperitoneal administration of BrdU.Meanwhile,physiological parameters,including body and muscle weight,were monitored throughout the experiment.Results The study revealed significant age-specific effects of treadmill training.In one-month-old mice,exercise intervention markedly enhanced spatial learning and memory,along with increased proliferation of hippocampal neural stem cells,but no significant alterations were observed in body or muscle weight.In six-month-old mice,treadmill training selectively improved spatial memory and led to increased muscle weight.Notably,three-month-old mice exhibited no significant exercise-induced changes in cognitive performance,hippocampal neurogenesis,or muscle weight.Conclusion These findings demonstrate that treadmill exercise exerts significant,age-dependent regulatory effects on spatial learning and memory,with the most pronounced and comprehensive improvements observed in one-month-old mice.The cognitive enhancements may be mediated,at least partially,through exercise-induced promotion of hippocampal neurogenesis.This study provides data for elucidation of the mechanistic basis of exercise-mediated cognitive enhancement and contributes to the potential applications of exercise interventions in cognitive optimization and neuroplasticity across different developmental stages.