Running throughout Middle-Age Keeps Old Adult-Born Neurons Wired

Area of Science:

• Neuroscience
• Aging Research
• Exercise Physiology

Background:

• Exercise, particularly running, is known to promote neurogenesis in the hippocampus.
• The integration and long-term connectivity of adult-born neurons during aging remain incompletely understood.
• Investigating the impact of sustained exercise on neuronal networks is crucial for understanding cognitive aging.

Purpose of the Study:

• To determine if long-term running affects the integration and connectivity of adult-born neurons in the aging hippocampus.
• To identify specific changes in afferent inputs to these neurons following prolonged exercise.
• To elucidate the role of exercise in maintaining neuronal networks vital for memory during aging.

Main Methods:

• Utilized retroviral labeling of neural progenitor cells in young adult mice (sedentary vs. running).
• Employed rabies virus tracing to identify monosynaptic inputs to "old" adult-born neurons six months later.
• Quantified afferent connections from hippocampal and (sub)cortical areas to these neurons.

Main Results:

• Long-term running significantly altered the network connectivity of adult-born neurons by middle age.
• Exercise increased inputs from hippocampal interneurons, potentially mitigating hyperexcitability.
• Running preserved perirhinal cortex innervation and enhanced inputs from the subiculum and entorhinal cortex.

Conclusions:

• Sustained exercise maintains the functional wiring of adult-born neurons generated in early life.
• These exercise-induced network modifications in the hippocampus are associated with preserved memory function during aging.
• Exercise represents a viable strategy to support cognitive health and combat age-related memory impairments.