In aged mice, cognitive flexibility tracked with the state and placement of mitochondria at presynaptic terminals rather than with gross structural changes in neurons or astrocytes. Gene expression linked to cognitive inflexibility was largely distinct from gene expression linked to chronological age, indicating that individual variability in learning capacity is driven by synaptic energy handling more than by age itself.
Key Points
- Presynaptic mitochondria correlated with cognitive inflexibility in aged mice
- Inflexibility-linked genes differed from chronological aging gene signatures
- mTOR signaling and amyloid handling associated with better performance
Longevity Analysis
Cognitive aging is being reframed as a bioenergetic problem localized to the synapse, where the supply and quality of energy production determines whether a brain can revise a learned rule. The separation between age-associated gene expression and inflexibility-associated gene expression suggests chronological age is a poor proxy for cognitive capacity, and that measurable mitochondrial function may serve as the more informative signal. Interventions that lower oxidative burden and support mitochondrial turnover — exercise, metabolic control, sleep-driven repair — act on the same variable this work identifies as decisive.
Original published by LifeSpan.io, by Josh Conway.