In aged mice, cognitive flexibility varied widely between individuals, and that variability tracked with the proportion of prefrontal synapses containing presynaptic mitochondria and with synaptosomal mitochondrial protein abundance rather than with overall synapse loss. Treatment with the mitochondria-targeted antioxidant MitoQ improved attentional set-shifting and lowered synaptic mitochondrial protein levels, including apoptotic signaling components. The work positions localized mitochondrial oxidative stress at the synapse, not gross structural decline, as a modifiable determinant of executive function in later life.
Key Points
- Presynaptic mitochondrial load inversely tracked cognitive flexibility in aged mice
- Synapse density declined with age but not with performance
- MitoQ restored set-shifting and reduced synaptosomal mitochondrial proteins
Longevity Analysis
Chronological age and functional decline were driven by largely separate protein signatures, which argues against treating cognitive aging as a single uniform process and in favor of identifying who carries specific molecular vulnerability. The determining factor was where oxidative stress occurred — at the energy-producing machinery embedded in prefrontal synapses — rather than how many connections remained, shifting the target from structural preservation to the quality of energy handling within neural circuits. Interventions delivered to the mitochondrial compartment improved flexible thinking without altering baseline learning, suggesting that executive capacity depends on sustained metabolic fidelity at the synapse and can be recovered even after decline has begun.
Original published by Wiley Aging Cell, by Rui Yamada, Hirotaka Nagai, Chisato Numa, Yunhui Zhu, Midori Nagai, Kohei Ota, Yusuke Kawashima, Nobuhiko Ohno, Tomoyuki Furuyashiki .