Brain connectivity linked to inhibition balance shifts with age
Left parietal-putamen connectivity predicted better cognitive flexibility in young adults (r = 0.41) but worse performance in older adults (r = -0.33).
Brain Communications
In a cross-sectional study of 40 younger (ages 18–35) and 40 older healthy adults (ages 60–85), researchers tracked how brain neurochemistry relates to network connectivity during a rule-switching task. The team used functional MRI and magnetic resonance spectroscopy to measure task-induced changes in the ratio of inhibitory GABA to excitatory glutamate and glutamine in two brain hubs: the inferior frontal cortex and inferior parietal lobe. Task-driven shifts in this neurochemical balance correlated with connectivity in both regions. Young adults showed stronger connectivity linked to higher inhibitory tone in the frontal cortex, whereas older adults showed a stronger pattern in the parietal lobe. Additionally, connectivity between the left inferior parietal lobe and bilateral putamen predicted better cognitive flexibility in younger adults, but predicted worse performance in older adults.
Why it matters
Cognitive flexibility typically declines in late life, but the underlying neurometabolic and network mechanisms are not fully resolved. These findings show that aging alters how local excitatory and inhibitory balance coordinates large-scale brain networks to support executive function.
Caveats
Because this study was cross-sectional, it cannot establish whether changes in neurometabolic balance cause altered network connectivity or cognitive decline over time. The sample was also restricted to 80 healthy individuals, with several participants excluded due to motion or spectral fitting errors.
The paper
Hasselt University · KU Leuven
Brain Communications · 28 Sep 2026 · CC BY