Preserved topography, lateralization, selectivity, and functional connectivity of the language network in older brains

Abstract

Healthy aging is associated with structural and functional brain changes. However, cognitive abilities vary in how they change with age: executive functions decline, while aspects of linguistic processing remain relatively preserved. This heterogeneity predicts differences among brain networks in whether and how they change with age. To evaluate this prediction, we used precision fMRI to examine the language-selective network and the Multiple Demand (MD) network, which supports executive functions, in older adults (N = 64) relative to young controls (N = 483). The MD network of older adults shows weaker, less spatially extensive, and more topographically variable activations during an executive function task and reduced within-network functional connectivity. In contrast, we find remarkable preservation of the language network in older adults: it responds during language comprehension as strongly and selectively as in younger adults, with similar left-hemispheric lateralization and within-network functional connectivity. These findings align with behavioral preservation of language comprehension in healthy aging. Here, the authors show that aging affects brain networks differently, with neural changes mirroring the preservation or decline of the cognitive functions they support. The multiple demand network exhibits age-related decline while the language network remains stable with age.