Thalamic atrophy and its impact on cognitive function in normal aging

The human thalamus serves as a central integrative hub, facilitating the transmission of information among the cerebral cortex, subcortical structures, and the peripheral nervous system, while supporting a range of higher cognitive functions. Although significant age-related changes in thalamic volume and microstructure have been reported, the specific differences in the volumes of thalamic nuclei and their associations with cognitive functions throughout adulthood remain unclear. T₁-weighted MRI scans from 314 cognitively healthy individuals were categorized into four age groups: young (20-35 years), early middle-aged (36-50 years), late middle-aged (51-65 years), and older (>65 years). Thalamus volumes and cognitive function scales were compared across age groups, and associations between thalamic volume and cognitive function with age were further analyzed. Significant atrophy was observed in all ventral thalamic nuclei in older adults, as well as in the paracentral (Pc), mediodorsal medial (MDm), lateral geniculate (LGN), and anterior pulvinar (PuA) nuclei. The volumes of thalamic subnuclei, particularly those in the ventral, posterior, medial and intralaminar groups, were positively correlated with cognitive performance, especially in executive-attentional and working memory during aging. These findings underscore the importance of thalamic subnuclei in maintaining cognitive function during healthy aging.