Age-related degradation of cerebellar functional network topology.

With the aging of global populations, understanding the role of the cerebellum in aging is crucial. However, existing studies primarily focus on structural and functional changes, leaving the topological properties of cerebellar functional networks in aging unclear. Here, we explored the aging effects on the topological organization of cerebellar functional networks and investigated the relationship between these changes and cognitive function. The results revealed that, compared with young adults, older adults exhibited declines in the global and local network efficiency, modularity, and small-world properties of the cerebellum. Additionally, reductions were observed in the betweenness centrality within the visual network (VN), the nodal efficiency (NE) within the VN and lateral somatomotor network (SMN(Lat)). Moreover, the nodal local efficiency (NLE) decreased in the default mode network and SMN(Lat) of older adults. Notably, the gamma value of the cerebellar network was positively correlated with Stroop task accuracy in the incongruent condition among older adults. Additionally, aging impaired whole-brain (including cerebellar) network efficiency but preserved modularity and small-world properties, and at the nodal level, cerebellar regions showed selective reductions in NE and NLE, alongside degree centrality reorganization. Exploratory analyses revealed gender-specific patterns in cerebellar network topology during aging, with males experiencing relatively limited declines and females showing more extensive deterioration. The findings indicated that aging is associated with disruptions in the global and regional topology of the cerebellar functional connectome, with females exhibiting more pronounced deterioration than males. The integrity of cerebellar network topology appeared crucial for maintaining cognitive control.