Fronto-parietal Network Segregation Predicts Maintained Cognition in the Cognitively Healthy Oldest-old (85+): evidence for dedifferentiation

The understanding of brain network interactions in cognitively healthy older adults informs how brain characteristics vary as individuals age and how these variations affect cognitive functioning. A functional connectivity analysis can reveal important insight into the brain9s organization, which is crucial to examining cognitive aging. We investigated functional network properties in 146 cognitively healthy participants aged 85+ in the McKnight Brain Aging Registry. We found that the segregation of the cortical association system and the segregation of the fronto-parietal network (FPN) were stronger predictors of cognition and executive function. Compared to other network metrics, the segregation of networks may be more closely linked with cognitive performance and age-related dedifferentiation. We also provide a healthy oldest-old (85+) cortical parcellation that can be used in future work in this age group. This study shows that network segregation of the oldest-old brain supports cognition. Specifically, the FPN plays an important role in supporting overall cognition and executive function in an aging population. By studying network dynamics and cognitive abilities of healthy brain aging, we advance the literature on dedifferentiation in the oldest-old.