Research On Healthy Aging Brain Network Dynamic Functional Connectivity Based On Magnetic Resonance Imaging

The brain undergoes structural and functional changes during aging.Previous studies measured the changes of functional connectivity through functional magnetic resonance imaging,and found that the functional connectivity and network integrity generally decreased under healthy aging.Some studies have explored the functional connections of aging in the resting state,discovering complex changes in functional connections between the network and an overall increase in functional connections between networks,while others have explored the effects of aging in the movie-watching state and found reduced inter subject functional correlations.In this study,we explored the differences in the stability of dynamic functional connections between the elderly and the young in both the viewing state and the resting state,and used clustering to obtain the differences in functional connectivity during viewing state,studying the impact of aging on brain functional connectivity.Dynamic functional architecture and dynamic functional connectivity variability were used to study the differences during viewing and resting states as well as changes in the dynamic functional connectivity between significant variant brain regions and whole brain between elderly and young people.The viewing and resting data consisting of 50 elderly and 49 young participants were collected.116 brain regions were extracted using Automatic Anatomical Labeling templates,and the dynamic functional architecture stability of voxel-brain regions was calculated using sliding window method.Subsequently,further analysis was conducted on significant brain regions.Research findings show that during the viewing state,the functional stability of the primary visual cortex and perceptual cortex decreases,while the stability of advanced functional brain regions related to higherorder visual processing,motion,and information processing increases.Compared to young people,the stability of advanced functional brain regions related to facial assessment of the elderly has increased,while the stability of functional brain regions related to memory and other functions has decreased.The stability changes caused by viewing may be mainly related to the functional cooperation changes between the primary and advanced functional regions,while the stability changes caused by aging may be mainly related to the functional changes between the advanced functional regions.The differences of the dynamic functional connection between the elderly and young people in the movie-watching state were studied.This study used K-means clustering to cluster the functional connection into four types of states,in which state 2 presents the overall high connection and state 1,3 and 4 present low connection.The results show that in state 1,the time variabilities of the elderly relative to the young are mainly increased connections between the advanced networks,and decreased between the advanced networks and the primary networks.State 2 has mainly reduced connection between advanced networks and increased between advanced networks and junior networks.State3 has mainly increased connections between high-level networks and between primary and high-level networks.State 4 has mainly increased connections between the cerebellum and the higher network,decreased connections between the cerebellum and the primary network,and decreased connections between the higher network and the higher network and the primary network.Aging results in changes in functional collaboration between networks.In general,the effects of aging on brain function were studied by means of dynamic functional structure stability and cluster state analysis.The results showed that the stability of the advanced functional areas of the brain generally increased while the primary functional areas generally decreased during film viewing,and aging mainly led to differences in the stability of the advanced functional areas.Viewing has resulted in changes in the connections between primary and advanced functional areas,while aging has resulted in changes in the connections between advanced functional areas.The changes in functional connectivity between brain regions reflect changes in information exchange,which may reveal the impact of aging on brain network function.