Whole-body networks: a holistic approach for studying aging.

Aging is a multi-organ disease, yet the traditional approach has been to study each organ in isolation. Such organ-specific studies have provided invaluable information regarding its pathomechanisms. However, an overall picture of the whole-body network (WBN) during aging is still incomplete. In this study, we analyzed the functional magnetic resonance imaging blood-oxygen level-dependent, respiratory rate and heart rate time series of a young and an elderly group during eyes-open resting-state. We constructed WBNs by exploring the time-lagged coupling between the different organs. First, we showed that our analytical pipeline could identify regional differences in the networks of both cohorts, allowing us to proceed with the remaining analyses. The comparison of the WBNs revealed a complex relationship where some connections were stronger and some weaker in the elderly. Finally, the interconnectivity and segregation of the WBNs were negatively correlated with the short-term memory and verbal learning of the young participants. This study: i) validated our methodology, ii) identified differences in the WBNs of the two groups and iii) showed correlations of WBNs with behavioral measures. In conclusion, the concept of WBN shows great potential for the understanding of aging and age-related diseases.