Figure 2.

The modular structure of healthy elderly becomes less distinctive with time. A, Consensus matrices map group-level modular partitions of young participants and elderly participants at each of the three time points to eight networks defined by Yeo et al. (2011). Each module is represented by a single color. With age and time, the modular structure becomes less distinctive, with brain regions within the same a priori subnetwork increasingly getting assigned to different modules. B, The alluvial plot represents changes in group-level modular assignment of brain regions in healthy elderly across three time points. Each block represents a module. Each line indicates a brain region. The color of each line represents the modular assignment of each brain region at the first time point. Among the modules, higher-order networks (e.g., default mode, control, and salience/ventral attention networks) showed the greatest assignment changes in the healthy elderly with time. Similar observations in module fragmentation were made particularly between young and elderly participants at baseline when repeating the analyses with equal scan lengths maintained across participants, where group differences in the modular structure between the two groups remained significant (Figure 2-1; Figure 2-2). DM, Default mode; CON, control; LIM, limbic; SVA, salience/ventral attention; DA, dorsal attention; SM, somatomotor; VIS, visual; TP, temporoparietal; DorsAttn, dorsal attention; SomMot, somatomotor; SalVentAttn, salience/ventral attention.