The Impact of Mental Activities and Age on Brain Network: An Analysis From Complex Network Perspective

The functional connections in the human brain offer many opportunities to explore changing dynamic patterns of the brain under different circumstances. Different factors such as age, mental activity, and health status may affect functional connectivity, connected regions, and the robustness of connections in the brain. In this study, we evaluate the functional connectivity of the whole brain changing with age from a complex network perspective during different processes in healthy adults. We conducted a functional Magnetic Resonance Imaging (fMRI) study that includes both resting and cognitive states with elderly and young participants (n = 38). To analyze the functional connectivity structure in view of graph theory, we used the minimum dominating sets (MDS) and then minimum hitting sets (MHS) of the connectivity networks. Based on our analysis, age, and mental activity show a significant effect on the hitting sets and dominating sets of the brain regions. The results also indicate that the working mechanism of the brain changes from local to diffused under the circumstances of a particular computational load with age. In this manner, the proposed method can be used as a complementary method for clinical procedures to evaluate and measure the effect of aging on the human brain.