Background: Few works studied the directed whole-brain interaction between different
brain regions of Alzheimer’s disease (AD). Here, we investigated the whole-brain effective connectivity
and studied the graph metrics associated with AD.
Methods: Large-scale Granger causality analysis was conducted to explore abnormal whole-brain
effective connectivity of patients with AD. Moreover, graph-theoretical metrics including smallworldness,
assortativity, and hierarchy, were computed from the effective connectivity network. Statistical
analysis identified the aberrant network properties of AD subjects when compared against
Results: Decreased small-worldness, and increased characteristic path length, disassortativity, and
hierarchy were found in AD subjects.
Conclusion: This work sheds insight into the underlying neuropathological mechanism of the brain
network of AD individuals such as less efficient information transmission and reduced resilience to a
random or targeted attack.