Abnormal Anatomical Rich-Club Organization and Structural–Functional Coupling in Mild Cognitive Impairment and Alzheimer's Disease

Abstract

Emerging research indicates interruptions in the wiring organization of the brain network in Mild cognitive impairment (MCI) and Alzheimer's disease (AD). Due to the important role of rich-club organization in distinguishing abnormalities of AD patients and the close relationship between structural connectivity (SC) and functional connectivity (FC), our study examined whether changes in SC-FC coupling and the relationship with abnormal rich-club organizations during the development of diseases may contribute to the pathophysiology of AD. Structural diffusion-tensor imaging (DTI) and resting-state functional magnetic resonance imaging (fMRI) were performed in 38 normal controls (NCs), 40 MCI patients and 19 AD patients. Measures of the rich-club structure and its role in global structural-functional coupling were administered. Our study found decreased levels of feeder and local connectivity in MCI and AD patients, which were the main contributing factors to the lower efficiency of the brain structural network. Another important finding was that we have more accurately characterized the changing pattern of functional brain dynamics. The enhanced coupling between SC and FC in MCI and AD patients might be due to disruptions in optimal structural organization. More interestingly, we also found increases in the SC-FC coupling for feeder and local connections in MCI and AD patients. SC-FC coupling also showed significant differences between MCI and AD patients, mainly between the abnormal feeder connections. The connection density and coupling strength were significantly correlated with clinical metrics in patients. The present findings enhanced our understanding of the neurophysiologic mechanisms associated with MCI and AD.

Alterations of brain network topology and structural connectivity‐functional connectivity coupling in capsular versus pontine stroke

“…Decreased coupling of SC‐FC may suggest a loss of coherence of functional and structural connectomes [18]. Disrupted couplings of SC‐FC have been reported in pathological states, such as epilepsy, schizophrenia, Alzheimer's disease, and SC‐FC coupling is correlated with the clinical symptoms [36,38–40]. In accordance with previous literature on ischemic stroke patients [19], the present study showed that the right‐lesion CS group had a significant decrease in SC‐FC coupling compared to the HC and the PS groups, and that SC‐FC coupling was positively correlated with FMA score.…”

Aberrant Topological Organization and Age-Related Differences of Human Connectome in Subjective Cognitive Decline by Using Regional Morphology from Magnetic Resonance Imaging

“…For rich-club organization, the distributions of hub regions were similar in two groups, and the decreased strength of feeder connectivity was showed in SCD group, which our results are consistent with previous network SCD studies based on diffusion MRI (Shu et al 2018;Yan et al 2018). Previous studies demonstrated that in AD and MCI patients the rich-club organization was persevered, and the connections including peripheral regions were attacked (Cao et al 2020;Daianu et al 2015). Although the hub regions characterized with high activity and metabolism may accelerate pathology of AD (Buckner et al 2009), whether the attacks beginning within hub regions or nonhub regions remains unclear.…”

Heritability and interindividual variability of regional structure-function coupling

“…Most previous publications investigating SC-FC relationships and their cognitive implications have explored correlations between impairment or cognition with the strength of the correlation between global, whole-brain SC and FC 19 , 22 , 47 , 48 . Studies in control populations have revealed worse cognitive performance in healthy aging was associated with longer latency in dynamic FC states that are more similar to SC 48 and that cognitive flexibility was associated with FC’s alignment with SC 22 .…”