Functional Disorganization of Small-World Brain Networks in Patients With Ischemic Leukoaraiosis

Abstract

Cognitive impairment is a key clinical feature of ischemic leukoaraiosis (ILA); however, the underlying neurobiological mechanism is still unclear. ILA has been associated with widespread gray and white matter (WM) damage mainly located in cortical-cortical and cortico-subcortical pathways. A total of 36 patients with ILA (Fazekas rating score ≥2) and 31 healthy controls (HCs) underwent comprehensive neuropsychological assessments (covering four cognitive domains, i.e., information processing speed, episodic memory, executive and visuospatial function) and resting-state functional MRI scans. Graph theory-based analyses were employed to explore the topological organization of the brain connectome in ILA patients, and we further sought to explore the associations of connectome-based metrics and neuropsychological performances. An efficient small-world architecture in the functional brain connectome was observed in the ILA and control groups. Moreover, compared with the HCs, the ILA patients showed increased path length and decreased network efficiency (i.e., global and local efficiency) in their functional brain networks. Further network-based statistic (NBS) analysis revealed a functional-disconnected network in ILA, which is comprised of functional connections linking different brain modules (i.e., default mode, frontoparietal, ventral attention and limbic systems) and connections within single modules (i.e., ventral attention and limbic systems). Intriguingly, the abnormal network metrics correlated with cognitive deficits in ILA patients. Therefore, our findings provide further evidence to support the concept that ILA pathologies could disrupt brain connections, impairing network functioning, and cognition via a "disconnection syndrome."

The 2-D Cluster Variation Method: Topography Illustrations and Their Enthalpy Parameter Correlations

“…Liao et al provide a concise summary of key measures useful in evaluating small-world-ness [ 49 ], and Zhu et al take a graph theory-based to investigate the topological organization of the brain connectome, with particular attention to small-world properties (2020) [ 50 ].…”

Network dynamics scale with levels of awareness

“…CC-BY-NC-ND 4.0 International license made available under a (which was not certified by peer review) is the author/funder, who has granted bioRxiv a license to display the preprint in perpetuity. It is The copyright holder for this preprint this version posted April 13, 2021. ; https://doi.org/10.1101/2021.04.12.439452 doi: bioRxiv preprint Sporns & Zwi, 2004;Takagi, 2018;Tan & Cheong, 2017;van den Heuvel et al, 2008;Wu et al, 2012;Yu et al, 2011;Zhu et al, 2020). Therefore, it is possible that the reconfiguration of SW topology over time may indicate variations in information processing (and therefore cognitive states (Bassett & Bullmore, 2017)), which would intuitively increase proportionally to the level of awareness (Carhart-Harris et al, 2014;Laureys et al, 2007;Tononi et al, 2016).…”

Aging Brains Degrade Driving Safety Performances of the Healthy Elderly

“…Radiological evaluations of the participants' LA were made using three kinds of MRI images: T1-weigted, T2-weighted, and FLAIR images. They are useful for differential diagnoses of LA from cerebral infarction and brain tumors (Zhu et al, 2020 ). LA was classified into six grades from G0 to G5 according to previously delineated criteria (Putaala et al, 2009 ; Park et al, 2013 ).…”