Selective vulnerability of Rich Club brain regions is an organizational principle of structural connectivity loss in Huntington’s disease
Author(s)
Type
Journal Article
Abstract
Huntington’s disease can be predicted many years before symptom onset, and thus makes an ideal model for studying the earliest mechanisms of neurodegeneration. Diffuse patterns of structural connectivity loss occur in the basal ganglia and cortex early in the disease. However, the organizational principles that underlie these changes are unclear. By understanding such principles we can gain insight into the link between the cellular pathology caused by mutant huntingtin and its downstream effect at the macroscopic level. The ‘rich club’ is a pattern of organization established in healthy human brains, where specific hub ‘rich club’ brain regions are more highly connected to each other than other brain regions. We hypothesized that selective loss of rich club connectivity might represent an organizing principle underlying the distributed pattern of structural connectivity loss seen in Huntington’s disease. To test this hypothesis we performed diffusion tractography and graph theoretical analysis in a pseudo-longitudinal study of 50 premanifest and 38 manifest Huntington’s disease participants compared with 47 healthy controls. Consistent with our hypothesis we found that structural connectivity loss selectively affected rich club brain regions in premanifest and manifest Huntington’s disease participants compared with controls. We found progressive network changes across controls, premanifest Huntington’s disease and manifest Huntington’s disease characterized by increased network segregation in the premanifest stage and loss of network integration in manifest disease. These regional and whole brain network differences were highly correlated with cognitive and motor deficits suggesting they have pathophysiological relevance. We also observed greater reductions in the connectivity of brain regions that have higher network traffic and lower clustering of neighbouring regions. This provides a potential mechanism that results in a characteristic pattern of structural connectivity loss targeting highly connected brain regions with high network traffic and low clustering of neighbouring regions. Our findings highlight the role of the rich club as a substrate for the structural connectivity loss seen in Huntington’s disease and have broader implications for understanding the connection between molecular and systems level pathology in neurodegenerative disease.
Date Issued
2015-09-17
Date Acceptance
2015-07-22
Citation
Brain, 2015, 138, pp.3327-3344
ISSN
1460-2156
Publisher
Oxford University Press
Start Page
3327
End Page
3344
Journal / Book Title
Brain
Volume
138
Copyright Statement
© The Author (2015). Published by Oxford University Press on behalf of the Guarantors of Brain. This is an Open Access article distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/4.0/), which permits unrestricted reuse, distribution, and reproduction in any medium, provided the original work is properly cited.
License URL
Subjects
Science & Technology
Life Sciences & Biomedicine
Clinical Neurology
Neurosciences
Neurosciences & Neurology
tractography
rich club
Huntington's disease
CLINICAL B-VALUES
IN-DIFFUSION MRI
SPHERICAL-DECONVOLUTION
PARKINSONS-DISEASE
ALZHEIMERS-DISEASE
BASAL GANGLIA
TRACTOGRAPHY
CONNECTOME
MECHANISMS
PATHOLOGY
Huntington’s disease
Adult
Basal Ganglia
Brain
Case-Control Studies
Caudate Nucleus
Cerebral Cortex
Diffusion Magnetic Resonance Imaging
Diffusion Tensor Imaging
Female
Humans
Huntington Disease
Image Processing, Computer-Assisted
Longitudinal Studies
Male
Middle Aged
Neostriatum
Neural Pathways
Putamen
Thalamus
Track-HD Investigators
Neurology & Neurosurgery
11 Medical And Health Sciences
17 Psychology And Cognitive Sciences
Publication Status
Published