Graph Theory Analysis of Cortical-Subcortical Networks in Late-Life Depression

Abstract

Objectives Late-life major depression (LLD) is characterized by distinct epidemiological and psychosocial factors, as well as medical co-morbidities that are associated with specific neuroanatomical differences. The purpose of this study was to use interregional correlations of cortical and subcortical volumes to examine cortical-subcortical structural network properties in subjects with LLD compared to healthy comparison subjects. Design Cross-sectional neuroimaging study Setting General community Participants We recruited 73 healthy elderly comparison subjects and 53 subjects with LLD who volunteered in response to advertisements. Measurements Brain network connectivity measures were generated by correlating regional volumes after controlling for age, gender, and intracranial volume using the Brain Connectivity Toolbox (www.brain-connectivity-toolbox.net). Results Results for overall network strength revealed that LLD networks showed a greater magnitude of associations for both positive and negative correlation weights compared to healthy elderly networks. LLD networks also demonstrated alterations in brain network structure when compared to healthy comparison subjects. LLD networks were also more vulnerable to targeted attacks compared to healthy elderly comparison subjects and this vulnerability was attenuated when controlling for white matter alterations. Conclusions Overall, this study demonstrates that cortical-subcortical network properties are altered in LLD and may reflect the underlying neuroanatomical vulnerabilities of the disorder.

Sparse Network-Based Models for Patient Classification Using fMRI

“…The most discriminative features revealed by our framework are consistent with the recent literature on functional connectivity in depression (Anand et al, 2005;Greicius et al, 2007;Furman et al, 2011;Wu et al, 2011;Fang et al, 2012;Ajilore et al, 2014), and highlight differences between the groups in cortico-limbic (in particular cortico-striatal) and cortico-cingulate circuitry associated with emotional regulation. A recent review on univariate and connectivity results from studies using fMRI data from MDD patients and emotional facial processing tasks has found a set of consistent regions that are though to be responsible for both a negative and positive bias in patients when processing these tasks (Stuhrmann et al, 2011).…”

Brain Connectivity in Late-Life Depression and Aging Revealed by Network Analysis

“…An earlier study from our group examining gray matter volume inter-correlations (rather than a white matter brain network as described in the current analysis), identified a similar pattern of lower global efficiency and higher global path length in LLD compared to a comparison group, as well as a higher global clustering coefficient in LLD 14 . Unfortunately the available methods precluded investigating individual differences.…”

Disrupted small world topology and modular organisation of functional networks in late-life depression with and without amnestic mild cognitive impairment

“…Altered topological properties of functional networks are associated with depression,21 22 and preclinical, prodromal and clinical AD 20 23–25. Recent graph theoretical applications to assess the grey matter structural covariance networks in LLD demonstrated vulnerabilities in the cortical-subcortical topological properties 26 27. Using diffusion tensor imaging, distinct changes in the network efficiency measures were associated with depression severity and remission in those with LLD 28 29.…”