title: Deficiency of brain structural sub-network underlying post-ischaemic stroke apathy.
abstract: OBJECTIVE
  This study aimed to reveal the structural basis of post-ischaemic stroke apathy, especially in relation to disruptions in structural connectivity.
  
  
  METHODS
  Eighty-eight participants were included. The Apathy Evaluation Scale, clinician version, was used to characterize the severity of apathy. Diffusion tensor imaging tractography was used to examine white matter integrity and to reconstruct white matter networks using 90 nodes based on the automated anatomical labeling atlas. The degree for each node was extracted to determine the relationship to the severity of apathy.
  
  
  RESULTS
  Apathy was not significantly associated with damage to any single brain region. The degrees of 24 nodes (limbic system, three nodes; frontal lobe, six; basal ganglia, two; temporal lobe, three; parietal lobe, three; insula, two; occipital lobe, five) were significantly correlated to the Apathy Evaluation Scale scores. These 24 nodes constituted an apathy-related sub-network and its global and local efficiencies were negatively correlated with apathy levels (global, r = -0.54, P < 0.01; local, r = -0.64, P < 0.01). Multivariate logistic regression indicated that decreased global efficiency of this sub-network was an independent risk factor for apathy (odds ratio 0.03, 95% confidence interval 0.01-0.04, P = 0.007). Efficiencies of the non-apathy-related sub-network (the remaining 66 nodes) did not correlate or predict the presence of apathy.
  
  
  CONCLUSIONS
  Post-stroke apathy is not due to the dysfunction of a single region or circuit. Rather, it results from disconnection of a complex sub-network of brain regions. This provides new insights into the neuroanatomical basis of post-stroke apathy.
authors.affiliation: Department of Experimental Psychology, University of Oxford, Oxford, UK; Department of Neurology, Guangzhou First People's Hospital, Guangzhou Medical University, Guangzhou, China.
authors.forename: S
authors.initials: S
authors.lastname: Yang
authors.forename: P
authors.initials: P
authors.lastname: Hua
authors.forename: X
authors.initials: X
authors.lastname: Shang
authors.forename: Z
authors.initials: Z
authors.lastname: Cui
authors.forename: S
authors.initials: S
authors.lastname: Zhong
authors.forename: G
authors.initials: G
authors.lastname: Gong
authors.forename: G
authors.initials: G
authors.lastname: William Humphreys
mesh_terms: D000368:Aged; D057565:Apathy / Q000502:physiology*; D002545:Brain Ischemia / Q000150:complications* / Q000473:pathology; D056324:Diffusion Tensor Imaging / Q000379:methods*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000473:pathology*; D020521:Stroke / Q000150:complications* / Q000473:pathology; D066127:White Matter / Q000473:pathology*
keywords: apathy; brain network; diffusion tensor imaging; stroke; white matter