title: Loneliness in late-life depression: structural and functional connectivity during affective processing.
abstract: Late-life depression (LLD) in the elderly was reported to present with emotion dysregulation accompanied by high perceived loneliness. Previous research has suggested that LLD is a disorder of connectivity and is associated with aberrant network properties. On the other hand, perceived loneliness is found to adversely affect the brain, but little is known about its neurobiological basis in LLD. The current study investigated the relationships between the structural connectivity, functional connectivity during affective processing, and perceived loneliness in LLD.
  
  
  
  The current study included 54 participants aged >60 years of whom 31 were diagnosed with LLD. Diffusion tensor imaging (DTI) data and task-based functional magnetic resonance imaging (fMRI) data of an affective processing task were collected. Network-based statistics and graph theory techniques were applied, and the participants' perceived loneliness and depression level were measured. The affective processing task included viewing affective stimuli.
  
  
  
  Structurally, a loneliness-related sub-network was identified across all subjects. Functionally, perceived loneliness was related to connectivity differently in LLD than that in controls when they were processing negative stimuli, with aberrant networking in subcortical area.
  
  
  
  Perceived loneliness was identified to have a unique role in relation to the negative affective processing in LLD at the functional brain connectional and network levels. The findings increas our understanding of LLD and provide initial evidence of the neurobiological mechanisms of loneliness in LLD. Loneliness might be a potential intervention target in depressive patients.
authors.affiliation: Laboratory of Neuropsychology,The University of Hong Kong,Hong Kong.
authors.forename: N M L
authors.initials: NM
authors.lastname: Wong
authors.affiliation: Department of Imaging Physics,University of Texas MD Anderson Cancer Center,USA.
authors.forename: H-L
authors.initials: HL
authors.lastname: Liu
authors.affiliation: Department of Psychiatry,Chang Gung Memorial Hospital,Keelung City,Taiwan.
authors.forename: C
authors.initials: C
authors.lastname: Lin
authors.affiliation: College of Biological Science and Technology, National Chiao Tung University,Taiwan.
authors.forename: C-M
authors.initials: CM
authors.lastname: Huang
authors.affiliation: Department of Medical Imaging and Intervention,Chang Gung Memorial Hospital,Taoyuan,Taiwan.
authors.forename: Y-Y
authors.initials: YY
authors.lastname: Wai
authors.affiliation: College of Medicine, Chang Gung University,Taiwan.
authors.forename: S-H
authors.initials: SH
authors.lastname: Lee
authors.affiliation: Laboratory of Neuropsychology,The University of Hong Kong,Hong Kong.
authors.forename: T M C
authors.initials: TM
authors.lastname: Lee
mesh_terms: D000368:Aged; D000375:Aging; D063132:Connectome / Q000379:methods*; D003865:Major Depressive Disorder / Q000000981:diagnostic imaging / Q000503:physiopathology*; D056324:Diffusion Tensor Imaging; D005260:Female; D006801:Humans; D008132:Loneliness; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000000981:diagnostic imaging / Q000503:physiopathology*
keywords: Connectivity; DTI; fMRI; late-life depression; loneliness