title: The organisation of the elderly connectome.
abstract: Investigations of the human connectome have elucidated core features of adult structural networks, particularly the crucial role of hub-regions. However, little is known regarding network organisation of the healthy elderly connectome, a crucial prelude to the systematic study of neurodegenerative disorders. Here, whole-brain probabilistic tractography was performed on high-angular diffusion-weighted images acquired from 115 healthy elderly subjects (age 76-94 years; 65 females). Structural networks were reconstructed between 512 cortical and subcortical brain regions. We sought to investigate the architectural features of hub-regions, as well as left-right asymmetries, and sexual dimorphisms. We observed that the topology of hub-regions is consistent with a young adult population, and previously published adult connectomic data. More importantly, the architectural features of hub connections reflect their ongoing vital role in network communication. We also found substantial sexual dimorphisms, with females exhibiting stronger inter-hemispheric connections between cingulate and prefrontal cortices. Lastly, we demonstrate intriguing left-lateralized subnetworks consistent with the neural circuitry specialised for language and executive functions, whilst rightward subnetworks were dominant in visual and visuospatial streams. These findings provide insights into healthy brain ageing and provide a benchmark for the study of neurodegenerative disorders such as Alzheimer's disease (AD) and frontotemporal dementia (FTD).
authors: Centre for Healthy Brain Ageing (CHeBA), School of Psychiatry, University of New South Wales, Sydney, NSW, Australia; School of Psychiatry, University of New South Wales, Sydney, NSW 2052, Australia; Systems Neuroscience Group, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD 4006, Australia.
authors: Alistair
authors: A
authors: Perry
authors: Centre for Healthy Brain Ageing (CHeBA), School of Psychiatry, University of New South Wales, Sydney, NSW, Australia; School of Psychiatry, University of New South Wales, Sydney, NSW 2052, Australia. Electronic address: w.wen@unsw.edu.au.
authors: Wei
authors: W
authors: Wen
authors: Systems Neuroscience Group, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD 4006, Australia.
authors: Anton
authors: A
authors: Lord
authors: Centre for Healthy Brain Ageing (CHeBA), School of Psychiatry, University of New South Wales, Sydney, NSW, Australia; School of Psychiatry, University of New South Wales, Sydney, NSW 2052, Australia.
authors: Anbupalam
authors: A
authors: Thalamuthu
authors: School of Psychiatry, University of New South Wales, Sydney, NSW 2052, Australia; Black Dog Institute, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia.
authors: Gloria
authors: G
authors: Roberts
authors: School of Psychiatry, University of New South Wales, Sydney, NSW 2052, Australia; Black Dog Institute, Prince of Wales Hospital, Hospital Road, Randwick, NSW 2031, Australia.
authors: Philip B
authors: PB
authors: Mitchell
authors: Centre for Healthy Brain Ageing (CHeBA), School of Psychiatry, University of New South Wales, Sydney, NSW, Australia; School of Psychiatry, University of New South Wales, Sydney, NSW 2052, Australia.
authors: Perminder S
authors: PS
authors: Sachdev
authors: School of Psychiatry, University of New South Wales, Sydney, NSW 2052, Australia; Systems Neuroscience Group, QIMR Berghofer Medical Research Institute, 300 Herston Road, Herston, QLD 4006, Australia; Metro North Mental Health Service, Royal Brisbane and Women's Hospital, Herston, QLD 4029, Australia.
authors: Michael
authors: M
authors: Breakspear
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001921:Brain / Q000033:anatomy & histology*; D063132:Connectome; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology; D012737:Sex Factors
keywords: Elderly; Lateralization; Network organisation; Sexual dimorphism; Structural connectome