title: Neuroimaging insights into network-based neurodegeneration.
abstract: OBJECTIVE
  Convergent evidence from a number of neuroscience disciplines supports the hypothesis that Alzheimer's disease and other neurodegenerative disorders progress along brain networks. This review considers the role of neuroimaging in strengthening the case for network-based neurodegeneration and elucidating potential mechanisms.
  
  
  RESULTS
  Advances in functional and structural MRI have recently enabled the delineation of multiple large-scale distributed brain networks. The application of these network-imaging modalities to neurodegenerative disease has shown that specific disorders appear to progress along specific networks. Recent work applying theoretical measures of network efficiency to in-vivo network imaging has allowed for the development and evaluation of models of disease spread along networks. Novel MRI acquisition and analysis methods are paving the way for in-vivo assessment of the layer-specific microcircuits first targeted by neurodegenerative diseases. These methodological advances coupled with large, longitudinal studies of subjects progressing from healthy aging into dementia will enable a detailed understanding of the seeding and spread of these disorders.
  
  
  CONCLUSIONS
  Neuroimaging has provided ample evidence that neurodegenerative disorders progress along brain networks, and is now beginning to elucidate how they do so.
authors.affiliation: Functional Imaging in Neuropsychiatric Disorders Laboratory, Department of Neurology and Neurological Sciences, Stanford University School of Medicine, Stanford, California 94305-5235, USA. greicius@stanford.edu
authors.forename: Michael D
authors.initials: MD
authors.lastname: Greicius
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Kimmel
mesh_terms: D001921:Brain / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D056324:Diffusion Tensor Imaging; D059907:Functional Neuroimaging; D006801:Humans; D008279:Magnetic Resonance Imaging; D009434:Neural Pathways / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D019636:Neurodegenerative Diseases / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology; D059906:Neuroimaging