title: Degradation in intrinsic connectivity networks across the Alzheimer's disease spectrum.
abstract: BACKGROUND
  Changes in intrinsic functional connectivity (iFC) have been reported at various stages of the Alzheimer's disease (AD) spectrum. We aimed to investigate such alterations over a variety of large-scale intrinsic brain networks (iBNs) across the spectrum of amyloid β positivity and uncover their relation to cognitive impairment.
  
  
  METHODS
  Eight iBNs were defined from resting-state functional magnetic resonance imaging data. In amyloid β-positive healthy subjects, prodromal, and AD patients (N = 70), within-network iFC (intra-iFC) and between-network iFC (inter-iFC) were correlated with scores of cognitive impairment.
  
  
  RESULTS
  Across all iBNs, a general degradation in intra-iFC along the scale of cognitive impairment severity was found. Only subtle changes in inter-iFC were identified.
  
  
  CONCLUSIONS
  Across the AD spectrum, changes in iFC that are strongly related to cognitive impairment occur within an extensive variety of networks.
authors.affiliation: Department of Psychology, Ludwig Maximilian University Munich, Munich, Germany; TUM-Neuroimaging Center, Neuro-Kopf-Zentrum, Technische Universität München, Munich, Germany.
authors.forename: Rachel
authors.initials: R
authors.lastname: Nuttall
authors.affiliation: TUM-Neuroimaging Center, Neuro-Kopf-Zentrum, Technische Universität München, Munich, Germany; Department of Neuroradiology, Technische Universität München, Munich, Germany.
authors.forename: Lorenzo
authors.initials: L
authors.lastname: Pasquini
authors.affiliation: TUM-Neuroimaging Center, Neuro-Kopf-Zentrum, Technische Universität München, Munich, Germany; Department of Psychiatry, Technische Universität München, Munich, Germany; Doppler Klinik, Division of Neuroradiology, Paracelsus Medical University Salzburg, Salzburg, Austria.
authors.forename: Martin
authors.initials: M
authors.lastname: Scherr
authors.affiliation: TUM-Neuroimaging Center, Neuro-Kopf-Zentrum, Technische Universität München, Munich, Germany; Department of Neuroradiology, Technische Universität München, Munich, Germany; Department of Psychiatry, Technische Universität München, Munich, Germany.
authors.forename: Christian
authors.initials: C
authors.lastname: Sorg
keywords: Alzheimer's disease; Cognitive impairment; Intrinsic brain networks; Intrinsic functional connectivity; Resting-state fMRI