title: Decoupling of structural and functional brain connectivity in older adults with white matter hyperintensities.
abstract: Age-related impairments in the default network (DN) have been related to disruptions in connecting white matter tracts. We hypothesized that the local correlation between DN structural and functional connectivity is negatively affected in the presence of global white matter injury. In 125 clinically normal older adults, we tested whether the relationship between structural connectivity (via diffusion imaging tractography) and functional connectivity (via resting-state functional MRI) of the posterior cingulate cortex (PCC) and medial prefrontal frontal cortex (MPFC) of the DN was altered in the presence of white matter hyperintensities (WMH). A significant correlation was observed between microstructural properties of the cingulum bundle and MPFC-PCC functional connectivity in individuals with low WMH load, but not with high WMH load. No correlation was observed between PCC-MPFC functional connectivity and microstructure of the inferior longitudinal fasciculus, a tract not passing through the PCC or MPFC. Decoupling of connectivity, measured as the absolute difference between structural and functional connectivity, in the high WMH group was related to poorer executive functioning and memory performance. These results suggest that such decoupling may reflect reorganization of functional networks in response to global white matter pathology and may provide an early marker of clinically relevant network alterations.
authors.affiliation: Dept. of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA. Electronic address: yreijmer@mgh.harvard.edu.
authors.forename: Y D
authors.initials: YD
authors.lastname: Reijmer
authors.affiliation: Dept. of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.
authors.forename: A P
authors.initials: AP
authors.lastname: Schultz
authors.affiliation: Image Sciences Institute, University Medical Center Utrecht, Utrecht, the Netherlands.
authors.forename: A
authors.initials: A
authors.lastname: Leemans
authors.affiliation: Dept. of Basic and Clinical Neuroscience, Institute of Psychiatry, Psychology & Neuroscience, King's College London, UK.
authors.forename: M J
authors.initials: MJ
authors.lastname: O'Sullivan
authors.affiliation: Dept. of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: M E
authors.initials: ME
authors.lastname: Gurol
authors.affiliation: Dept. of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Dept. of Psychiatry, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA; Dept. of Neurology, Brigham and Women's Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: R
authors.initials: R
authors.lastname: Sperling
authors.affiliation: Dept. of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: S M
authors.initials: SM
authors.lastname: Greenberg
authors.affiliation: Dept. of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
authors.forename: A
authors.initials: A
authors.lastname: Viswanathan
authors.affiliation: Dept. of Radiology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA; Athinoula A. Martinos Center for Biomedical Imaging, Massachusetts General Hospital, Charlestown, MA, USA.
authors.forename: T
authors.initials: T
authors.lastname: Hedden
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D001931:Brain Mapping; D056324:Diffusion Tensor Imaging; D005260:Female; D006179:Gyrus Cinguli / Q000033:anatomy & histology* / Q000502:physiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009434:Neural Pathways / Q000033:anatomy & histology / Q000502:physiology; D009483:Neuropsychological Tests; D017397:Prefrontal Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D066127:White Matter / Q000033:anatomy & histology* / Q000502:physiology*
keywords: Aging; Cognition; Connectivity; Diffusion tensor imaging; Functional MRI; White matter hyperintensities