title: Unilateral disruptions in the default network with aging in native space.
abstract: BACKGROUND
  Disruption of the default-mode network (DMN) in healthy elders has been reported in many studies.
  
  
  METHODS
  In a group of 51 participants (25 young, 26 elder) we examined DMN connectivity in subjects' native space. In the native space method, subject-specific regional masks (obtained independently for each subject) are used to extract regional fMRI times series. This approach substitutes the spatial normalization and subsequent smoothing used in prevailing methods, affords more accurate spatial localization, and provides the power to examine connectivity separately in the two hemispheres instead of averaging regions across hemispheres.
  
  
  RESULTS
  The native space method yielded new findings which were not detectable by the prevailing methods. The most reliable and robust disruption in elders' DMN connectivity were found between supramarginal gyrus and superior-frontal cortex in the right hemisphere only. The mean correlation between these two regions in young participants was about 0.5, and dropped significantly to 0.04 in elders (P = 2.1 × 10(-5)). In addition, the magnitude of functional connectivity between these regions in the right hemisphere correlated with memory (P = 0.05) and general fluid ability (P = 0.01) in elder participants and with speed of processing in young participants (P = 0.008). These relationships were not observed in the left hemisphere.
  
  
  CONCLUSIONS
  These findings suggest that analysis of DMN connectivity in subjects' native space can improve localization and power and that it is important to examine connectivity separately in each hemisphere.
authors.affiliation: Cognitive Neuroscience Division, Department of Neurology, Columbia University College of Physicians and Surgeons New York, New York.
authors.forename: Qolamreza R
authors.initials: QR
authors.lastname: Razlighi
authors.affiliation: Cognitive Neuroscience Division, Department of Neurology, Columbia University College of Physicians and Surgeons New York, New York.
authors.forename: Christian
authors.initials: C
authors.lastname: Habeck
authors.affiliation: Cognitive Neuroscience Division, Department of Neurology, Columbia University College of Physicians and Surgeons New York, New York.
authors.forename: Jason
authors.initials: J
authors.lastname: Steffener
authors.affiliation: Cognitive Neuroscience Division, Department of Neurology, Columbia University College of Physicians and Surgeons New York, New York.
authors.forename: Yunglin
authors.initials: Y
authors.lastname: Gazes
authors.affiliation: Cognitive Neuroscience Division, Department of Neurology, Columbia University College of Physicians and Surgeons New York, New York.
authors.forename: Laura B
authors.initials: LB
authors.lastname: Zahodne
authors.affiliation: Cognitive Neuroscience Division, Department of Neurology, Columbia University College of Physicians and Surgeons New York, New York.
authors.forename: Anna
authors.initials: A
authors.lastname: Mackay-Brandt
authors.affiliation: Cognitive Neuroscience Division, Department of Neurology, Columbia University College of Physicians and Surgeons New York, New York.
authors.forename: Yaakov
authors.initials: Y
authors.lastname: Stern
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging / Q000502:physiology*; D002540:Cerebral Cortex / Q000503:physiopathology*; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging / Q000379:methods*; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology*; D011597:Psychomotor Performance / Q000502:physiology*; D055815:Young Adult
keywords: Age-related brain change; SPM; cognitive performance; fMRI analysis; interhemispheric averaging; resting-state BOLD fMRI; spatial normalization