title: Age-dependent differences in brain tissue microstructure assessed with neurite orientation dispersion and density imaging.
abstract: Human aging is accompanied by progressive changes in executive function and memory, but the biological mechanisms underlying these phenomena are not fully understood. Using neurite orientation dispersion and density imaging, we sought to examine the relationship between age, cellular microstructure, and neuropsychological scores in 116 late middle-aged, cognitively asymptomatic participants. Results revealed widespread increases in the volume fraction of isotropic diffusion and localized decreases in neurite density in frontal white matter regions with increasing age. In addition, several of these microstructural alterations were associated with poorer performance on tests of memory and executive function. These results suggest that neurite orientation dispersion and density imaging is capable of measuring age-related brain changes and the neural correlates of poorer performance on tests of cognitive functioning, largely in accordance with published histological findings and brain-imaging studies of people of this age range. Ultimately, this study sheds light on the processes underlying normal brain development in adulthood, knowledge that is critical for differentiating healthy aging from changes associated with dementia.
authors.affiliation: Department of Medicine, Wisconsin Alzheimer's Disease Research Center, University of Wisconsin, Madison, WI, USA; Neuroscience and Public Policy Program, University of Wisconsin, Madison, WI, USA.
authors.forename: Andrew P
authors.initials: AP
authors.lastname: Merluzzi
authors.affiliation: Waisman Laboratory for Brain Imaging and Behavior, Madison, WI, USA.
authors.forename: Douglas C
authors.initials: DC
authors.lastname: Dean
authors.affiliation: Waisman Laboratory for Brain Imaging and Behavior, Madison, WI, USA.
authors.forename: Nagesh
authors.initials: N
authors.lastname: Adluru
authors.affiliation: Waisman Laboratory for Brain Imaging and Behavior, Madison, WI, USA.
authors.forename: Gaurav S
authors.initials: GS
authors.lastname: Suryawanshi
authors.affiliation: Department of Medicine, Wisconsin Alzheimer's Disease Research Center, University of Wisconsin, Madison, WI, USA; Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Ozioma C
authors.initials: OC
authors.lastname: Okonkwo
authors.affiliation: Department of Medicine, Wisconsin Alzheimer's Disease Research Center, University of Wisconsin, Madison, WI, USA.
authors.forename: Jennifer M
authors.initials: JM
authors.lastname: Oh
authors.affiliation: Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Bruce P
authors.initials: BP
authors.lastname: Hermann
authors.affiliation: Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Mark A
authors.initials: MA
authors.lastname: Sager
authors.affiliation: Department of Medicine, Wisconsin Alzheimer's Disease Research Center, University of Wisconsin, Madison, WI, USA; Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veteran's Hospital, Madison, WI, USA.
authors.forename: Sanjay
authors.initials: S
authors.lastname: Asthana
authors.affiliation: Department of Computer Science & Centre for Medical Image Computing, University College London, UK.
authors.forename: Hui
authors.initials: H
authors.lastname: Zhang
authors.affiliation: Department of Medicine, Wisconsin Alzheimer's Disease Research Center, University of Wisconsin, Madison, WI, USA; Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA; Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veteran's Hospital, Madison, WI, USA.
authors.forename: Sterling C
authors.initials: SC
authors.lastname: Johnson
authors.affiliation: Waisman Laboratory for Brain Imaging and Behavior, Madison, WI, USA; Department of Medical Physics, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA; Department of Psychiatry, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA.
authors.forename: Andrew L
authors.initials: AL
authors.lastname: Alexander
authors.affiliation: Department of Medicine, Wisconsin Alzheimer's Disease Research Center, University of Wisconsin, Madison, WI, USA; Wisconsin Alzheimer's Institute, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA. Electronic address: bbb@medicine.wisc.edu.
authors.forename: Barbara B
authors.initials: BB
authors.lastname: Bendlin
mesh_terms: D000368:Aged; D000375:Aging / Q000473:pathology* / Q000523:psychology; D001921:Brain / Q000000981:diagnostic imaging* / Q000473:pathology* / Q000502:physiology; D003071:Cognition; D003704:Dementia / Q000473:pathology / Q000523:psychology; D038524:Diffusion Magnetic Resonance Imaging; D056344:Executive Function; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D016501:Neurites / Q000473:pathology*; D009483:Neuropsychological Tests
keywords: Aging; Cognition; Diffusion-weighted imaging; MRI; Microstructure; Neurites