title: Brain aging in humans, chimpanzees (Pan troglodytes), and rhesus macaques (Macaca mulatta): magnetic resonance imaging studies of macro- and microstructural changes.
abstract: Among primates, humans are uniquely vulnerable to many age-related neurodegenerative disorders. We used structural and diffusion magnetic resonance imaging (MRI) to examine the brains of chimpanzees and rhesus monkeys across each species' adult lifespan, and compared these results with published findings in humans. As in humans, gray matter volume decreased with age in chimpanzees and rhesus monkeys. Also like humans, chimpanzees showed a trend for decreased white matter volume with age, but this decrease occurred proportionally later in the chimpanzee lifespan than in humans. Diffusion MRI revealed widespread age-related decreases in fractional anisotropy and increases in radial diffusivity in chimpanzees and macaques. However, both the fractional anisotropy decline and the radial diffusivity increase started at a proportionally earlier age in humans than in chimpanzees. Thus, even though overall patterns of gray and white matter aging are similar in humans and chimpanzees, the longer lifespan of humans provides more time for white matter to deteriorate before death, with the result that some neurological effects of aging may be exacerbated in our species.
authors.affiliation: Department of Anthropology, Emory University, Atlanta, GA, USA.
authors.forename: Xu
authors.initials: X
authors.lastname: Chen
authors.forename: Bhargav
authors.initials: B
authors.lastname: Errangi
authors.forename: Longchuan
authors.initials: L
authors.lastname: Li
authors.forename: Matthew F
authors.initials: MF
authors.lastname: Glasser
authors.forename: Lars T
authors.initials: LT
authors.lastname: Westlye
authors.forename: Anders M
authors.initials: AM
authors.lastname: Fjell
authors.forename: Kristine B
authors.initials: KB
authors.lastname: Walhovd
authors.forename: Xiaoping
authors.initials: X
authors.lastname: Hu
authors.forename: James G
authors.initials: JG
authors.lastname: Herndon
authors.forename: Todd M
authors.initials: TM
authors.lastname: Preuss
authors.forename: James K
authors.initials: JK
authors.lastname: Rilling
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000473:pathology*; D000818:Animals; D001921:Brain / Q000473:pathology*; D002540:Cerebral Cortex / Q000473:pathology; D038524:Diffusion Magnetic Resonance Imaging; D005260:Female; D006801:Humans; D008018:Life Cycle Stages / Q000502:physiology; D008253:Macaca mulatta; D008875:Middle Aged; D019636:Neurodegenerative Diseases / Q000209:etiology / Q000473:pathology; D002679:Pan troglodytes; D055815:Young Adult
keywords: Brain aging; Chimpanzees; Comparative anatomy; Diffusion tensor imaging; Female; Humans; Magnetic resonance imaging; Non-human primates; Rhesus macaques