title: Lower cognitive reserve in the aging human immunodeficiency virus-infected brain.
abstract: More HIV-infected individuals are living longer; however, how their brain function is affected by aging is not well understood. One hundred twenty-two men (56 seronegative control [SN] subjects, 37 HIV subjects with normal cognition [HIV+NC], 29 with HIV-associated neurocognitive disorder [HAND]) performed neuropsychological tests and had acceptable functional magnetic resonance imaging scans at 3 Tesla during tasks with increasing attentional load. With older age, SN and HIV+NC subjects showed increased activation in the left posterior (reserve, "bottom-up") attention network for low attentional-load tasks, and further increased activation in the left posterior and anterior ("top-down") attention network on intermediate (HIV+NC only) and high attentional-load tasks. HAND subjects had only age-dependent decreases in activation. Age-dependent changes in brain activation differed between the 3 groups, primarily in the left frontal regions (despite similar brain atrophy). HIV and aging act synergistically or interactively to exacerbate brain activation abnormalities in different brain regions, suggestive of a neuroadaptive mechanism in the attention network to compensate for declined neural efficiency. While the SN and HIV+NC subjects compensated for their declining attention with age by using reserve and "top-down" attentional networks, older HAND subjects were unable to compensate which resulted in cognitive decline.
authors.affiliation: Department of Medicine, Division of Neurology, John A. Burns School of Medicine, University of Hawai'i at Manoa, and the Queen's Medical Center, Honolulu, HI 96813, USA. lchang@hawaii.edu
authors.forename: Linda
authors.initials: L
authors.lastname: Chang
authors.forename: John L
authors.initials: JL
authors.lastname: Holt
authors.forename: Renat
authors.initials: R
authors.lastname: Yakupov
authors.forename: Caroline S
authors.initials: CS
authors.lastname: Jiang
authors.forename: Thomas
authors.initials: T
authors.lastname: Ernst
mesh_terms: D000328:Adult; D000368:Aged; D000375:Aging; D001288:Attention; D001921:Brain / Q000503:physiopathology*; D001931:Brain Mapping; D003072:Cognition Disorders / Q000209:etiology / Q000503:physiopathology*; D058245:Cognitive Reserve; D018792:Encephalitis, Viral / Q000150:complications / Q000503:physiopathology*; D015658:HIV Infections / Q000150:complications* / Q000503:physiopathology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009415:Nerve Net / Q000503:physiopathology; D055815:Young Adult