title: White matter hyperintensities are associated with visual search behavior independent of generalized slowing in aging.
abstract: A fundamental controversy is whether cognitive decline with advancing age can be entirely explained by decreased processing speed, or whether specific neural changes can elicit cognitive decline, independent of slowing. These hypotheses are anchored by studies of healthy older individuals where age is presumed the sole influence. Unfortunately, advancing age is also associated with asymptomatic brain white matter injury. We hypothesized that differences in white matter injury extent, manifest by MRI white matter hyperintensities (WMH), mediate differences in visual attentional control in healthy aging, beyond processing speed differences. We tested young and cognitively healthy older adults on search tasks indexing speed and attentional control. Increasing age was associated with generally slowed performance. WMH were also associated with slowed search times independent of processing speed differences. Consistent with evidence attributing reduced network connectivity to WMH, these results conclusively demonstrate that clinically silent white matter injury contributes to slower search performance indicative of compromised cognitive control, independent of generalized slowing of processing speed.
authors.affiliation: University of California Davis, Imaging of Dementia and Aging Lab, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Department of Neurology, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Neuroscience Graduate Group, 1544 Newton Court, Davis, CA 95618, United States. Electronic address: snlockhart@ucdavis.edu.
authors.forename: Samuel N
authors.initials: SN
authors.lastname: Lockhart
authors.affiliation: University of California Davis, Imaging of Dementia and Aging Lab, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Department of Neurology, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Department of Psychology, 1544 Newton Court, Davis, CA 95618, United States. Electronic address: aroach@ucdavis.edu.
authors.forename: Alexandra E
authors.initials: AE
authors.lastname: Roach
authors.affiliation: University of California Davis, Neuroscience Graduate Group, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Department of Psychology, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Center for Mind and Brain, 267 Cousteau Place, Davis, CA 95618, United States. Electronic address: sjluck@ucdavis.edu.
authors.forename: Steven J
authors.initials: SJ
authors.lastname: Luck
authors.affiliation: University of California Davis, Neuroscience Graduate Group, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Department of Psychology, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Center for Mind and Brain, 267 Cousteau Place, Davis, CA 95618, United States. Electronic address: jgeng@ucdavis.edu.
authors.forename: Joy
authors.initials: J
authors.lastname: Geng
authors.affiliation: University of California Davis, Department of Neurology, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Division of Biostatistics, One Shields Avenue, Davis, CA 95616, United States. Electronic address: labeckett@phs.ucdavis.edu.
authors.forename: Laurel
authors.initials: L
authors.lastname: Beckett
authors.affiliation: University of California Davis, Imaging of Dementia and Aging Lab, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Department of Neurology, 1544 Newton Court, Davis, CA 95618, United States. Electronic address: ocarmichael@ucdavis.edu.
authors.forename: Owen
authors.initials: O
authors.lastname: Carmichael
authors.affiliation: University of California Davis, Imaging of Dementia and Aging Lab, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Department of Neurology, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Neuroscience Graduate Group, 1544 Newton Court, Davis, CA 95618, United States; University of California Davis, Department of Psychology, 1544 Newton Court, Davis, CA 95618, United States. Electronic address: charles.decarli@ucdmc.ucdavis.edu.
authors.forename: Charles
authors.initials: C
authors.lastname: DeCarli
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D000704:Analysis of Variance; D001288:Attention / Q000502:physiology*; D001921:Brain / Q000502:physiology*; D003071:Cognition / Q000502:physiology*; D003463:Cues; D005260:Female; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D009413:Nerve Fibers, Myelinated / Q000502:physiology*; D009483:Neuropsychological Tests; D010775:Photic Stimulation; D011930:Reaction Time / Q000502:physiology; D055815:Young Adult
keywords: Aging; Cerebrovascular disease; Cognitive control; Cognitive neuroscience; Neuroimaging; Visual attention