title: Functional connectivity: a source of variance in the association between cardiorespiratory fitness and cognition?
abstract: Over the next 20 years the number of Americans diagnosed with dementia is expected to more than double (CDC, 2007). It is, therefore, an important public health initiative to understand what factors contribute to the longevity of a healthy mind. Both default mode network (DMN) function and increased aerobic fitness have been associated with better cognitive performance and reduced incidence of Alzheimer's disease among older adults. Here we examine the association between aerobic fitness, functional connectivity in the DMN, and cognitive performance. Results showed significant age-related deficits in functional connectivity in both local and distributed DMN pathways. However, in a group of healthy elderly adults, almost half of the age-related disconnections showed increased functional connectivity as a function of aerobic fitness level. Finally, we examine the hypothesis that functional connectivity in the DMN is one source of variance in the relationship between aerobic fitness and cognition. Results demonstrate instances of both specific and global DMN connectivity mediating the relationship between fitness and cognition. We provide the first evidence for functional connectivity as a source of variance in the association between aerobic fitness and cognition, and discuss results in the context of neurobiological theories of cognitive aging and disease.
authors.affiliation: Beckman Institute & Department of Psychology, University of Illinois at Urbana-Champaign, 405 N. Mathews Ave, Urbana, IL 61801, USA. mvoss@illinois.edu
authors.forename: Michelle W
authors.initials: MW
authors.lastname: Voss
authors.forename: Kirk I
authors.initials: KI
authors.lastname: Erickson
authors.forename: Ruchika S
authors.initials: RS
authors.lastname: Prakash
authors.forename: Laura
authors.initials: L
authors.lastname: Chaddock
authors.forename: Edward
authors.initials: E
authors.lastname: Malkowski
authors.forename: Heloisa
authors.initials: H
authors.lastname: Alves
authors.forename: Jennifer S
authors.initials: JS
authors.lastname: Kim
authors.forename: Katherine S
authors.initials: KS
authors.lastname: Morris
authors.forename: Siobhan M
authors.initials: SM
authors.lastname: White
authors.forename: Thomas R
authors.initials: TR
authors.lastname: Wójcicki
authors.forename: Liang
authors.initials: L
authors.lastname: Hu
authors.forename: Amanda
authors.initials: A
authors.lastname: Szabo
authors.forename: Emily
authors.initials: E
authors.lastname: Klamm
authors.forename: Edward
authors.initials: E
authors.lastname: McAuley
authors.forename: Arthur F
authors.initials: AF
authors.lastname: Kramer
mesh_terms: D000368:Aged; D003072:Cognition Disorders / Q000175:diagnosis / Q000453:epidemiology*; D003865:Major Depressive Disorder / Q000175:diagnosis / Q000453:epidemiology; D005260:Female; D006179:Gyrus Cinguli / Q000503:physiopathology; D006331:Heart Diseases / Q000175:diagnosis / Q000453:epidemiology*; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008569:Memory Disorders / Q000175:diagnosis / Q000453:epidemiology; D009415:Nerve Net / Q000503:physiopathology*; D009483:Neuropsychological Tests; D012140:Respiratory Tract Diseases / Q000175:diagnosis / Q000453:epidemiology*; D012720:Severity of Illness Index; D013028:Space Perception / Q000502:physiology; D011795:Surveys and Questionnaires