Activity/rest cycle and disturbances of structural backbone of cerebral networks in aging.
Although aging is associated with alterations of both activity/rest cycle and brain structure, few studies have evaluated associations between these processes. The aim of this study was to examine relationship between activity/rest cycle quality and brain structural integrity in aging subjects by exploring both grey and white matter compartments.



Fifty-eight elderly subjects (76±0.5 years; 41% female) without dementia, sleep disorders and medications were included in the analysis. Actigraphy was used to measure parameters of activity/rest cycle (24-h amplitude, 24-h fragmentation and 24-h stability) and sleep (total sleep time and sleep fragmentation) over a minimal period of 5 days. Whole brain linear regression analyses were performed on grey matter volumes maps using voxel based morphometry and on white matter integrity using tract based statistics analyses.



A lower 24-h amplitude and a higher sleep fragmentation were independently associated with a reduction of white matter integrity in models including age and gender as covariates. The association between 24-h amplitude and white matter integrity decreased but remained significant in a model accounted for sleep fragmentation, indicating a specific effect of 24-h cycle disturbances. No association with grey matter volumes was observed.



In elderly, not only sleep but also 24-h cycle disturbances were associated with altered structural connectivity. This alteration of structural backbone networks related to activity/rest cycle disturbances in aging might constitute a cerebral frailty factor for the development of cognitive impairment.
Université de Bordeaux, INCIA, UMR 5287 - équipe NeuroImagerie et Cognition Humaine, F-33000 Bordeaux, France; CNRS, INCIA, UMR 5287 - équipe NeuroImagerie et Cognition Humaine, F-33000 Bordeaux, France. Electronic address: marion.baillet@u-bordeaux.fr.
Marion
M
Baillet
Université de Bordeaux, INCIA, UMR 5287 - équipe NeuroImagerie et Cognition Humaine, F-33000 Bordeaux, France; CNRS, INCIA, UMR 5287 - équipe NeuroImagerie et Cognition Humaine, F-33000 Bordeaux, France.
Bixente
B
Dilharreguy
Université de Bordeaux, ISPED, Centre INSERM U1219 - Bordeaux Population Health Research Center, F-33000 Bordeaux, France; INSERM, ISPED, Centre INSERM U1219 - Bordeaux Population Heath Research Center, F-33000 Bordeaux, France.
Karine
K
Pérès
Université de Bordeaux, ISPED, Centre INSERM U1219 - Bordeaux Population Health Research Center, F-33000 Bordeaux, France; INSERM, ISPED, Centre INSERM U1219 - Bordeaux Population Heath Research Center, F-33000 Bordeaux, France.
Jean-François
JF
Dartigues
Université de Bordeaux, INCIA, UMR 5287 - équipe NeuroImagerie et Cognition Humaine, F-33000 Bordeaux, France; CNRS, INCIA, UMR 5287 - équipe NeuroImagerie et Cognition Humaine, F-33000 Bordeaux, France.
Willy
W
Mayo
Université de Bordeaux, INCIA, UMR 5287 - équipe NeuroImagerie et Cognition Humaine, F-33000 Bordeaux, France; CNRS, INCIA, UMR 5287 - équipe NeuroImagerie et Cognition Humaine, F-33000 Bordeaux, France; EPHE, PSL Research University, F-33000 Bordeaux, France.
Gwenaëlle
G
Catheline
D056044:Actigraphy; D000368:Aged; D000375:Aging; D002540:Cerebral Cortex / Q000033:anatomy & histology* / Q000502:physiology*; D038524:Diffusion Magnetic Resonance Imaging; D056324:Diffusion Tensor Imaging; D015444:Exercise; D005260:Female; D066128:Gray Matter / Q000033:anatomy & histology / Q000502:physiology; D006801:Humans; D008297:Male; D012146:Rest; D012890:Sleep; D012892:Sleep Deprivation; D066127:White Matter / Q000033:anatomy & histology / Q000502:physiology
Actigraphy; Activity/rest cycle; Aging; Diffusion tensor Imaging