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- Nilsonne, G., et al.
(författare)
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Increased global FMRI signal variability after partial sleep deprivation : Findings from the Stockholm sleepy brain study
- 2017
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Ingår i: SLEEP. - : Oxford University Press (OUP). - 0161-8105 .- 1550-9109. ; 40, s. A40-A40
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Konferensbidrag (refereegranskat)abstract
- Introduction: Neural correlates of sleep deprivation are not fully understood and the difference between young and older adults in this regard has received little attention. We aimed to investigate the effect of partial sleep deprivation on resting state connectivity.Methods: 30 younger (20–30 years) and 23 older (65–75 years) healthy participants underwent MR imaging after normal sleep and partial sleep deprivation (3 h sleep). We acquired two runs of eyes-open resting state functional magnetic resonance images. Participants were monitored with eye-tracking to ensure their eyes remained open during scanning.Results: Global signal variability, defined as log-transformed standard deviation of average gray matter signal, was increased following partial sleep deprivation (0.16 [0.07, 0.24], p = 0.0004). In contrast to previous studies, we did not find that partial sleep deprivation inhibited connectivity in the default mode network, nor in other major networks investigated.Conclusion: Sleep deprivation caused increased global signal variability. This novel finding should be confirmed using independent data. Our finding of no difference in default mode connectivity in the sleep deprived state, could possibly be due to stricter monitoring of participants’ wakefulness compared to some earlier studies.
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- Nilsonne, G, et al.
(författare)
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Leukocyte telomere length and hippocampus volume: a meta-analysis
- 2015
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Ingår i: F1000Research. - : F1000 Research Ltd. - 2046-1402. ; 4, s. 1073-
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Tidskriftsartikel (refereegranskat)abstract
- Leukocyte telomere length has been shown to correlate to hippocampus volume, but effect estimates differ in magnitude and are not uniformly positive. This study aimed primarily to investigate the relationship between leukocyte telomere length and hippocampus gray matter volume by meta-analysis and secondarily to investigate possible effect moderators. Five studies were included with a total of 2107 participants, of which 1960 were contributed by one single influential study. A random-effects meta-analysis estimated the effect to r = 0.12 [95% CI -0.13, 0.37] in the presence of heterogeneity and a subjectively estimated moderate to high risk of bias. There was no evidence that apolipoprotein E (APOE) genotype was an effect moderator, nor that the ratio of leukocyte telomerase activity to telomere length was a better predictor than leukocyte telomere length for hippocampus volume. This meta-analysis, while not proving a positive relationship, also is not able to disprove the earlier finding of a positive correlation in the one large study included in analyses. We propose that a relationship between leukocyte telomere length and hippocamus volume may be mediated by transmigrating monocytes which differentiate into microglia in the brain parenchyma.
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