| 1. |
- Fjell, Anders M., et al.
(författare)
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Poor Self-Reported Sleep is Related to Regional Cortical Thinning in Aging but not Memory Decline-Results From the Lifebrain Consortium
- 2021
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Ingår i: Cerebral Cortex. - : Oxford University Press. - 1047-3211 .- 1460-2199. ; 31:4, s. 1953-1969
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Tidskriftsartikel (refereegranskat)abstract
- We examined whether sleep quality and quantity are associated with cortical and memory changes in cognitively healthy participants across the adult lifespan. Associations between self-reported sleep parameters (Pittsburgh Sleep Quality Index, PSQI) and longitudinal cortical change were tested using five samples from the Lifebrain consortium (n = 2205, 4363 MRIs, 18-92 years). In additional analyses, we tested coherence with cell-specific gene expression maps from the Allen Human Brain Atlas, and relations to changes in memory performance. "PSQI # 1 Subjective sleep quality" and "PSQI #5 Sleep disturbances" were related to thinning of the right lateral temporal cortex, with lower quality and more disturbances being associated with faster thinning. The association with "PSQI #5 Sleep disturbances" emerged after 60 years, especially in regions with high expression of genes related to oligodendrocytes and S1 pyramidal neurons. None of the sleep scales were related to a longitudinal change in episodic memory function, suggesting that sleep-related cortical changes were independent of cognitive decline. The relationship to cortical brain change suggests that self-reported sleep parameters are relevant in lifespan studies, but small effect sizes indicate that self-reported sleep is not a good biomarker of general cortical degeneration in healthy older adults.
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| 2. |
- Vidal-Pineiro, Didac, et al.
(författare)
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Maintained Frontal Activity Underlies High Memory Function Over 8 Years in Aging
- 2019
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Ingår i: Cerebral Cortex. - : OXFORD UNIV PRESS INC. - 1047-3211 .- 1460-2199. ; 29:7, s. 3111-3123
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Tidskriftsartikel (refereegranskat)abstract
- Aging is characterized by substantial average decline in memory performance. Yet contradictory explanations have been given for how the brains of high-performing older adults work: either by engagement of compensatory processes such as recruitment of additional networks or by maintaining young adults' patterns of activity. Distinguishing these components requires large experimental samples and longitudinal follow-up. Here, we investigate which features are key to high memory in aging, directly testing these hypotheses by studying a large sample of adult participants (n > 300) with fMRI during an episodic memory experiment where item-context relationships were implicitly encoded. The analyses revealed that low levels of activity in frontal networks-known to be involved in memory encoding-were associated with low memory performance in the older adults only. Importantly, older participants with low memory performance and low frontal activity exhibited a strong longitudinal memory decline in an independent verbal episodic memory task spanning 8 years back (n = 52). These participants were also characterized by lower hippocampal volumes and steeper rates of cortical atrophy. Altogether, maintenance of frontal brain function during encoding seems to be a primary characteristic of preservation of memory function in aging, likely reflecting intact ability to integrate information.
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