scholarly journals Alzheimer’s pathology is associated with dedifferentiation of functional memory networks in aging

2020 ◽  
Author(s):  
Kaitlin E. Cassady ◽  
Jenna N. Adams ◽  
Xi Chen ◽  
Anne Maass ◽  
Theresa M. Harrison ◽  
...  

AbstractIn presymptomatic Alzheimer’s disease (AD), beta-amyloid plaques (Aβ) and tau tangles accumulate in distinct spatiotemporal patterns within the brain, tracking closely with episodic memory decline. Here, we tested whether age-related changes in the segregation of the brain’s functional episodic memory networks - anterior-temporal (AT) and posterior-medial (PM) networks - are associated with the accumulation of Aβ, tau and memory decline using fMRI and PET. We found that AT and PM networks were less segregated in older than younger adults and this reduced specialization was associated with more tau and Aβ in the same regions. The effect of network dedifferentiation on memory depended on the amount of Aβ and tau, with low segregation and pathology associated with better performance at baseline and low segregation and high pathology related to worse performance over time. This pattern suggests a compensation phase followed by a degenerative phase in the early, preclinical phase of AD.

2020 ◽  
Author(s):  
Myriam C. Sander ◽  
Yana Fandakova ◽  
Markus Werkle-Bergner

Episodic memory decline is a hallmark of cognitive aging and a multifaceted phenomenon. We review studies that target age differences across different memory processing stages, i.e., from encoding to retrieval. The available evidence cumulates in the proposition that older adults form memories of lower quality than younger adults, which has negative downstream consequences for later processing stages. We argue that low memory quality in combination with age-related neural decline of key regions of the episodic memory network puts older adults in a double jeopardy situation that finally results in broader memory impairments in older compared to younger adults.


2021 ◽  
Author(s):  
Jamie Murray ◽  
David Donaldson

Healthy aging leads to a significant decline in episodic memory, producing a reduction in thelikelihood of successful recollection, such that older adults remember less than younger adults.Emerging evidence from behavioral and neuroimaging studies demonstrate that recollectedinformation can also be more or less precise, highlighting a source of variability in memoryperformance not typically considered in studies of aging. Consequently, it is unknown whetherolder adults, compared to younger adults, only show a significant reduction in recollection rate or also exhibit a decline in recollection precision. Here, we provide new insight into age-relatedmemory decline by employing a novel source task that allows us to examine both the quantity(rate) and quality (precision) of episodic memory retrieval. First, we validated our task,demonstrating that it can effectively capture variability in both the rate and precision in olderadults. Second, we directly compared younger and older adults’ performance as a function ofstudy-test delay, showing significant reductions in both the rate and precision of recollectionwith age. Finally, we asked whether age-related changes in recollection can be accounted for bya reduction in attention, revealing that the division of attention in young adults results in areduction in rate but shows little evidence for a change in precision. Our results raise questionsabout the nature of age-related memory decline, highlighting the importance of measuring boththe quality and quantity of memory, and suggest new routes to achieve the early detection anddiagnosis of abnormal aging deficits.


2014 ◽  
Vol 67 (10) ◽  
pp. 1910-1924 ◽  
Author(s):  
Amy H. Criss ◽  
William Aue ◽  
Aslı Kılıç

Performance in episodic memory is determined both by accurate retrieval from memory and by decision processes. A substantial body of literature suggests slightly poorer episodic memory accuracy for older than younger adults; however, age-related changes in the decision mechanisms in memory have received much less attention. Response bias, the willingness to endorse an item as remembered, is an important decision factor that contributes to episodic memory performance, and therefore understanding age-related changes in response bias is critical to theoretical development. We manipulate list strength in order to investigate two aspects of response bias. First, we evaluate whether criterion placement in episodic memory differs for older and younger adults. Second, we ask whether older adults have the same degree of flexibility to adjust the criterion in response to task demands as younger adults. Participants were tested on weakly and strongly encoded lists where word frequency (Experiment 1) or similarity between targets and foils (Experiment 2) was manipulated. Both older and younger adults had higher hit rates and lower false-alarm rates for strong lists than for weak lists (i.e., a strength-based mirror effect). Older adults were more conservative (less likely to endorse an item as studied) than younger adults, and we found no evidence that older and younger adults differ in their ability to flexibly adjust their criterion based on the demands of the task.


2008 ◽  
Vol 32 (5) ◽  
pp. 381-389 ◽  
Author(s):  
Heike M. Buhl

This study investigates age-related changes and dyadic-specific differences in adult child–parent relationships. Using an individuation framework, two German samples of 224 and 105 participants aged between 21 and 47 years were administered the Network of Relationships Inventory, the Emotional Autonomy Scale and the Authority Reciprocity Questionnaire. Factor analyses resulted in a measurement model valid for adult children, their mothers and fathers. The model includes connectedness (with emotional and cognitive aspects) as well as individuality (assessed as power symmetry). Connectedness decreased with age. Symmetry in father–child relationships increased over time, while mother–child relationships were perceived to be symmetrical by early adulthood. Child–mother relationships were more connected than child–father relationships. Sons described themselves as more powerful than did daughters.


1997 ◽  
Vol 93 (3) ◽  
pp. 233-240 ◽  
Author(s):  
M. Ueno ◽  
Ichiro Akiguchi ◽  
Masanori Hosokawa ◽  
Masahiko Shinnou ◽  
Haruhiko Sakamoto ◽  
...  

2022 ◽  
Author(s):  
Kendra Leigh Seaman ◽  
Alexander P. Christensen ◽  
Katherine Senn ◽  
Jessica Cooper ◽  
Brittany Shane Cassidy

Trust is a key component of social interaction. Older adults, however, often exhibit excessive trust relative to younger adults. One explanation is that older adults may learn to trust differently than younger adults. Here, we examine how younger (N=33) and older adults (N=30) learn to trust over time. Participants completed a classic iterative trust game with three partners. Younger and older adults shared similar amounts but differed in how they shared money. Compared to younger adults, older adults invested more with untrustworthy partners and less with trustworthy partners. As a group, older adults displayed less learning than younger adults. However, computational modeling shows that this is because older adults are more likely to forget what they have learned over time. Model-based fMRI analyses revealed several age-related differences in neural processing. Younger adults showed prediction error signals in social processing areas while older adults showed over-recruitment of several cortical areas. Collectively, these findings suggest that older adults attend to and learn from social cues differently from younger adults.


PLoS ONE ◽  
2021 ◽  
Vol 16 (6) ◽  
pp. e0253053
Author(s):  
Jamie L. Romeiser ◽  
Dylan M. Smith ◽  
Sean A. P. Clouston

Background As the global burden of dementia increases, the absence of treatment underscores the need for identification of factors that may improve cognitive reserve–the ability to stave off cognitive decline in old age. The beneficial association between musical instrument engagement and episodic memory has been identified in children, young adults, and older adults. Yet, previous studies in musical instrument engagement have rarely examined the potential for adolescence and adulthood exposures to independently improve cognition, nor have they been linked with the rate of memory decline over time in older adults. We investigated whether adolescent musical instrument engagement and continued musical instrument engagement over the adult life course were separately associated with higher episodic memory, as well as rate of decline in a large longitudinal cohort. Methods Data were from a prospective cohort of high school graduates from 1957. High school music engagement (HSME) was ascertained through graduate yearbooks and assessed as membership in musical performance groups. A questionnaire was used to assess musical engagement through adulthood (MEA) at ages 35, 55, and 65. The episodic memory score was composed of immediate and delayed recall task scores, and was assessed when participants were aged approximately 65 and 72 years old among 5,718 individuals. Linear mixed models were used to assess the association between music, and memory performance and decline over time. Results Of high school graduates who participated in the study, 38.1% played music in high school, and 21.1% played music in adulthood. While musical engagement was more common in those who played in childhood, 40% of those who played continuously as an adult did not play in high school. High HSME (B = 0.348, p = 0.049) and continuous MEA (B = 0.424, p = 0.012) were associated with higher memory scores at age 65 after covariate adjustment. When examining memory decline, the benefits of high HSME decreased over time (B = -0.435, p = 0.048), while the rate of decline did not differ between MEA groups. Exploratory models revealed differential benefits for HSME and immediate recall, and MEA and delayed recall. Conclusion This study provides further evidence that musical engagement in childhood or adulthood is associated with non-musical cognitive reserve. These two exposures may act differentially in different domains of episodic memory. Further work is needed to determine the relationship between musicianship and the rate of cognitive decline.


2016 ◽  
Vol 5 (1) ◽  
pp. 30-38 ◽  
Author(s):  
Jennifer J. Heisz ◽  
Ana Kovacevic

Age-related changes in the brain can compromise cognitive function. However, in some cases, the brain is able to functionally reorganize to compensate for some of this loss. The present paper reviews the benefits of exercise on executive functions in older adults and discusses a potential mechanism through which exercise may change the way the brain processes information for better cognitive outcomes. Specifically, older adults who are more physically active demonstrate a shift toward local neural processing that is associated with better executive functions. We discuss the use of neural complexity as a sensitive measure of the neural network plasticity that is enhanced through exercise. We conclude by highlighting the future work needed to improve exercise prescriptions that help older adults maintain their cognitive and physical functions for longer into their lifespan.


1984 ◽  
Vol 100 (1) ◽  
pp. 19-23 ◽  
Author(s):  
J. Balthazart ◽  
M. Schumacher ◽  
G. Malacarne

ABSTRACT It has been suggested that testosterone is less effective at inducing crowing behaviour in young birds than in adults because of the presence of higher levels of steroid 5β-reductase in the young brain, which converts testosterone to inactive 5β-reduced metabolites. This hypothesis was tested indirectly by comparing the relative potencies of 5α-dihydrotestosterone (5α-DHT), which cannot be converted to 5β-metabolities, and testosterone at inducing crowing in young gonadectomized male and female quail. The promotion of cloacal gland growth by these treatments was also assessed since there are no age-related changes in 5β-reductase in this organ. Silicone elastomer implants (2·5, 5 and 10 mm) containing 5α-DHT were more effective at stimulating crowing than similar implants of testosterone whilst there was little difference in their potency at inducing cloacal gland growth. These results are consistent with the hypothesis that brain steroid 5β-reductase regulates the behavioural activity of testosterone in the brain of young birds. J. Endocr. (1984) 100, 19–23


1992 ◽  
Vol 137 (2) ◽  
pp. 169-172 ◽  
Author(s):  
Yoshihisa Kitamura ◽  
Xue-Hui Zhao ◽  
Toshio Ohnuki ◽  
Makiko Takei ◽  
Yasuyuki Nomura

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