Contributions of representational distinctiveness and stability to memory performance and age differences

2021 ◽  
Author(s):  
Verena R. Sommer ◽  
Myriam C. Sander
Keyword(s):  
Episodic Memory ◽  
Age Differences ◽  
Cognitive Aging ◽  
Memory Performance ◽  
Activity Patterns ◽  
Stimulus Category ◽  
Neural Representations ◽  
Age Related ◽  
Pattern Similarity ◽  
Versatile Tool

Long-standing theories of cognitive aging suggest that memory decline is associated with age-related differences in the way information is represented in the brain. In the last years, these hypotheses have been substantiated by novel neuroscientific evidence that was derived from multivariate pattern similarity analyses. This approach enabled researchers to take a representational perspective on brain and cognition, and allowed them to study the properties of neural representations that support successful episodic memory. In young adults, two prominent representational properties have been identified as crucial for memory performance, namely the distinctiveness and the stability of neural representations. Distinctiveness describes the relation of neural representations to each other, i.e., how similar or dissimilar they are, while stability characterizes how much or how little representations change over time. However, researchers have only recently started to explore age differences in these representational properties and how they interact to support episodic memory in old age. Here, we review studies that used multivariate analysis tools for different neuroimaging techniques to clarify how representational distinctiveness, stability, and their interactions relate to memory performance across adulthood, and specifically during aging. While most evidence on age differences in neural representations involved how stimulus category information is represented, recent studies demonstrated that particularly item-level stability and specificity of activity patterns are positively linked to memory success and decline during aging. Overall, multivariate methods offer a promising and versatile tool for our understanding of age differences in the neural representations underlying episodic memory.

scholarly journals Neural differentiation is moderated by age in scene- but not face-selective cortical regions

2020 ◽  
Author(s):  
Sabina Srokova ◽  
Paul F. Hill ◽  
Joshua D. Koen ◽  
Danielle R. King ◽  
Michael D. Rugg
Keyword(s):  
Cognitive Aging ◽  
Neural Differentiation ◽  
Memory Performance ◽  
Retrosplenial Cortex ◽  
Stimulus Category ◽  
Age Related ◽  
Pattern Similarity ◽  
Cortical Regions ◽  
Neural Selectivity ◽  
Parahippocampal Place Area

AbstractThe aging brain is characterized by neural dedifferentiation – an apparent decrease in the functional selectivity of category-selective cortical regions. Age-related reductions in neural differentiation have been proposed to play a causal role in cognitive aging. Recent findings suggest, however, that age-related dedifferentiation is not equally evident for all stimulus categories and, additionally, that the relationship between neural differentiation and cognitive performance is not moderated by age. In light of these findings, in the present experiment younger and older human adults (males and females) underwent fMRI as they studied words paired with images of scenes or faces prior to a subsequent memory task. Neural selectivity was measured in two scene-selective (parahippocampal place area and retrosplenial cortex) and two face-selective (fusiform and occipital face areas) regions of interest using both a univariate differentiation index and multivoxel pattern similarity analysis. Both methods provided highly convergent results which revealed evidence of age-related reductions in neural dedifferentiation in scene-selective but not face-selective cortical regions. Additionally, neural differentiation in the parahippocampal place area demonstrated a positive, age-invariant relationship with subsequent source memory performance (recall of the image category paired with each recognized test word). These findings extend prior findings suggesting that age-related neural dedifferentiation is not a ubiquitous phenomenon, and that the specificity of neural responses to scenes is predictive subsequent memory performance independently of age.Significance StatementIncreasing age is associated with reduced neural specificity in cortical regions that are selectively responsive to a given perceptual stimulus category (age-related neural dedifferentiation), a phenomenon which has been proposed to contribute to cognitive aging. Recent findings reveal that age-related neural dedifferentiation is not present for all types of visual stimulus categories, and the factors which determine when the phenomenon arises remain unclear. Here, we demonstrate that scene- but not face-selective cortical regions exhibit age-related neural dedifferentiation during an attentionally-demanding task. Additionally, we report that higher neural selectivity in the scene-selective ‘parahippocampal place area’ is associated with better memory performance after controlling for variance associated with age group, adding to evidence that neural differentiation impacts cognition across the adult lifespan.

scholarly journals Neural pattern similarity differentially affects memory performance of younger and older adults: Age differences in neural similarity and memory

2019 ◽  
Author(s):  
Verena R. Sommer ◽  
Yana Fandakova ◽  
Thomas H. Grandy ◽  
Yee Lee Shing ◽  
Markus Werkle-Bergner ◽  
...  
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Memory Performance ◽  
Activity Patterns ◽  
Quality Of Information ◽  
Neural Representations ◽  
Age Related ◽  
Pattern Similarity ◽  
The Brain

AbstractAge-related memory decline is associated with changes in neural functioning but little is known about how aging affects the quality of information representation in the brain. Whereas a long-standing hypothesis of the aging literature links cognitive impairments to less distinct neural representations in old age, memory studies have shown that high similarity between activity patterns benefits memory performance for the respective stimuli. Here, we addressed this apparent conflict by investigating between-item representational similarity in 50 younger (19–27 years old) and 63 older (63–75 years old) human adults (male and female) who studied scene-word associations using a mnemonic imagery strategy while electroencephalography was recorded. We compared the similarity of spatiotemporal frequency patterns elicited during encoding of items with different subsequent memory fate. Compared to younger adults, older adults’ memory representations were more similar to each other but items that elicited the most similar activity patterns early in the encoding trial were those that were best remembered by older adults. In contrast, young adults’ memory performance benefited from decreased similarity between earlier and later periods in the encoding trials, which might reflect their better success in forming unique memorable mental images of the joint picture–word pair. Our results advance the understanding of the representational properties that give rise to memory quality as well as how these properties change in the course of aging.Significance statementDeclining memory abilities are one of the most evident limitations for humans when growing older. Despite recent advances of our understanding of how the brain represents and stores information in distributed activation patterns, little is known about how the quality of information representation changes during aging and thus affects memory performance. We investigated how the similarity between neural representations relates to subsequent memory quality in younger and older adults. We present novel evidence that the interaction of pattern similarity and memory performance differs between age groups: Older adults benefited from increased similarity during early encoding whereas young adults benefited from decreased similarity between early and later encoding. These results provide insights into the nature of memory and age-related memory deficits.

scholarly journals ALCOHOL CONSUMPTION AND MEMORY: A LONGITUDINAL ANALYSIS OF RECIPROCAL IMPACTS ACROSS OLD AGE

2019 ◽  
Vol 3 (Supplement_1) ◽  
pp. S651-S651
Author(s):  
Oliver K Schilling
Keyword(s):  
Alcohol Consumption ◽  
Episodic Memory ◽  
Old Age ◽  
Cognitive Aging ◽  
Memory Performance ◽  
Longitudinal Change ◽  
Moderate Alcohol Consumption ◽  
Age Related ◽  
Lagged Effects

Abstract Research on the association of alcohol consumption with cognitive aging revealed mixed evidence: Whereas a u-shaped relationship has been found in many studies, suggesting that low to moderate alcohol consumption predicts more favorable cognitive outcomes than abstinence, other findings suggest that alcohol is a more linearly related risk factor for cognitive decline. These inconsistencies may partly be due to methodological variation in the statistical modeling of intraindividual changes in both, alcohol consumption and cognition across old age. The present study analyzed longitudinal change in and the mutual effects between alcohol consumption habits and verbal episodic memory (word list recall), using vector autoregressive (VAR) mixed models with nonlinear cross-lagged effects. Data from the English Longitudinal Study of Ageing was examined, including N=13388 aged 50+ (M=67.6, SD=9.25; 54.7% female), assessed at up to eight occasions with two-year follow-up intervals (2002/3–2016/17). The self-reported one-year frequency of alcohol drinking days (ADD) served as indicator of alcohol consumption. Basically, ADD predicted follow-up memory performance in a reverse u-shaped fashion, indicating best memory performance after moderate ADD, compared with both ends of the ADD continuum (i.e., drinking never vs. every day). Considering moderators, most notably age did not interact with cross-lagged effects, suggesting that those observed across an older age-range were not more (or less) vulnerable to effects of alcohol consumption on memory performance. Thus, this study adds further support for non-detrimental, if not beneficial, effects of moderate alcohol consumption on cognitive aging – regarding in particular age-related loss of episodic memory.

scholarly journals Tracking age differences in neural distinctiveness across representational levels

2020 ◽  
Author(s):  
Malte Kobelt ◽  
Verena R. Sommer ◽  
Attila Keresztes ◽  
Markus Werkle-Bergner ◽  
Myriam C. Sander
Keyword(s):  
Age Differences ◽  
Computational Models ◽  
Recognition Performance ◽  
Memory Performance ◽  
Aging Brain ◽  
Information Representation ◽  
Age Related ◽  
Fmri Study ◽  
Pattern Similarity ◽  
Neural Information

SummaryThe distinctiveness of neural information representation is crucial for successful memory performance but declines with advancing age. Computational models implicate age-related neural dedifferentiation on the level of item representations, but previous studies mostly focused on age differences of categorical information representation in higher-order visual regions. In an age-comparative fMRI study, we combined univariate analyses and whole-brain searchlight pattern similarity analyses to elucidate age differences in neural distinctiveness at both category and item levels and their relation to memory. Age-related neural dedifferentiation was shown as reduced category-selective processing in ventral visual cortex and impoverished item specificity in occipital regions. Importantly, successful subsequent memory performance built upon high item stability which was greater in younger than older adults. Finally, we identified a multivariate profile of neural distinctiveness across representational levels that captured both age group and recognition performance differences, emphasizing that neural dedifferentiation is a generalized phenomenon in the aging brain.

scholarly journals Effects of Age Differences in Memory Formation on Neural Mechanisms of Consolidation and Retrieval

2020 ◽  
Author(s):  
Myriam C. Sander ◽  
Yana Fandakova ◽  
Markus Werkle-Bergner
Keyword(s):  
Older Adults ◽  
Episodic Memory ◽  
Age Differences ◽  
Cognitive Aging ◽  
Younger Adults ◽  
Memory Decline ◽  
Memory Processing ◽  
Memory Impairments ◽  
Age Related ◽  
Memory Network

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.

scholarly journals Distinguishing the Impact of Age on Semantic and Nonsemantic Associations in Episodic Memory

2020 ◽  
Author(s):  
Gabriel Jarjat ◽  
Geoff Ward ◽  
Pascal Hot ◽  
Sophie Portrat ◽  
Vanessa M Loaiza
Keyword(s):  
Episodic Memory ◽  
Age Differences ◽  
Source Memory ◽  
Memory Performance ◽  
Age Difference ◽  
Unrelated Pair ◽  
Age Related ◽  
Semantic Associations ◽  
Bayesian Implementation ◽  
The Impact

Abstract Objectives Refreshing, or the act of briefly foregrounding recently presented but now perceptually absent representations, has been identified as a possible source of age differences in working memory and episodic memory. We investigated whether the refreshing deficit contributes to the well-known age-related deficit for retrieving nonsemantic associations, but has no impact on existing semantic associations. Method Younger and older adults judged the relatedness of stimulus word pairs (e.g., pink–blue or pink–cop) after repeating or refreshing one of the words. During a later source recognition memory test, participants determined whether each item recognized as old was presented on the left or right (nonsemantic source memory) and presented in a related or unrelated pair (semantic source memory). The data were analyzed using a hierarchical Bayesian implementation of a multinomial model of multidimensional source memory. Results Neither age group exhibited a refreshing benefit to nonsemantic or semantic source memory parameters. There was a large age difference in nonsemantic source memory, but no age difference in semantic source memory. Discussion The study suggests that the nature of the association is most important to episodic memory performance in older age, irrespective of refreshing, such that source memory is unimpaired for semantically meaningful information.

scholarly journals Age Differences In Retrieval-Related Reinstatement Reflect Age-Related Dedifferentiation At Encoding

2020 ◽  
Vol 31 (1) ◽  
pp. 106-122 ◽  
Author(s):  
Paul F Hill ◽  
Danielle R King ◽  
Michael D Rugg
Keyword(s):  
Age Differences ◽  
Memory Performance ◽  
Independent Manner ◽  
Younger Adults ◽  
Age Related ◽  
Pattern Similarity ◽  
Age Dependent ◽  
Neural Selectivity ◽  
With Memory ◽  
Robust Evidence

Abstract Age-related reductions in neural selectivity have been linked to cognitive decline. We examined whether age differences in the strength of retrieval-related cortical reinstatement could be explained by analogous differences in neural selectivity at encoding, and whether reinstatement was associated with memory performance in an age-dependent or an age-independent manner. Young and older adults underwent fMRI as they encoded words paired with images of faces or scenes. During a subsequent scanned memory test participants judged whether test words were studied or unstudied and, for words judged studied, also made a source memory judgment about the associated image category. Using multi-voxel pattern similarity analyses, we identified robust evidence for reduced scene reinstatement in older relative to younger adults. This decline was however largely explained by age differences in neural differentiation at encoding; moreover, a similar relationship between neural selectivity at encoding and retrieval was evident in young participants. The results suggest that, regardless of age, the selectivity with which events are neurally processed at the time of encoding can determine the strength of retrieval-related cortical reinstatement.

scholarly journals Resting‐State EEG Microstates Parallel Age‐Related Differences in Allocentric Spatial Working Memory Performance

2021 ◽  
Author(s):  
Adeline Jabès ◽  
Giuliana Klencklen ◽  
Paolo Ruggeri ◽  
Christoph M. Michel ◽  
Pamela Banta Lavenex ◽  
...  
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Resting State ◽  
Cognitive Aging ◽  
Temporal Dynamics ◽  
Spatial Working Memory ◽  
Brain Activity ◽  
Memory Performance ◽  
Brain Regions ◽  
Age Related

AbstractAlterations of resting-state EEG microstates have been associated with various neurological disorders and behavioral states. Interestingly, age-related differences in EEG microstate organization have also been reported, and it has been suggested that resting-state EEG activity may predict cognitive capacities in healthy individuals across the lifespan. In this exploratory study, we performed a microstate analysis of resting-state brain activity and tested allocentric spatial working memory performance in healthy adult individuals: twenty 25–30-year-olds and twenty-five 64–75-year-olds. We found a lower spatial working memory performance in older adults, as well as age-related differences in the five EEG microstate maps A, B, C, C′ and D, but especially in microstate maps C and C′. These two maps have been linked to neuronal activity in the frontal and parietal brain regions which are associated with working memory and attention, cognitive functions that have been shown to be sensitive to aging. Older adults exhibited lower global explained variance and occurrence of maps C and C′. Moreover, although there was a higher probability to transition from any map towards maps C, C′ and D in young and older adults, this probability was lower in older adults. Finally, although age-related differences in resting-state EEG microstates paralleled differences in allocentric spatial working memory performance, we found no evidence that any individual or combination of resting-state EEG microstate parameter(s) could reliably predict individual spatial working memory performance. Whether the temporal dynamics of EEG microstates may be used to assess healthy cognitive aging from resting-state brain activity requires further investigation.

scholarly journals Intact context memory performance in adults with autism spectrum disorder

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Sidni A. Justus ◽  
Patrick S. Powell ◽  
Audrey Duarte
Keyword(s):  
Autism Spectrum Disorder ◽  
Selective Attention ◽  
Episodic Memory ◽  
Memory Performance ◽  
Autism Spectrum ◽  
Spectrum Disorder ◽  
Memory Accuracy ◽  
Age Related ◽  
Adults With Asd ◽  
Context Memory

AbstractResearch on memory in autism spectrum disorder (ASD) finds increased difficulty encoding contextual associations in episodic memory and suggests executive dysfunction (e.g., selective attention, cognitive flexibility) and deficient metacognitive monitoring as potential contributing factors. Findings from our lab suggest that age-related impairments in selective attention contribute to those in context memory accuracy and older adults tended to show dependence in context memory accuracy between relevant and irrelevant context details (i.e., hyper-binding). Using an aging framework, we tested the effects of selective attention on context memory in a sample of 23 adults with ASD and 23 typically developed adults. Participants studied grayscale objects flanked by two types of contexts (color, scene) on opposing sides and were told to attend to only one object-context relationship, ignoring the other context. At test, participants made object and context recognition decisions and judgment of confidence decisions allowing for an evaluation of context memory performance, hyper-binding, and metacognitive performance for context judgments in a single task. Results showed that adults with ASD performed similarly to typically developed adults on all measures. These findings suggest that context memory performance is not always disrupted in adults with ASD, even when demands on selective attention are high. We discuss the need for continued research to evaluate episodic memory in a wider variety of adults with ASD.

Episodic Future Thinking and Cognitive Aging

2018 ◽  
Author(s):  
Daniel L. Schacter ◽  
Aleea L. Devitt ◽  
Donna Rose Addis
Keyword(s):  
Older Adults ◽  
Problem Solving ◽  
Episodic Memory ◽  
Prospective Memory ◽  
Cognitive Aging ◽  
Episodic Future Thinking ◽  
Future Thinking ◽  
Age Related ◽  
Prosocial Intentions ◽  
Age Related Changes

Episodic future thinking refers to the ability to imagine or simulate experiences that might occur in an individual’s personal future. It has been known for decades that cognitive aging is associated with declines in episodic memory, and recent research has documented correlated age-related declines in episodic future thinking. Previous research has considered both cognitive and neural mechanisms that are responsible for age-related changes in episodic future thinking, as well as effects of aging on the functions served by episodic future thinking. Studies concerned with mechanism indicate that multiple cognitive mechanisms contribute to changes in episodic future thinking during aging, including episodic memory retrieval, narrative style, and executive processes. Recent studies using an episodic specificity induction—brief training in recollecting episodic details of a recent experience—have proven useful in separating the contributions of episodic retrieval from other non-episodic processes during future thinking tasks in both old and young adults. Neuroimaging studies provide preliminary evidence of a role for age-related changes in default and executive brain networks in episodic future thinking and autobiographical planning. Studies concerned with function have examined age-related effects on the link between episodic future thinking and a variety of processes, including everyday problem-solving, prospective memory, prosocial intentions, and intertemporal choice/delay discounting. The general finding in these studies is for age-related reductions, consistent with the work on mechanisms that consistently reveals reduced episodic detail in older adults when they imagine future events. However, several studies have revealed that episodic simulation nonetheless confers some benefits for tasks tapping adaptive functions in older adults, such as problem-solving, prospective memory, and prosocial intentions, even though age-related deficits on these tasks are not eliminated or reduced by episodic future thinking.

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