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.

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.

Inefficient Encoding as an Explanation for Age-Related Deficits in Recollection-Based Processing

2014 ◽  
Vol 28 (3) ◽  
pp. 148-161 ◽  
Author(s):  
David Friedman ◽  
Ray Johnson
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cognitive Processes ◽  
Brain Activity ◽  
Memory Performance ◽  
Brain Regions ◽  
Semantic Retrieval ◽  
Age Related ◽  
The Face ◽  
Episodic Memories

A cardinal feature of aging is a decline in episodic memory (EM). Nevertheless, there is evidence that some older adults may be able to “compensate” for failures in recollection-based processing by recruiting brain regions and cognitive processes not normally recruited by the young. We review the evidence suggesting that age-related declines in EM performance and recollection-related brain activity (left-parietal EM effect; LPEM) are due to altered processing at encoding. We describe results from our laboratory on differences in encoding- and retrieval-related activity between young and older adults. We then show that, relative to the young, in older adults brain activity at encoding is reduced over a brain region believed to be crucial for successful semantic elaboration in a 400–1,400-ms interval (left inferior prefrontal cortex, LIPFC; Johnson, Nessler, & Friedman, 2013 ; Nessler, Friedman, Johnson, & Bersick, 2007 ; Nessler, Johnson, Bersick, & Friedman, 2006 ). This reduced brain activity is associated with diminished subsequent recognition-memory performance and the LPEM at retrieval. We provide evidence for this premise by demonstrating that disrupting encoding-related processes during this 400–1,400-ms interval in young adults affords causal support for the hypothesis that the reduction over LIPFC during encoding produces the hallmarks of an age-related EM deficit: normal semantic retrieval at encoding, reduced subsequent episodic recognition accuracy, free recall, and the LPEM. Finally, we show that the reduced LPEM in young adults is associated with “additional” brain activity over similar brain areas as those activated when older adults show deficient retrieval. Hence, rather than supporting the compensation hypothesis, these data are more consistent with the scaffolding hypothesis, in which the recruitment of additional cognitive processes is an adaptive response across the life span in the face of momentary increases in task demand due to poorly-encoded episodic memories.

scholarly journals Behavioral and fMRI evidence that arousal enhances bottom-up attention and memory selectivity in young but not older adults

2021 ◽  
Author(s):  
Sara N Gallant ◽  
Briana L Kennedy ◽  
Shelby L Bachman ◽  
Ringo Huang ◽  
Tae-Ho Lee ◽  
...  
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Age Differences ◽  
Emotional Experience ◽  
Noradrenergic System ◽  
Attention And Memory ◽  
Bottom Up ◽  
Age Related ◽  
Selective Processing ◽  
The Brain

During a challenge or emotional experience, increases in arousal help us focus on the most salient or relevant details and ignore distracting stimuli. The noradrenergic system integrates signals about arousal states throughout the brain and helps coordinate this adaptive attentional selectivity. However, age-related changes in the noradrenergic system and attention networks in the brain may reduce the efficiency of arousal to modulate selective processing in older adults. In the current neuroimaging study, we examined age differences in how arousal affects bottom-up attention to category-selective stimuli differing in perceptual salience. We found a dissociation in how arousal modulates selective processing in the young and older brain. In young adults, emotionally arousing sounds enhanced selective incidental memory and brain activity in the extrastriate body area for salient versus non-salient images of bodies. Older adults showed no such advantage in selective processing under arousal. These age differences could not be attributed to changes in the arousal response or less neural distinctiveness in old age. Rather, our results suggest that, relative to young adults, older adults become less effective at focusing on salient over non-salient details during increases in emotional arousal.

scholarly journals Preparing for the Worst: Evidence that Older Adults Proactively Downregulate Negative Affect

2019 ◽  
Vol 30 (3) ◽  
pp. 1291-1306 ◽  
Author(s):  
Brittany Corbett ◽  
M Natasha Rajah ◽  
Audrey Duarte
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Negative Affect ◽  
Emotional Processing ◽  
Memory Performance ◽  
Recognition Task ◽  
Emotional Suppression ◽  
Age Related ◽  
Pls Analysis ◽  
The Impact

Abstract Previous studies have only investigated age-related differences in emotional processing and encoding in response to, not in anticipation of, emotional stimuli. In the current study, we investigated age-related differences in the impact of emotional anticipation on affective responses and episodic memory for emotional images. Young and older adults were scanned while encoding negative and neutral images preceded by cues that were either valid or invalid predictors of image valence. Participants were asked to rate the emotional intensity of the images and to complete a recognition task. Using multivariate behavioral partial least squares (PLS) analysis, we found that greater anticipatory recruitment of the amygdala, ventromedial prefrontal cortex (vmPFC), and hippocampus in older adults predicted reduced memory for negative than neutral images and the opposite for young adults. Seed PLS analysis further showed that following negative cues older adults, but not young adults, exhibited greater activation of vmPFC, reduced activation of amygdala, and worse memory for negative compared with neutral images. To the best of our knowledge, this is the first study to provide evidence that the “positivity effect” seen in older adults’ memory performance may be related to the spontaneous emotional suppression of negative affect in anticipation of, not just in response to, negative stimuli.

scholarly journals Age-related neural dedifferentiation for individual stimuli: An across-participant pattern similarity analysis

2021 ◽  
Author(s):  
Joshua D Koen
Keyword(s):  
Older Adults ◽  
Memory Effect ◽  
Source Memory ◽  
Computational Models ◽  
Similarity Analysis ◽  
Memory Encoding ◽  
Neural Representations ◽  
Age Related ◽  
Pattern Similarity ◽  
Subsequent Memory Effect

Age-related neural dedifferentiation - reductions in the regional specificity and precision of neural representations - is proposed to compromise the ability of older adults to form sufficiently distinct neural representations to support episodic memory encoding. The computational model that spurred investigations of age-related neural dedifferentiation initially characterized this phenomenon as a reduction in the specificity of neural patterns for individual items or stimuli. Most investigations have focused on reductions in neural differentiation for patterns of neural activity associated with category level information, such as reduced neural selectivity between categories of visual stimuli (e.g., scenes, objects, and faces). Here, I report a novel across-participant pattern similarity analysis method to measure neural distinctiveness for individual stimuli that were presented to participants on a single occasion. Measures of item level pattern similarity during encoding showed a graded positive subsequent memory effect in younger, with no significant subsequent memory effect in older adults. These results suggest that age-related reductions in the distinctiveness of neural patterns for individual stimuli during age differences in memory encoding. Moreover, a measure of category level similarity demonstrated a significant subsequent memory effect associated with item recognition (regardless of an object source memory detail), whereas the effect in older was associated with source memory. These results converge with predictions of computational models of dedifferentiation showing age-related reductions in the distinctiveness of neural patterns across multiple levels of representation. Moreover, the results suggest that different levels of neural representations support successful encoding in young and older adults.

scholarly journals Age-related associative memory deficit: simulation and strategies to improve performance

2021 ◽  
Author(s):  
Brenda Iok Wong
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Associative Memory ◽  
Divided Attention ◽  
Resource Competition ◽  
Memory Performance ◽  
Attentional Resources ◽  
Age Related ◽  
Associative Deficit ◽  
Encoding Strategies

According to the associative deficit hypothesis, older adults experience greater difficulty in remembering associations between pieces of information (associative memory) than young adults, despite their relatively intact memory for individual items (item memory). Recent research suggests that this deficit might be related to older adults’ reduced availability of attentional resources – the reservoir of mental energy needed for the operations of cognition functions. The purpose of this Dissertation was to examine the role of attentional resources in associative deficit, and to explore encoding manipulations that might alleviate the deficit in older adults. In Study 1, young adults’ attentional resources during encoding of word pairs were depleted using a divided attention task. These participants showed an associative deficit commonly observed in older adults, and were less likely to use effective encoding strategies and recollection-based processes to support their memory in comparison to young adults under full attention. The resemblance in memory performance between young adults under divided attention and older adults suggests that lack of attentional resources might be a contributing factor in older adults’ associative deficit. In Study 2, participants’ resource load during encoding was reduced by learning individual items and their associations sequentially in two phases. Older adults in this condition showed equivalent memory performance to young adults, and were more likely to use effective encoding strategies and recollection-based processes than older adults in Study 1 who studied items and associations simultaneously. Finally, Study 3 employed a value-directed learning paradigm, in which participants studied high- and low-value word pairs. Older adults showed similar memory performance for both high- and low-value word pairs as young adults, without any signs of associative deficit. Assigning value to associative information might prompt older adults to prioritize associative encoding over item encoding, which benefits their associative memory. Taken together, these results suggest that depletion of attentional resources during encoding could impair associative memory. Furthermore, older adults’ associative deficit could be effectively alleviated with sufficient environmental support during encoding, such as when resource competition between item and associative encoding is minimized (Study 2) or when being guided to prioritize encoding of associations over items (Study 3).

Age moderation of the association between negative subsequent memory effects and episodic memory performance

2020 ◽  
Author(s):  
Patrick Pruitt ◽  
Lingfei Tang ◽  
Jessica Hayes ◽  
Noa Ofen ◽  
Jessica S. Damoiseaux
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Episodic Memory ◽  
Functional Neuroimaging ◽  
Memory Performance ◽  
Age Groups ◽  
Recognition Task ◽  
Memory Formation ◽  
Memory Effects ◽  
Age Related

Negative subsequent memory effects in functional MRI studies of memory formation, have been linked to individual differences in memory performance, yet the effect of age on this association is currently unclear. To provide insight into the brain systems related to memory across the lifespan, we examined functional neuroimaging data acquired during episodic memory formation and behavioral performance from a memory recognition task in a sample of 109 participants, including three developmental age groups (8-12, 13-17, 18-25 year-olds) and one additional group of older adults (55-85 year-olds). Young adults showed the highest memory performance and strongest negative subsequent memory effects, while older adults showed reduced negative subsequent memory effects relative to young adults. Across the sample, negative subsequent memory effects were associated with better memory performance, and there was a significant interaction between negative subsequent memory effects and memory performance by age groups. Posthoc analyses revealed that this effect was driven by a strong association between negative subsequent memory effects and memory performance in adolescents and young adults, but not in children and older adults. These findings suggest that negative subsequent memory effects may differentially support memory performance across a lifespan trajectory characterized by developmental maturation and age-related deterioration.

scholarly journals Dose-Dependent Effects of Oral Tyrosine Administration on Plasma Tyrosine Levels and Cognition in Aging

2017 ◽  
Author(s):  
Ondine van de Rest ◽  
Mirjam Bloemendaal ◽  
Rianne de Heus ◽  
Esther Aarts
Keyword(s):  
Older Adults ◽  
Working Memory ◽  
Young Adults ◽  
Body Weight ◽  
Memory Performance ◽  
Plasma Concentrations ◽  
Age Related ◽  
Plasma Response ◽  
Plasma Tyrosine ◽  
Dose Dependent

The effects of tyrosine on plasma response and cognition in aging are unknown. We assessed the dose-dependent response to tyrosine administration in older adults in both plasma tyrosine concentrations and working memory performance. In this double blind randomized cross-over trial 17 older adults (aged 60-75 years) received a single administration of 100, 150 or 200 mg/kg body weight of tyrosine. For comparison, 17 young adults (aged 18-35 years) received a dose of 150 mg/kg body weight of tyrosine. Tyrosine plasma concentrations were determined before and 90, 120, 150, 180, 210 and 240 minutes after tyrosine intake. Working memory was assessed using the N-back task at 90 minutes after tyrosine administration. Older adults showed a dose-dependent increase in plasma tyrosine concentrations (p<.001), and the plasma response was higher than for young adults with the same dose (p<.001). Load-dependent working memory performance decreased with higher doses of tyrosine (p=.048), especially in older adults with greater dose-dependent plasma tyrosine responses (p=.035). Our results show an age-related increase in plasma tyrosine response, which was associated with a dose-dependent decline in cognitive functioning in older adults.

scholarly journals Age-related associative memory deficit: simulation and strategies to improve performance

2021 ◽  
Author(s):  
Brenda Iok Wong
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Associative Memory ◽  
Divided Attention ◽  
Resource Competition ◽  
Memory Performance ◽  
Attentional Resources ◽  
Age Related ◽  
Associative Deficit ◽  
Encoding Strategies

According to the associative deficit hypothesis, older adults experience greater difficulty in remembering associations between pieces of information (associative memory) than young adults, despite their relatively intact memory for individual items (item memory). Recent research suggests that this deficit might be related to older adults’ reduced availability of attentional resources – the reservoir of mental energy needed for the operations of cognition functions. The purpose of this Dissertation was to examine the role of attentional resources in associative deficit, and to explore encoding manipulations that might alleviate the deficit in older adults. In Study 1, young adults’ attentional resources during encoding of word pairs were depleted using a divided attention task. These participants showed an associative deficit commonly observed in older adults, and were less likely to use effective encoding strategies and recollection-based processes to support their memory in comparison to young adults under full attention. The resemblance in memory performance between young adults under divided attention and older adults suggests that lack of attentional resources might be a contributing factor in older adults’ associative deficit. In Study 2, participants’ resource load during encoding was reduced by learning individual items and their associations sequentially in two phases. Older adults in this condition showed equivalent memory performance to young adults, and were more likely to use effective encoding strategies and recollection-based processes than older adults in Study 1 who studied items and associations simultaneously. Finally, Study 3 employed a value-directed learning paradigm, in which participants studied high- and low-value word pairs. Older adults showed similar memory performance for both high- and low-value word pairs as young adults, without any signs of associative deficit. Assigning value to associative information might prompt older adults to prioritize associative encoding over item encoding, which benefits their associative memory. Taken together, these results suggest that depletion of attentional resources during encoding could impair associative memory. Furthermore, older adults’ associative deficit could be effectively alleviated with sufficient environmental support during encoding, such as when resource competition between item and associative encoding is minimized (Study 2) or when being guided to prioritize encoding of associations over items (Study 3).

scholarly journals Age-related Changes in the Sleep-dependent Reorganization of Declarative Memories

2016 ◽  
Vol 28 (6) ◽  
pp. 792-802 ◽  
Author(s):  
Bengi Baran ◽  
Janna Mantua ◽  
Rebecca M. C. Spencer
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Functional Connectivity ◽  
Memory Retrieval ◽  
Slow Wave Sleep ◽  
Memory Performance ◽  
Memory Recall ◽  
Functional Brain ◽  
Age Related ◽  
Age Related Changes

Consolidation of declarative memories has been associated with slow wave sleep in young adults. Previous work suggests that, in spite of changes in sleep, sleep-dependent consolidation of declarative memories may be preserved with aging, although reduced relative to young adults. Previous work on young adults shows that, with consolidation, retrieval of declarative memories gradually becomes independent of the hippocampus. To investigate whether memories are similarly reorganized over sleep at the neural level, we compared functional brain activation associated with word pair recall following a nap and equivalent wake in young and older adults. SWS during the nap predicted better subsequent memory recall and was negatively associated with retrieval-related hippocampal activation in young adults. In contrast, in older adults there was no relationship between sleep and memory performance or with retrieval-related hippocampal activation. Furthermore, compared with young adults, postnap memory retrieval in older adults required strong functional connectivity of the hippocampus with the PFC, whereas there were no differences between young and older adults in the functional connectivity of the hippocampus following wakefulness. These results suggest that, although neural reorganization takes place over sleep in older adults, the shift is unique from that seen in young adults, perhaps reflecting memories at an earlier stage of stabilization.

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