scholarly journals The relationship between age, neural differentiation, and memory performance

2018 ◽  
Author(s):  
Joshua D. Koen ◽  
Nedra Hauck ◽  
Michael D. Rugg
Keyword(s):  
Episodic Memory ◽  
Neural Differentiation ◽  
Memory Performance ◽  
Younger Adults ◽  
Age Related ◽  
Cortical Regions ◽  
Age Related Cognitive Decline ◽  
Neural Selectivity ◽  
The Relationship ◽  
Differentiation Index

AbstractHealthy aging is associated with decreased neural selectivity (dedifferentiation) in category-selective cortical regions. This finding has prompted the suggestion that dedifferentiation contributes to age-related cognitive decline. Consistent with this possibility, dedifferentiation has been reported to negatively correlate with fluid intelligence in older adults. Here, we examined whether dedifferentiation is associated with performance in another cognitive domain – episodic memory – that is also highly vulnerable to aging. Given the proposed role of differentiation in age-related cognitive decline, we predicted there would be a stronger link between dedifferentiation and episodic memory performance in older than in younger adults. Young (18-30 yrs) and older (64-75 yrs) male and female humans underwent fMRI scanning while viewing images of objects and scenes prior to a subsequent recognition memory test. We computed a differentiation index in two regions-of-interest (ROIs): parahippocampal place area (PPA) and lateral occipital complex (LOC). This index quantified the selectivity of the BOLD response to an ROI’s preferred versus non-preferred category (scenes for PPA, objects for LOC). The differentiation index in the PPA, but not the LOC, was lower in older than in younger adults. Additionally, the PPA differentiation index predicted recognition memory performance for the studied items. This relationship was independent of and not moderated by age. The PPA differentiation index also predicted performance on a latent ‘fluency’ factor derived from a neuropsychological test battery; this relationship was also age invariant. These findings suggest that two independent factors, one associated with age, and the other with cognitive performance, drive neural differentiation.Significance StatementAging is associated with neural dedifferentiation – reduced neural selectivity in ‘category selective’ cortical brain regions – which has been proposed to mediate cognitive aging. Here, we examined whether neural differentiation is predictive of episodic memory performance, and whether the relationship is moderated by age. A neural differentiation index was estimated for scene-(PPA) and object-(LOC) selective cortical regions while participants studied images for a subsequent memory test. Age related reductions were observed for the PPA, but not the LOC, differentiation index. Importantly, the PPA differentiation index demonstrated age invariant correlations with subsequent memory performance and a fluency factor derived from a neuropsychological battery. Together, these findings suggest that neural differentiation is associated with two independent factors: age and cognitive performance.

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 Age-Related Neural Dedifferentiation and Cognition

2019 ◽  
Author(s):  
Joshua Koen ◽  
Sabina Srokova ◽  
Michael Rugg
Keyword(s):  
Episodic Memory ◽  
Brain Regions ◽  
Functional Specificity ◽  
Neural Representations ◽  
Age Related ◽  
Functional Brain Networks ◽  
Age Related Cognitive Decline ◽  
Neural Selectivity ◽  
Invariant Relationship ◽  
Existing Data

This review focuses on possible contributions of neural dedifferentiation to age-related cognitive decline. Neural dedifferentiation is held to reflect a breakdown in the functional specificity of brain regions and networks that compromises the fidelity of neural representations supporting episodic memory and related cognitive functions. The evidence for age-related dedifferentiation is robust when it is operationalized as neural selectivity for different categories of perceptual stimuli or as decreased segregation or modularity of resting-state functional brain networks. Neural dedifferentiation for perceptual categories appears to demonstrate a negative, age-invariant relationship with performance on tests of memory and fluid processing. Whether this pattern extends to network-level measures of dedifferentiation cannot currently be determined due to insufficient evidence. The existing data highlight the importance of further examination of neural dedifferentiation as a factor contributing to episodic memory and to cognitive performance more generally.

scholarly journals Ageing and apoE change DHA homeostasis: relevance to age-related cognitive decline

2013 ◽  
Vol 73 (1) ◽  
pp. 80-86 ◽  
Author(s):  
Marie Hennebelle ◽  
Mélanie Plourde ◽  
Raphaël Chouinard-Watkins ◽  
Christian-Alexandre Castellano ◽  
Pascale Barberger-Gateau ◽  
...  
Keyword(s):  
Older Adults ◽  
Young Adults ◽  
Cognitive Decline ◽  
Human Subjects ◽  
Epidemiological Studies ◽  
Physiological Factors ◽  
Younger Adults ◽  
Age Related ◽  
Age Related Cognitive Decline ◽  
The Relationship

Epidemiological studies fairly convincingly suggest that higher intakes of fatty fish and n-3 fatty acids are associated with reduced risk of Alzheimer's disease (AD). DHA in plasma is normally positively associated with DHA intake. However, despite being associated with lower fish and DHA intake, unexpectedly, plasma (or brain) DHA is frequently not lower in AD. This review will highlight some metabolic and physiological factors such as ageing and apoE polymorphism that influence DHA homeostasis. Compared with young adults, blood DHA is often slightly but significantly higher in older adults without any age-related cognitive decline. Higher plasma DHA in older adults could be a sign that their fish or DHA intake is higher. However, our supplementation and carbon-13 tracer studies also show that DHA metabolism, e.g. transit through the plasma, apparent retroconversion and β-oxidation, is altered in healthy older compared with healthy young adults. ApoE4 increases the risk of AD, possibly in part because it too changes DHA homeostasis. Therefore, independent of differences in fish intake, changing DHA homeostasis may tend to obscure the relationship between DHA intake and plasma DHA which, in turn, may contribute to making older adults more susceptible to cognitive decline despite older adults having similar or sometimes higher plasma DHA than in younger adults. In conclusion, recent development of new tools such as isotopically labelled DHA to study DHA metabolism in human subjects highlights some promising avenues to evaluate how and why DHA metabolism changes during ageing and AD.

scholarly journals Cardiorespiratory Fitness Is Associated With Cognitive Performance in Older But Not Younger Adults

2014 ◽  
Vol 71 (3) ◽  
pp. 474-482 ◽  
Author(s):  
Scott M. Hayes ◽  
Daniel E. Forman ◽  
Mieke Verfaellie
Keyword(s):  
Executive Function ◽  
Episodic Memory ◽  
Cognitive Decline ◽  
Cardiorespiratory Fitness ◽  
Neuropsychological Testing ◽  
Memory Task ◽  
Age Related ◽  
Age Related Cognitive Decline ◽  
The Relationship ◽  
Better Than

Abstract Objectives: Aging is associated with declines in executive function and episodic memory. Cardiorespiratory fitness (CRF) has been associated with enhanced executive function in older adults (OA), but the relationship with episodic memory remains unclear. The purpose of the study was to examine the relationship between CRF and cognition in young and OA and whether CRF mitigates age-related cognitive decline. Methods: Participants completed exercise testing to evaluate CRF (peak VO 2 ) and neuropsychological testing to assess cognition. Results: In OA, peak VO 2 was positively related to executive function, as well as to accuracy on an experimental face–name memory task and visual episodic memory. In young adults (YA), a relationship between peak VO 2 and cognition was not evident. High-fit OA performed as well as YA on executive function measures. On episodic memory measures, YA performed better than high-fit OA, who in turn performed better than low-fit OA. Conclusions: CRF is positively associated with executive function and episodic memory in OA and attenuates age-related cognitive decline. We provide preliminary support for the age-dependence hypothesis, which posits that cognition and CRF relationships may be most readily observed during lifetime periods of significant neurocognitive development.

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 Effects of amnesia on processing in the hippocampus and default mode network during a naturalistic memory task: a case study

2018 ◽  
Author(s):  
Christiane Oedekoven ◽  
James L. Keidel ◽  
Stuart Anderson ◽  
Angus Nisbet ◽  
Chris Bird
Keyword(s):  
Functional Connectivity ◽  
Episodic Memory ◽  
Memory Performance ◽  
Memory Task ◽  
Structural Mri ◽  
Brain Regions ◽  
Left Hippocampus ◽  
Cortical Regions ◽  
The Right ◽  
Encoding And Retrieval

Despite their severely impaired episodic memory, individuals with amnesia are able to comprehend ongoing events. Online representations of a current event are thought to be supported by a network of regions centred on the posterior midline cortex (PMC). By contrast, episodic memory is widely believed to be supported by interactions between the hippocampus and these cortical regions. In this MRI study, we investigated the encoding and retrieval of lifelike events (video clips) in a patient with severe amnesia likely resulting from a stroke to the right thalamus, and a group of 20 age-matched controls. Structural MRI revealed grey matter reductions in left hippocampus and left thalamus in comparison to controls. We first characterised the regions activated in the controls while they watched and retrieved the videos. There were no differences in activation between the patient and controls in any of the regions. We then identified a widespread network of brain regions, including the hippocampus, that were functionally connected with the PMC in controls. However, in the patient there was a specific reduction in functional connectivity between the PMC and a region of left hippocampus when both watching and attempting to retrieve the videos. A follow up analysis revealed that in controls the functional connectivity between these regions when watching the videos was correlated with memory performance. Taken together, these findings support the view that the interactions between the PMC and the hippocampus enable the encoding and retrieval of multimodal representations of the contents of an event.

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.

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.

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