Span, CRUNCH, and Beyond: Working Memory Capacity and the Aging Brain

Neuroimaging data emphasize that older adults often show greater extent of brain activation than younger adults for similar objective levels of difficulty. A possible interpretation of this finding is that older adults need to recruit neuronal resources at lower loads than younger adults, leaving no resources for higher loads, and thus leading to performance decrements [Compensation-Related Utilization of Neural Circuits Hypothesis; e.g., Reuter-Lorenz, P. A., & Cappell, K. A. Neurocognitive aging and the compensation hypothesis. Current Directions in Psychological Science, 17, 177–182, 2008]. The Compensation-Related Utilization of Neural Circuits Hypothesis leads to the prediction that activation differences between younger and older adults should disappear when task difficulty is made subjectively comparable. In a Sternberg memory search task, this can be achieved by assessing brain activity as a function of load relative to the individual's memory span, which declines with age. Specifically, we hypothesized a nonlinear relationship between load and both performance and brain activity and predicted that asymptotes in the brain activation function should correlate with performance asymptotes (corresponding to working memory span). The results suggest that age differences in brain activation can be largely attributed to individual variations in working memory span. Interestingly, the brain activation data show a sigmoid relationship with load. Results are discussed in terms of Cowan's [Cowan, N. The magical number 4 in short-term memory: A reconsideration of mental storage capacity. Behavioral and Brain Sciences, 24, 87–114, 2001] model of working memory and theories of impaired inhibitory processes in aging.

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Older adults benefit from more widespread brain network integration during working memory

10.1101/642447 ◽

2019 ◽

Cited By ~ 1

Author(s):

C.A. Crowell ◽

S.W. Davis ◽

L. Beynel ◽

L. Deng ◽

D. Lakhlani ◽

...

Keyword(s):

Older Adults ◽

Working Memory ◽

Network Connectivity ◽

Task Demands ◽

Global Network ◽

Aging Brain ◽

Network Integration ◽

Younger Adults ◽

Age Related ◽

Cortical Regions

AbstractNeuroimaging evidence suggests that the aging brain relies on a more distributed set of cortical regions than younger adults in order to maintain successful levels of performance during demanding cognitive tasks. However, it remains unclear how task demands give rise to this age-related expansion in cortical networks. To investigate this issue, we used functional magnetic resonance imaging to measure univariate activity, network connectivity, and cognitive performance in younger and older adults during a working memory (WM) task. In the WM task investigated, participants hold letters online (maintenance) while reordering them alphabetically (manipulation). WM load was titrated to obtain four individualized difficulty levels. Network integration—defined as the ratio of within-versus between-network connectivity—was linked to individual differences in WM capacity. The study yielded three main findings. First, as task difficulty increased, network integration decreased in younger adults, whereas it increased in older adults. Second, age-related increases in network integration were driven by increases in right hemispheric connectivity to both left and right cortical regions, a finding that helps to reconcile extant theories of compensatory recruitment in aging to address the multivariate dynamics of global network functioning. Lastly, older adults with higher WM capacity demonstrated higher levels of network integration in the most difficult condition. These results shed light on the mechanisms of age-related network reorganization by suggesting that changes in network connectivity may act as an adaptive form of compensation, with older adults recruiting a more distributed cortical network as task demands increase.Significance statementOlder adults often activate brain regions not engaged by younger adults, but the circumstances under which this widespread network emerges are unclear. Here, we examined the effects of aging on network connectivity between task regions recruited during a working memory (WM) manipulation task, and the rest of the brain. We found an age-related increase in the more global network integration in older adults, and an association between this integration and working memory capacity in older adults. The findings are generally consistent with the compensatory interpretation of these effects.

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Theoretical Perspectives on Age Differences in Brain Activation: HAROLD, PASA, CRUNCH—How Do They STAC Up?

Oxford Research Encyclopedia of Psychology ◽

10.1093/acrefore/9780190236557.013.400 ◽

2018 ◽

Cited By ~ 3

Author(s):

Sara B. Festini ◽

Laura Zahodne ◽

Patricia A. Reuter-Lorenz

Keyword(s):

Older Adults ◽

Age Differences ◽

Brain Activity ◽

General Pattern ◽

Empirical Work ◽

Brain Activation ◽

Cognitive Change ◽

Younger Adults ◽

Theoretical Perspectives ◽

Age Related

Cognitive neuroimaging studies often report that older adults display more activation of neural networks relative to younger adults, referred to as overactivation. Greater or more widespread activity frequently involves bilateral recruitment of both cerebral hemispheres, especially the frontal cortex. In many reports, overactivation has been associated with superior cognitive performance, suggesting that this activity may reflect compensatory processes that offset age-related decline and maintain behavior. Several theories have been proposed to account for age differences in brain activation, including the Hemispheric Asymmetry Reduction in Older Adults (HAROLD) model, the Posterior-Anterior Shift in Aging (PASA) theory, the Compensation-Related Utilization of Neural Circuits Hypothesis (CRUNCH), and the Scaffolding Theory of Aging and Cognition (STAC and STAC-r). Each model has a different explanatory scope with regard to compensatory processes, and each has been highly influential in the field. HAROLD contrasts the general pattern of bilateral prefrontal activation in older adults with that of more unilateral activation in younger adults. PASA describes both anterior (e.g., frontal) overactivation and posterior (e.g., occipital) underactivation in older adults relative to younger adults. CRUNCH emphasizes that the level or extent of brain activity can change in response to the level of task demand at any age. Finally, STAC and STAC-r take the broadest perspective to incorporate individual differences in brain structure, the capacity to implement functional scaffolding, and life-course neural enrichment and depletion factors to predict cognition and cognitive change across the lifespan. Extant empirical work has documented that compensatory overactivation can be observed in regions beyond the prefrontal cortex, that variations in task difficulty influence the degree of brain activation, and that younger adults can show compensatory overactivation under high mental demands. Additional research utilizing experimental designs (e.g., transcranial magnetic stimulation), longitudinal assessments, greater regional precision, both verbal and nonverbal material, and measures of individual difference factors will continue to refine our understanding of age-related activation differences and adjudicate among these various accounts of neurocognitive aging.

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Neural Correlates of Working Memory Training: Evidence for Plasticity in Older Adults

10.1101/869164 ◽

2019 ◽

Author(s):

Alexandru D. Iordan ◽

Katherine A. Cooke ◽

Kyle D. Moored ◽

Benjamin Katz ◽

Martin Buschkuehl ◽

...

Keyword(s):

Older Adults ◽

Working Memory ◽

Brain Activity ◽

Neural Correlates ◽

Memory Training ◽

Younger Adults ◽

Neural Efficiency ◽

Improved Performance ◽

Task Positive Network ◽

New Evidence

AbstractBrain activity typically increases with increasing working memory (WM) load, regardless of age, before reaching an apparent ceiling. However, older adults exhibit greater brain activity and reach ceiling at lower loads than younger adults, possibly reflecting compensation at lower loads and dysfunction at higher loads. We hypothesized that WM training would bolster neural efficiency, such that the activation peak would shift towards higher memory loads after training. Pre-training, older adults showed greater recruitment of the WM network than younger adults across all loads, with decline at the highest load. Ten days of adaptive training on a verbal WM task improved performance and led to greater brain responsiveness at higher loads for both groups. For older adults the activation peak shifted rightward towards higher loads. Finally, training increased task-related functional connectivity in older adults, both within the WM network and between this task-positive network and the task-negative/default-mode network. These results provide new evidence for functional plasticity with training in older adults and identify a potential signature of improvement at the neural level.

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

Brain Topography ◽

10.1007/s10548-021-00835-3 ◽

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.

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Neuropsychological deficits in adults age 60 and above with attention deficit hyperactivity disorder

European Psychiatry ◽

10.1016/j.eurpsy.2017.06.005 ◽

2017 ◽

Vol 45 ◽

pp. 90-96 ◽

Cited By ~ 14

Author(s):

L.B. Thorell ◽

Y. Holst ◽

H. Chistiansen ◽

J.J.S. Kooij ◽

D. Bijlenga ◽

...

Keyword(s):

Older Adults ◽

Working Memory ◽

Neuropsychological Deficits ◽

Delay Aversion ◽

Speed Of Processing ◽

Negative Effects ◽

Significant Group ◽

Younger Adults ◽

Memory Decline ◽

Memory Inhibition

AbstractObjective:Neuropsychological deficits are of major importance in ADHD, yet no previous studies have assessed clinically referred samples of older adults. The authors compared older adults with ADHD (60–75 years) with both younger adults with ADHD (18–45 years) and older healthy controls with regard to various neuropsychological deficits.Methods:Well-established tests were used to investigate working memory, inhibition, switching, planning, fluency, and speed of processing. Self-ratings of executive functioning and delay-related behaviors were also included. Both variable-oriented and person-oriented analyses were conducted.Results:Older adults with ADHD differed from controls with regard to working memory, inhibition, switching, and delay-related behaviors. In comparison to younger adults with ADHD, they performed at a similar level with regard to working memory and planning, but significantly better with regard to inhibition, switching, fluency, speed of processing, and delay aversion. Despite several significant group differences relative to controls, person-oriented analyses demonstrated that a majority of older adults with ADHD performed within the average range on each test and 20% showed no clear deficit within any neuropsychological domain.Conclusions:The results are in line with models of heterogeneity that have identified different neuropsychological subtypes in ADHD as well as a subgroup of patients without any clear neuropsychological deficits. For older adults with ADHD, it will be important to assess their functioning across time as normal aging is related to memory decline and these patients could therefore end up with severe deficits as they grow older, which in turn could have serious negative effects on daily life functioning.

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Age-Related Differences in Resting-State EEG and Allocentric Spatial Working Memory Performance

Frontiers in Aging Neuroscience ◽

10.3389/fnagi.2021.704362 ◽

2021 ◽

Vol 13 ◽

Author(s):

Adeline Jabès ◽

Giuliana Klencklen ◽

Paolo Ruggeri ◽

Jean-Philippe Antonietti ◽

Pamela Banta Lavenex ◽

...

Keyword(s):

Older Adults ◽

Working Memory ◽

Resting State ◽

Spatial Working Memory ◽

Brain Activity ◽

Memory Performance ◽

Group Differences ◽

Age Group ◽

Eeg Activity ◽

Recording Conditions

During normal aging resting-state brain activity changes and working memory performance declines as compared to young adulthood. Interestingly, previous studies reported that different electroencephalographic (EEG) measures of resting-state brain activity may correlate with working memory performance at different ages. Here, we recorded resting-state EEG activity and tested allocentric spatial working memory in healthy young (20–30 years) and older (65–75 years) adults. We adapted standard EEG methods to record brain activity in mobile participants in a non-shielded environment, in both eyes closed and eyes open conditions. Our study revealed some age-group differences in resting-state brain activity that were consistent with previous results obtained in different recording conditions. We confirmed that age-group differences in resting-state EEG activity depend on the recording conditions and the specific parameters considered. Nevertheless, lower theta-band and alpha-band frequencies and absolute powers, and higher beta-band and gamma-band relative powers were overall observed in healthy older adults, as compared to healthy young adults. In addition, using principal component and regression analyses, we found that the first extracted EEG component, which represented mainly theta, alpha and beta powers, correlated with spatial working memory performance in older adults, but not in young adults. These findings are consistent with the theory that the neurobiological bases of working memory performance may differ between young and older adults. However, individual measures of resting-state EEG activity could not be used as reliable biomarkers to predict individual allocentric spatial working memory performance in young or older adults.

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Advanced Aging Enhances the Positivity Effect in Memory: Due to Cognitive Control or Age-Related Decline in Emotional Processing?

Collabra Psychology ◽

10.1525/collabra.222 ◽

2019 ◽

Vol 5 (1) ◽

Cited By ~ 2

Author(s):

Michiko Sakaki ◽

Jasmine A. L. Raw ◽

Jamie Findlay ◽

Mariel Thottam

Keyword(s):

Older Adults ◽

Cognitive Control ◽

Emotional Processing ◽

Aging Brain ◽

Control Mechanisms ◽

Younger Adults ◽

Positivity Effect ◽

Old Adults ◽

Age Related ◽

Conditioned Responses

Older adults typically remember more positive than negative information compared to their younger counterparts; a phenomenon referred to as the ‘positivity effect.’ According to the socioemotional selectivity theory (SST), the positivity effect derives from the age-related motivational shift towards attaining emotionally meaningful goals which become more important as the perception of future time becomes more limited. Cognitive control mechanisms are critical in achieving such goals and therefore SST predicts that the positivity effect is associated with preserved cognitive control mechanisms in older adults. In contrast, the aging-brain model suggests that the positivity effect is driven by an age-related decline in the amygdala which is responsible for emotional processing and emotional learning. The aim of the current research was to address whether the age-related positivity effect is associated with cognitive control or impaired emotional processing associated with aging. We included older old adults, younger old adults and younger adults and tested their memory for emotional stimuli, cognitive control and amygdala-dependent fear conditioned responses. Consistent with prior research, older adults, relative to younger adults, demonstrate better memory for positive over negative images. We further found that within a group of older adults, the positivity effect increases as a function of age, such that older old adults demonstrated a greater positivity effect compared to younger older adults. Furthermore, the positivity effect in older old adults was associated with preserved cognitive control, supporting the prediction of SST. Contrary to the prediction of the aging-brain model, participants across all groups demonstrated similar enhanced skin conductance responses to fear conditioned stimuli – responses known to rely on the amygdala. Our results support SST and suggest that the positivity effect in older adults is achieved by the preserved cognitive control mechanisms and is not a reflection of the impaired emotional function associated with age.

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Resolving Age-Related Differences in Working Memory: Equating Perception and Attention Makes Older Adults Remember as Well as Younger Adults

Experimental Aging Research ◽

10.1080/0361073x.2019.1586120 ◽

2019 ◽

Vol 45 (2) ◽

pp. 120-134 ◽

Cited By ~ 4

Author(s):

Paul Verhaeghen ◽

Shriradha Geigerman ◽

Haoxiang Yang ◽

Alejandra C. Montoya ◽

Dobromir Rahnev

Keyword(s):

Older Adults ◽

Working Memory ◽

Younger Adults ◽

Age Related

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Digit Force Controls and Corresponding Brain Activities in Finger Pressing Performance: A Comparison Between Older Adults and Young Individuals

Journal of Aging and Physical Activity ◽

10.1123/japa.2018-0252 ◽

2020 ◽

Vol 28 (1) ◽

pp. 94-103

Author(s):

Pai-Yun Cheng ◽

Hsiao-Feng Chieh ◽

Chien-Ju Lin ◽

Hsiu-Yun Hsu ◽

Jia-Jin J. Chen ◽

...

Keyword(s):

Older Adults ◽

Infrared Spectroscopy ◽

Force Control ◽

Near Infrared ◽

Brain Activity ◽

Hand Function ◽

Young Group ◽

Primary Motor Area ◽

Group Response ◽

The Brain

This study aims toward an investigation and comparison of the digital force control and the brain activities of older adults and young groups during digital pressing tasks. A total of 15 young and 15 older adults were asked to perform force ramp tasks at different force levels with a custom pressing system. Near-infrared spectroscopy was used to collect the brain activities in the prefrontal cortex and primary motor area. The results showed that the force independence and hand function of the older adults were worse than that of the young adults. The cortical activations in the older adults were higher than those in the young group during the tasks. A significant hemodynamic between-group response and mild negative correlations between brain activation and force independence ability were found. Older adults showed poor force independence ability and manual dexterity and required additional brain activity to compensate for the degeneration.

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Electrophysiological differences in older and younger adults’ anaphoric but not cataphoric pronoun processing in the absence of age-related behavioural slowdown

Scientific Reports ◽

10.1038/s41598-020-75550-3 ◽

2020 ◽

Vol 10 (1) ◽

Author(s):

Seçkin Arslan ◽

Katerina Palasis ◽

Fanny Meunier

Keyword(s):

Older Adults ◽

Short Term Memory ◽

Memory Span ◽

Event Related Potentials ◽

Brain Regions ◽

Younger Adults ◽

Behavioural Responses ◽

Age Related ◽

Related Potentials ◽

Anterior Negativity

Abstract This study reports on an event-related potentials experiment to uncover whether per-millisecond electrophysiological brain activity and analogous behavioural responses are age-sensitive when comprehending anaphoric (referent-first) and cataphoric (pronoun-first) pronouns. Two groups of French speakers were recruited (young n = 18; aged 19–35 and older adults n = 15; aged 57–88) to read sentences where the anaphoric/cataphoric pronouns and their potential referents either matched or mismatched in gender. Our findings indicate that (1) the older adults were not less accurate or slower in their behavioural responses to the mismatches than the younger adults, (2) both anaphoric and cataphoric conditions evoked a central/parietally distributed P600 component with similar timing and amplitude in both the groups. Importantly, mean amplitudes of the P600 effect were modulated by verbal short-term memory span in the older adults but not in the younger adults, (3) nevertheless, the older but not the younger adults displayed an additional anterior negativity emerging on the frontal regions in response to the anaphoric mismatches. These results suggest that pronoun processing is resilient in healthy ageing individuals, but that functional recruitment of additional brain regions, evidenced with the anterior negativity, compensates for increased processing demands in the older adults’ anaphora processing.

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