Memory and Executive Function in Aging and AD

Lower aperiodic EEG activity is associated with reduced verbal fluency performance across adulthood

Age-related cognitive decline associations with human electroencephalography (EEG) have previously focused on periodic activity. However, EEG primarily consists of non-oscillatory aperiodic activity, characterised with an exponent and offset value. In a secondary analysis of a cohort of 111 healthy participants aged 17 - 71 years, we examined the associations of the aperiodic exponent and offset in resting EEG with a battery of cognitive tests consisting of the Colour-Word Interference Test, Wechsler Adult Intelligence Scale IV Digit Span Test, Rey Auditory Learning Test, Delis-Kaplan Executive Function System Trail Making Test, and the Verbal Fluency Test. Using Principal Component Analysis and K-Means Clustering, we identified clusters of electrodes that exhibited similar aperiodic exponent and offset activity during resting-state eyes-closed EEG. Robust linear models were then used to model how aperiodic activity interacted with age and their associations with performance during each cognitive test. Offset by age interactions were identified for the Verbal Fluency Test, where smaller offsets were associated with poorer performance in adults as early as 33 years of age. Greater aperiodic activity is increasingly related to better verbal fluency performance with age in adulthood.

Integration of automatic MRI segmentation techniques with neuropsychological assessments for early diagnosis and prognosis of Alzheimer's disease. A systematic review

BACKGROUND

This systematic review investigates the integration of automatic segmentation techniques of magnetic resonance imaging (MRI) with neuropsychological assessments for early diagnosis and prognosis of Alzheimer's Disease (AD).

OBJECTIVES

Focus on studies that utilise automated MRI segmentation and neuropsychological evaluations across the AD spectrum.

DATA SOURCES

A literature search was conducted on the PubMed database on 7 November 2024, using key terms related to MRI, segmentation, brain structures, AD, and cognitive decline.

STUDY ELIGIBILITY CRITERIA

Studies including individuals with AD, mild cognitive impairment (MCI), or subjective cognitive decline (SCD), utilising structural MRI, focusing on grey matter and automatic segmentation, and reporting cognitive assessments were included.

STUDY APPRAISAL AND SYNTHESIS METHODS

Data were extracted and synthesised focusing on associations between MRI measures and cognitive tests, and discriminative values for diagnosis or prognosis.

RESULTS

Seven studies were included, showing a significant association between structural changes in the medial temporal lobe and cognitive decline. The combination of MRI volumetric measures and neuropsychological scores enhanced diagnostic accuracy. Neuropsychological measures demonstrated superiority in the identification of patients with MCI and mild AD in comparison to MRI measures alone.

LIMITATIONS

Heterogeneity across studies, selection and measurement bias, and lack of non-response data were noted.

CONCLUSIONS AND IMPLICATIONS

This review emphasises the necessity of integrating automated MRI segmentation with neuropsychological assessments for the diagnosis and prognosis of AD. While MRI is valuable, neuropsychological testing remains essential for early detection. Future studies should focus on developing integrated predictive models and refining neuroimaging techniques.

Co-Community Network Analysis Reveals Alterations in Brain Networks in Alzheimer's Disease

Background: Alzheimer's disease (AD) is a common neurodegenerative disease. Functional magnetic resonance imaging (fMRI) can be used to measure the temporal correlation of blood-oxygen-level-dependent (BOLD) signals in the brain to assess the brain's intrinsic connectivity and capture dynamic changes in the brain. In this study, our research goal is to investigate how the brain network structure, as measured by resting-state fMRI, differs across distinct physiological states. Method: With the research goal of addressing the limitations of BOLD signal-based brain networks constructed using Pearson correlation coefficients, individual brain networks and community detection are used to study the brain networks based on co-community probability matrices (CCPMs). We used CCPMs and enrichment analysis to compare differences in brain network topological characteristics among three typical brain states. Result: The experimental results indicate that AD patients with increasing disease severity levels will experience the isolation of brain networks and alterations in the topological characteristics of brain networks, such as the Somatomotor Network (SMN), dorsal attention network (DAN), and Default Mode Network (DMN). Conclusion: This work suggests that using different data-driven methods based on CCPMs to study alterations in the topological characteristics of brain networks would provide better information complementarity, which can provide a novel analytical perspective for AD progression and a new direction for the extraction of neuro-biomarkers in the early diagnosis of AD.

Accelerated iTBS-Induced changes in resting-state functional connectivity correspond with cognitive improvement in amnestic MCI

BACKGROUND

Published results of our Phase I safety and feasibility trial of accelerated intermittent theta burst stimulation (a-iTBS) in mild cognitive impairment (MCI) due to Alzheimer's disease showed a large effect-size improvement in cognition.

OBJECTIVE

Further demonstrate target engagement by identifying whether changes in local and network-level functional connectivity relate to the observed cognitive improvement.

METHODS

Eighteen patients with MCI received 3-day a-iTBS (8 sessions/day) to the left dorsolateral prefrontal cortex at Beam F3 (14,400 total pulses) and completed MRI and cognitive testing at pre- and post-treatment. Based on electric field models, we selected 3 stimulated target regions of interest (ROIs) which belonged to the frontoparietal (FPN), default mode (DMN), and ventral attention (VAT) networks (3 target networks). Metrics of resting-state functional connectivity were computed at the ROI level (within-network degree: number of connections) and network level (segregation: strength of connectivity within-network relative to other networks). We correlated changes in cognition and connectivity of the target ROIs and networks; off-target ROI (primary visual) and networks served as negative controls.

RESULTS

Improvements in cognition were associated with connectivity changes in the target ROIs and networks, but not in off-target negative controls. Positive associations were observed for degree of the l-DMN and segregation of target networks overall, with significant effects for DMN and VAT.

CONCLUSION

Cognitive improvement following a-iTBS in MCI may be attributable to local and network-level reconfigurations in functional connectivity. These findings will inform larger trials designed to further evaluate the neural mechanisms of a-iTBS for cognition in MCI.

Executive control from healthy ageing to cognitive impairment: A systematic review of stroop and simon effects using psychophysiological and imaging techniques

BACKGROUND

The prevalence of cognitive impairment and dementia in the ageing population emphasises the need for strategies to mitigate cognitive decline. While research on Alzheimer's Disease (AD) has focused on early risk factors, less attention has been paid to protective factors such as cognitive reserve (CR) and cognitive control (CC).

METHODS

This review examines age-related changes in the prefrontal cortex (PFC) in healthy ageing and cognitive impairment. We analysed studies using Stroop and Simon tasks in conjunction with EEG, EEG/ERP, fNIRS and fMRI.

RESULTS

Of the 1411 articles reviewed, 49 studies met our criteria. The results suggest that the Stroop and Simon effects are essential for distinguishing between healthy ageing and cognitive impairment. Increased activity of the PFC supports task performance, especially in cognitive ageing. However, when compensatory mechanisms fail, deficits in Stroop and Simon effects may indicate cognitive impairment and reduced activation of the PFC.

CONCLUSION

This review emphasises the critical role of CR in attenuating age-related cognitive decline and highlights the importance of the PFC in maintaining CC.

Common Variants in PLXNA4 and Correlation to Neuroimaging Phenotypes in Healthy, Mild Cognitive Impairment, and Alzheimer's Disease Cohorts

A comprehensive genome-wide association study (GWAS) has validated the identification of the Plexin-A 4 (PLXNA4) gene as a novel susceptibility factor for Alzheimer's disease (AD). Nonetheless, the precise role of PLXNA4 gene polymorphisms in the pathophysiology of AD remains to be established. Consequently, this study is aimed at exploring the relationship between PLXNA4 gene polymorphisms and neuroimaging phenotypes intimately linked to AD. This study encompassed 812 subjects with PLXNA4 genotype data, procured from the Alzheimer's Disease Neuroimaging Initiative (ADNI) database. Employing a tagging strategy, we identified five common variant sites within the PLXNA4 gene and assessed their associations with glucose metabolism, atrophy in AD-related brain regions (including the medial temporal lobe, hippocampus, and parahippocampal gyrus), and intracerebral Aβ deposition. We conducted a comprehensive analysis using a multiple linear regression model, with neuroimaging phenotypes as the dependent variable and PLXNA4 gene polymorphisms as the independent variable while incorporating APOE e4 carrier status, education level, age, and gender as covariates. The subjects were stratified into three groups based on their disease status: the Alzheimer's disease (AD) group, the mild cognitive impairment (MCI) group, and the cognitively normal healthy control (CN) group. Within each group, we examined the associations between PLXNA4 gene polymorphisms and various neuroimaging phenotypes. Our study identified significant associations between the rs156676-A and rs78036292-G alleles and the baseline volumes of the anterior cingulate and middle temporal gyrus, respectively, across the entire population. After 1 year of follow-up, a significant correlation was observed between the rs6467431-G allele and accelerated volumetric atrophy of the parahippocampal gyrus in the overall population. Additionally, at the 2-year follow-up, significant correlations were observed between three PLXNA4 loci (rs1863015, rs6467431, rs67468325) and volumetric atrophy in the anterior cingulate, middle temporal gyrus, and hippocampus across the entire population. Specifically, the rs1863015-G allele notably accelerated atrophy of the left middle temporal gyrus and bilateral hippocampus, whereas the A alleles of rs6467431 and rs67468325 markedly accelerated atrophy specifically in the bilateral hippocampus. Subgroup analysis further validated these findings. Additionally, in the baseline CN group, the rs78036292 allele showed a significant correlation with intracerebral Aβ deposition, while in the 2-year follow-up CN group, rs67468325 was significantly associated with alterations in glucose metabolism rates in the right cingulate gyrus. Our findings indicate that PLXNA4 genotypes may modulate the development of AD through their regulation of intracerebral Aβ deposition. Additionally, PLXNA4 genotypes are strongly associated with AD-related brain atrophy and glucose metabolism, suggesting that they may alter susceptibility to AD by modulating neurodegenerative biomarkers.

Heterogeneous tau deposition patterns in the preclinical stage link to domain-specific cognitive deficits

INTRODUCTION

The spatial heterogeneity of tau deposition is closely linked to clinical variants of Alzheimer's disease (AD). Detecting these patterns in the preclinical stage is challenging, but second-generation tau tracers provide a unique opportunity to do so.

METHODS

We used independent component analysis (ICA) and tau positron emission tomography (PET) imaging with the 18F-MK6240 tracer in 590 cognitively healthy adults (mean age 66.58 ± 5.13 years, 340 females) to identify tau patterns in the preclinical stage.

RESULTS

Using all individuals, seven distinct patterns emerged, with medial temporal lobe (MTL) involvement associated with age, Aβ burden, apolipoprotein E (APOE) genotype, and plasma total tau. Bilateral amygdala-hippocampus tau deposition was associated negatively with memory (t = -2.64, p < 0.01), while broader neocortical patterns, especially asymmetric ones, were linked to deficits in language (t < -3.13, p < 0.002) and reasoning (t < -2.63, p < 0.01).

DISCUSSION

These findings advance our understanding of preclinical tau heterogeneity, offering new insights for early AD intervention.

HIGHLIGHTS

Seven tau deposition patterns were identified in preclinical stages of AD, including medial temporal lobe and asymmetric neocortical patterns. Medial temporal lobe patterns were strongly linked to age, APOE genotype, Aβ burden, and plasma total tau levels. Neocortical patterns, especially asymmetric ones, were linked to domain-specific cognitive deficits, notably in language and reasoning. This research highlights the potential of using tau deposition patterns for early detection and tailoring interventions in preclinical AD.

Slow but Steady: Similarities and Differences in Executive Functioning Between Autistic and Non-Autistic Adults

Prior research has established differences between autistic and non-autistic individuals across the domains of executive function (EF). While some early theories portrayed these differences as universal to the autism spectrum, recent findings have been quite mixed. Factors like small samples, the components of EF being measured, and the age and intelligence quotient (IQ) of those being compared may contribute to this diversity in results. Moreover, research suggests performance over time might fluctuate in different patterns for autistic and non-autistic individuals. To test EF differences and the possible influence of these factors upon them, we recruited a sample of over 900 autistic and non-autistic participants (with generally average/above average IQ levels) from 18 to 77 years of age. They completed a battery of tasks measuring inhibition, cognitive flexibility, working memory, and attentional orienting to social and nonsocial cues. We found that performance was similar between groups in our primary measures of EF, although autistic participants were consistently slower, more susceptible to the effects of spatial cueing, and more prone to certain errors in the working memory task. Differences between groups were generally not influenced by participants' age, gender, or IQ. Performance over time varied only in the working memory task. While autistic adults may still face related challenges in real life, these findings suggest that being autistic does not necessarily imply executive dysfunction on a basic cognitive level, contradicting theories assuming universal impairments therein. Moreover, the lack of influence of included demographic factors suggests that explanations for discrepancies in the literature lie elsewhere.

Neurocognitive correlates of cerebral mitochondrial function and energy metabolism using phosphorus magnetic resonance spectroscopy in older adults

The goal of the current study was to learn about the role of cerebral mitochondrial function on cognition. Based on established cognitive neuroscience, clinical neuropsychology, and cognitive aging literature, we hypothesized mitochondrial function within a focal brain region would map onto cognitive behaviors linked to that brain region. To test this hypothesis, we used phosphorous (31P) magnetic resonance spectroscopy (MRS) to derive indirect markers of mitochondrial function and energy metabolism across two regions of the brain (bifrontal, left temporal). We administered cognitive tasks sensitive to frontal-executive or temporal-hippocampal systems to a sample of 70 cognitively unimpaired older adults with subjective memory complaints and a first-degree family history of Alzheimer's disease and predicted better executive function and recent memory performance would be related to greater frontal and temporal 31P MRS indirect markers, respectively. Results of separate hierarchical linear regressions indicated better recent memory scores were related to 31P MRS indirect markers of lower static energy and higher energy reserve within the left temporal voxel; these findings were associated with moderate effect sizes. Contrary to predictions, executive function performance was unrelated to 31P MRS indirect markers within the bilateral frontal voxel, which may reflect a combination of theoretical and/or methodological issues. Findings represent a snapshot of the relationship between cognition and 31P MRS indirect markers of mitochondrial function, providing potential avenues for future work investigating mitochondrial underpinnings of cognition. 31P MRS may provide a sensitive neuroimaging marker for differences in aspects of memory among persons at-risk for mild cognitive impairment or dementia.

Exploring new markers for biological aging from bioimpedance analysis and cognitive functions in older adults

Aging is a complex process that affects human health and lifespan. While chronological age (CA) is a significant risk factor for many diseases, it does not fully capture biological changes that influence health span. This study explores cognitive measures using the Seoul Neuropsychological Screening Battery and body composition profiles as potential biological age (BA) markers in the older population. Multiple linear regression, principal component analysis (PCA), and the Klemera-Doubal (KDM) methods were used to construct sex-specific BA formulas from 296 healthy individuals (160 women, 136 men, mean age: 70.3 years). The BA formulas were applied to a new cohort of 708 diseased people (376 women, 332 men, mean age: 73.5 years) to generate BAs for each sex. Subsequently, we compared the classification power of CA, BAs, and selected variables when differentiating the healthy group from the comorbidity cohort, with sex stratification. As a result, we found that BAs from PCA and KDM were significantly higher than CA in the diseased group but comparable in the healthy group. BAs from PCA and KDM methods yielded higher classification accuracies than CA alone. Notably, frontal executive domain score and body reactance emerged as two promising markers for aging. These findings suggest that body composition measures and cognitive assessments offer a more accurate reflection of biological health than CA alone. A cohort with a wider age range is needed to generalize these findings.

Age-Related differences in the relationship between sustained attention and associative memory and Memory-Guided inference

Episodic memory enables the encoding and retrieval of novel associations, as well as the bridging across learned associations to draw novel inferences. A fundamental goal of memory science is to understand the factors that give rise to individual and age-related differences in memory-dependent cognition. Variability in episodic memory could arise, in part, from both individual differences in sustained attention and diminished attention in aging. We first report that, relative to young adults (N = 23; M = 20.0 years), older adults (N = 26, M = 68.7 years) demonstrated lower associative memory and memory-guided associative inference performance and that this age-related reduction in associative inference occurs even when controlling for associative memory performance. Next, we confirm these age-related memory differences by using a high-powered, online replication study (young adults: N = 143, M = 26.2 years; older adults N = 133, M = 67.7 years), further demonstrating that age-related differences in memory do not reflect group differences in sustained attention (as assayed by the gradual-onset continuous performance task; gradCPT). Finally, we report that individual differences in sustained attention explain between-person variability in associative memory and inference performance in the present, online young adult sample, but not in the older adult sample. These findings extend understanding of the links between attention and memory in young adults, demonstrating that differences in sustained attention was related to differences in memory-guided inference. By contrast, our data suggest that the present age-related differences in memory-dependent behavior and the memory differences between older adults are due to attention-independent mechanisms.

Association Between Serum Follicle-Stimulating Hormone Levels and Cognitive Function in Middle-Aged and Older Women

BACKGROUND

Researchers have proposed that there is a potential link between follicle-stimulating hormone (FSH) and cognitive function, yet the evidence remains inconclusive. The current study aims to identify the association between serum FSH levels and cognitive performance, and to examine whether this association varies by cognitive diagnosis, serum estradiol (E2) levels, or cognitive domain.

METHODS

This multicenter cross-sectional study used a clinical database comprising female visitors to memory clinics at three referral hospitals in Korea. Venous blood samples were collected to determine serum FSH and E2 concentrations via immunoradiometric assay. Cognitive performance was evaluated using either the Korean version of the Consortium to Establish a Registry for Alzheimer's Disease or the Seoul Neuropsychological Screening Battery, while cognitive diagnoses were made via clinical diagnostic interviews.

RESULTS

Among the 159 participants (normal cognition [NC], n = 70; mild cognitive impairment [MCI], n = 52; Alzheimer's disease [AD] dementia, n = 37), there were no significant differences in serum FSH levels associated with cognitive diagnosis. In women with NC, serum FSH levels were found to be positively correlated with cognitive performance in global cognition, nonverbal memory, and executive function, even after adjusting for serum E2 level and its interaction with serum FSH level. However, no significant correlations were observed in women with MCI and AD dementia.

CONCLUSION

The association between circulating FSH and cognition may be independent from circulating E2, but it may depend on disease progression or cognitive domains. This suggests a potential role of gonadotropin in cognitive decline in elderly women.

Modularity Measures of Functional Brain Networks Predict Individual Differences in Long-Term Memory

Long-term memory (LTM) is crucial to daily functioning, and individuals show a wide range in LTM capacity. In this study, we ask: How does the brain's functional organization explain individual differences in LTM? We focused on two important, widely studied forms of LTM, general recognition and recollection memory. Inspired by recent work on graph theory and modularity of the brain, we explored how modularity measures of brain activity during encoding could predict individual differences in later LTM performance. Specifically, we examined two modularity measures that describe distinct aspects of network functioning: diversity-the extent a node connects with different modules-and locality-the extent a node has more connections within its own modules. Combining modularity measures and connectome-predictive modeling (CPM), a powerful framework for predicting individual differences in behavior from brain functional connectivity, we found that diversity and locality measures together significantly predicted individual differences in both general recognition and recollection memory. Modularity-based predictions were less strong than CPM models using only connectivity features. With regard to predictive neuroanatomy, we found that the default mode network was the most consistently selected brain network across our models. Our findings extend previous work on how the modularity of the brain is related to cognition and demonstrate that successful LTM is supported by critical connector hubs coordinating between and within networks during encoding. More broadly, they demonstrate the utility of a graph-based approach to reveal how modularity of brain networks relates to individual differences in LTM.

Cognitive function among methadone assisted treatment patient in Malaysia

BACKGROUND

The use of non-medical opioids has reached 60 million in 2021. Methadone-assisted treatment (MAT) is a widely used harm-reduction strategy for opioid addiction. However, methadone can cause cognitive impairment, which can impede treatment.

METHODS

This cross-sectional study was conducted between July 1st and July 31, 2023. A total of 114 participants, comprising 76 MAT patients and 38 healthy subjects (controls), were recruited. Sociodemographic questionnaire, DSM-5 and neuropsychiatric cognitive (NUCOG) assessments were used. A general linear model was used to examine cognitive function between the MMT and control groups while controlling for all possible confounders.

RESULTS

The MAT group performed significantly lower on the NUCOG total score (p < .001) and visuoconstructional (p < .001), memory (p < .001), executive (p = .016), and language (p < .001) scores than the control group. No significant differences were found between the groups in terms of the attention score (p = .457). Adjusted confounders included age, education level, income, and marital status.

CONCLUSIONS

Patients on MAT demonstrated cognitive impairment, particularly in the visuoconstructional, memory, executive, and language domains, compared to the control group. However, there are confounding factors that needs to be addressed in order to come with better treatment and intervention strategies.

Analysing Differences in Cognitive Health, Physical Fitness and Brain Activity in Older Women With and Without MCI

The purpose of this study is analyse the differences in cognitive health, geriatric fitness, and brain activity between female elderly people with and without mild cognitive impairment (MCI) to contribute to the development of strategies for the prevention and management of MCI. The study included 56 female elderly residents of G city, and the participants were divided into an MCI group (32) and a non-MCI group (24). Cognitive health was assessed by an MMSE, and geriatric physical fitness was measured by various indicators such as strength, flexibility, and balance ability. Brain activity was measured by EEG(Electroencephalogram) to record concentration, stress, and left and right brain activity. Data were processed using independent samples t-tests and multiple regression analyses. The results showed that the MCI group was older, had more chronic diseases, and had a lower MMSE scores compared to the non-MCI group. In geriatric fitness measures, the non-MCI group had higher scores in handgrip strength and balance ability. In brain activity analyses, the MCI group had higher workloads and left brain activity than the non-MCI group, but there was no significant correlation with overall cognitive health. Regression analyses showed that, among the elderly physical fitness variables, vigour had a significant effect on cognitive health, suggesting that physical robustness may enhance cognitive reserve. The MCI group had lower cognitive health and physical fitness compared to the non-MCI group and showed some differences in brain activity. In particular, handgrip strength had a significant effect on cognitive health, suggesting that an exercise programme focused on strength training may be an effective intervention for the prevention and management of MCI.

Sequence of decline on the NIH-toolbox cognitive battery in a predominantly Latino sample with autosomal dominant Alzheimer's disease

BACKGROUND

Understanding the sequential progression of cognitive decline in autosomal dominant Alzheimer's disease (ADAD) in the Latino population is crucial for enhancing early identification for targeted interventions. Given the tablet-based administration and increasing frequency of use in epidemiological research, validating this progression within the NIH Toolbox cognitive battery (NIHTB-CB) is important.

OBJECTIVE

The first aim was to utilize an innovative Event-Based Modeling (EBM) analytic approach to estimate the sequence of cognitive declines in persons at risk for ADAD enriched for being of Latino origin. The second aim was to examine associations between EBM-derived estimates of cognitive disease severity and independent cognitive outcomes within carriers and noncarriers.

METHODS

This cross-sectional observational study (N = 30) included 16 ADAD mutation carriers and 14 noncarriers who completed the NIHTB-CB in their primary language (n = 8 Spanish; n = 22 English). An EBM was constructed to compare ADAD mutation carriers and noncarriers on NIHTB-CB performance. We utilized linear regression to examine the associations between the EBM-derived cognitive-decline disease stage and independent outcomes (e.g., performance on the Cognitive Abilities Screening Instrument (CASI) and estimated years to dementia diagnosis).

RESULTS

The EBM estimated that tests assessing episodic memory were the first to become abnormal in the sequence of ADAD-related cognitive decline. Each higher estimated cognitive-decline disease stage was associated with approximately a three-point decline in the CASI and two years closer to dementia diagnosis.

CONCLUSIONS

Findings support the EBM applied to the tablet-based NIHTB-CB to estimate the likely progression of cognitive decline in Latinos with ADAD.

Network Segregation and Integration Changes in Healthy Aging: Evidence From EEG Subbands During the Visual Short-Term Memory Binding Task

Working memory, which tends to be the most vulnerable cognitive domain to aging, is thought to depend on a functional brain network for efficient communication. The dynamic communication within this network is represented by segregation and integration. This study aimed to investigate healthy aging by examining age effect on outcomes of graph theory analysis during the visual short-term memory binding (VSTMB) task. VSTMB tasks rely on the integration of visual features and are less sensitive to semantic and verbal strategies. Effects of age on neuropsychological test scores, along with the EEG graph-theoretical integration, segregation and global organization metrics in frequencies from delta to gamma band were investigated. Neuropsychological assessment showed low sensitivity as a measure of age-related changes. EEG results indicated that network architecture changed more effectively during middle age, while this effectiveness appears to vanish or show compensatory mechanisms in the elderly. These differences were further found to be related to cognitive domain scores. This study is the first to demonstrate differences in working memory network architecture across a broad age range.

Dopaminergic deficits along the spectrum of Alzheimer's disease

Both post-mortem and in vivo data argue for dopamine dysfunction in patients with Alzheimer's Disease (AD). However, the timing and regional progression of dopaminergic systems alterations in AD are still debated. The aim of the study was to investigate in vivo the pattern of dopaminergic changes and connectivity using DAT-SPECT imaging in patients across the AD spectrum. Fifty-nine AD patients (n = 21 AD-MCI; n = 38 AD-DEM) and a control group (CG) of n = 45 age- and sex-matched individuals entered the study and underwent 123I-FP-CIT dopaminergic imaging. The occipital binding was used as reference region to obtain single-subject binding in different brain regions. Between-group differences in 123I-FP-CIT binding in both mesolimbic and nigrostriatal dopaminergic pathways were assessed using an ANCOVA test, adjusting for the effect of center of imaging acquisition, age, and sex. Regions resulting from the voxel-wise direct comparison between AD-MCI and AD-DEM were considered as a seed of interest for a voxel-wise interregional correlation analysis. Both AD-MCI and AD-DEM patients showed dopaminergic depletion within the basal ganglia, whereas cortico-limbic regions (namely hippocampus, amygdala, anterior and middle cingulate, frontal cortex and thalamus) resulted impaired only in the dementia phase. The brain voxel-wise interregional correlation analysis showed a progressive pattern of disruption of caudate/thalamus dopaminergic connectivity to hippocampus and amygdala from AD-MCI to AD-DEM stages. This study indicates basal ganglia dopaminergic alterations and connectivity disruption in the nigrostriatal and mesolimbic systems already in early stage AD, extending to several cortico-limbic regions in dementia phases.

Social Determinants of Health and Functional Brain Connectivity Predict Long-Term Physical Activity in Older Adults with a New Cardiovascular Diagnosis

Background

Physical activity is essential for preventing cognitive decline, stroke and dementia in older adults. A new cardiovascular diagnosis offers a critical window for positive lifestyle changes. However, sustaining physical activity behavior change remains challenging and the underlying mechanisms are poorly understood.

Methods

To identify the neural, behavioral and contextual predictors of successful longer-term behavior change after a new cardiovascular diagnosis, we used support vector machine learning to predict changes in moderate-to-vigorous physical activity over four years in 295 cognitively unimpaired older adults from the UK Biobank, testing three models that incorporated baseline: (i) demographic, cognitive, and contextual factors, (ii) baseline resting-state functional connectivity alone, and (iii) combined multimodal features across all predictors.

Results

The combined multi-modal model had the highest predictive power (r=0.28, p=0.001). Key predictors included greenspace access, social support, retirement status, executive function, and between-network functional connectivity within the default mode, frontoparietal control and salience/ventral attention networks.

Conclusions

These findings underscore the importance of social and structural determinants of health and uncover neural mechanisms that may support lifestyle modifications. In addition to furthering our understanding of the mechanisms underlying successful physical activity behavior change, these findings help to guide the design of interventions and health policy with the ultimate goal of preventing cardiovascular disease burden and late-life cognitive decline.

Spontaneous blinking and brain health in aging: Large-scale evaluation of blink-related oscillations across the lifespan

Blink-related oscillations (BROs) are newly discovered neurophysiological brainwave responses associated with spontaneous blinking, and represent environmental monitoring and awareness processes as the brain evaluates new visual information appearing after eye re-opening. BRO responses have been demonstrated in healthy young adults across multiple task states and are modulated by both task and environmental factors, but little is known about this phenomenon in aging. To address this, we undertook the first large-scale evaluation of BRO responses in healthy aging using the Cambridge Centre for Aging and Neuroscience (Cam-CAN) repository, which contains magnetoencephalography (MEG) data from a large sample (N = 457) of healthy adults across a broad age range (18-88) during the performance of a simple target detection task. The results showed that BRO responses were present in all age groups, and the associated effects exhibited significant age-related modulations comprising an increase in sensor-level global field power (GFP) and source-level theta and alpha spectral power within the bilateral precuneus. Additionally, the extent of cortical activations also showed an inverted-U relationship with age, consistent with neurocompensation with aging. Crucially, these age-related differences were not observed in the behavioral measures of task performance such as reaction time and accuracy, suggesting that blink-related neural responses during the target detection task are more sensitive in capturing aging-related brain function changes compared to behavioral measures alone. Together, these results suggest that BRO responses are not only present throughout the adult lifespan, but the effects can also capture brain function changes in healthy aging-thus providing a simple yet powerful avenue for evaluating brain health in aging.

The Dynamics of Cognitive Decline towards Alzheimer's Disease Progression: Results from ADSP-PHC's Harmonized Cognitive Composites

INTRODUCTION

Accurately assessing temporal order of cognitive decline across multiple domains is critical in Alzheimer's disease (AD). Existing literature presented controversial conclusions likely due to the use of a single cohort and different analytical strategies.

METHODS

Harmonized composite cognitive measures in memory, language and executive functions from 13 cohorts in the ADSP-PHC data are used. A novel double anchoring events-based sigmoidal mixed model was developed using time to the incident of AD diagnosis as the time scale.

RESULTS

Decline in memory occurred before decline in language which was followed by the decline in executive function. Throughout the entire AD continuum, APOE-ε4 non-carriers and non-Hispanic Whites showed better memory performance, respectively, in all three cognitive domains.

DISCUSSION

Using harmonized data across multiple cohorts is the key to accurately characterizing the temporal order of AD biomarkers. Time to incident AD diagnosis should be used as the time scale for reproducibility purposes.

A neural implementation of cognitive reserve: Insights from a longitudinal fMRI study of set-switching in aging

Aging is often accompanied by changes in brain structure and executive functions, particularly in tasks involving cognitive flexibility, such as task-switching. However, substantial individual differences in the degree of cognitive impairment indicate that some individuals can cope with brain changes more effectively than others, suggesting higher cognitive reserve (CR). This study identified a neural basis for CR by examining the longitudinal relationship between task-related brain activation, structural brain changes, and changes in cognitive performance during an executive task-switching paradigm including single and dual conditions. Fifty-two older individuals were assessed at baseline and followed up after five years. Structural brain changes related to task-switching performance were analyzed using elastic net regression. Task-related functional brain activation was measured using ordinal trends canonical variate analysis (OrT CVA), capturing patterns of activation increasing from single to dual conditions. A differential task-related expression score (dOrT) was calculated as the difference in pattern expression scores between single and dual conditions at baseline. A linear regression model tested whether dOrT moderated the impact of brain changes on changes in switch cost over five years. Results showed a significant interaction between changes in brain structure and dOrT activation on switch cost change, indicating a moderation effect of task-related activation. Higher dOrT buffered the impact of brain structural decline on switch costs, enabling older adults to better cope with age-related brain structural changes and preserve cognitive flexibility. These findings suggest that these task-related activation patterns represent a neural basis for CR.

Midlife dynamics of white matter architecture in lexical production

We aimed to examine the white matter changes associated with lexical production difficulties, beginning in midlife with increased naming latencies. To delay lexical production decline, middle-aged adults may rely on domain-general and language-specific compensatory mechanisms proposed by the LARA model (Lexical Access and Retrieval in Aging). However, the white matter changes supporting these mechanisms remains largely unknown. Using data from the CAMCAN cohort, we employed an unsupervised and data-driven methodology to examine the relationships between diffusion-weighted imaging and lexical production. Our findings indicate that midlife is marked by alterations in brain structure within distributed dorsal, ventral, and anterior cortico-subcortical networks, marking the onset of lexical production decline around ages 53-54. Middle-aged adults may initially adopt a "semantic strategy" to compensate for lexical production challenges, but this strategy seems compromised later (ages 55-60) as semantic control declines. These insights underscore the interplay between domain-general and language-specific processes in the trajectory of lexical production performance in healthy aging and hint at potential biomarkers for language-related neurodegenerative pathologies.

Electroencephalogram criticality in cognitive impairment: a monitoring biomarker?

Critical states present scale-free dynamics, optimizing neuronal complexity and serving as a potential biomarker in cognitively impaired patients. We explored electroencephalogram (EEG) criticality in amnesic Mild Cognitive Impairment patients with clinical improvement in working memory, verbal memory, verbal fluency and overall executive functions after the completion of a 6-month prospective memory training. We compared "before" and "after" stationary resting-state EEG records of right-handed MCI patients (n = 17; 11 females), using the method of critical fluctuations and Haar wavelet analysis. Improvement of criticality indices was observed in most electrodes, with mean values being higher after prospective memory training. Significant criticality enhancement was found in the subgroup analysis of frontotemporal electrodes [mean dif: 0.10; Z = 7, p = 0.019]. In the isolated electrode signal analysis, significant post-intervention improvement was noted in pooled criticality indices of electrodes T6 [mean dif: 0.204; t(10) = -2.3, p = 0.044] and F4 [mean dif: 0.0194; t(10) = -2.82; p = 0.018]. EEG criticality agreed with clinical improvement, consisting a possible quantifiable and easy-to-obtain biomarker in MCI and Alzheimer's disease (AD), especially in patients under cognitive training/rehabilitation. We highlight the role of EEG in prognostication, monitoring and potentially early treatment optimization in MCI or AD patients. Further standardization of the methodology in larger patient cohorts could be valuable for AD theragnostics in patients receiving disease-modifying treatments by providing insights regarding synaptic brain plasticity.

Graphical Abstract

Critical states' scale-free dynamics optimize neuronal complexity, emerging as biomarkers in cognitive neuroscience. Applying the method of critical fluctuations and Haar wavelet analysis in stationary EEG time-series, we demonstrate criticality enhancement in the frontotemporal electroencephalographic (EEG) recordings of mild cognitive impairment (MCI) patients after a 6-month prospective memory training, suggesting EEG criticality as a possible monitoring biomarker in MCI and Alzheimer's disease.

Supplementary Information

The online version contains supplementary material available at 10.1007/s11571-024-10155-4.

Effects of age on the relationship between sleep quality and cognitive performance: Findings from the Human Connectome Project-Aging cohort

BACKGROUND

The association between sleep quality and cognition is widely established, but the role of aging in this relationship is largely unknown.

OBJECTIVE

To examine how age impacts the sleep-cognition relationship and determine whether there are sensitive ranges when the relationship between sleep and cognition is modified. This investigation could help identify individuals at risk for sleep-related cognitive impairment.

SUBJECTS

Sample included 711 individuals (ages 36.00-89.83, 59.66 ± 14.91, 55.7 % female) from the Human Connectome Project-Aging (HCP-A).

METHODS

The association between sleep quality (Pittsburgh Sleep Quality Index, PSQI) and cognition (Crystallized Cognition Composite and Fluid Cognition Composite from the NIH Toolbox, the Trail Making Test, TMT, and the Rey Auditory Verbal Learning Test, RAVLT) was measured using linear regression models, with sex, race, use of sleep medication, hypertension, and years of education as covariates. The interaction between sleep and age on cognition was tested using the moderation analysis, with age as both continuous linear and nonlinear (quadratic) terms.

RESULTS

There was a significant interaction term between the PSQI and nonlinear age term (age2) on TMT-B (p = 0.02) and NIH Toolbox crystallized cognition (p = 0.02), indicating that poor sleep quality was associated with worse performance on these measures (sensitive age ranges 50-75 years for TMT-B and 66-70 years for crystallized cognition).

CONCLUSIONS

The sleep-cognition relationship may be modified by age. Individuals in the middle age to early older adulthood age band may be most vulnerable to sleep-related cognitive impairment.

The interplay of age, gender and amyloid on brain and cognition in mid-life and older adults

Deficits in memory are seen as a canonical sign of aging and a prodrome to dementia in older adults. However, our understanding of age-related cognition and brain morphology occurring throughout a broader spectrum of adulthood remains limited. We quantified the relationship between cognitive function and brain morphology (sulcal width, SW) using three cross-sectional observational datasets (PISA, AIBL, ADNI) from mid-life to older adulthood, assessing the influence of age, sex, amyloid (Aβ) and genetic risk for dementia. The data comprised cognitive, genetic and neuroimaging measures of a total of 1570 non-clinical mid-life and older adults (mean age 72, range 49-90 years, 1330 males) and 1365 age- and sex-matched adults with mild cognitive impairment (MCI) or Alzheimer's disease (AD). Among non-clinical adults, we found robust modes of co-variation between regional SW and multidomain cognitive function that differed between the mid-life and older age range. These cortical and cognitive profiles derived from healthy cohorts predicted out-of-sample AD and MCI. Furthermore, Aβ-deposition and educational attainment levels were associated with cognition but not SW. These findings underscoring the complex interplay between factors influencing cognition and brain structure from mid-life onwards, providing valuable insights for future research into neurodegeneration and the development of future screening algorithms.

The language network ages well: Preserved selectivity, lateralization, and within-network functional synchronization in older brains

Healthy aging is associated with structural and functional brain changes. However, cognitive abilities differ from one another in how they change with age: whereas executive functions, like working memory, show age-related decline, aspects of linguistic processing remain relatively preserved (Hartshorne et al., 2015). This heterogeneity of the cognitive-behavioral landscape in aging predicts differences among brain networks in whether and how they should change with age. To evaluate this prediction, we used individual-subject fMRI analyses ('precision fMRI') to examine the language-selective network (Fedorenko et al., 2024) and the Multiple Demand (MD) network, which supports executive functions (Duncan et al., 2020), in older adults (n=77) relative to young controls (n=470). In line with past claims, relative to young adults, the MD network of older adults shows weaker and less spatially extensive activations during an executive function task and reduced within-network functional synchronization. However, in stark contrast to the MD network, we find remarkable preservation of the language network in older adults. Their language network responds to language as strongly and selectively as in younger adults, and is similarly lateralized and internally synchronized. In other words, the language network of older adults looks indistinguishable from that of younger adults. Our findings align with behavioral preservation of language skills in aging and suggest that some networks remain young-like, at least on standard measures of function and connectivity.

Executive functions in older adults with generalised anxiety disorder and healthy controls: Associations with heart rate variability, brain-derived neurotrophic factor, and physical fitness

Executive functions (EF) decline with age and this decline in older adults with generalised anxiety disorder (GAD) may be influenced by heart rate variability (HRV), brain-derived neurotrophic factor (BDNF), and physical fitness. Understanding these relationships is important for tailored treatments in this population. In this study, 51 adults with GAD (M age = 66.46, SD = 4.08) and 51 healthy controls (M age = 67.67, SD = 4.04) were assessed on cognitive inhibition (Stroop task), shifting (Trails part 4), flexibility (Wisconsin Card Sorting Test - Perseverative errors), working memory (Digit Span Backwards), IQ (Wechsler Abbreviated Scale of Intelligence), high frequency HRV, serum mature BDNF levels, and VO2 max. Results indicated that participants with GAD exhibited better cognitive inhibition compared to controls, with no general reduction in EF. Cognitive inhibition was predicted by gender, HRV, and BDNF levels, while cognitive shifting was predicted by gender and IQ, and cognitive flexibility and working memory by IQ. The enhanced cognitive inhibition in GAD participants might stem from maladaptive use of this function, characteristic of GAD, or protection from EF decline due to normal HRV. Increased BDNF levels, possibly due to good fitness, or compensatory mechanisms related to the disorder, might also play a role. These findings highlight the complexity of EF and related mechanisms in GAD, highlighting the need for interventions that consider both cognitive and physiological factors for optimal outcomes.

A phase I trial of accelerated intermittent theta burst rTMS for amnestic MCI

BACKGROUND

Emerging evidence suggests that repetitive transcranial magnetic stimulation (rTMS) enhances cognition in mild cognitive impairment (MCI). Accelerated intermittent theta burst stimulation (iTBS) rTMS protocols are promising as they substantially reduce burden by shortening the treatment course, but the safety, feasibility, and acceptability of iTBS have not been established in MCI.

METHODS

24 older adults with amnestic MCI (aMCI) due to possible Alzheimer's disease enrolled in a phase I trial of open-label accelerated iTBS to the left dorsolateral prefrontal cortex (8 stimulation sessions of 600 pulses of iTBS/day for 3 days). Participants rated common side effects during and after each session and retrospectively (at post-treatment and 4-week follow-up). They completed brain MRI (for safety assessments and electric field modeling), neuropsychiatric evaluations, and neuropsychological testing before and after treatment; a subset of measures was administered at follow-up.

RESULTS

Retention was high (95%) and there were no adverse neuroradiological, neuropsychiatric, or neurocognitive effects of treatment. Participants reported high acceptability, minimal side effects, and low desire to quit despite some rating the treatment as tiring. Electric field modeling data suggest that all participants received safe and therapeutic cortical stimulation intensities. We observed a significant, large effect size (d=0.98) improvement in fluid cognition using the NIH Toolbox Cognition Battery from pre-treatment to post-treatment.

CONCLUSIONS

Our findings support the safety, feasibility, and acceptability of accelerated iTBS in aMCI. In addition, we provide evidence of target engagement in the form of improved cognition following treatment. These promising results directly inform future trials aimed at optimizing treatment parameters.

TRIAL REGISTRATION NUMBER

NCT04503096.

Brain reserve in midlife is associated with executive function changes across 12 years

We examined how brain reserve in midlife, measured by brain-predicted age difference scores (Brain-PADs), predicted executive function concurrently and longitudinally into early old age, and whether these associations were moderated by young adult cognitive reserve or APOE genotype. 508 men in the Vietnam Era Twin Study of Aging (VETSA) completed neuroimaging assessments at mean age 56 and six executive function tasks at mean ages 56, 62, and 68 years. Results indicated that greater brain reserve at age 56 was associated with better concurrent executive function (r=.10, p=.040) and less decline in executive function over 12 years (r=.34, p=.001). These associations were not moderated by cognitive reserve or APOE genotype. Twin analysis suggested associations with executive function slopes were driven by genetic influences. Our findings suggest that greater brain reserve allowed for better cognitive maintenance from middle- to old age, driven by a genetic association. The results are consistent with differential preservation of executive function based on brain reserve that is independent of young adult cognitive reserve or APOE genotype.

The effect of cognitive reserve on the cognitive connectome in healthy ageing

During ageing, different cognitive functions decline at different rates. Additionally, cognitive reserve may influence inter-individual variability in age-related cognitive decline. These complex relationships can be studied by constructing a so-called cognitive connectome and characterising it with advanced graph-theoretical network analyses. This study examined the effect of cognitive reserve on the cognitive connectome across age. A total of 334 cognitively healthy participants were stratified into early middle age (37-50 years; n = 110), late middle age (51-64 years; n = 106), and elderly (65-78 years; n = 118) groups. Within each age group, individuals were subdivided into high and low cognitive reserve. For each subgroup, a cognitive connectome was constructed based on correlations between 47 cognitive variables. Applying graph theory, different global network measures were compared between the groups. Graph-theoretical network analyses revealed that individuals with high cognitive reserve were characterized by a stable cognitive connectome across age groups. High cognitive reserve groups only differed in modularity. In contrast, individuals with low cognitive reserve showed a marked reconfiguration of cognitive connectomes across age groups with differences extending over a variety of network measures including network strength, global efficiency, modularity, and small-worldness. Our results suggest a stabilizing effect of cognitive reserve on the cognitive connectome. Gaining further insights into these findings and underlying mechanisms will contribute to our understanding of age-related cognitive decline and guide the development of strategies to preserve cognitive function in ageing.

The impact of reward and punishment sensitivity on memory and executive performance in individuals with amnestic mild cognitive impairment

Amnestic mild cognitive impairment (aMCI) is defined by memory impairment but executive function (EF) deficits could be also a common feature. This study examined the underlying neurocognitive processes associated with executive function (EF) deficits in patients with aMCI using the Wisconsin Card Sorting Test (WCST) and computational modeling. Forty-two patients with aMCI and thirty-eight matched Controls performed the WSCT and underwent neurocognitive assessment. The Attentional Learning Model was applied the WCST. Patients with aMCI demonstrated deficits in feedback-learning. More specifically, patients showed increased Reward-Sensitivity and reduced Punishment-Sensitivity. These alterations were associated with poor WSCT performance and deficits in EF and Memory. Goal-directed deficits in aMCI, as observed in the WCST, are associated with difficulties in updating attention after feedback as its changes too rapidly following positive feedback and too slowly following negative feedback. Consequently, memory and EF deficits interact and reinforce each other generating performance deficits in patients with aMCI.

Small effects of olfactory identification and discrimination on global cognitive and executive performance over 1 year in aging people without a history of age-related cognitive impairment

Olfactory and cognitive performance share neural correlates profoundly affected by physiological aging. However, whether odor identification and discrimination scores predict global cognitive status and executive function in healthy older people with intact cognition is unclear. Therefore, in the present study, we set out to elucidate these links in a convenience sample of 204 independently living, cognitively intact healthy Czech adults aged 77.4 ± 8.7 (61-97 years) over two waves of data collection (one-year interval). We used the Czech versions of the Montreal Cognitive Assessment (MoCA) to evaluate global cognition, and the Prague Stroop Test (PST), Trail Making Test (TMT), and several verbal fluency (VF) tests to assess executive function. As a subsidiary aim, we aimed to examine the contribution of olfactory performance towards achieving a MoCA score above vs. below the published cut-off value. We found that the MoCA scores exhibited moderate associations with both odor identification and discrimination. Furthermore, odor identification significantly predicted PST C and C/D scores. Odor discrimination significantly predicted PST C/D, TMT B/A, and standardized composite VF scores. Our findings demonstrate that olfaction, on the one hand, and global cognition and executive function, on the other, are related even in healthy older people.

New 1,2,4-oxadiazole derivatives as potential multifunctional agents for the treatment of Alzheimer's disease: design, synthesis, and biological evaluation

A series of new 1,2,4-oxadiazole-based derivatives were synthesized and evaluated for their anti-AD potential. The results revealed that eleven compounds (1b, 2a-c, 3b, 4a-c, and 5a-c) exhibited excellent inhibitory potential against AChE, with IC50 values ranging from 0.00098 to 0.07920 µM. Their potency was 1.55 to 125.47 times higher than that of donepezil (IC50 = 0.12297 µM). In contrast, the newly synthesized oxadiazole derivatives with IC50 values in the range of 16.64-70.82 µM exhibited less selectivity towards BuChE when compared to rivastigmine (IC50 = 5.88 µM). Moreover, oxadiazole derivative 2c (IC50 = 463.85 µM) was more potent antioxidant than quercetin (IC50 = 491.23 µM). Compounds 3b (IC50 = 536.83 µM) and 3c (IC50 = 582.44 µM) exhibited comparable antioxidant activity to that of quercetin. Oxadiazole derivatives 3b (IC50 = 140.02 µM) and 4c (IC50 = 117.43 µM) showed prominent MAO-B inhibitory potential. They were more potent than biperiden (IC50 = 237.59 µM). Compounds 1a, 1b, 3a, 3c, and 4b exhibited remarkable MAO-A inhibitory potential, with IC50 values ranging from 47.25 to 129.7 µM. Their potency was 1.1 to 3.03 times higher than that of methylene blue (IC50 = 143.6 µM). Most of the synthesized oxadiazole derivatives provided significant protection against induced HRBCs lysis, revealing the nontoxic effect of the synthesized compounds, thus making them safe drug candidates. The results unveiled oxadiazole derivatives 2b, 2c, 3b, 4a, 4c, and 5a as multitarget anti-AD agents. The high AChE inhibitory potential can be computationally explained by the synthesized oxadiazole derivatives' significant interactions with the AChE active site. Compound 2b showed good physicochemical properties. All these data suggest that 2b could be considered as a promising candidate for future development.

The effects of cultural engagement on health and well-being: a systematic review

Purpose

This paper examines the effectiveness of culture-based activities in improving health-related outcomes among middle-aged and older adults. Based on the biopsychosocial model, this review aims to explore the impact of cultural engagement on health and well-being.

Methods

We conducted a systematic literature review based on peer-reviewed articles retrieved from various electronic databases. In total, 11 studies were included in this review. Our study population consisted of healthy adults aged over 40 years.

Results

The results provide evidence of positive association between cultural participation and better mental health (e.g., cognitive decline, depression, anxiety), frailty, resilience, well-being and social relations.

Conclusion

This review suggests that cultural engagement serves as an effective means for individuals to maintain and enhance their health and well-being. The field is mostly limited by the heterogeneity of the studies and poor conceptualization of cultural activities. Thus, it is recommended that future research consider the effects of different cultural interventions in developing effective strategies for promoting healthy lifestyles and enhancing quality of life in later stages of life.

Aperiodic component of EEG power spectrum and cognitive performance are modulated by education in aging

Recent studies have shown a growing interest in the so-called "aperiodic" component of the EEG power spectrum, which describes the overall trend of the whole spectrum with a linear or exponential function. In the field of brain aging, this aperiodic component is associated both with age-related changes and performance on cognitive tasks. This study aims to elucidate the potential role of education in moderating the relationship between resting-state EEG features (including aperiodic component) and cognitive performance in aging. N = 179 healthy participants of the "Leipzig Study for Mind-Body-Emotion Interactions" (LEMON) dataset were divided into three groups based on age and education. Older adults exhibited lower exponent, offset (i.e. measures of aperiodic component), and Individual Alpha Peak Frequency (IAPF) as compared to younger adults. Moreover, visual attention and working memory were differently associated with the aperiodic component depending on education: in older adults with high education, higher exponent predicted slower processing speed and less working memory capacity, while an opposite trend was found in those with low education. While further investigation is needed, this study shows the potential modulatory role of education in the relationship between the aperiodic component of the EEG power spectrum and aging cognition.

Comparable cerebral cortex activity and gait performance in elderly hypertensive and healthy individuals during dual-task walking: A fNIRS study

BACKGROUND

Hypertension increases the risk of cognitive impairment and related dementia, causing impaired executive function and unusual gait parameters. However, the mechanism of neural function illustrating this is unclear. Our research aimed to explore the differences of cerebral cortex activation, gait parameters, and working memory performance between healthy older adults (HA) and older hypertensive (HT) patients when performing cognitive and walking tasks.

METHOD

A total of 36 subjects, including 12 healthy older adults and 24 older hypertensive patients were asked to perform series conditions including single cognitive task (SC), single walking task (SW), and dual-task (DT), wearing functional near-infrared spectroscopy (fNIRS) equipment and Intelligent Device for Energy Expenditure and Activity equipment to record cortical hemodynamic reactions and various gait parameters.

RESULTS

The left somatosensory cortex (L-S1) and bilateral supplementary motor area (SMA) showed higher cortical activation (p < .05) than HA when HT performed DT. The intragroup comparison showed that HT had higher cortical activation (p < .05) when performing DT as SW. The cognitive performance of HT was significantly worse (p < .05) than HA when executing SC. The activation of the L-S1, L-M1, and bilateral SMA in HT were significantly higher during SW (p < .05).

CONCLUSION

Hypertension can lead to cognitive impairment in the elderly, including executive function and walking function decline. As a result of these functional declines, elderly patients with hypertension are unable to efficiently allocate brain resources to support more difficult cognitive interference tasks and need to meet more complex task demands by activating more brain regions.

Evaluating frontoparietal network topography for diagnostic markers of Alzheimer's disease

Numerous prospective biomarkers are being studied for their ability to diagnose various stages of Alzheimer's disease (AD). High-density electroencephalogram (EEG) methods show promise as an accurate, economical, non-invasive approach to measuring the electrical potentials of brains associated with AD. Event-related potentials (ERPs) may serve as clinically useful biomarkers of AD. Through analysis of secondary data, the present study examined the performance and distribution of N4/P6 ERPs across the frontoparietal network (FPN) using EEG topographic mapping. ERP measures and memory as a function of reaction time (RT) were compared between a group of (n = 63) mild untreated AD patients and a control group of (n = 73) healthy age-matched adults. Based on the literature presented, it was expected that healthy controls would outperform patients in peak amplitude and mean component latency across three parameters of memory when measured at optimal N4 (frontal) and P6 (parietal) locations. It was also predicted that the control group would exhibit neural cohesion through FPN integration during cross-modal tasks, thus demonstrating healthy cognitive functioning consistent with older healthy adults. By targeting select frontal and parietal EEG reference channels based on N4/P6 component time windows and positivity, our findings demonstrated statistically significant group variations between controls and patients in N4/P6 peak amplitudes and latencies during cross-modal testing. Our results also support that the N4 ERP might be stronger than its P6 counterpart as a possible candidate biomarker. We conclude through topographic mapping that FPN integration occurs in healthy controls but is absent in AD patients during cross-modal memory tasks.

Fear extinction is impaired in aged rats

Normal aging is accompanied by broad loss of cognitive function in humans and rodents, including declines in cognitive flexibility. In extinction, a conditional stimulus (CS) that was previously paired with a footshock is presented alone. This procedure reliably reduces conditional freezing behavior in young adult rats. Here, we aimed to investigate how normal aging affects extinction learning. Using young (3 months) and aged (20 months) male and female Long Evans rats, we compared extinction (using 20 CS-alone presentations) to a no extinction control (equal exposure to the conditioning chamber without CS presentations) following delay fear conditioning. We found that young animals in the extinction group showed a decrease in freezing following extinction; aged animals did not. We next examined changes in neural activity using expression of the immediate early gene zif268. In young animals, extinction corresponded with decreased expression of zif268 in the basolateral amygdala and anterior retrosplenial cortex; this was not observed in aged animals. Further, aged animals showed increased zif268 expression in each region examined, suggesting that dysfunction in neural activity precedes cognitive deficits. These results demonstrate that aging impacts both extinction learning and neural activity.

Brain network changes and cognitive function after cardiac arrest

Survival rates after out-of-hospital cardiac arrest have improved over the past two decades. Despite this progress, long-term cognitive impairment remains prevalent even in those with early recovery of consciousness after out-of-hospital cardiac arrest; however, little is known about the determinants and underlying mechanisms. We utilized the REcovery after cardiac arrest surVIVAL cohort of out-of-hospital cardiac arrest survivors who fully regained consciousness to correlate cognition measurements with brain network changes using resting-state functional MRI and the Montreal Cognitive Assessment at hospital discharge and a comprehensive neuropsychological assessment at three-month follow-up. About half of out-of-hospital cardiac arrest survivors displayed cognitive impairments at discharge, and in most, cognitive deficits persisted at three-month follow-up, particularly in the executive and visuospatial functions. Compared to healthy controls, out-of-hospital cardiac arrest survivors exhibited increased connectivity between resting-state networks, particularly involving the frontoparietal network. The increased connectivity between the frontoparietal and visual networks was associated with less favourable cognitive outcomes (β = 14.0, P = 0.01), while higher education seemed to confer some cognitive protection (β = -2.06, P = 0.03). In sum, the data highlight the importance of subtle cognitive impairment, also in out-of-hospital cardiac arrest survivors who are eligible for home discharge, and the potential of functional MRI to identify alterations in brain networks correlating with cognitive outcomes.

Design, synthesis and biological evaluation of 1-aryldonepezil analogues as anti-Alzheimer's disease agents

Aim: To design and synthesize a novel series of 1-aryldonepezil analogues. Materials & methods: The 1-aryldonepezil analogues were synthesized through palladium/PCy3-catalyzed Suzuki reaction and were evaluated for cholinesterase inhibitory activities and neuroprotective effects. In silico docking of the most effective compound was conducted. Results: The 4-tert-butylphenyl analogue exhibited good inhibitory potency against acetylcholinesterase and butyrylcholinesterase and had a favorable neuroprotective effect on H2O2-induced SH-SY5Y cell injury. Conclusion: The 4-tert-butylphenyl derivative is a promising lead compound for anti-Alzheimer's disease drug development.

The Real-World Usability, Feasibility, and Performance Distributions of Deploying a Digital Toolbox of Computerized Assessments to Remotely Evaluate Brain Health: Development and Usability Study

BACKGROUND

An ongoing global challenge is managing brain health and understanding how performance changes across the lifespan.

OBJECTIVE

We developed and deployed a set of self-administrable, computerized assessments designed to measure key indexes of brain health across the visual and auditory sensory modalities. In this pilot study, we evaluated the usability, feasibility, and performance distributions of the assessments in a home-based, real-world setting without supervision.

METHODS

Potential participants were untrained users who self-registered on an existing brain training app called BrainHQ. Participants were contacted via a recruitment email and registered remotely to complete a demographics questionnaire and 29 unique assessments on their personal devices. We examined participant engagement, descriptive and psychometric properties of the assessments, associations between performance and self-reported demographic variables, cognitive profiles, and factor loadings.

RESULTS

Of the 365,782 potential participants contacted via a recruitment email, 414 (0.11%) registered, of whom 367 (88.6%) completed at least one assessment and 104 (25.1%) completed all 29 assessments. Registered participants were, on average, aged 63.6 (SD 14.8; range 13-107) years, mostly female (265/414, 64%), educated (329/414, 79.5% with a degree), and White (349/414, 84.3% White and 48/414, 11.6% people of color). A total of 72% (21/29) of the assessments showed no ceiling or floor effects or had easily modifiable score bounds to eliminate these effects. When correlating performance with self-reported demographic variables, 72% (21/29) of the assessments were sensitive to age, 72% (21/29) of the assessments were insensitive to gender, 93% (27/29) of the assessments were insensitive to race and ethnicity, and 93% (27/29) of the assessments were insensitive to education-based differences. Assessments were brief, with a mean duration of 3 (SD 1.0) minutes per task. The pattern of performance across the assessments revealed distinctive cognitive profiles and loaded onto 4 independent factors.

CONCLUSIONS

The assessments were both usable and feasible and warrant a full normative study. A digital toolbox of scalable and self-administrable assessments that can evaluate brain health at a glance (and longitudinally) may lead to novel future applications across clinical trials, diagnostics, and performance optimization.

Finding the Words: How Does the Aging Brain Process Language? A Focused Review of Brain Connectivity and Compensatory Pathways

As people age, there is a natural decline in cognitive functioning and brain structure. However, the relationship between brain function and cognition in older adults is neither straightforward nor uniform. Instead, it is complex, influenced by multiple factors, and can vary considerably from one person to another. Reserve, compensation, and maintenance mechanisms may help explain why some older adults can maintain high levels of performance while others struggle. These mechanisms are often studied concerning memory and executive functions that are particularly sensitive to the effects of aging. However, language abilities can also be affected by age, with changes in production fluency. The impact of brain changes on language abilities needs to be further investigated to understand the dynamics and patterns of aging, especially successful aging. We previously modeled several compensatory profiles of language production and lexical access/retrieval in aging within the Lexical Access and Retrieval in Aging (LARA) model. In the present paper, we propose an extended version of the LARA model, called LARA-Connectivity (LARA-C), incorporating recent evidence on brain connectivity. Finally, we discuss factors that may influence the strategies implemented with aging. The LARA-C model can serve as a framework to understand individual performance and open avenues for possible personalized interventions.

Amelioration of age-related cognitive decline and anxiety in mice by Centella asiatica extract varies by sex, dose and mode of administration

Background: A water extract (CAW) of the Ayurvedic plant Centella asiatica administered in drinking water has been shown to improve cognitive deficits in mouse models of aging and neurodegenerative diseases. Here the effects of CAW administered in drinking water or the diet on cognition, measures of anxiety and depression-like behavior in healthy aged mice are compared. Methods: Three- and eighteen-month-old male and female C57BL6 mice were administered rodent AIN-93M diet containing CAW (0, 0.2, 0.5 or 1% w/w) to provide 0, 200 mg/kg/d, 500 mg/kg/d or 1,000 mg/kg/d CAW for a total of 5 weeks. An additional group of eighteen-month-old mice were treated with CAW (10 mg/mL) in their drinking water CAW for a total of 5 weeks to deliver the same exposure of CAW as the highest dietary dose (1,000 mg/kg/d). CAW doses delivered were calculated based on food and water consumption measured in previous experiments. In the fourth and fifth weeks, mice underwent behavioral testing of cognition, anxiety and depression (n = 12 of each sex per treatment group in each test). Results: Aged mice of both sexes showed cognitive deficits relative to young mice while only female aged mice showed increased anxiety compared to the young female mice and no differences in depression were observed between the different ages. CAW (1,000 mg/kg/d) in the drinking water improved deficits in aged mice in learning, executive function and recognition memory in both sexes and attenuated the increased measures of anxiety observed in the aged female mice. However, CAW in the diet only improved executive function in aged mice at the highest dose (1,000 mg/kg/d) in both sexes and did so less robustly than when given in the water. There were no effects of CAW on depression-like behavior in aged animals regardless of whether it was administered in the diet or the water. Conclusions: These results suggest that CAW can ameliorate age-related changes in measures of anxiety and cognition and that the mode of administration is important for the effects of CAW on resilience to these age-related changes.

Impact of high-fat diet on cognitive behavior and central and systemic inflammation with aging and sex differences in mice

Aging and age-related diseases are associated with cellular stress, metabolic imbalance, oxidative stress, and neuroinflammation, accompanied by cognitive impairment. Lifestyle factors such as diet, sleep fragmentation, and stress can potentiate damaging cellular cascades and lead to an acceleration of brain aging and cognitive impairment. High-fat diet (HFD) has been associated with obesity, metabolic disorders like diabetes, and cardiovascular disease. HFD also induces neuroinflammation, impairs learning and memory, and may increase anxiety-like behavior. Effects of a HFD may also vary between sexes. The interaction between Age- and Sex- and Diet-related changes in neuroinflammation and cognitive function is an important and poorly understood area of research. This study was designed to examine the effects of HFD on neuroinflammation, behavior, and neurodegeneration in mice in the context of aging or sex differences. In a series of studies, young (2-3 months) or old (12-13 months) C57BL/6J male mice or young male and female C57Bl/6J mice were fed either a standard diet (SD) or a HFD for 5-6 months. Behavior was assessed in Activity Chamber, Y-maze, Novel Place Recognition, Novel Object Recognition, Elevated Plus Maze, Open Field, Morris Water Maze, and Fear Conditioning. Post-mortem analyses assessed a panel of inflammatory markers in the plasma and hippocampus. Additionally, proteomic analysis of the hypothalamus, neurodegeneration, neuroinflammation in the locus coeruleus, and neuroinflammation in the hippocampus were assessed in a subset of young and aged male mice. We show that HFD increased body weight and decreased locomotor activity across groups compared to control mice fed a SD. HFD altered anxiety-related exploratory behavior. HFD impaired spatial learning and recall in young male mice and impaired recall in cued fear conditioning in young and aged male mice, with no effects on spatial learning or fear conditioning in young female mice. Effects of Age and Sex were observed on neuroinflammatory cytokines, with only limited effects of HFD. HFD had a more significant impact on systemic inflammation in plasma across age and sex. Aged male mice had induction of microglial immunoreactivity in both the locus coeruleus (LC) and hippocampus an effect that HFD exacerbated in the hippocampal CA1 region. Proteomic analysis of the hypothalamus revealed changes in pathways related to metabolism and neurodegeneration with both aging and HFD in male mice. Our findings suggest that HFD induces widespread systemic inflammation and limited neuroinflammation. In addition, HFD alters exploratory behavior in male and female mice, and impairs learning and memory in male mice. These results provide valuable insight into the impact of diet on cognition and aging pathophysiology.

Caudate functional networks influence brain structural changes with aging

Neurogenesis decline with aging may be associated with brain atrophy. Subventricular zone neuron precursor cells possibly modulate striatal neuronal activity via the release of soluble molecules. Neurogenesis decay in the subventricular zone may result in structural alterations of brain regions connected to the caudate, particularly to its medial component. The aim of this study was to investigate how the functional organization of caudate networks relates to structural brain changes with aging. One hundred and fifty-two normal subjects were recruited: 52 young healthy adults (≤35 years old), 42 middle-aged (36 ≤ 60 years old) and 58 elderly subjects (≥60 years old). In young adults, stepwise functional connectivity was used to characterize regions that connect to the medial and lateral caudate at different levels of link-step distances. A statistical comparison between the connectivity of medial and lateral caudate in young subjects was useful to define medial and lateral caudate connected regions. Atrophy of medial and lateral caudate connected regions was estimated in young, middle-aged and elderly subjects using T1-weighted images. Results showed that middle-aged and elderly adults exhibited decreased stepwise functional connectivity at one-link step from the caudate, particularly in the frontal, parietal, temporal and occipital brain regions, compared to young subjects. Elderly individuals showed increased stepwise functional connectivity in frontal, parietal, temporal and occipital lobes compared to both young and middle-aged adults. Additionally, elderly adults displayed decreased stepwise functional connectivity compared to middle-aged subjects in specific parietal and subcortical areas. Moreover, in young adults, the medial caudate showed higher direct connectivity to the basal ganglia (left thalamus), superior, middle and inferior frontal and inferior parietal gyri (medial caudate connected region) relative to the lateral caudate. Considering the opposite contrast, lateral caudate showed stronger connectivity to the basal ganglia (right pallidum), orbitofrontal, rostral anterior cingulate and insula cortices (lateral caudate connected region) compared to medial caudate. In elderly subjects, the medial caudate connected region showed greater atrophy relative to the lateral caudate connected region. Brain regions linked to the medial caudate appear to be more vulnerable to aging than lateral caudate connected areas. The adjacency to the subventricular zone may, at least partially, explain these findings. Stepwise functional connectivity analysis can be useful to evaluate the role of the subventricular zone in network disruptions in age-related neurodegenerative disorders.

Behaviorally meaningful functional networks mediate the effect of Alzheimer's pathology on cognition

Tau pathology is associated with cognitive impairment in both aging and Alzheimer's disease, but the functional and structural bases of this relationship remain unclear. We hypothesized that the integrity of behaviorally meaningful functional networks would help explain the relationship between tau and cognitive performance. Using resting state fMRI, we identified unique networks related to episodic memory and executive function cognitive domains. The episodic memory network was particularly related to tau pathology measured with positron emission tomography in the entorhinal and temporal cortices. Further, episodic memory network strength mediated the relationship between tau pathology and cognitive performance above and beyond neurodegeneration. We replicated the association between these networks and tau pathology in a separate cohort of older adults, including both cognitively unimpaired and mildly impaired individuals. Together, these results suggest that behaviorally meaningful functional brain networks represent a functional mechanism linking tau pathology and cognition.

Quantification of mediation effects of white matter functional characteristics on cognitive decline in aging

Cognitive decline with aging involves multifactorial processes, including changes in brain structure and function. This study focuses on the role of white matter functional characteristics, as reflected in blood oxygenation level-dependent signals, in age-related cognitive deterioration. Building on previous research confirming the reproducibility and age-dependence of blood oxygenation level-dependent signals acquired via functional magnetic resonance imaging, we here employ mediation analysis to test if aging affects cognition through white matter blood oxygenation level-dependent signal changes, impacting various cognitive domains and specific white matter regions. We used independent component analysis of resting-state blood oxygenation level-dependent signals to segment white matter into coherent hubs, offering a data-driven view of white matter's functional architecture. Through correlation analysis, we constructed a graph network and derived metrics to quantitatively assess regional functional properties based on resting-state blood oxygenation level-dependent fluctuations. Our analysis identified significant mediators in the age-cognition relationship, indicating that aging differentially influences cognitive functions by altering the functional characteristics of distinct white matter regions. These findings enhance our understanding of the neurobiological basis of cognitive aging, highlighting the critical role of white matter in maintaining cognitive integrity and proposing new approaches to assess interventions targeting cognitive decline in older populations.

Investigating the individual and joint effects of socioeconomic status and lifestyle factors on mild cognitive impairment in older Italians living independently in the community: results from the NutBrain study

OBJECTIVES

Despite extensive research, a clear understanding of the role of the interaction between lifestyle and socioeconomic status (SES) on cognitive health is still lacking. We investigated the joint association of socioeconomic factors in early to midlife and lifestyle in later life and Mild Cognitive Impairment (MCI).

DESIGN

Observational cross-sectional study.

SETTING

NutBrain study in northern Italy.

PARTICIPANTS

773 community-dwelling adults aged 65 years and older (73.2 ± 6.0 SD, 58.6% females) participating in the NutBrain study (2019-2023).

MEASUREMENTS

Three SES indicators (home ownership, educational level, occupation) and five lifestyle factors (adherence to Mediterranean diet, physical activity, smoking habits, social network, leisure activities) were selected. Each factor was scored and summed to calculate SES and healthy lifestyle scores; their joint effect was also examined. The association with MCI was assessed by logistic regression controlling for potential confounders. Sex-stratified analysis was performed.

RESULTS

In total, 24% of the subjects had MCI. The multivariable logistic model showed that a high SES and a high lifestyle score were associated with 81.8% (OR0.182; 95%CI 0.095-0.351), and 44.1% (OR0.559; 95%CI 0.323-0.968) lower odds of having MCI, respectively. When examining the joint effect of SES and lifestyle factors, the cognitive benefits of a healthy lifestyle were most pronounced in participants with low SES. A healthier lifestyle score was found to be significantly associated with lower odds of MCI, only in females.

CONCLUSIONS

According to our findings, SES was positively associated with preserved cognitive function, highlighting the importance of active lifestyles in reducing socioeconomic health inequalities, particularly among those with a relatively low SES.

TRIAL REGISTRATION

Trial registration number NCT04461951, date of registration July 7, 2020 (retrospectively registered, ClinicalTrials.gov).

Intrinsic functional brain connectivity changes following aerobic exercise, computerized cognitive training, and their combination in physically inactive healthy late-middle-aged adults: the Projecte Moviment

Lifestyle interventions have positive neuroprotective effects in aging. However, there are still open questions about how changes in resting-state functional connectivity (rsFC) contribute to cognitive improvements. The Projecte Moviment is a 12-week randomized controlled trial of a multimodal data acquisition protocol that investigated the effects of aerobic exercise (AE), computerized cognitive training (CCT), and their combination (COMB). An initial list of 109 participants was recruited from which a total of 82 participants (62% female; age = 58.38 ± 5.47) finished the intervention with a level of adherence > 80%. Only in the COMB group, we revealed an extended network of 33 connections that involved an increased and decreased rsFC within and between the aDMN/pDMN and a reduced rsFC between the bilateral supplementary motor areas and the right thalamus. No global and especially local rsFC changes due to any intervention mediated the cognitive benefits detected in the AE and COMB groups. Projecte Moviment provides evidence of the clinical relevance of lifestyle interventions and the potential benefits when combining them.