Longitudinal changes in gray matter correspond to changes in cognition across the lifespan: implications for theories of cognition

CSL-CTEA: a systematic method for evaluating novel intelligent cognitive assessment tools

With the intensification of global population aging, the incidence of cognitive disorders such as dementia continues to rise. The Mini-Mental State Examination (MMSE) and other alternative tools can help doctors detect subtle changes in cognitive function at an early stage. These assessment tools can make a diagnosis before symptoms become severe, providing opportunities for early intervention, which is crucial for delaying disease progression and improving the quality of life of patients. However, traditional cognitive assessment methods are overly complex and affected by various factors. With the development of artificial intelligence technology, many new assessment tools are constantly being developed and improved. How to evaluate the effectiveness of intelligent electronic cognitive assessment tools is particularly important. We have proposed the Correlation and Supervised Learning-based Cognitive Tool Effectiveness Assessment Method (CSL-CTEA) to evaluate the effectiveness of intelligent electronic cognitive assessment tools, including: (1) experimental design and data collection based on traditional scales and intelligent electronic assessment tools, (2) consistency and correlation tests; (3) accuracy analysis of assessment results based on supervised learning. We used CSL-CTEA to explore the effectiveness of a certain electronic assessment. This intelligent electronic cognitive assessment tool includes voice tests, orientation tests, and picture recognition tests to assess cognitive abilities from multiple perspectives. The results show that the electronic assessment is in good agreement with traditional cognitive assessment methods. The various indicators of the electronic assessment can explain the changes in MMSE scores to some extent. The study also found that the electronic assessment performs well in determining whether the subject is at cognitive risk. To some extent, the electronic assessment can replace traditional cognitive assessment methods such as MMSE to help people judge whether they are at risk of cognitive decline.

The Dallas Lifespan Brain Study: A Comprehensive Adult Lifespan Data Set of Brain and Cognitive Aging

The Dallas Lifespan Brain Study (DLBS) was designed to integrate brain and cognition across the adult lifespan. Participants (n = 464) were between age 21 and 89 years at time of first assessment and returned approximately every 3.5-5 years for a second (n = 338) and third epoch (n = 224) of data collection. The three epochs included a comprehensive neuropsychological battery, questionnaires that assessed physical health, psychosocial status, and brain health, structural MRI scans (including T1-weighted imaging and diffusion-weighted imaging), a hypercapnia scan, an arterial spin labeling scan, and four functional fMRI scans. Additionally, measures of amyloid and tau were collected with AV-45 (Florbetapir) and AV-1451 (Flortaucipir). Key innovations were robust sampling of middle-aged participants and inclusion of PET data for amyloid and tau in a cognitively normal sample. This large data set has recently been published on OpenNeuro.org open-access and provides the opportunity for researchers to test many hypotheses about brain and cognition across human adulthood, including longitudinal hypotheses, with these data across a multi-year span.

Effects of aerobic exercise and cardiorespiratory fitness on white matter free water fraction in older adults: a 1-year randomized controlled trial

Free water fraction (FWF), derived from diffusion MRI, is a sensitive biomarker of white matter microstructure and may be modifiable through lifestyle interventions. The mid-anterior corpus callosum (CC) has been proposed as particularly responsive to physical exercise and the related increases in cardiorespiratory fitness. This study examined the effects of aerobic exercise training and fitness on FWF in the CC and on cognitive performance in older adults. Seventy-three participants (mean age 69 ± 5 years, 77% women) were randomized to a 1-year aerobic training or stretching intervention. FWF was assessed using diffusion tensor MRI, fitness via maximal oxygen uptake (VO2max), and cognition using a composite score of reasoning, memory, and processing speed. Linear mixed models revealed a significant increase in VO2max following aerobic training compared to stretching, while cognitive performance improved in both groups. A significant region × group × time interaction was observed for FWF, although Bonferroni-corrected pairwise comparisons showed no significant group difference. However, complete-case analysis of the mid-anterior CC showed a significant FWF reduction in the CC body following aerobic training compared to stretching (- 2.71 ± 5.44% vs. 0.63 ± 6.42%, p = 0.048). Tract-based spatial statistics indicated that lower baseline VO2max predicted greater FWF increases in the CC body and genu across groups. Baseline FWF was negatively correlated with cognitive performance. These findings suggest that 1 year of aerobic training may reduce FWF in the CC body and that higher physical fitness preserves white matter microstructure and support cognitive health in older adults.

Causal Association Between Major Depressive Disorder and Cortical Structure: A Bidirectional Mendelian Randomization Study and Mediation Analysis

BACKGROUND

Previous observational studies have reported a possible association between major depressive disorder (MDD) and abnormal cortical structure. However, it is unclear whether MDD causes reductions in global cortical thickness (CT) and global area (SA).

OBJECTIVE

We aimed to test the bidirectional causal relationship between MDD and CT and SA using a Mendelian randomization (MR) design and performed exploratory analyses of MDD on CT and SA in different brain regions.

METHODS

Summary-level data were obtained from two GWAS meta-analysis studies: one screening for single nucleotide polymorphisms (SNPs) predicting the development of MDD (n = 135,458) and the other identifying SNPs predicting the magnitude of cortical thickness (CT) and surface area (SA) (n = 51,665).

RESULTS

The results showed that MDD caused a decrease in CT in the medial orbitofrontal region, a decrease in SA in the paracentral region, and an increase in SA in the lateral occipital region. C-reactive protein, tumor necrosis factor alpha (TNF-α), interleukin-1β, and interleukin-6 did not mediate the reduction. We also found that a reduction in CT in the precentral region and a reduction in SA in the orbitofrontal regions might be associated with a higher risk of MDD.

CONCLUSION

Our study did not suggest an association between MDD and cortical CT and SA.

Associations of cardiorespiratory fitness with cerebral cortical thickness and gray matter volume across the adult lifespan

High cardiorespiratory fitness (CRF) is associated with reduced cortical thinning and gray matter (GM) shrinkage in older adults. We investigated associations of CRF measured with peak oxygen consumption (V̇o2peak) with cortical thickness and GM volume across the adult lifespan. We hypothesized that higher CRF is associated with less cortical thinning and GM shrinkage across the adult lifespan, which is associated with better cognitive performance. This cross-sectional study recruited 172 sedentary yet healthy adults (65% women, 22-81 yr) who underwent treadmill exercise testing to measure V̇o2peak, structural magnetic resonance imaging to assess cortical thickness and GM volume, and a comprehensive cognitive test battery to assess fluid cognitive function. Linear regression models were used to examine the associations of total and regional cortical thickness and GM volume with age, V̇o2peak, and age × V̇o2peak interaction after adjusting for sex, education, and total intracranial volume, and the associations of cortical thickness and GM volume with fluid cognitive performance. Mean and regional cortical thickness and total GM volume were associated negatively with age, whereas no associations were observed with V̇o2peak. However, a significant interaction between age and V̇o2peak on the right superior parietal volume indicated that aging was associated with smaller right superior parietal volume in the lower CRF group, whereas no association was observed in the higher CRF group. Larger right superior parietal volume was associated with better fluid cognitive performance. These findings highlight the importance of maintaining CRF to prevent or slow brain aging from an adult lifespan perspective.NEW & NOTEWORTHY High cardiorespiratory fitness may mitigate regional gray matter shrinkage across the adult lifespan.

Cognitive and gray matter volume predictors of learning across two types of casual video games in older Adults: Action vs Strategy

Video game based and other computerized cognitive interventions are generally efficacious in bolstering cognition in adults over the age of 60, though specific efficacy varies widely by intervention methodology. Furthermore, there is reason to suspect that the process of learning complex tasks like video games is a major factor underpinning training-related transfer to cognition. The current study examined the neurocognitive predictors of learning of video games, and how those predictors may differentially relate to games of different genres. Learning rates from two different types of games, one action and another strategy, were calculated for 32 older adults (mean age = 66.29 years, 65 % Female). An extensive cognitive battery as well as structural measures of regional gray matter volumes were examined to identify the cognitive and the brain structure contributors to the learning rates for each type of game. A broad leftlateralized gray matter volume construct, as well as cognitive constructs of processing speed, episodic memory and reasoning, were found to significantly predict learning of the Strategy game, but not the Action game. Additionally, this gray matter construct was found to entirely mediate the relationships between the Strategy game learning and cognition, esp. episodic memory and reasoning. The contributions of age-sensitive cognitive skills as well as related brain volumes of lateral fronto-parietal regions to Strategy video games implicate the examined game as a potential game training tool in normal aging.

Eight brain structures mediate the age-related alterations of the working memory: forward and backward digit span tasks

Introduction

Working memory (WM) as one of the executive functions is an essential neurocognitive ability for daily life. Findings have suggested that aging is often associated with working memory and neural decline, but the brain structures and resting-state brain networks that mediate age-related differences in WM remain unclear.

Methods

A sample consisting of 252 healthy participants in the age range of 20 to 70years was used. Several cognitive tasks, including the n-back task and the forward and backward digit span tests were used. Also, resting-state functional imaging, as well as structural imaging using a 3T MRI scanner, were performed, resulting in 85 gray matter volumes and five resting-state networks, namely the anterior and posterior default mode, the right and left executive control, and the salience networks. Also, mediation analyses were used to investigate the role of gray matter volumes and resting-state networks in the relationship between age and WM.

Results

Behaviorally, aging was associated with decreased performance in the digit span task. Also, aging was associated with a decreased gray matter volume in 80 brain regions, and with a decreased activity in the anterior default mode network, executive control, and salience networks. Importantly, the path analysis showed that the GMV of the medial orbitofrontal, precentral, parieto-occipital, amygdala, middle occipital, posterior cingulate, and thalamus areas mediated the age-related differences in the forward digit span task, and the GMV of superior temporal gyrus mediated the age-related differences in the backward digit span task.

Discussion

This study identified the brain structures mediating the relationship between age and working memory, and we hope that our research provides an opportunity for early detection of individuals at risk of age-related memory decline.

Towards a neurodevelopmental cognitive perspective of temporal processing

The ability to organize and memorize the unfolding of events over time is a fundamental feature of cognition, which develops concurrently with the maturation of the brain. Nonetheless, how temporal processing evolves across the lifetime as well as the links with the underlying neural substrates remains unclear. Here, we intend to retrace the main developmental stages of brain structure, function, and cognition linked to the emergence of timing abilities. This neurodevelopmental perspective aims to untangle the puzzling trajectory of temporal processing aspects across the lifetime, paving the way to novel neuropsychological assessments and cognitive rehabilitation strategies.

Reserve, resilience and maintenance of episodic memory and other cognitive functions in aging

We tested if cognitive and brain reserve and maintenance explain individual differences in episodic memory and other cognitive domains from late middle to early older adulthood. We used The Vietnam Era Twin Study of Aging data (n=1604 men) with episodic memory measured at mean ages of 56, 62 and 68 years, and magnetic resonance imaging data for a subsample of participants (n=321). Cognitive reserve -young adult general cognitive ability at a mean age of 20 years and, to a lesser degree, educational attainment- was positively related to episodic memory performance at each assessment, but not to memory change. We found no evidence for the associations of brain reserve or brain maintenance on memory change. Results were highly similar when looking at processing speed, executive function and verbal fluency. In conclusion, higher young adult cognitive reserve was related to better episodic memory in midlife and older adulthood, but it did not confer better cognitive maintenance with respect to memory. This supports the importance of early cognitive development in dementia prevention.

Cognitive aging and the life course: A new look at the Scaffolding theory

Our understanding of human neurocognitive aging, its developmental roots, and life course influences has been transformed by brain imaging technologies, increasing availability of longitudinal data sets, and analytic advances. The Scaffolding Theory of Aging and Cognition is a life course model, proposed originally in 2009, featuring adaptivity and compensatory potential as lifelong mechanisms for meeting neurocognitive challenges posed by the environment and by developing or declining brain circuitry. Here, we review the scaffolding theory in relation to new evidence addressing when during the life course potentially enriching and depleting factors exert their effects on brain health and scaffolding, and we consider the implications for separable, and potentially reciprocal, influences on the level of cognitive function and the rate of decline in later life.