Functional connectivity: a source of variance in the association between cardiorespiratory fitness and cognition?

Microbiota-gut-brain axis: the mediator of exercise and brain health

The brain controls the nerve system, allowing complex emotional and cognitive activities. The microbiota-gut-brain axis is a bidirectional neural, hormonal, and immune signaling pathway that could link the gastrointestinal tract to the brain. Over the past few decades, gut microbiota has been demonstrated to be an essential component of the gastrointestinal tract that plays a crucial role in regulating most functions of various body organs. The effects of the microbiota on the brain occur through the production of neurotransmitters, hormones, and metabolites, regulation of host-produced metabolites, or through the synthesis of metabolites by the microbiota themselves. This affects the host's behavior, mood, attention state, and the brain's food reward system. Meanwhile, there is an intimate association between the gut microbiota and exercise. Exercise can change gut microbiota numerically and qualitatively, which may be partially responsible for the widespread benefits of regular physical activity on human health. Functional magnetic resonance imaging (fMRI) is a non-invasive method to show areas of brain activity enabling the delineation of specific brain regions involved in neurocognitive disorders. Through combining exercise tasks and fMRI techniques, researchers can observe the effects of exercise on higher brain functions. However, exercise's effects on brain health via gut microbiota have been little studied. This article reviews and highlights the connections between these three interactions, which will help us to further understand the positive effects of exercise on brain health and provide new strategies and approaches for the prevention and treatment of brain diseases.

The influence of marathon running on resting-state EEG activity: a longitudinal observational study

Physical activity (PA) has positive effects on various health aspects and neuronal functions, including neuronal plasticity. Exceeding a certain exercise frequency and duration has been associated with negative effects. Our study investigated the effects of excessive PA with a marathon run (MA) and regular PA (training and recovery phases) on electrocortical activity, as measured by electroencephalography (EEG). Thirty healthy marathon runners (26 male, 45 ± 9 yrs) were enrolled in the study. Four resting-state 32 channel EEG recordings were conducted: 12-8 weeks before MA (T-1), 14-4 days prior to MA (T0), 1-6 days after (T2), and 13-15 weeks after MA (T3). Power spectrum analyses were conducted using standardized Low-Resolution Electromagnetic Tomography (sLORETA) and included the following frequency bands: delta (1.5-6 Hz), theta (6.5-8.0 Hz), alpha1 (8.5-10 Hz), alpha2 (10.5-12.0 Hz), beta1 (12.5-18.0 Hz), beta2 (18.5-21.0 Hz), beta3 (21.5-30.0 Hz), and total power (1.5-30 Hz). Statistical nonparametric mapping showed reduced power both in the alpha-2 (log-F ratio = - 0.705, threshold log-F ratio =  ± 0.685, p < 0.05) and in the delta frequency band (log-F ratio = -0.699, threshold log-F ratio =  ± 0.685, p < 0.05) in frontal cortical areas after MA (T2 vs. T0). These effects diminished at long-term follow-up (T3). The results can be interpreted as correlates for subacute neuroplasticity induced by strenuous and prolonged PA. Although previous studies reported an increase in alpha frequency during and directly postexercise, the adverse observation a few days after exercise cessation suggests counterregulatory mechanisms, whose complex origin can be suspected in subcortical circuits, changes in neurotransmitter systems and modulation of affectivity.

Data-driven MRI analysis reveals fitness-related functional change in default mode network and cognition following an exercise intervention

Previous research has indicated that cardiorespiratory fitness (CRF) is structurally and functionally neuroprotective in older adults. However, questions remain regarding the mechanistic role of CRF on cognitive and brain health. The purposes of this study were to investigate if higher pre-intervention CRF was associated with greater change in functional brain connectivity during an exercise intervention and to determine if the magnitude of change in connectivity was related to better post-intervention cognitive performance. The sample included low-active older adults (n = 139) who completed a 6-month exercise intervention and underwent neuropsychological testing, functional neuroimaging, and CRF testing before and after the intervention. A data-driven multi-voxel pattern analysis was performed on resting-state MRI scans to determine changes in whole-brain patterns of connectivity from pre- to post-intervention as a function of pre-intervention CRF. Results revealed a positive correlation between pre-intervention CRF and changes in functional connectivity in the precentral gyrus. Using the precentral gyrus as a seed, analyses indicated that CRF-related connectivity changes within the precentral gyrus were derived from increased correlation strength within clusters located in the Dorsal Attention Network (DAN) and increased anti-correlation strength within clusters located in the Default Mode Network (DMN). Exploratory analysis demonstrated that connectivity change between the precentral gyrus seed and DMN clusters were associated with improved post-intervention performance on perceptual speed tasks. These findings suggest that in a sample of low-active and mostly lower-fit older adults, even subtle individual differences in CRF may influence the relationship between functional connectivity and aspects of cognition following a 6-month exercise intervention.

Physical activity improves the visual-spatial working memory of individuals with mild cognitive impairment or Alzheimer's disease: a systematic review and network meta-analysis

Objective

Our network meta-analysis aimed to ascertain the effect of physical activity on the visual-spatial working memory of individuals with mild cognitive impairment and Alzheimer's disease as well as to propose tailored exercise interventions for each group.

Methods

Employing a frequentist approach, we performed a network meta-analysis to compare the effectiveness of different exercise interventions in improving the visual-spatial working memory of individuals with mild cognitive impairment and Alzheimer's disease. Subsequently, we explored the moderating variables influencing the effectiveness of the exercise interventions through a subgroup analysis.

Results

We included 34 articles involving 3,074 participants in the meta-analysis, comprised of 1,537 participants from studies on mild cognitive impairment and 1,537 participants from studies on Alzheimer's disease. The articles included exhibited an average quality score of 6.6 (score studies) and 6.75 (reaction time [RT] studies), all passing the inconsistency test (p > 0.05). In the mild cognitive impairment literature, mind-body exercise emerged as the most effective exercise intervention (SMD = 0.61, 95% CI: 0.07-1.14). In Alzheimer's disease research, aerobic exercise was identified as the optimal exercise intervention (SMD = 0.39, 95% CI: 0.06-0.71).

Conclusion

The results of the subgroup analysis suggest that the most effective approach to enhancing the visual-spatial working memory of individuals with mild cognitive impairment entails exercising at a frequency of three or more times per week for over 60 min each time and at a moderate intensity for more than 3 months. Suitable exercise options include mind-body exercise, multicomponent exercise, resistance exercise, and aerobic exercise. For individuals with Alzheimer's disease, we recommend moderately intense exercise twice per week for over 90 min per session and for a duration of 3 months or longer, with exercise options encompassing aerobic exercise and resistance exercise.

Smartphone application-based rehabilitation in patients with chronic respiratory and cardiovascular diseases

Rehabilitation improves symptoms, quality of life, and survival in patients with chronic respiratory or cardiovascular disease. We evaluated smartphone application-based rehabilitation programs for patients with chronic respiratory or cardiovascular diseases. This was a single-center prospective single arm study. Participants underwent smartphone application-based pulmonary or cardiac rehabilitation for 12 weeks. A total of 93 participants were recruited, and 75 visited after rehabilitation. Their median age was 67.0 (interquartile range, 60.0-70.8) years, and 60 (80.0%) were men. For patients with chronic respiratory disease (n = 41), VO2peak (median 13.7 to 15.4 ml/kg/min, P = 0.049), chronic obstructive pulmonary disease assessment test (median 14 to 6, P < 0.001), Euro-QoL 5-Dimension 5-Level (EQ-5D-5L) index (median 0.795 to 0.862, P = 0.001), and Health-related Quality of Life Instrument with 8 Items (HINT-8) index (median 0.784 to 0.855, P < 0.001) were significantly improved. For patients with chronic cardiovascular disease (n = 34), VO2peak (median 21.8 to 23.3, P = 0.007), EQ-5D-5L index (median 0.871 to 1.000, P = 0.037), and HINT-8 index (median 0.890 to 0.903, P < 0.001) were significantly improved. The smartphone application-based rehabilitation program improved exercise capacity and quality of life in patients with chronic respiratory or cardiovascular disease.Trial registration: https://clinicaltrials.gov/ct2/show/NCT05383950 (20/05/2022).

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.

An examination of the validity of neuropsychological and physical testing batteries in Latin-American adults aged over 55 years

BACKGROUND

Valid and reliable measurements are necessary to understand and monitor age-related changes.

AIMS

To describe the factor structure and provide validity evidence of a neuropsychological and a physical testing batteries using factor analysis.

METHODS

We performed a secondary analysis of data from the Epidemiology and Development of Alzheimer's Disease (EDAD) project. Community-dwelling adults aged 55 to 85 years underwent comprehensive physical and neuropsychological assessments. An exploratory factor analysis was performed on both assessment batteries. The models were later confirmed with a random subsample using confirmatory factor analysis.

RESULTS

Data from 238 adults (163 females and 75 males) was included. The neuropsychological model revealed a four-factor structure formed by "Executive Functioning", "Verbal Memory", "Logical Memory", and "Labeling And Reading" (Extraction Sums of Squared Loadings [ESSL] = 56.41% explained variance; Standardized Root Mean Square Residual [SRMSR] = 0.06; Comparative Fit Index [CFI] = 0.98). The physical model was formed by a two-factor structure including "Health-related Fitness and "Functional Fitness" (ESSL = 50.54% explained variance; SRMSR = 0.07; CFI = 0.93).

DISCUSSION

To our knowledge, this is the first study to analyze the structure of comprehensive testing batteries for the Latin-American older adults. Our analysis contributes to the understanding of theoretical constructs that are evaluated in the EDAD project.

CONCLUSION

Our findings provide validity evidence for simplified and reduced testing batteries, which imply shorter testing times and fewer resources.

Basal forebrain functional connectivity as a mediator of associations between cardiorespiratory fitness and cognition in healthy older women

Age-related cholinergic dysfunction within the basal forebrain (BF) is one of the key hallmarks for age-related cognitive decline. Given that higher cardiorespiratory fitness (CRF) induces neuroprotective effects that may differ by sex, we investigated the moderating effects of sex on the associations between CRF, BF cholinergic function, and cognitive function in older adults. 176 older adults (68.5 years) were included from the Nathan Kline Institute Rockland Sample. Functional connectivity (rsFC) of the BF subregions including the medial septal nucleus/diagonal band of Broca (MS/DB) and nucleus basalis of Meynert (NBM) were computed from resting-sate functional MRI. Modified Astrand-Ryhming submaximal cycle ergometer protocol was used to estimate CRF. Trail making task and inhibition performance during the color word interference test from the Delis-Kaplan Executive Function System and Rey Auditory Verbal Learning Test were used to examine cognitive function. Linear regression models were used to assess the associations between CRF, BF rsFC, and cognitive performance after controlling for age, sex, and years of education. Subsequently, we measured the associations between the variables in men and women separately to investigate the sex differences. There was an association between higher CRF and greater rsFC between the NBM and right middle frontal gyrus in older men and women. There were significant associations between CRF, NBM rsFC, and trail making task number-letter switching performance only in women. In women, greater NBM rsFC mediated the association between higher CRF and better trail making task number-letter switching performance. These findings provide evidence that greater NBM rsFC, particularly in older women, may be an underlying neural mechanism for the relationship between higher CRF and better executive function.

Hippocampal Resting State Functional Connectivity Associated with Physical Activity in Periadolescent Children

Periadolescence is a neurodevelopmental period characterized by structural and functional brain changes that are associated with cognitive maturation. The development of the functional connectivity of the hippocampus contributes to cognitive maturation, especially memory processes. Notably, hippocampal development is influenced by lifestyle factors, including physical activity. Physical activity has been associated with individual variability in hippocampal functional connectivity. However, this relationship has not been characterized in a developmental cohort. In this study, we aimed to fill this gap by investigating the relationship between physical activity and the functional connectivity of the hippocampus in a cohort of periadolescents aged 8-13 years (N = 117). The participants completed a physical activity questionnaire, reporting the number of days per week they performed 60 min of physical activity; then, they completed a resting-state functional MRI scan. We observed that greater physical activity was significantly associated with differences in hippocampal functional connectivity in frontal and temporal regions. Greater physical activity was associated with decreased connectivity between the hippocampus and the right superior frontal gyrus and increased connectivity between the hippocampus and the left superior temporal sulcus. Capturing changes in hippocampal functional connectivity during key developmental periods may elucidate how lifestyle factors including physical activity influence brain network connectivity trajectories, cognitive development, and future disease risk.

Cardiorespiratory fitness is associated with hippocampal resting state connectivity in women newly diagnosed with breast cancer

Background

Breast cancer and its treatment are associated with aberrant patterns of resting state functional connectivity (rsFC) between the hippocampus and several areas of the brain, which may account for poorer cognitive outcomes in patients. Higher cardiorespiratory fitness (CRF) has been associated with enhanced rsFC and cognitive performance; however, these associations have not been well studied in breast cancer. We examined the relationship between CRF, rsFC of the hippocampus, and cognitive performance among women newly diagnosed with breast cancer.

Methods

Thirty-four postmenopausal women newly diagnosed with Stage 0-IIIa breast cancer (Mage = 63.59 ± 5.73) were enrolled in a 6-month randomized controlled trial of aerobic exercise vs. usual care. During baseline assessments, participants completed functional brain imaging, a submaximal CRF test, and cognitive testing. Whole-brain, seed-based analyses were used to examine the relationship between CRF and hippocampal rsFC, with age, years of education, and framewise displacement included as covariates. Cognition was measured with a battery of validated neurocognitive measures, reduced to seven composite factors.

Results

Higher CRF was positively associated with greater rsFC of the hippocampus to a cluster within the dorsomedial and dorsolateral frontal cortex (z-max = 4.37, p = 0.003, cluster extent = 1,020 voxels). Connectivity within cluster peaks was not significantly related to cognitive factors (all ps > 0.05).

Discussion

CRF was positively associated with hippocampal rsFC to frontal cortex structures, comprising a network of regions commonly suppressed in breast cancer. Future longitudinal research is needed to explore whether baseline rsFC predicts long-term cognitive resilience in breast cancer.

Design and baseline characteristics of the Cognitive and Aerobic Resilience for the Brain (CARB) study

BACKGROUND

Treatments that delay progression of cognitive impairment in older adults are of great public health significance. This manuscript outlines the protocol, recruitment, baseline characteristics, and retention for a randomized controlled trial of cognitive and aerobic physical training to improve cognition in individuals with subjective cognitive dysfunction, the "Cognitive and Aerobic Resilience for the Brain" (CARB) study.

METHODS

Community-dwelling, older adults with self-reported memory loss were randomly assigned to receive either computer-based cognitive training, aerobic physical training, combined cognitive and physical training, or education control. Treatment was delivered 2- to 3-times per week in 45- to 90-min sessions for 12 weeks by trained facilitators videoconferencing into subject's home. Outcome assessments of were taken at the baseline, immediately following training, and 3-months after training.

RESULTS

191 subjects were randomized into the trial (mean age, 75.5 years; 68% female; 20% non-white; mean education, 15.1 years; 30% with 1+ APOE e4 allele). The sample was generally obese, hypertensive, and many were diabetic, while cognition, self-reported mood, and activities of daily living were in the normal range. There was excellent retention throughout the trial. Interventions were completed at high rates, participants found the treatments acceptable and enjoyable, and outcome assessments were completed at high rates.

CONCLUSIONS

This study was designed to determine the feasibility of recruiting, intervening, and documenting response to treatment in a population at risk for progressive cognitive decline. Older adults with self-reported memory loss were enrolled in high numbers and were well engaged with the intervention and outcome assessments.

Diabetes, brain health, and treatment gains in post-stroke aphasia

In post-stroke aphasia, language improvements following speech therapy are variable and can only be partially explained by the lesion. Brain tissue integrity beyond the lesion (brain health) may influence language recovery and can be impacted by cardiovascular risk factors, notably diabetes. We examined the impact of diabetes on structural network integrity and language recovery. Seventy-eight participants with chronic post-stroke aphasia underwent six weeks of semantic and phonological language therapy. To quantify structural network integrity, we evaluated the ratio of long-to-short-range white matter fibers within each participant's whole brain connectome, as long-range fibers are more susceptible to vascular injury and have been linked to high level cognitive processing. We found that diabetes moderated the relationship between structural network integrity and naming improvement at 1 month post treatment. For participants without diabetes (n = 59), there was a positive relationship between structural network integrity and naming improvement (t = 2.19, p = 0.032). Among individuals with diabetes (n = 19), there were fewer treatment gains and virtually no association between structural network integrity and naming improvement. Our results indicate that structural network integrity is associated with treatment gains in aphasia for those without diabetes. These results highlight the importance of post-stroke structural white matter architectural integrity in aphasia recovery.

Large-Scale Network Connectivity and Cognitive Function Changes After Exercise Training in Older Adults with Intact Cognition and Mild Cognitive Impairment

Background

Despite growing evidence regarding the association between exercise training (ET) and functional brain network connectivity, little is known about the effects of ET on large-scale within- and between-network functional connectivity (FC) of core brain networks.

Objective

We investigated the effects of ET on within- and between-network functional connectivity of the default mode network (DMN), frontoparietal network (FPN), and salience network (SAL) in older adults with intact cognition (CN) and older adults diagnosed with mild cognitive impairment (MCI). The association between ET-induced changes in FC and cognitive performance was examined.

Methods

33 older adults (78.0±7.0 years; 16 MCI and 17 CN) participated in this study. Before and after a 12-week walking ET intervention, participants underwent a graded exercise test, Controlled Oral Word Association Test (COWAT), Rey Auditory Verbal Learning Test (RAVLT), a narrative memory test (logical memory; LM), and a resting-state fMRI scan. We examined the within (_W) and between (_B) network connectivity of the DMN, FPN, and SAL. We used linear regression to examine associations between ET-related changes in network connectivity and cognitive function.

Results

There were significant improvements in cardiorespiratory fitness, COWAT, RAVLT, and LM after ET across participants. Significant increases in DMN_W and SAL_W, and DMN-FPN_B, DMN-SAL_B, and FPN-SAL_B were observed after ET. Greater SAL_W and FPN-SAL_B were associated with enhanced LM immediate recall performance after ET in both groups.

Conclusion

Increased within- and between-network connectivity following ET may subserve improvements in memory performance in older individuals with intact cognition and with MCI due to Alzheimer's disease.

Brief moderate-intensity aerobic exercise improves the executive function of Chinese undergraduates regardless of mobile phone addiction: Evidence from the antisaccade task

Introduction

Previous studies have shown that brief moderate-intensity aerobic exercise can improve the executive function of healthy adults. The present study sought to examine and compare the effects of brief moderate-intensity aerobic exercise on the executive functions of undergraduates with and without mobile phone addiction.

Method

Thirty-two healthy undergraduates with mobile phone addiction were recruited and randomly assigned to either an exercise or control group. Likewise, 32 healthy undergraduates without mobile phone addiction were recruited and randomly assigned to either an exercise or control group. Participants were asked to perform moderate-intensity aerobic exercise for 15 minutes for the exercise groups. The executive functions of all participants were assessed via the antisaccade task twice (i.e., pre-test and post-test).

Results

The results showed that the saccade latency, variability of saccade latency, and error rate decreased significantly from pre-test to post-test for all participants. More importantly, after the 15-min moderate-intensity aerobic exercise intervention, participants in the exercise groups showed significantly shorter saccade latency than their counterparts in the control groups, regardless of whether they are with mobile phone addiction.

Discussion

This result is consistent with previous studies demonstrating that brief moderate-intensity aerobic exercise can improve one’s executive function. Furthermore, the absence of significant interaction among Time, Group, and Intervention implies that the effects of brief moderate-intensity aerobic exercise on executive function are comparable between participants with and without mobile phone addiction. The present study supports the previous conclusion that brief moderate-intensity aerobic exercise can improve one’s executive function effectively, and extends it to the population with mobile phone addiction. In summary, the present study has some implications for understanding of the relationship between exercise, executive function, and mobile phone addiction.

Roles of physical activity and diet in cognitive aging: is more better?

Objective: To determine the synergistic effects of nutrition, specifically adherence to the Mediterranean-DASH Intervention for Neurodegenerative Delay (MIND) diet, and physical activity on cognition and brain outcomes in a cross-sectional healthy aging cohort. Methods: A total of 132 adults (age range 52-91; Clinical Dementia Rating = 0) from the UCSF Brain Aging Project completed a 15-item MIND diet food frequency questionnaire and an 11-item self-report measure of weekly physical activity (Physical Activity Scale [PASE]). Cognitive outcomes included executive functioning, episodic memory, and language. Neuroimaging outcomes consisted of total grey matter volume and total white matter volume, adjusted for total intracranial volumes. All regression interaction models adjusted for age, sex, education, and a composite vascular burden score. Results: There was a significant interaction between PASE and MIND on executive functioning and total grey matter volume. Low levels of both related to disproportionately poorer cognitive and brain structural outcomes. Increasing levels of either, but not both, PASE or MIND related to better executive functioning and gray matter outcomes. For memory, language, and total white matter volume, the interaction between PASE and MIND showed the same directionality but did not reach statistical significance. Conclusions: Higher levels of physical activity associated with better executive functioning and gray matter volume, particularly when diet was poor. Similarly, higher levels of MIND diet adherence were associated with better brain and cognitive outcomes when physical activity was low. However, highest levels of physical activity and MIND diet together did not necessarily lead to disproportionately better cognitive and brain volume outcomes.

Physically active undergraduates perform better on executive-related oculomotor control: Evidence from the antisaccade task and pupillometry

Previous studies have shown that exercise can improve executive function in young and older adults. However, it remains controversial whether a sufficient amount of physical activity leads to higher-level executive function. To examine the effect of physical activity on executive function, we used eye-tracking technology and the antisaccade task in 41 young undergraduates with various levels of physical activity. Moreover, we also investigated their differences in cognitive ability by examining their pupil size during the antisaccade task. Eye-tracking results showed that physically active individuals showed shorter saccade latency and higher accuracy in the antisaccade task than their physically inactive counterparts. Furthermore, the former showed larger pupil size during the preparatory period of antisaccade. These findings suggest that individuals with higher-level physical activity have higher-level executive function. The larger pupil sizes of physically active individuals may imply that their locus coeruleus-norepinephrine system and executive-related prefrontal cortex are more active, which contributes to their higher-level cognitive ability.

Proceedings from the Albert Charitable Trust Inaugural Workshop on 'Understanding the Acute Effects of Exercise on the Brain'

An inaugural workshop supported by "The Leo and Anne Albert Charitable Trust," was held October 4-7, 2019 in Scottsdale, Arizona, to focus on the effects of exercise on the brain and to discuss how physical activity may prevent or delay the onset of aging-related neurodegenerative conditions. The Scientific Program Committee (led by Dr. Jeff Burns) assembled translational, clinical, and basic scientists who research various aspects of the effects of exercise on the body and brain, with the overall goal of gaining a better understanding as to how to delay or prevent neurodegenerative diseases. In particular, research topics included the links between cardiorespiratory fitness, the cerebrovasculature, energy metabolism, peripheral organs, and cognitive function, which are all highly relevant to understanding the effects of acute and chronic exercise on the brain. The Albert Trust workshop participants addressed these and related topics, as well as how other lifestyle interventions, such as diet, affect age-related cognitive decline associated with Alzheimer's and other neurodegenerative diseases. This report provides a synopsis of the presentations and discussions by the participants, and a delineation of the next steps towards advancing our understanding of the effects of exercise on the aging brain.

Association between Physical Activity Levels and Brain Volumes in Adults Visiting Radio-Imaging Center of Tertiary Care Hospital

BACKGROUND AND AIM

There is evidence to support the favorable impact of physical activity (PA) on brain volume. However, the empirical evidence exploring the relationship between physical and sedentary behavior remains mixed. We aimed to explore the relationship between PA and sedentary behavior and brain volume.

METHODS

The study sample (n = 150, mean age = 39.7 years) included patients interviewed with the International Physical Activity Questionnaire (IPAQ) who underwent an MRI brain scan. From the images obtained, we measured total intracranial, gray matter, and white matter volume along with the hippocampus, amygdala, parahippocampal gyrus, and posterior cingulate cortex (PCC). Multivariable linear regression analysis was done.

RESULTS AND DISCUSSION

Left hippocampus and overall PA were positively and significantly associated (β = 0.71, p = 0.021) whereas time spent on vigorous physical activity showed a negative association (β = -0.328, p = 0.049) with left hippocampal volume.

CONCLUSION

We found a positive association between total PA and the left hippocampus, whereas vigorous PA showed a negative association with the left hippocampus.

Relationship between Cardiorespiratory Fitness and Executive Function in Young Adults: Mediating Effects of Gray Matter Volume

We evaluated the association between cardiorespiratory fitness (CRF) and executive function (EF) in young adults and the mediating effects of GMV on this relationship. This study involved 217 college students. An incremental load exercise program was used to evaluate VO₂max. EF was estimated by the Flanker task, the 2-back task, and the more-odd shifting task, while structural magnetic resonance and region-based morphometry (RBM) were used to analyze GMV. The high CRF group had a shorter updating reaction time (RT) (p ≤ 0.05). CRF was positively correlated with the right orbital part of the middle frontal gyrus (ORBmid.R) GMV (p ≤ 0.05). ORBmid.R GMV was negatively correlated with updating RT (p ≤ 0.05). Model 4 in SPSS was used to assess the mediating effects of ORBmid.R GMV between CRF and updating RT. ORBmid.R GMV was established to have a partially mediating role between CRF and updating RT, which accounted for 19.6% of the total effect value. These findings indicate that the negative correlation between CRF and EF was significant, and ORBmid.R GMV played a mediating role in the relationship between CRF and EF, providing new evidence toward comprehensively revealing that CRF promotes EF performance.

A Single Bout of Exercise Provides a Persistent Benefit to Cognitive Flexibility

Purpose: A single bout of exercise enhances activity within the cortical networks that support executive function. It is, however, unclear whether exercise improves each core component of executive function and for how long a putative benefit might persist. Method: In Experiment 1, participants completed 20-min of aerobic exercise (via cycle ergometer) and cognitive flexibility-a core component of executive function-was examined pre-exercise, and at immediate, 30- and 60-min post-exercise assessments. Experiment 2 entailed a non-exercise control (i.e., participants sat on the ergometer without exercising) involving the same timeline of cognitive flexibility assessment. Cognitive flexibility was measured via stimulus-driven (SD) and minimally delayed (MD) saccades arranged in an AABB paradigm. SD and MD saccades require a response at target onset and after target offset, respectively, with the latter requiring executive control. Work has shown that reaction times for a SD saccade preceded by a MD saccade are longer than when a SD saccade is preceded by its same task-type, whereas the converse switch does not influence performance (i.e., the unidirectional switch-cost). Results: Experiment 1 showed a unidirectional switch-cost at each assessment; however, the switch-cost magnitude was decreased at immediate and 30-min assessments compared to the pre- and 60-min assessments. In contrast, Experiment 2 did not elicit a change in switch-cost magnitude across the different assessments. Discussion/Conclusion: Thus, a single-bout of exercise benefitted the cognitive flexibility component of executive function in the immediate and 30-min post-exercise assessments.

PE augmented mindfulness: A neurocognitive framework for research and future healthcare

Various well-controlled studies have suggested that practitioners in mindfulness can be prone to patient drop-out (e.g., due to chronic stress, pathology, cognitive reactivity), despite researchers having identified the underlying mechanisms that link mindfulness to mental health. In this article, a framework for physical exercise (PE) augmented mindfulness is proposed, which posits that consistently practiced PE before meditation can support (early-stage) mindfulness. Neurocognitive research shows PE (aerobic exercises or yoga) and mindfulness to impact similar pathways of stress regulation that involve cognitive control and stress regulation, thereby supporting the proposed synergistic potential of PE augmented mindfulness. Research focused on the psychophysiological impact of PE, showed its practice to promote short-term neurocognitive changes that can promote both cognitive control and the attainment of mindful awareness (MA). In order to chart dose responses required for protocol development, further research will be presented. Together these findings are discussed in light of future research on this multidisciplinary topic, protocol development, mindful walking, and further application in healthcare and beyond.

Examining the Effect of Increased Aerobic Exercise in Moderately Fit Adults on Psychological State and Cognitive Function

Regular physical exercise can decrease the risk for obesity, diabetes, and cardiovascular disease, increase life expectancy, and promote psychological health and neurocognitive functioning. Cross-sectional studies show that cardiorespiratory fitness level (VO2 max) is associated with enhanced brain health, including improved mood state and heightened cognitive performance. Interventional studies are consistent with these cross-sectional studies, but most have focused on low-fit populations. Few such studies have asked if increasing levels of physical activity in moderately fit people can significantly enhance mood, motivation, and cognition. Therefore, the current study investigated the effects of increasing aerobic exercise in moderately fit individuals on psychological state and cognitive performance. We randomly assigned moderately fit healthy adults, 25-59 years of age, who were engaged in one or two aerobic exercise sessions per week to either maintain their exercise regimen (n = 41) or increase their exercise regimen (i.e., 4-7 aerobic workouts per week; n = 39) for a duration of 3 months. Both before and after the intervention, we assessed aerobic capacity using a modified cardiorespiratory fitness test, and hippocampal functioning via various neuropsychological assessments including a spatial navigation task and the Mnemonic Similarity Task as well as self-reported measures including the Positive and Negative Affect Scale, Beck Anxiety Inventory, State-Trait Anxiety Inventory, Perceived Stress Scale, Rumination Scale, Eating Disorders Examination, Eating Attitudes Test, Body Attitudes Test, and Behavioral Regulation of Exercise Questionnaire. Consistent with our initial working hypotheses, we found that increasing exercise significantly decreased measures of negative affect, including fear, sadness, guilt, and hostility, as well as improved body image. Further, we found that the total number of workouts was significantly associated with improved spatial navigation abilities and body image as well as reduced anxiety, general negative affect, fear, sadness, hostility, rumination, and disordered eating. In addition, increases in fitness levels were significantly associated with improved episodic memory and exercise motivation as well as decreased stress and disordered eating. Our findings are some of the first to indicate that in middle-aged moderately-fit adults, continuing to increase exercise levels in an already ongoing fitness regimen is associated with additional benefits for both psychological and cognitive health.

Passive exercise increases cerebral blood flow velocity and supports a postexercise executive function benefit

Executive function entails high-level cognitive control supporting activities of daily living. Literature has shown that a single-bout of exercise involving volitional muscle activation (i.e., active exercise) improves executive function and that an increase in cerebral blood flow (CBF) may contribute to this benefit. It is, however, unknown whether non-volitional exercise (i.e., passive exercise) wherein an individual's limbs are moved via an external force elicits a similar executive function benefit. This is a salient question given that proprioceptive and feedforward drive from passive exercise increases CBF independent of the metabolic demands of active exercise. Here, in a procedural validation participants (n = 2) used a cycle ergometer to complete separate 20-min active and passive (via mechanically driven flywheel) exercise conditions and a non-exercise control condition. Electromyography showed that passive exercise did not increase agonist muscle activation or increase ventilation or gas exchange variables (i.e., V̇O₂ and V̇CO₂ ). In a main experiment participants (n = 28) completed the same exercise and control conditions and transcranial Doppler ultrasound showed that active and passive exercise (but not the control condition) increased CBF through the middle cerebral artery (ps <.001); albeit the magnitude was less during passive exercise. Notably, antisaccade reaction times prior to and immediately after each condition showed that active (p < .001) and passive (p = .034) exercise improved an oculomotor-based measure of executive function, whereas no benefit was observed in the control condition (p = .85). Accordingly, results evince that passive exercise 'boosts' an oculomotor-based measure of executive function and supports convergent evidence that increased CBF mediates this benefit.

Getting Fit to Counteract Cognitive Aging: Evidence and Future Directions

Physical activity has shown tremendous promise for counteracting cognitive aging, but also tremendous variability in cognitive benefits. We describe evidence for how exercise affects cognitive and brain aging, and whether cardiorespiratory fitness is a key factor. We highlight a brain network framework as a valuable paradigm for the mechanistic insight needed to tailor physical activity for cognitive benefits.

Improving cognitive function through high-intensity interval training in breast cancer patients undergoing chemotherapy – the CLARITY Trial: Protocol for a randomized study. (Preprint)

BACKGROUND

More than 75% of patients with breast cancer treated with chemotherapy experience cognitive impairments (eg, memory and attention problems), commonly known as chemo-brain. Exercise, especially aerobic high-intensity interval training (HIIT), is associated with better cognitive function in healthy populations. However, clinical trials testing the impact of exercise interventions on chemotherapy-induced cognitive decline in patients with cancer are lacking, and the mechanisms through which exercise could improve cognitive function are unclear.

OBJECTIVE

The objective of the Improving Cognitive Function Through High-Intensity Interval Training in Breast Cancer Patients Undergoing Chemotherapy trial is to examine the effects of HIIT on cognitive function in patients with breast cancer undergoing chemotherapy.

METHODS

This 2-arm, single-center, pilot randomized controlled trial will randomize 50 patients with breast cancer undergoing chemotherapy to HIIT or attention control. The HIIT group will perform a supervised 16-week, thrice-weekly intervention, with each session including a 5-minute warm-up at 10% maximal power output (POmax), 10 sets of alternating 1-minute high-intensity (90% POmax) and 1-minute recovery (10% POmax) intervals, and a 5-minute cooldown (10% POmax). The attention control group will receive a stretching program with no exercise components and be asked to maintain their exercise levels for 16 weeks. The primary outcomes of the study are executive function and memory measured using the National Institutes of Health toolbox and resting-state connectivity and diffusion tensor imaging microstructure evaluated using magnetic resonance imaging. The secondary and tertiary outcomes include cardiorespiratory fitness, body composition, physical fitness, and psychosocial health. The study has been approved by the institutional review board of the Dana-Farber Cancer Institute (20-222).

RESULTS

The trial was funded in January 2019, with recruitment started in June 2021. As of May 2022, a total of 4 patients have consented and been randomized (n=2, 50% to exercise; n=1, 25% to control; and n=1, 25% nonrandomized). Trial completion is expected in January 2024.

CONCLUSIONS

This first-of-its-kind study incorporates a novel exercise intervention (ie, HIIT) and comprehensive cognitive measures. If positive, our findings will establish the pilot efficacy of HIIT on chemotherapy-induced cognitive function in patients with breast cancer, providing the foundation for future larger phase-II and phase-III trials to confirm the findings and potentially establish HIIT as a standard of care for women undergoing chemotherapy for breast cancer.

TRIAL REGISTRATION

ClinicalTrials.gov NCT04724499; https://clinicaltrials.gov/ct2/show/NCT04724499.

INTERNATIONAL REGISTERED REPORT IDENTIFIER (IRRID)

DERR1-10.2196/39740.

Structural and functional variations in the prefrontal cortex are associated with learning in pre-adolescent common marmosets (Callithrix jacchus)

There is substantial evidence linking the prefrontal cortex (PFC) to a variety of cognitive abilities, with adolescence being a critical period in its development. In the current study, we investigated the neural basis of differences in learning in pre-adolescent common marmosets. At 8 months old, marmosets were given anatomical and resting state MRI scans (n=24). At 9 months old, association learning and inhibitory control was tested using a 'go/no go' visual discrimination (VD) task. Marmosets were grouped into 'learners' (n=12) and 'non-learners' (n=12), and associations between cognitive performance and sub-regional PFC volumes, as well as PFC connectivity patterns, were investigated. 'Learners' had significantly (p<0.05) larger volumes of areas 11, 25, 47 and 32 than 'non-learners', although 'non-learners' had significantly larger volumes of areas 24a and 8v than 'learners'. There was also a significant correlation between average % correct responses to the 'punished' stimulus and volume of area 47. Further, 'non-learners' had significantly greater global PFC connections, as well as significantly greater numbers of connections between the PFC and basal ganglia, cerebellum and hippocampus, compared to 'non-learners'. These results suggest that larger sub-regions of the orbitofrontal cortex and ventromedial PFC, as well more refined PFC connectivity patterns to other brain regions associated with learning, may be important in successful response inhibition. This study therefore offers new information on the neurodevelopment of individual differences in cognition during pre-adolescence in non-human primates.

Subjective Well-Being and Bilateral Anterior Insula Functional Connectivity After Exercise Intervention in Older Adults With Mild Cognitive Impairment

While it is well known that exercise training is associated with improvement in subjective well-being among older adults, it is unclear if individuals with cognitive impairment experience the same effects elicited by exercise on subjective well-being. We further explored whether the bilateral anterior insula network may be an underlying neural mechanism for the exercise training-related improvements in subjective well-being. We investigated the effects of exercise training on subjective well-being in older adults (78.4 ± 7.1 years) with mild cognitive impairment (MCI; n = 14) and a cognitively normal (CN; n = 14) control group. We specifically assessed the relationship between changes in subjective well-being and changes in functional connectivity (FC) with the bilateral anterior insula from before to after exercise training. Cardiorespiratory fitness, subjective well-being, and resting-state fMRI were measured before and after a 12-week moderate-intensity walking intervention. A seed-based correlation analysis was conducted using the bilateral anterior insula as a priori seed regions of interest. The associations between bilateral anterior insula FC with other brain regions and subjective well-being were computed before and after exercise training, respectively, and the statistical difference between the correlations (before vs after exercise training) was evaluated. There was a significant Group (MCI vs CN) × Time (before vs after exercise training) interaction for subjective well-being, such that while those with MCI demonstrated significantly increased subjective well-being after exercise training, no changes in subjective well-being were observed in CN. Participants with MCI also showed an exercise training-related increase in the bilateral anterior insula FC. While there was no significant correlation between subjective well-being and bilateral anterior insula FC before exercise training, a positive association between subjective well-being and bilateral anterior insula FC was found in the MCI group after exercise training. Our findings indicate that 12 weeks of exercise training may enhance subjective well-being in older adults diagnosed with MCI and, further, suggest that increased bilateral anterior insula FC with other cortical regions may reflect neural network plasticity associated with exercise training-related improvements in subjective well-being.

Resting state networks mediate the association between both cardiovascular fitness and gross motor skills with neurocognitive functioning

Recent evidence suggests that cardiovascular fitness and gross motor skill performance are related to neurocognitive functioning by influencing brain structure and functioning. This study investigates the role of resting‐state networks (RSNs) in the relation of cardiovascular fitness and gross motor skills with neurocognitive functioning in healthy 8‐ to 11‐year‐old children (n = 90, 45 girls, 10% migration background). Cardiovascular fitness and gross motor skills were related to brain activity in RSNs. Furthermore, brain activity in RSNs mediated the relation of both cardiovascular fitness (Frontoparietal network and Somatomotor network) and gross motor skills (Somatomotor network) with neurocognitive functioning. The results indicate that brain functioning may contribute to the relation between both cardiovascular fitness and gross motor skills with neurocognitive functioning.

Daily-Life Physical Activity of Healthy Young Adults Associates With Function and Structure of the Hippocampus

Previous research on Physical Activity (PA) has been highly valuable in elucidating how PA affects the structure and function of the hippocampus in elderly populations that take part in structured interventions. However, how PA affects the hippocampus in younger populations that perform PA during daily-life activities remains poorly understood. In addition, this research has not examined the impact of PA on the internal structure of the hippocampus. Here, we performed a cross-sectional exploration of the way structural and functional aspects of the hippocampus are associated with habitual PA performed during work, leisure time, and sports in the daily lives of healthy young adults (n = 30; 14 female; mean age = 23.9 y.o.; SD = 7.8 y.o.). We assessed PA in these three different contexts through a validated questionnaire. The results show that PA performed during work time correlated with higher subicular volumes. In addition, we found that PA changed functional connectivity (FC) between a location in the middle/posterior hippocampus and regions of the default mode network, and between a location in the anterior hippocampus and regions of the somatomotor network. No statistical effects of PA performed during leisure time and sports were found. The results generalize the impact of PA on younger populations and show how PA performed in daily-life situations correlates with the precise internal structure and functional connectivity of the hippocampus.

Comparative efficacy of various exercise interventions on cognitive function in patients with mild cognitive impairment or dementia: A systematic review and network meta-analysis

BACKGROUND

Exercise is a promising nonpharmacological therapy for cognitive dysfunction, but it is unclear which type of exercise is most effective. The objective of this study was to compare and rank the effectiveness of various exercise interventions on cognitive function in patients with mild cognitive impairment (MCI) or dementia and to examine the effects of exercise on the symptoms relevant to cognitive impairment.

METHODS

We searched PubMed, Web of Science, Embase, Cochrane Central Register of Controlled Trials, SPORTDiscus, and PsycInfo through September 2019 and included randomized controlled trials that examined the effectiveness of exercise interventions in patients with MCI or dementia. Primary outcomes included global cognition, executive cognition, and memory cognition. Secondary outcomes included activities of daily living, neuropsychiatric symptoms, and quality of life. Pairwise analyses and network meta-analyses were performed using a random effects model.

RESULTS

A total of 73 articles from 71 trials with 5606 participants were included. All types of exercise were effective in increasing or maintaining global cognition, and resistance exercise had the highest probability of being the most effective intervention in slowing the decrease in global cognition (standard mean difference (SMD) = 1.05, 95% confidence interval (95%CI): 0.56-1.54), executive function (SMD = 0.85, 95%CI: 0.21-1.49), and memory function (SMD = 0.32, 95%CI: 0.01-0.63) in patients with cognitive dysfunction. Subgroup analyses for patients with MCI revealed different effects, and multicomponent exercise was most likely to be the optimal exercise therapy for preventing the decline of global cognition (SMD = 0.99, 95%CI: 0.44-1.54) and executive function (SMD = 0.72, 95%CI: 0.06-1.38). However, only resistance exercise showed significant effects on memory function for patients with MCI (SMD = 0.35, 95%CI: 0.01-0.69). Exercise interventions also showed various effects on the secondary outcomes.

CONCLUSION

Resistance exercise has the highest probability of being the optimal exercise type for slowing cognitive decline in patients with cognitive dysfunction, especially in patients with dementia. Multicomponent exercise tends to be most effective in protecting global cognition and executive function in patients with MCI.

Interrelationships between exercise, functional connectivity, and cognition among healthy adults: A systematic review

The main purpose of this systematic review was to examine past literature focusing on the potential relationship between exercise (or physical activity or cardiorespiratory fitness [CRF]) and functional brain connectivity in healthy adults. Among the studies meeting this purpose, we also evaluated studies investigating whether, and how, functional connectivity may influence the exercise-cognition relationship. A systematic review was employed through several electronic databases (PsychInfo, PubMed, and Google Scholar) in accordance with PRISMA guidelines. The literature search identified 656 records, and a total of 12 studies met the inclusion criteria. Among these 12 studies, there were 4, 7, and 1 study, respectively, examining the relationship between exercise and frontal lobe connectivity, temporal lobe connectivity, and whole-brain connectivity. Also, 7 studies examined the relationship between functional connectivity and cognitive performance across multiple brain regions as a function of exercise. Existing literature suggests that CRF, habitual physical activity, and varying intensities of acute exercise can strengthen functional connections among a wide variety of regions and subcortical structures of the human brain. These exercise-induced functional connectivity changes within and between specific brain structures/networks supporting cognitive processing may improve various domains of cognitive function. Given these complex associations, a thorough understanding of how functional connectivity plays a mediating role in the exercise-cognition interaction is needed in future studies.

Exercise Training Improves Memory Performance in Older Adults: A Narrative Review of Evidence and Possible Mechanisms

Exercise, neurotransmitters, growth factors, myokines, and potential effects on the brain.

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Cognitive Aging and the Promise of Physical Activity

Is the field of cognitive aging irretrievably concerned with decline and deficits, or is it shifting to emphasize the hope of preservation and enhancement of cognitive function in late life? A fragment of an answer comes from research attempting to understand the reasons for individual variability in the extent and rate of cognitive decline. This body of work has created a sense of optimism based on evidence that there are some health behaviors that amplify cognitive performance or mitigate the rate of age-related cognitive decline. In this context, we discuss the role of physical activity on neurocognitive function in late adulthood and summarize how it can be conceptualized as a constructive approach both for the maintenance of cognitive function and as a therapeutic for enhancing or optimizing cognitive function in late life. In this way, physical activity research can be used to shape perceptions of cognitive aging. Expected final online publication date for the Annual Review of Clinical Psychology, Volume 18 is May 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.

The effects of age and physical exercise on multimodal signal responses: Implications for semi-autonomous vehicle takeover requests

The present study examined whether the non-chronological age factor, engagement in physical exercise, affected responses to multimodal (combinations of visual, auditory, and/or tactile) signals differently between younger and older adults in complex environments. Forty-eight younger and older adults were divided into exercise and non-exercise groups, and rode in a simulated Level 3 autonomous vehicle under four different task conditions (baseline, video watching, headway estimation, and video-headway combination), while being asked to respond to various multimodal warning signals. Overall, bi- and trimodal warnings had faster response times for both age groups across driving conditions, but was more pronounced for older adults. Engagement in physical exercise was associated with smaller maximum braking force for younger participants only, and also corresponded to longer average fixation durations, compared to the non-exercise group. Findings from this research can help to guide decisions about the design of warning and information systems for semi-autonomous vehicles.

The Effects of Cardiorespiratory and Motor Skill Fitness on Intrinsic Functional Connectivity of Neural Networks in Individuals with Parkinson's Disease

Background:

Studies in aging older adults have shown the positive association between cognition and exercise related fitness, particularly cardiorespiratory fitness. These reports have also demonstrated the association of high cardiorespiratory fitness, as well as other types of fitness, on the reversal of age-related decline in neural network connectivity, highlighting the potential role of fitness on age- and disease-related brain changes. While the clinical benefits of exercise are well-documented in Parkinson’s disease (PD), the extent to which cardiorespiratory fitness (assessed by estimated VO_2max testing) or motor skill fitness (assessed by the Physical Performance Test (PPT)) affects neural network connectivity in PD remains to be investigated. The purpose of this study was to explore the hypothesis that higher fitness level is associated with an increase in the intrinsic network connectivity of cognitive networks commonly affected in PD.

Methods:

In this cross-sectional resting state fMRI, we used a multivariate statistical approach based on high-dimensional independent component analysis (ICA) to investigate the association between two independent fitness metrics (estimated VO_2max and PPT) and resting state network connectivity.

Results:

We found that increased estimated VO_2max was associated with increased within network connectivity in cognitive networks known to be impaired in PD, including those sub-serving memory and executive function. There was a similar trend for high levels of PPT to be associated with increased within network connectivity in distinct resting state networks. The between functional network connectivity analysis revealed that cardiorespiratory fitness was associated with increased functional connectivity between somatosensory motor network and several cognitive networks sub-serving memory, attention, and executive function.

Conclusion:

This study provides important empirical data supporting the potential association between two forms of fitness and multiple resting state networks impacting PD cognition. Linking fitness to circuit specific modulation of resting state network connectivity will help establish a neural basis for the positive effects of fitness and specific exercise modalities and provide a foundation to identify underlying mechanisms to promote repair.

Evidence for exercise-related plasticity in functional and structural neural network connectivity

The number of studies investigating exercise and cardiorespiratory fitness (CRF)-related changes in the functional and structural organization of brain networks continues to rise. Functional and structural connectivity are critical biomarkers for brain health and many exercise-related benefits on the brain are better represented by network dynamics. Here, we reviewed the neuroimaging literature to better understand how exercise or CRF may facilitate and maintain the efficiency and integrity of functional and structural aspects of brain networks in both younger and older adults. Converging evidence suggests that increased exercise performance and CRF modulate functional connectivity of the brain in a way that corresponds to behavioral changes such as cognitive and motor performance improvements. Similarly, greater physical activity levels and CRF are associated with better cognitive and motor function, which may be brought about by enhanced structural network integrity. This review will provide a comprehensive understanding of trends in exercise-network studies as well as future directions based on the gaps in knowledge that are currently present in the literature.

Beyond IQ: The Importance of Metacognition for the Promotion of Global Wellbeing

Global policy makers increasingly adopt subjective wellbeing as a framework within which to measure and address human development challenges, including policies to mitigate consequential societal problems. In this review, we take a systems-level perspective to assemble evidence from studies of wellbeing, of collective intelligence, and of metacognition and argue for a virtuous cycle for health promotion in which the increased collective intelligence of groups: (1) enhances the ability of such groups to address consequential societal problems; (2) promotes the wellbeing of societies and the individual wellbeing of people within groups; and, finally, (3) enables prosocial actions that further promote collective problem-solving and global wellbeing. Notably, evidence demonstrates that effective collaboration and teamwork largely depend on social skills for metacognitive awareness—the capacity to evaluate and control our own mental processes in the service of social problem-solving. Yet, despite their importance, metacognitive skills may not be well-captured by measures of general intelligence. These skills have instead been the focus of decades of research in the psychology of human judgment and decision-making. This literature provides well-validated tests of metacognitive awareness and demonstrates that the capacity to use analysis and deliberation to evaluate intuitive responses is an important source of individual differences in decision-making. Research in network neuroscience further elucidates the topology and dynamics of brain networks that enable metacognitive awareness, providing key targets for intervention. As such, we further discuss emerging scientific interventions to enhance metacognitive skills (e.g., based on mindfulness meditation, and physical activity and aerobic fitness), and how such interventions may catalyze the virtuous cycle to improve collective intelligence, societal problem-solving, and global wellbeing.

Mechanistic Effects of Aerobic Exercise in Alzheimer's Disease: Imaging Findings From the Pilot FIT-AD Trial

Despite strong evidence from animal models of Alzheimer's disease (AD) supporting aerobic exercise as a disease-modifying treatment for AD, human mechanistic studies are limited with mixed findings. The objective of this pilot randomized controlled trial was to examine the effects of 6-month aerobic exercise on hippocampal volume, temporal meta-regions of interest (ROI) cortical thickness, white matter hyperintensity (WMH) volume, and network failure quotient (NFQ), measured with MRI, in community-dwelling older adults with AD dementia. Additionally, the relationships between 6- and 12-month changes in MRI biomarkers and the AD Assessment Scale-Cognition (ADAS-Cog) were examined. Sixty participants were randomized, but one was excluded because baseline MRI failed quality control: 38 randomized to cycling and 21 to stretching. The intervention was moderate-intensity cycling for 20–50 mins, three times a week for 6 months. Control was low-intensity stretching. The study outcomes include hippocampal volume, temporal meta-ROI cortical thickness, WMH volume, and NFQ. Outcomes were measured at baseline, 6 months, and 12 months. The sample averaged 77.3 ± 6.3 years old with 15.6 ± 2.9 years of education and 53% men. Both groups experienced significant declines over 6 months in hippocampal volume (2.64% in cycling vs. 2.89% in stretching) and temporal meta-ROI cortical thickness (0.94 vs. 1.54%), and over 12 months in hippocampal volume (4.47 vs. 3.84%) and temporal meta-ROI cortical thickness (2.27 vs. 1.79%). These declines did not differ between groups. WMH volume increased significantly with the cycling group increasing less (10.9%) than stretching (24.5%) over 6 months (f = 4.47, p = 0.04) and over 12 months (12.1 vs. 27.6%, f = 5.88, p = 0.02). NFQ did not change significantly over time. Pairwise correlational analyses showed a significant negative correlation between 6-month changes in hippocampal volume and ADAS-Cog (r = −0.34, p < 0.05). To conclude, aerobic exercise may reduce the decline in hippocampal volume and temporal meta-ROI cortical thickness during the intervention period, but the effect sizes are likely to be very small and dose-dependent and reverse once the intervention stops. Aerobic exercise is effective on slowing down WMH progression but has no effect on NFQ. Hippocampal atrophy was associated with cognitive decline during the intervention period.

Clinical Trial Registration:www.ClinicalTrials.gov, identifier: NCT01954550.

Effects of Dual-Task Training on Gait Parameters in Elderly Patients with Mild Dementia

This study aimed to investigate the effectiveness of dual-task training (DTT) compared to single-task training (STT), on gait parameters in elderly patients with mild dementia (MD). Twenty-four elderly patients with MD were randomly assigned to the DTT (n = 13) or the STT group (n = 11). The DTT group performed a specific cognitive-motor DTT, while the STT group received only motor task training. Both training sessions lasted 8 weeks, with a frequency of 3 days per week, and the cognitive functions and gait parameters were measured. A statistically significant interaction effect was found between the two groups in stride length, stride velocity, cadence, step length, swing phase, stance phase, and double support phase (p < 0.05). After 8 weeks, the DTT group showed significant improvement in spatiotemporal parameters, except for the kinematic parameters (p < 0.05). In the between-group analysis, the DTT group showed more improvement than the STT group in stride velocity, step length, swing phase, stance phase, and double support (p < 0.05). These findings suggest that improvements in spatiotemporal gait parameters after DTT are reported in patients with MD. Our results can guide therapists to include dual tasks in their gait rehabilitation programs for the treatment of mild dementia.

Exercise intensity-specific changes to cerebral blood velocity do not modulate a postexercise executive function benefit

Executive function is transiently improved (i.e., <60-min) following a single bout of aerobic exercise. A candidate mechanism for this improvement is an exercise-mediated increase in cerebral blood flow (CBF). Further, it has been proposed that an increase in CBF across the continuum of increasing exercise intensities improves the magnitude of a postexercise executive function benefit (i.e., drive theory); however, this proposal has not been empirically tested. Here, participants completed four experimental sessions: a V̇O_2peak test to determine cardiorespiratory fitness and estimated lactate threshold (LT), followed by separate 10-min sessions of light- (i.e., 25 W), moderate- (i.e., 80% estimated LT), and heavy-intensity (i.e., 15% of the difference between LT and V̇O_2peak) aerobic exercise. An estimate of CBF during exercise was achieved via transcranial Doppler ultrasound and near-infrared spectroscopy to quantify blood velocity (BV) through the middle cerebral artery and deoxygenated hemoglobin (HHb), respectively. Executive function was assessed before and after each session via the executive-mediated antisaccade task (i.e., saccade mirror-symmetrical to a target). Results demonstrated that BV increased in relation to increasing exercise intensity, whereas HHb decreased by a comparable magnitude independent of intensity. In terms of executive function, null hypothesis and equivalence tests indicated a comparable magnitude postexercise reduction in antisaccade reaction time across exercise intensities. Accordingly, the magnitude of CBF change during exercise does not impact the magnitude of a postexercise executive function benefit.

Acute exercise effects on inhibitory control and the pupillary response in young adults

Previous research has established an impact of acute exercise on cognitive performance, which has inspired investigations into neurobiological mechanisms that may underlie the observed benefits. Pupillary responses have been posited to reflect activation of such underlying neurobiological mechanisms. The current study recruited healthy young adults to investigate the effects of a single bout of moderate-to-vigorous intensity aerobic exercise on subsequent performance and pupillary responses during an inhibitory control task. Results showed that an acute bout of exercise was related to shorter reaction times and increased tonic pupil dilation during an inhibitory control task. Although pupillary responses did not mediate the acute exercise effect on inhibitory control, higher cardiorespiratory fitness was associated with greater phasic pupil dilation following exercise relative to seated rest. The current study supported the plausibility of the pupillary response as a marker of LC-NE system activation that is sensitive to acute exercise. Whether pupillary responses could account for transient benefits of acute exercise on brain and cognition remains unclear.

Prefrontal Plasticity after a 3-Month Exercise Intervention in Older Adults Relates to Enhanced Cognitive Performance

This study examined exercise intervention effects on older adults' brain structures and function. Brain data were analyzed from 47 healthy adults between 61 and 82 years of age who, in a previous study, showed cognitive improvement following a 3-month intervention. The participants were assigned to a motor exercise intervention group (n = 24), performing exercise training programs for a 12-week period, or a waiting control group (n = 23), abstaining from any exercise program. Structural analysis of the frontal cortex and hippocampus revealed increased gray matter volume and/or thickness in several prefrontal areas in the intervention group and reduced hippocampal gray matter volume in the control group. Importantly, the volume increase in the middle frontal sulcus in the intervention group was associated with a general cognitive improvement after the intervention. Functional analysis showed that the prefrontal functional connectivity during a working memory task differently changed in response to the intervention or waiting in the two groups. The functional connectivity decreased in the intervention group, whereas the corresponding connectivity increased in the control group, which was associated with maintaining cognitive performance. The current longitudinal findings indicate that short-term exercise intervention can induce prefrontal plasticity associated with cognitive performance in older adults.

The comparisons of inhibitory control and post-error behaviors between different types of athletes and physically inactive adults

To properly behave and correct mistakes, individuals must inhibit inappropriate actions and detect errors for future behavioral adjustment. Increasing evidence has demonstrated that athletes are superior in cognitive functions and this benefit varied dependent on the types of sport that individuals involved in, but less is known on whether athletes have a different error-related behavioral pattern. The purpose of this study was to compare the behavioral performance of inhibition and error monitoring between individuals who participated in an open-skill sport (n = 12), a closed-skill sport (n = 12), and a sedentary lifestyle (n = 16). A combined flanker/stop signal task was presented and the derived stop signal reaction time (SSRT), post-correct accuracy and reaction time (RT), as well as post-error accuracy and RT were compared across groups. Our findings indicated there was no difference in SSRT between groups. Surprisingly, significant post-error slowing (PES) was observed only in controls but not in sport groups, the controls also exhibited significantly longer post-error RT compared with the open-skill group. However, there was no difference in the post-error accuracy between groups, indicating a higher efficiency in the post-error processing among open- and closed-skill groups by requiring comparatively less time for behavioral adjustments. The present study is the first to disclose the discrepancies in PES between different types of athletes and controls. The findings suggest that sport training along with higher amounts of physical activity is associated with a more efficient behavioral pattern for error processing especially when the sport requires open skills in nature.

Association Between Greater Cerebellar Network Connectivity and Improved Phonemic Fluency Performance After Exercise Training in Older Adults

Little is known about the effects of exercise training (ET) on lexical characteristics during fluency task and its association with cerebellum functional connectivity. The purposes of this study were (1) to investigate whether ET alters response patterns during phonemic and semantic fluency tasks and (2) to assess the association between ET-related changes in cerebellum functional connectivity (FC) and lexical characteristics during fluency tasks. Thirty-five older adults (78.0 ± 7.1 years; 17 mild cognitive impairment (MCI) and 18 healthy cognition (HC)) underwent a 12-week treadmill ET. Before and after ET, cardiorespiratory fitness tests, phonemic and semantic fluency tests, and resting-state fMRI scans were administered. We utilized a seed-based correlation analysis to measure cerebellum FC and linear regression to assess the association of residualized ET-induced Δcerebellum FC with Δtask performance. Improved mean switches and frequency during the phonemic fluency task were observed following ET in all participants. There were significant associations between ET-induced increases in cerebellum FC and greater phonemic fluency task log frequency, increases in mean switches, and a reduction in the number of syllables in HC. Lastly, there was a significant interaction between group and cerebellar connectivity on phonemic fluency mean log frequency and number of syllables. A 12-week walking ET is related to enhanced phonemic fluency lexical characteristics in older adults with MCI and HC. The association between ET-induced increases in cerebellum FC and enhanced response patterns after ET suggests that the cerebellum may play an important role in ET-related improvement in phonemic fluency performance in cognitively healthy older adults.

Neural and Genetic Bases for Human Ability Traits

The judgement of human ability is ubiquitous, from school admissions to job performance reviews. The exact make-up of ability traits, however, is often narrowly defined and lacks a comprehensive basis. We attempt to simplify the spectrum of human ability, similar to how five personality traits are widely believed to describe most personalities. Finding such a basis for human ability would be invaluable since neuropsychiatric disease diagnoses and symptom severity are commonly related to such differences in performance. Here, we identified four underlying ability traits within the National Institutes of Health Toolbox normative data (n = 1, 369): (1) Motor-endurance, (2) Emotional processing, (3) Executive and cognitive function, and (4) Social interaction. We used the Human Connectome Project young adult dataset (n = 778) to show that Motor-endurance and Executive and cognitive function were reliably associated with specific brain functional networks (r ² = 0.305 ± 0.021), and the biological nature of these ability traits was also shown by calculating their heritability (31 and 49%, respectively) from twin data.

Physical fitness, hippocampal functional connectivity and academic performance in children with overweight/obesity: The ActiveBrains project

OBJECTIVES

Physical fitness is a modifiable factor associated with enhanced brain health during childhood. To our knowledge, the present study is the first to examine: (i) whether physical fitness components (i.e., cardiorespiratory, motor and muscular fitness) are associated with resting state functional connectivity of hippocampal seeds to different cortical regions in children with overweight/obesity, and (ii) whether resting state hippocampal functional connectivity is coupled with better academic performance.

PATIENTS AND METHODS

In this cross-sectional study, a total of 99 children with overweight/obesity aged 8-11 years were recruited from Granada, Spain (November 2014 to February 2016). The physical fitness components were assessed following the ALPHA health-related fitness test battery. T1-weighted and resting-state fMRI images were acquired with a 3.0 Tesla Siemens Magnetom Tim Trio system. Academic performance was assessed by the Woodcock-Muñoz standardized test. Hippocampal seed-based procedures with post-hoc regression analyses were performed.

RESULTS

In the fully adjusted models, cardiorespiratory fitness was independently associated with greater hippocampal connectivity between anterior hippocampus and frontal regions (β ranging from 0.423 to 0.424, p < 0.001). Motor fitness was independently associated with diminished hippocampal connectivity between posterior hippocampus and frontal regions (β ranging from -0.583 to -0.694, p < 0.001). However, muscular fitness was not independently associated with hippocampal functional connectivity. Positive resting state hippocampal functional connectivity was related to better written expression (β ranging from 0.209 to 0.245; p < 0.05).

CONCLUSIONS

Physical fitness components may associate with functional connectivity between hippocampal subregions and frontal regions, independent of hippocampal volume, in children with overweight/obesity. Particularly, cardiorespiratory fitness may enhance anterior hippocampal functional connectivity and motor fitness may diminish posterior hippocampal functional connectivity. In addition, resting state hippocampal functional connectivity may relate to better written expression.

Exercise and Executive Function during Follicular and Luteal Menstrual Cycle Phases

PURPOSE

A single bout of aerobic or resistance exercise improves executive function. We sought to determine whether menstrual cycle variations in ovarian hormone concentrations differentially influence the expression and/or magnitude of a postexercise executive benefit.

METHODS

Eumenorrheic female participants completed 20-min single bouts of aerobic exercise (via cycle ergometer) at a moderate intensity (i.e., 80% of estimated lactate threshold) during the early follicular and midluteal phases of their menstrual cycle. Pre- and postexercise executive function was examined via antisaccades-an executive task requiring a saccade mirror-symmetrical to a visual stimulus. Antisaccades are an ideal tool for examining postexercise executive changes because the task is mediated via the same frontoparietal networks as modified following single-bout and chronic exercise.

RESULTS

Antisaccade reaction times decreased from the pre- to postexercise assessments by an average of 22 ms (P = 0.003), and this benefit was independent of changes in directional errors or end point accuracy (P's > 0.26). In other words, participants did not decrease their postexercise reaction times at the cost of increased planning times or execution errors. Most notably, the postexercise antisaccade benefit did not vary in magnitude across follicular or luteal phases (P = 0.33) and a two one-sided test statistic (i.e., equivalence testing) provided support for the null hypothesis (P = 0.008).

CONCLUSIONS

A postexercise executive benefit is independent of hormonal variations in the menstrual cycle. Further, our results evince that the phase of a female participant's menstrual cycle should not be a limiting factor in determining their inclusion in exercise neuroscience research.

Acute Effects of Two Types of Dumbbell Exercise on Oxygenated Hemodynamic Concentration of Cerebral Activation in Healthy Young Male Adults: A Functional Near-Infrared Spectroscopy Study

Purpose: To examine cerebral cortical activation differences in the frontal cortex and parietal lobe during the performance of two types of dumbbell exercise.

Methods: A total of 22 young healthy male adults (mean age, 23.8 ± 2.05 years; height, 1.75 ± 0.06 m; weight, 71.4 ± 8.80 kg) participated in a crossover design study that involved two experimental exercise conditions: momentum dumbbell and conventional dumbbell. Performance tasks included 10, 10-s sets of single-arm dumbbell exercise, with a rest interval of 60 s between sets and a 5-min washout period between conditions. The primary outcome was the cerebral concentrations of oxygenated hemoglobin (HbO₂) in the frontal cortex and parietal lobe assessed during performance of both exercises using functional near-infrared spectroscopy (fNIRS). The secondary outcome was upper-limb muscle activation measured using surface electromyography (sEMG). Outcome data were ascertained during exercise.

Results: A significant between-condition difference in HbO₂ was observed in the frontal and parietal regions with an increase in HbO₂ during momentum, relative to conventional, dumbbell exercise (p < 0.05). Compared to conventional dumbbell exercise, performing a momentum dumbbell exercise led to a higher level of muscle activation in the anterior and posterior deltoids of the upper arm and in the flexor carpi radialis and extensor carpi radialis longus of the forearm (p < 0.05). However, no between-condition differences were found in the biceps and triceps brachii (p > 0.05).

Conclusion: Dynamic, compared with conventional, dumbbell exercise resulted in higher hemodynamic responses and greater upper-limb muscle activation in young healthy adults. The findings of this study showed differential cortical hemodynamic responses during performance of the two types of dumbbell exercise with a higher activation level produced during momentum-based dumbbell exercise.