Caudate Volume Mediates the Interaction between Total Sleep Time and Executive Function after Acute Exercise in Healthy Older Adults

Hippocampal functional connectivity mediates the association between cardiorespiratory fitness and cognitive function in healthy young adults

OBJECTIVE

Higher cardiorespiratory fitness (CRF) induces neuroprotective effects in the hippocampus, a key brain region for memory and learning. We investigated the association between CRF and functional connectivity (FC) of the hippocampus in healthy young adults. We also examined the association between hippocampal FC and neurocognitive function. Lastly, we tested whether hippocampal FC mediates the association between 2-Min Walk Test (2MWT) and neurocognitive function.

METHODS

913 young adults (28.7 ± 3.7 years) from the Human Connectome Project were included in the analyses. The 2MWT performance result was used as a proxy for cardiovascular endurance. Fluid and crystalized composite neurocognitive scores were used to assess cognition. Resting-state functional MRI data were processed to measure hippocampal FC. Linear regression was used to examine the association between 2MWT, hippocampal FC, and neurocognitive outcomes after controlling for age, sex, years of education, body mass index, systolic blood pressure, and gait speed.

RESULTS

Better 2MWT performance was associated with greater FC between the anterior hippocampus and right posterior cingulate and left middle temporal gyrus. No associations between 2MWT and posterior hippocampal FC, whole hippocampal FC, and caudate FC (control region) were observed. Greater anterior hippocampal FC was associated with better crystalized cognition scores. Lastly, greater FC between the anterior hippocampus and right posterior cingulate mediated the association between better 2MWT scores and higher crystalized cognition scores.

CONCLUSIONS

Anterior hippocampal FC may be one underlying neurophysiological mechanism that promotes the association between 2MWT performance and crystalized composite cognitive function in healthy young adults.

The effect of acute exercise on objectively measured sleep and cognition in older adults

Background

Exercise can improve cognition in aging, however it is unclear how exercise influences cognition, and sleep may partially explain this association. The current study aimed to investigate whether objectively measured sleep mediates the effect of an acute exercise intervention on cognition in older adults.

Methods

Participants were 30 cognitively unimpaired, physically active older adults (69.2 ± 4.3 years) with poor sleep (determined via self-report). After a triple baseline cognitive assessment to account for any natural fluctuation in cognitive performance, participants completed either a single bout of 20-minutes of high intensity exercise on a cycle ergometer, or a control condition, in a cross-over trial design. Cognition was measured immediately post-intervention and the following day, and sleep (total sleep time, sleep onset latency, sleep efficiency, % of rapid eye movement sleep, light sleep and deep sleep) was characterized using WatchPAT™ at baseline (5 nights) and measured for one night after both exercise and control conditions.

Results

Results showed no effect of the exercise intervention on cognition immediately post-intervention, nor an effect of acute exercise on any sleep variable. There was no mediating effect of sleep on associations between exercise and cognition. However, a change from baseline to post-intervention in light sleep and deep sleep did predict change in episodic memory at the ~24 h post-intervention cognitive assessment, regardless of intervention condition.

Discussion

There was no effect of acute high intensity exercise on sleep or cognition in the current study. However, results suggest that associations between sleep and cognition may exist independently of exercise in our sample. Further research is required, and such studies may aid in informing the most effective lifestyle interventions for cognitive health.

The Effects of Exergaming on Executive and Physical Functions in Older Adults With Dementia: Randomized Controlled Trial

BACKGROUND

Despite increasing interest in the effects of exergaming on cognitive function, little is known about its effects on older adults with dementia.

OBJECTIVE

The purpose of this is to investigate the effects of exergaming on executive and physical functions in older adults with dementia compared to regular aerobic exercise.

METHODS

In total, 24 older adults with moderate dementia participated in the study. Participants were randomized into either the exergame group (EXG, n=13, 54%) or the aerobic exercise group (AEG, n=11, 46%). For 12 weeks, EXG engaged in a running-based exergame and AEG performed a cycling exercise. At baseline and postintervention, participants underwent the Ericksen flanker test (accuracy % and response time [RT]) while recording event-related potentials (ERPs) that included the N2 and P3b potentials. Participants also underwent the senior fitness test (SFT) and the body composition test pre- and postintervention. Repeated-measures ANOVA was performed to assess the effects of time (pre- vs postintervention), group (EXG vs AEG), and group×time interactions.

RESULTS

Compared to AEG, EXG demonstrated greater improvements in the SFT (F_1.22=7.434, P=.01), reduction in body fat (F_1.22=6.476, P=.02), and increase in skeletal mass (F_1.22=4.525, P=.05), fat-free mass (F_1.22=6.103, P=.02), and muscle mass (F_1.22=6.636, P=.02). Although there was a significantly shorter RT in EXG postintervention (congruent P=.03, 95% CI 13.581-260.419, incongruent P=.04, 95% CI 14.621-408.917), no changes occurred in AEG. EXG also yielded a shorter N2 latency for central (Cz) cortices during both congruent conditions compared to AEG (F_1.22=4.281, P=.05). Lastly, EXG presented a significantly increased P3b amplitude compared to AEG during the Ericksen flanker test (congruent: frontal [Fz] F_1.22=6.546, P=.02; Cz F_1.22=5.963, P=.23; parietal [Pz] F_1.22=4.302, P=.05; incongruent: Fz F_1.22=8.302, P=.01; Cz F_1.22=15.199, P=.001; Pz F_1.22=13.774, P=.001).

CONCLUSIONS

Our results suggest that exergaming may be associated with greater improvements in brain neuronal activity and enhanced executive function task performance than regular aerobic exercise. Exergaming characterized by both aerobic exercise and cognitive stimulation can be used as an effective intervention to improve cognitive and physical functions in older adults with dementia.

TRIAL REGISTRATION

Clinical Research Information Service KCT0008238; https://cris.nih.go.kr/cris/search/detailSearch.do/24170.

Effectiveness of a Single Prolonged Aerobic Exercise Session on Executive Function Task Performance in Physically Active Adults (21-70 Years of Age)

We sought to examine the effectiveness of an acute prolonged exercise session on post-exercise executive function in physically active adults and to assess if age or pre-exercise cognitive performance was predictive of the magnitude of change in executive task performance. Self-registered cyclists were recruited prior to participating in a 161-km mass-participation cycling event. Cyclists were excluded if they had not previously participated in a similar endurance event, were young (<18 y), or were cognitively impaired (Mini CogTM < 3 units). Immediately after completing the exercise session, the time taken to complete Trail Making Test Part A and Part B (TMT A + B) was assessed. A faster time to complete the TMT A + B was observed after exercise (+8.5%; p = 0.0003; n = 62; age range = 21-70 y). The magnitude of change in TMT A + B performance (pre vs. post) was influenced by pre-exercise TMT A + B performance (r2 = 0.23, p < 0.0001), not age (r2 =0.002; p = 0.75). Prolonged exercise had a small-to-moderate effect on post-exercise compared to pre-exercise executive function task performance (Cohen's d = 0.38-0.49). These results support the effectiveness of a single prolonged exercise bout to augment executive function in physically active adults, irrespective of age.

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.

Cardiorespiratory Fitness as a Moderator of Sleep-Related Associations with Hippocampal Volume and Cognition

The objective of this study was to understand the associations of sleep and cardiorespiratory fitness with hippocampal volume and global cognition among older adults (n = 30, age = 65.8 years, female = 73.3%). Wrist actigraphy provided objective measures of nighttime sleep including sleep duration, average wake bout length (WBL; sleep disturbance), and wake-to-sleep transition probability (WTSP; sleep consolidation). Cardiorespiratory fitness was quantified via cycle exercise using a modified heart rate recovery approach. Magnetic resonance imaging was used to determine hippocampal volume and the Mini-Mental State Examination was used to assess global cognition. Fitness moderated associations of sleep with hippocampal volume and cognitive performance, whereby the association of WBL-an index of poor sleep-with hippocampal atrophy was stronger among less-fit individuals, and the association of sleep duration with cognitive performance was stronger among more-fit individuals. Across the fitness levels, a longer WBL was associated with lower cognitive performance, and a higher WTSP-an index of more consolidated sleep-was associated with greater hippocampal volume. Sleep and fitness were unrelated to the volume of an amygdala control region, suggesting a degree of neuroanatomical specificity. In conclusion, higher cardiorespiratory fitness may attenuate sleep disturbance-related hippocampal atrophy and magnify the cognitive benefits of good sleep. Prospective studies are needed to confirm these findings.

Sleep duration is associated with Caudate volume and executive function

The ineligible role of the caudate nucleus in sleep has been implicated. Previous literature showed that the caudate volume is associated with longer habitual sleep duration in older adults. However, the association between sleep duration and caudate volume remains unknown in the younger population. In this study, we examined the caudate volume in youth to older adults (10 to 85 years old) with a greater sample size (N = 464). The volumetric size of the caudate nucleus showed significantly positive association with habitual sleep duration, especially in younger population. Sleep duration showed a significant association with executive function performance. However, caudate volume did not significantly predict executive function. Our results suggested that sleep duration is associated with the caudate volume and executive function. It is also suggested that there are some external mechanisms that modulate executive function which prevent the caudate-sleep relation's effect on executive function.

Brain morphometry and connectivity differs between adolescent- and adult-onset major depressive disorder

BACKGROUND

Early-onset (EO) major depressive disorder (MDD) patients experience more depressive episodes and an increased risk of relapse. Thus, on a neurobiological level, adult EO patients might display brain structure and function different from adult-onset (AO) patients.

METHODS

A total of 103 patients (66 females) underwent magnetic resonance imaging. Structural measures of gray matter volume (GMV) and functional connectivity networks during resting state were compared between EO (≤19 years) and AO groups. Four residual major depression symptoms, mood, anxiety, insomnia, and somatic symptoms, were correlated with GMV between groups.

RESULTS

We found comparatively increased GMV in the EO group, namely the medial prefrontal and insular cortex, as well as the anterior hippocampus. Functional networks in EO patients showed a comparatively weaker synchronization of the left hippocampus with the adjacent amygdala, and a stronger integration with nodes in the contralateral prefrontal cortex and supramarginal gyrus. Volumetric analysis of depression symptoms associated the caudate nuclei with symptoms of insomnia, and persisting mood symptoms with the right amygdala, while finding no significant clusters for somatic and anxiety symptoms.

CONCLUSIONS

The study highlights the important role of the hippocampus and the prefrontal cortex in EO patients as part of emotion-regulation networks. Results in EO patients demonstrated subcortical volume changes irrespective of sleep and mood symptom recovery, which substantiates adolescence as a pivotal developmental phase for MDD. Longitudinal studies are needed to differentiate neural recovery trajectories while accounting for age of onset.

Better Subjective Sleep Quality Partly Explains the Association Between Self-Reported Physical Activity and Better Cognitive Function

Background: Physical activity has been associated with better cognitive function and better sleep quality. Yet, whether the beneficial effect of physical activity on cognitive function can be explained by an indirect pathway involving better sleep quality is unclear. Objective: To investigate whether sleep quality mediates the association between physical activity and cognitive function in adults 50 years of age or older. Methods: 86,541 community-dwelling European adults were included in the study. Physical activity and sleep quality were self-reported. Indicators of cognitive function (immediate recall, delayed recall, verbal fluency) were assessed using objective tests. All measures were collected six times between 2004 and 2017. The mediation was tested using multilevel mediation analyses. Results: Results showed that self-reported physical activity was associated with better self-reported sleep quality, which was associated with better performance in all three indicators of cognitive function, demonstrating an indirect effect of physical activity on cognitive function through sleep quality. The mediating effect of sleep quality accounted for 0.41%, 1.46%, and 8.88% of the total association of physical activity with verbal fluency, immediate recall, and delayed recall, respectively. Conclusion: These findings suggest that self-reported sleep quality partly mediates the association between self-reported physical activity and cognitive function. These results need to be confirmed by device-based data of physical activity and sleep quality.

Differential associations of regional cerebellar volume with gait speed and working memory

The relationship between gait speed and working memory is well-understood in older adults. However, it remains to be determined whether this relationship also exists in younger adults; and there is little known regarding the possible neural mechanism underlying the association between gait speed and working memory. The aims of this study are to determine if there is: (1) an association between gait speed and working memory performance; and (2) a mediating role of cerebellar subregion volume in the correlation between gait speed and working memory in healthy younger adults. 1054 younger adults (28.7 ± 3.6 years) from the Human Connectome Project were included in the analyses. A four-meter gait test was used to assess gait speed. The 2-back task was used to measure working memory performance [accuracy and response time (RT)]. T1-weighted structural MRI data (obtained using Siemens 3 T MRI scanner) was used to assess cerebellar subregion volumes. Linear regression and mediation analysis were used to examine the relationships between the variables after controlling for age, sex, and education. There was no association between gait speed and 2-back working memory performance in younger adults. Greater Crus I and whole cerebellar volumes were associated with better 2-back working memory accuracy. Greater VIIIa volume was associated with faster gait speed. Greater Crus 1 and VIIIa volumes were also associated with higher fluid cognition. The present study suggests that specific subregions of the cerebellar volumes are distinctively associated with gait speed and working memory performance in healthy younger adults.

Assessing the joint effects of brain aging and gut microbiota on the risks of psychiatric disorders

We aim to explore the potential interaction effects of brain aging and gut microbiota on the risks of sleep, anxiety and depression disorders. The genome-wide association study (GWAS) datasets of brain aging (N = 21,407) and gut microbiota (N = 3,890) were obtained from published studies. Individual level genotype and phenotype data of psychiatric traits (including sleep, anxiety and depression) were all from the UK Biobank (N = 107,947-374,505). We first calculated the polygenic risk scores (PRS) of 62 brain aging modes and 114 gut microbiota taxa as the instrumental variables, and then constructed linear and logistic regression analyses to systematically explore the potential interaction effects of brain aging and gut microbiota on psychiatric disorders. We observed the interaction effects of brain aging and gut microbiota on sleep, anxiety and depression disorders, such as Putamen/caudate T2* vs. Rhodospirillales (β = -0.012, P = 8.4 × 10^-4) was negatively associated with chronotype, Fornix MD vs. Holdemanella (β = -0.007, P = 1.76 × 10^-2) was negatively related to general anxiety disorder (GAD) scores, and White matter lesions vs. Acidaminococcaceae (β = 0.019, P = 1.29 × 10^-3) was positively correlated with self-reported depression. Interestingly, Putamen volume vs. Intestinibacter was associated with all three psychiatric disorders, including chronotype (negative correlation), GAD scores (positive correlation) and self-reported depression (positive correlation). Our study results suggest the significant impacts of brain aging and gut microbiota on the development of sleep, anxiety and depression disorders, providing new clues for clarifying the pathogenesis of these disorders.

Cardiovascular Endurance Modifies the Link between Subjective Sleep Quality and Entorhinal Cortex Thickness in Younger Adults

INTRODUCTION

Poor sleep is linked to impaired cognitive function, cortical brain atrophy, and lower cortical thickness. Independently, higher cardiovascular endurance has neuroprotective effects. It remains in question, however, whether cardiovascular endurance moderates the relationship between sleep and brain health. The aims of this study included the following: 1) the association between subjective sleep quality and cognitive performance, hippocampus volume, and entorhinal cortex (EC) thickness, and 2) the moderating effects of cardiovascular endurance on the associations of sleep quality with cognitive and magnetic resonance imaging measures in healthy younger adults.

METHODS

A total of 1095 younger adults (28.8 ± 3.6 yr) from the Human Connectome Project were included in the analyses. The 2-min walk test was used as a proxy of cardiovascular endurance. Self-reported sleep quality was measured using the Pittsburgh Sleep Quality Index. Composite cognitive tests were used to assess global cognition, and T1-weighted structural magnetic resonance imaging data (obtained using Siemens 3T scanner) was used to assess hippocampus volume and EC thickness. Linear regression was used to examine the moderating effects of fitness on the relationships between sleep and each of these neurocognitive outcomes after controlling for age, sex, and education year.

RESULTS

Poorer sleep quality was associated with both a lower crystalized intelligence score (B = -0.198, P = 0.034) and lower EC thickness (B = -0.013, P = 0.003). With greater 2-min walk test score, the association between greater Pittsburgh Sleep Quality Index score and lower EC thickness was attenuated (B = 0.0008, P = 0.028).

CONCLUSIONS

Higher cardiovascular endurance may mitigate the relationship between poorer subjective sleep quality and lower EC thickness. Future longitudinal studies should examine the interactive effects of sleep and fitness on brain health among older and more vulnerable populations.

Relationships between physical activity, sleep and cognitive function: A narrative review

Physical activity and exercise can improve cognitive function and reduce the risk for dementia. Other lifestyle factors, including sleep, are associated with cognitive function and dementia risk, and exercise is an effective therapeutic strategy for improving sleep. Based on these associations, it has been hypothesised that sleep might be an important mediator for the effects of exercise on cognition. Here, we review the current literature to evaluate whether sleep and physical activity are independently or jointly associated with cognitive function. The extant literature in this area is minimal, and the causal relationships between physical activity, sleep and cognition have not been examined. A small number of cross-sectional studies in this area suggest that physical activity may attenuate some of the negative impact that poor sleep has on cognition, and also that sleep may be a mechanism through which physical activity improves cognitive abilities. Further research may enable the development of individually tailored intervention programs to result in the greatest cognitive benefit, ultimately delaying the onset of Alzheimer's disease.

Hippocampal Functional Connectivity and Memory Performance After Exercise Intervention in Older Adults with Mild Cognitive Impairment

Background:

Exercise training (ET) has neuroprotective effects in the hippocampus, a key brain region for memory that is vulnerable to age-related dysfunction.

Objective:

We investigated the effects of ET on functional connectivity (FC) of the hippocampus in older adults with mild cognitive impairment (MCI) and a cognitively normal (CN) control group. We also assessed whether the ET-induced changes in hippocampal FC (Δhippocampal-FC) are associated with changes in memory task performance (Δmemory performance).

Methods:

32 older adults (77.0±7.6 years; 16 MCI and 16 CN) participated in the present study. Cardiorespiratory fitness tests, memory tasks (Rey Auditory Verbal Learning Test (RAVLT) and Logical Memory Test (LM)), and resting-state fMRI were administered before and after a 12-week walking ET intervention. We utilized a seed-based correlation analysis using the bilateral anterior and posterior hippocampi as priori seed regions of interest. The associations of residualized ET-induced Δhippocampal-FC and Δmemory performance were assessed using linear regression.

Results:

There were significant improvements in RAVLT Trial 1 and LM test performance after ET across participants. At baseline, MCI, compared to CN, demonstrated significantly lower posterior hippocampal FC. ET was associated with increased hippocampal FC across groups. Greater ET-related anterior and posterior hippocampal FC with right posterior cingulate were associated with improved LM recognition performance in MCI participants.

Conclusion:

Our findings indicate that hippocampal FC is significantly increased following 12-weeks of ET in older adults and, moreover, suggest that increased hippocampal FC may reflect neural network plasticity associated with ET-related improvements in memory performance in individuals diagnosed with MCI.

Cortical and Subcortical Brain Volume Alterations Following Endurance Running at 38.6 km and 119.2 km in Male Athletes

BACKGROUND Although several studies have shown that ultramarathon running causes severe physical and mental stress and harms organ systems, its effect on brain tissue remains unclear. The purpose of this study was to investigate the volumetric change of cortical and subcortical brain structures following 38.6-km and 119.8-km mountain races. MATERIAL AND METHODS A total of 23 healthy male runners (age, 49.05±5.99 years) were classified as short-trail (ST; n=9) and ultra-trail (UT; n=14) endurance running. Pre- and post-test scanning of brain tissue was performed by using a 3-Tesla magnetic resonance imaging (MRI). Pre- and post-race differences in cortical and subcortical volumes in the ST and UT groups were separately determined by Wilcoxon signed-rank test. RESULTS Cortical gray matter (GM) and cerebral GM volume significantly increased after the race in both ST and UT groups, whereas the volume of the thalamus, caudate, pallidus, and hippocampus significantly increased only in the UT group. Cerebrospinal fluid (CSF) and white-matter (WM) volumes did not change after endurance running and remained unaltered in both groups. CONCLUSIONS Endurance running has a site-specific acute effect on cortical and subcortical structures and may attenuate GM volume decrease in older adult male athletes. The increased volume of subcortical structures might be a response of physical exercise and additional physical stress experienced by ultramarathon runners.

Blood pressure-related differences in brain health between young African Americans and Caucasian Americans

Background

Although there are moderating effects of race on blood pressure (BP) and brain health in older adults, it is currently unknown if these race‐related differences in cardiovascular and associated brain function are also present in younger adults. The purpose of this study was to investigate the interaction between race and BP on brain health in younger African (AA) and Caucasian Americans (CA).

Methods

We studied 971 younger adults (29.1 ± 3.5 years; 180 AAs and 791 CAs) who volunteered to participate in the Human Connectome Project. Cognitive composite scores, brain volume, and cortical thickness using MRI were cross‐sectionally assessed. ANCOVA was used to examine interactions between race and mean arterial pressure (MAP) on cognitive test scores and brain structure.

Results

After controlling for age, sex, education, and BMI, there were significant Race × MAP interaction effects on cognitive composite scores and cortical thickness. Among AAs but not CAs, as MAP increased, both global cognitive performance and entorhinal cortex (ERC) thickness decreased.

Conclusions

MAP was an important moderator of racial differences in cognitive performance and ERC thickness. Our findings suggest that young AAs may carry a greater hypertension‐associated risk for cognitive brain health deficit. Interventions that address early signs of hypertension in AAs are needed to determine if the racial disparities in BP‐related brain health in late adulthood can be reduced.

Effects of Acute Visual Stimulation Exercise on Attention Processes: An ERP Study

BACKGROUNDS

It remains to be determined whether visual stimuli during exercise differentially influence the attention process. The purpose of the present study was to examine if different color stimuli during aerobic exercise are associated with different attention processes.

METHODS

22 college students completed a four 30-min running session during the presentation of different color stimuli (blue, green, red, and yellow) and without color stimulus on separate visits. The Kanizsa triangle task was administrated before and immediately after exercise to assess the attention process. Behavioral performance (accuracy and response time (RT)) and event-related potential (P2, N2b and P3a) were recorded during the test.

RESULTS

Valid/invalid cue RT during the Kaniza test performance was significantly faster following the presentation of color stimuli during treadmill exercise compared to the seated rest. During exercise, these changes were larger after green and yellow stimuli than red in invalid cue RT. P2, N2b and P3a amplitudes of green were significantly larger than the other colors for both valid and invalid cues. Red color showed the lowest P2 and P3a amplitudes for both valid and invalid cues among colors.

CONCLUSION

The distinctive neurocognitive changes during aerobic exercise suggest different effects of color stimuli on visual search attention, attention capture, attentional orienting and processing speed. This study will be a first step to understand the optimal environmental setting during exercise for subsequent improvements in the attention process.

The Contribution of Functional Magnetic Resonance Imaging to the Understanding of the Effects of Acute Physical Exercise on Cognition

The fact that a single bout of acute physical exercise has a positive impact on cognition is well-established in the literature, but the neural correlates that underlie these cognitive improvements are not well understood. Here, the use of neuroimaging techniques, such as functional magnetic resonance imaging (fMRI), offers great potential, which is just starting to be recognized. This review aims at providing an overview of those studies that used fMRI to investigate the effects of acute physical exercises on cerebral hemodynamics and cognition. To this end, a systematic literature survey was conducted by two independent reviewers across five electronic databases. The search returned 668 studies, of which 14 studies met the inclusion criteria and were analyzed in this systematic review. Although the findings of the reviewed studies suggest that acute physical exercise (e.g., cycling) leads to profound changes in functional brain activation, the small number of available studies and the great variability in the study protocols limits the conclusions that can be drawn with certainty. In order to overcome these limitations, new, more well-designed trials are needed that (i) use a more rigorous study design, (ii) apply more sophisticated filter methods in fMRI data analysis, (iii) describe the applied processing steps of fMRI data analysis in more detail, and (iv) provide a more precise exercise prescription.