Behavioral and Neurophysiological Aspects of Inhibition-The Effects of Acute Cardiovascular Exercise

Acute aerobic exercise at different intensities modulates inhibitory control and cortical excitability in adults with attention-deficit hyperactivity disorder (ADHD)

BACKGROUND

This study aimed to investigate the effects of different aerobic exercise intensities on inhibitory control and cortical excitability in adults with attention-deficit/hyperactivity disorder (ADHD).

METHODS

The study was conducted in a within-subject design. Twenty-four adults with ADHD completed a stop signal task and received cortical excitability assessment by transcranial magnetic stimulation (TMS) before and after a single session of low-, moderate-, high-intensity aerobic exercise or a control intervention.

RESULTS

Acute moderate-, and high-intensity aerobic exercise improved inhibitory control in adults with ADHD. Moreover, the improving effect was similar between moderate-, and high-intensity aerobic exercise conditions. As shown by the brain physiology results, short interval intracortical inhibition was significantly increased following both, moderate- and high-intensity aerobic exercise intervention conditions. Additionally, the alteration of short interval intracortical inhibition and inhibitory control improvement were positively correlated.

CONCLUSIONS

The moderate-, and high-intensity aerobic exercise-dependent alterations of cortical excitability in adults with ADHD might partially explain the inhibitory control-improving effects of aerobic exercise in this population.

Aerobic Exercise Improves Cortical Inhibitory Function After Stroke: A Preliminary Investigation

BACKGROUND AND PURPOSE

Aerobic exercise can elicit positive effects on neuroplasticity and cognitive executive function but is poorly understood after stroke. We tested the effect of 4 weeks of aerobic exercise training on inhibitory and facilitatory elements of cognitive executive function and electroencephalography markers of cortical inhibition and facilitation. We investigated relationships between stimulus-evoked cortical responses, blood lactate levels during training, and aerobic fitness postintervention.

METHODS

Twelve individuals with chronic (>6 months) stroke completed an aerobic exercise intervention (40 minutes, 3×/wk). Electroencephalography and motor response times were assessed during congruent (response facilitation) and incongruent (response inhibition) stimuli of a Flanker task. Aerobic fitness capacity was assessed as o2peak during a treadmill test pre- and postintervention. Blood lactate was assessed acutely (<1 minute) after exercise each week. Cortical inhibition (N2) and facilitation (frontal P3) were quantified as peak amplitudes and latencies of stimulus-evoked electroencephalographic activity over the frontal cortical region.

RESULTS

Following exercise training, the response inhibition speed increased while response facilitation remained unchanged. A relationship between earlier cortical N2 response and faster response inhibition emerged postintervention. Individuals who produced higher lactate during exercise training achieved faster response inhibition and tended to show earlier cortical N2 responses postintervention. There were no associations between o2peak and metrics of behavioral or neurophysiologic function.

DISCUSSION AND CONCLUSIONS

These preliminary findings provide novel evidence for selective benefits of aerobic exercise on inhibitory control during the initial 4-week period after initiation of exercise training and implicate a potential therapeutic effect of lactate on poststroke inhibitory control.

Acute high-intensity interval exercise improves food-related cognition in young adults with obesity: An ERP study

Purpose Cognitive function, particularly food-related cognition, is critical for maintaining a healthy weight and preventing the acceleration of obesity. High-Intensity Interval Exercise (HIIE) is an increasingly popular form of exercise and has been shown to improve physical fitness and cognitive function. However, there is limited research on the effects and underlying mechanisms of HIIE on general and food-related cognition among adults with obesity. The aim of the current study was to examine the influence of a single bout of HIIE on food-related cognition among young adults with obesity. Methods Fifteen young men with obesity (BMI = 33.88 ± 4.22, age = 24.60 ± 5.29 years) were recruited. Participants took part in a HIIE condition consisting of 30 minutes of stationary cycle exercise (5-min warm-up, 20-min HIIE and 5-min cool down), and a control session consisting of a time and attention-matched period of sedentary rest in a counterbalanced order. Behavioral (reaction time and accuracy) and event-related potential measures (P3 and the late positive potential, LPP) elicited during a food-related Flanker task were measured after the HIIE and control session. Results Shorter response times were observed following HIIE, regardless of congruency or picture type, with no change in accuracy. Increased P3 and LPP amplitudes were observed following HIIE relative to the control session. Conclusion The findings suggest a single bout of HIIE has a beneficial effect on general and food-related cognition among young adults with obesity, with increased recruitment of cognitive resources to support cognitive control. Future research is warranted to examine the dose-response relationship between acute bouts or longer participation in HIIE on food-related cognition in obesity.

Effects of combined physical and cognitive training on executive function of adolescent shooting athletes: A functional near-infrared spectroscopy study

Individual executive function improvement through physical and cognitive training is a research hotspot in physical education and cognitive science. However, few studies have evaluated whether combined physical and cognitive training (CPCT) has greater benefits for executive function performance and cerebral oxygenation in adolescent athletes than cognitive training alone. This study randomly assigned 33 adolescent shooting athletes to a CPCT (n ​= ​17) or computerized cognitive training (CCT, n ​= ​16) group and compared their executive function after six weeks of training. All subjects were assessed using the 2-back, task-switching, and Stroop tests before and after training. The prefrontal cortex oxygenated hemoglobin (Oxy-Hb) activation level was monitored while executing the three tasks using functional near-infrared spectroscopy. Our results showed that the CPCT and CCT groups similarly improved their updating function as indicated by the 2-back task accuracy. The CPCT group significantly improved the switching function in the task-switching test accuracy, while the CCT group did not. However, both groups did not improve in behavioral performance as indicated by the inhibition function in the Stroop task. Cerebral oxygenation, indicated by the oxy-Hb activation level in the frontal pole area of the prefrontal lobe, significantly improved in the CPCT group during the three cognitive tasks, whereas the CCT group showed no change. These findings indicated that CPCT endowed greater advantages in task-switching in the behavioral performance of the executive function than CCT. Moreover, CPCT was superior to CCT in increasing task-efficient cerebral oxygenation during the activation of the prefrontal cortex in adolescent shooting athletes.

Modulation of pain perceptions following treadmill running with different intensities in females

We aimed to compare the effects of three intensities of treadmill running on exercise-induced hypoalgesia (EIH) in healthy individuals. We anticipated that the primary and secondary changes in pain perception and modulation may differ between running intensities. Sixty-six women were randomly assigned to one of three treadmill running intensities for 35 min: 40% reserved heart rate (HRR), 55% HRR, or 70% HRR. The effects of EIH were assessed using pressure pain thresholds (PPT) and tolerance thresholds (PPTol). We measured conditional pain modulation (CPM). Compared with baseline, PPT and PPTol significantly increased in all groups during running and at the 5-10-min follow-up. The PPT and PPTol changes in the moderate- and low-intensity groups were significantly higher than those in the high-intensity group during running and 24 h after running, while the CPM responses of the high-intensity group were significantly reduced at the 24-h follow-up. Moderate- and low-intensity running may elicit significant primary and secondary (persisting over 24 h) EIH effects and increase CPM responses in females. However, high-intensity running induced only limited analgesic effects and reduced CPM responses, which may be attributed to the activation of endogenous pain modulation.

Myokines as mediators of exercise-induced cognitive changes in older adults: protocol for a comprehensive living systematic review and meta-analysis

Background

The world's population is aging, but life expectancy has risen more than healthy life expectancy (HALE). With respect to brain and cognition, the prevalence of neurodegenerative disorders increases with age, affecting health and quality of life, and imposing significant healthcare costs. Although the effects of physical exercise on cognition in advanced age have been widely explored, in-depth fundamental knowledge of the underlying mechanisms of the exercise-induced cognitive improvements is lacking. Recent research suggests that myokines, factors released into the blood circulation by contracting skeletal muscle, may play a role in mediating the beneficial effect of exercise on cognition. Our goal in this ongoing (living) review is to continuously map the rapidly accumulating knowledge on pathways between acute or chronic exercise-induced myokines and cognitive domains enhanced by exercise.

Method

Randomized controlled studies will be systematically collected at baseline and every 6 months for at least 5 years. Literature search will be performed online in PubMed, EMBASE, PsycINFO, Web of Science, SportDiscus, LILACS, IBECS, CINAHL, SCOPUS, ICTRP, and ClinicalTrials.gov. Risk of bias will be assessed using the Revised Cochrane Risk of Bias tool (ROB 2). A random effects meta-analysis with mediation analysis using meta-analytic structural equation modeling (MASEM) will be performed. The primary research question is to what extent exercise-induced myokines serve as mediators of cognitive function. Secondarily, the pooled effect size of specific exercise characteristics (e.g., mode of exercise) or specific older adults' populations (e.g., cognitively impaired) on the relationship between exercise, myokines, and cognition will be assessed. The review protocol was registered in PROSPERO (CRD42023416996).

Discussion

Understanding the triad relationship between exercise, myokines and cognition will expand the knowledge on multiple integrated network systems communicating between skeletal muscles and other organs such as the brain, thus mediating the beneficial effects of exercise on health and performance. It may also have practical implications, e.g., if a certain myokine is found to be a mediator between exercise and cognition, the optimal exercise characteristics for inducing this myokine can be prescribed. The living review is expected to improve our state of knowledge and refine exercise regimes for enhancing cognitive functioning in diverse older adults' populations.

Registration

Systematic review and meta-analysis protocol was registered with the International Prospective Register of Systematic Reviews (PROSPERO) on the 24th of April 2023 (registration number CRD42023416996).

The role of inhibitory control in sport performance: Systematic review and meta-analysis in stop-signal paradigm

Inhibitory control is an executive function that is closely and bidirectionally related to sports practice. The objective of this systematic review and meta-analysis was to study the effect of this relationship when response suppression is assessed within the Stop-Signal Paradigm. Twenty-four articles met the inclusion criteria and were selected for qualitative analysis, of which 11 studies were further analyzed through meta-analytic techniques. The standardized mean difference (SMD) was estimated for the stop-signal reaction time, and the influence of moderator variables was assessed. Athletes showed shorter stop-signal reaction time than non-athlete controls (SMD=0.44; 95% CI=0.14, 0.73), and this effect was mediated by age (SMD=-0.56; 95% CI=-1.11, -0.01). Athletes' superior stop-signal reaction time may be a result of extensive practice in cognitively demanding competitive environments. Young athletes can benefit the most from sports practice. In addition, engaging individuals in more cognitively demanding activities may obtain better response suppression enhancements, although the evidence in the stop-signal task is limited. Finally, some stop-signal task methodological aspects should be considered in future research.

The effect of acute exercise on cognitive and motor inhibition - Does fitness moderate this effect?

BACKGROUND

Given the extensive evidence on improvements in cognitive inhibition immediately following exercise, and the literature indicating that cognitive and motor inhibitory functions are mediated by overlapping brain networks, the aim of this study was to assess, for the first time, the effect of moderate intensity acute aerobic exercise on multi-limb motor inhibition, as compared to cognitive inhibition.

METHOD

Participants were 36 healthy adults aged 40-60 years old (mean age 46.8 ± 5.7), who were randomly assigned to experimental or control groups. One-to-two weeks following baseline assessment, participants were asked to perform a three-limb (3-Limb) inhibition task and a vocal version of the Stroop before and after either acute moderate-intense aerobic exercise (experimental group) or rest (control).

RESULTS

Similar rates of improvement were observed among both groups from baseline to the pre-test. Conversely, a meaningful, yet non-significant trend was seen among the experimental group in their pretest to posttest improvement in both cognitive and motor tasks. In addition, exploratory analysis revealed significant group differences in favor of the experimental group among highly fit participants on the 3-Limb task. A significant correlation was indicated between the inhibition conditions, i.e., choice in the motor inhibition and color/word (incongruent) in the cognitive inhibition, especially in the improvement observed following the exercise.

DISCUSSION

Moderate-intensity acute aerobic exercise is a potential stimulator of both multi-limb motor inhibition and cognitive inhibition. It appears that high-fit participants benefit from exercise more than low-fit people. Additionally, performance on behavioral tasks that represent motor and cognitive inhibition is related. This observation suggests that fitness levels and acute exercise contribute to the coupling between cognitive and motor inhibition. Neuroimaging methods would allow examining brain-behavior associations of exercise-induced changes in the brain.

Effects of Acute High-Intensity Interval Exercise and High-Intensity Continuous Exercise on Inhibitory Function of Overweight and Obese Children

This study aimed to examine whether a single bout each of high-intensity interval exercise (HIIE) and high-intensity continuous exercise (HICE) could improve inhibitory functions of overweight and obese children, and which mode of exercise was more beneficial. Seventy-two overweight and obese children, with (26.02 ± 1.05 kg/m²), aged 10-14 years (11.56 ± 1.03 years), were randomly assigned to three groups. The HIIE group completed a 30-min treadmill exercise session (5-min warm up, 20-min HIIE, and 5-min cool-down). The HICE group performed 30 min of rope skipping, while the control (CON) group watched a designated cartoon on a tablet computer for the same duration. Reaction time and number of errors in the Stroop test were determined before and after the intervention. The difference between pre- and post-test reaction time scores was higher in the HIIE and HICE groups than in the CON group, while the pre- and post-test difference in the number of errors was similar between groups. Overall, it is likely that both acute HIIE and HICE were similarly efficient in facilitating cognitive and inhibitory functions of children with overweight and obesity conditions, supporting the benefits of acute high-intensity exercise probability for cognitive functions of children in general, as well as of the population with overweight and obesity conditions.

Exerkines and long-term synaptic potentiation: Mechanisms of exercise-induced neuroplasticity

Physical exercise may improve cognitive function by modulating molecular and cellular mechanisms within the brain. We propose that the facilitation of long-term synaptic potentiation (LTP)-related pathways, by products induced by physical exercise (i.e., exerkines), is a crucial aspect of the exercise-effect on the brain. This review summarizes synaptic pathways that are activated by exerkines and may potentiate LTP. For a total of 16 exerkines, we indicated how blood and brain exerkine levels are altered depending on the type of physical exercise (i.e., cardiovascular or resistance exercise) and how they respond to a single bout (i.e., acute exercise) or multiple bouts of physical exercise (i.e., chronic exercise). This information may be used for designing individualized physical exercise programs. Finally, this review may serve to direct future research towards fundamental gaps in our current knowledge regarding the biophysical interactions between muscle activity and the brain at both cellular and system levels.

Impact of interhemispheric inhibition on bimanual movement control in young and old

Interhemispheric interactions demonstrate a crucial role for directing bimanual movement control. In humans, a well-established paired-pulse transcranial magnetic stimulation paradigm enables to assess these interactions by means of interhemispheric inhibition (IHI). Previous studies have examined changes in IHI from the active to the resting primary motor cortex during unilateral muscle contractions; however, behavioral relevance of such changes is still inconclusive. In the present study, we evaluated two bimanual tasks, i.e., mirror activity and bimanual anti-phase tapping, to examine behavioral relevance of IHI for bimanual movement control within this behavioral framework. Two age groups (young and older) were evaluated as bimanual movement control demonstrates evident behavioral decline in older adults. Two types of IHI with differential underlying mechanisms were measured; IHI was tested at rest and during a motor task from the active to the resting primary motor cortex. Results demonstrate an association between behavior and short-latency IHI in the young group: larger short-latency IHI correlated with better bimanual movement control (i.e., less mirror activity and better bimanual anti-phase tapping). These results support the view that short-latency IHI represents a neurophysiological marker for the ability to suppress activity of the contralateral side, likely contributing to efficient bimanual movement control. This association was not observed in the older group, suggesting age-related functional changes of IHI. To determine underlying mechanisms of impaired bimanual movement control due to neurological disorders, it is crucial to have an in-depth understanding of age-related mechanisms to disentangle disorder-related mechanisms of impaired bimanual movement control from age-related ones.

The Effects of Combined Physical and Cognitive Training on Inhibitory Control: A Systematic Review and Meta-Analysis

While strong inhibitory control is critical for health and wellbeing, there are no broadly applicable effective behavioural interventions that enhance it. This meta-analysis examined the neurocognitive rationale for combined physical and cognitive training and synthesised the rapidly growing body of evidence examining combined paradigms to enhance inhibitory control. Across the research to date, there was a small positive effect (n studies = 16, n participants = 832) of combined training on improving inhibitory control. Sub-group analyses showed small-moderate positive effects when the physical component of the combined training was moderately intense, as opposed to low or vigorous intensities; moderate positive effects were found in older adults, as compared to adolescents and adults; and healthy individuals and those with vascular cognitive impairment, as compared to ADHD, ASD, mild cognitive impairment and cancer survivors. This is the first meta-analysis to provide evidence that combined physical, specifically when moderately intense, and cognitive training has the capacity to improve inhibitory control, particularly when delivered to healthy individuals and those experiencing age-related decline.

Anatomo-Functional Origins of the Cortical Silent Period: Spotlight on the Basal Ganglia

The so-called cortical silent period (CSP) refers to the temporary interruption of electromyographic signal from a muscle following a motor-evoked potential (MEP) triggered by transcranial magnetic stimulation (TMS) over the primary motor cortex (M1). The neurophysiological origins of the CSP are debated. Previous evidence suggests that both spinal and cortical mechanisms may account for the duration of the CSP. However, contextual factors such as cortical fatigue, experimental procedures, attentional load, as well as neuropathology can also influence the CSP duration. The present paper summarizes the most relevant evidence on the mechanisms underlying the duration of the CSP, with a particular focus on the central role of the basal ganglia in the "direct" (excitatory), "indirect" (inhibitory), and "hyperdirect" cortico-subcortical pathways to manage cortical motor inhibition. We propose new methods of interpretation of the CSP related, at least partially, to the inhibitory hyperdirect and indirect pathways in the basal ganglia. This view may help to explain the respective shortening and lengthening of the CSP in various neurological disorders. Shedding light on the complexity of the CSP's origins, the present review aims at constituting a reference for future work in fundamental research, technological development, and clinical settings.