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1.
J Physiol ; 602(3): 461-484, 2024 Feb.
Artigo em Inglês | MEDLINE | ID: mdl-38165254

RESUMO

Acute cardiovascular physical exercise improves cognitive performance, as evidenced by a reduction in reaction time (RT). However, the mechanistic understanding of how this occurs is elusive and has not been rigorously investigated in humans. Here, using positron emission tomography (PET) with [11 C]raclopride, in a multi-experiment study we investigated whether acute exercise releases endogenous dopamine (DA) in the brain. We hypothesized that acute exercise augments the brain DA system, and that RT improvement is correlated with this endogenous DA release. The PET study (Experiment 1: n = 16) demonstrated that acute physical exercise released endogenous DA, and that endogenous DA release was correlated with improvements in RT of the Go/No-Go task. Thereafter, using two electrical muscle stimulation (EMS) studies (Experiments 2 and 3: n = 18 and 22 respectively), we investigated what triggers RT improvement. The EMS studies indicated that EMS with moderate arm cranking improved RT, but RT was not improved following EMS alone or EMS combined with no load arm cranking. The novel mechanistic findings from these experiments are: (1) endogenous DA appears to be an important neuromodulator for RT improvement and (2) RT is only altered when exercise is associated with central signals from higher brain centres. Our findings explain how humans rapidly alter their behaviour using neuromodulatory systems and have significant implications for promotion of cognitive health. KEY POINTS: Acute cardiovascular exercise improves cognitive performance, as evidenced by a reduction in reaction time (RT). However, the mechanistic understanding of how this occurs is elusive and has not been rigorously investigated in humans. Using the neurochemical specificity of [11 C]raclopride positron emission tomography, we demonstrated that acute supine cycling released endogenous dopamine (DA), and that this release was correlated with improved RT. Additional electrical muscle stimulation studies demonstrated that peripherally driven muscle contractions (i.e. exercise) were insufficient to improve RT. The current study suggests that endogenous DA is an important neuromodulator for RT improvement, and that RT is only altered when exercise is associated with central signals from higher brain centres.


Assuntos
Dopamina , Tomografia por Emissão de Pósitrons , Humanos , Racloprida , Tempo de Reação , Tomografia por Emissão de Pósitrons/métodos , Exercício Físico , Neurotransmissores
2.
Brain Cogn ; 180: 106205, 2024 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-39053200

RESUMO

Team-based physical activity (PA) can improve social cognition; however, few studies have investigated the neurobiological mechanism underlying this benefit. Accordingly, a hyper-scanning protocol aimed to determine whether the interbrain synchrony (IBS) is influenced by an acute bout of team-based PA (i.e., tandem rope skipping). Specifically, we had socially avoidant participants (SOA, N=15 dyads) and their age-matched controls (CO, N=16 dyads) performed a computer-based cooperative task while EEG was recorded before and after two different experimental conditions (i.e., 30-min of team-based PA versus sitting). Phase locking value (PLV) was used to measure IBS. Results showed improved frontal gamma band IBS after the team-based PA compared to sitting when participants received successful feedback in the task (Mskipping = 0.016, Msittting = -0.009, p = 0.082, ηp2 = 0.387). The CO group showed a larger change in frontal and central gamma band IBS when provided failure feedback in the task (Mskipping = 0.017, Msittting = -0.009, p = 0.075, ηp2 = 0.313). Thus, results suggest that socially avoidant individuals may benefit from team-based PA via improved interbrain synchrony. Moreover, our findings deepen our understanding of the neurobiological mechanism by which team-based PA may improve social cognition among individuals with or without social avoidance.


Assuntos
Eletroencefalografia , Humanos , Masculino , Feminino , Adulto , Adulto Jovem , Eletroencefalografia/métodos , Exercício Físico/fisiologia , Cognição Social , Amigos , Comportamento Cooperativo , Ritmo Gama/fisiologia , Encéfalo/fisiologia
3.
J Therm Biol ; 119: 103775, 2024 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-38211547

RESUMO

Cold water immersion (CWI) evokes the life-threatening reflex cold shock response (CSR), inducing hyperventilation, increasing cardiac arrhythmias, and increasing drowning risk by impairing safety behaviour. Repeated CWI induces CSR habituation (i.e., diminishing response with same stimulus magnitude) after ∼4 immersions, with variation between studies. We quantified the magnitude and coefficient of variation (CoV) in the CSR in a systematic review and meta-analysis with search terms entered to Medline, SportDiscus, PsychINFO, Pubmed, and Cochrane Central Register. Random effects meta-analyses, including effect sizes (Cohen's d) from 17 eligible groups (k), were conducted for heart rate (HR, n = 145, k = 17), respiratory frequency (fR, n = 73, k = 12), minute ventilation (Ve, n = 106, k = 10) and tidal volume (Vt, n = 46, k=6). All CSR variables habituated (p < 0.001) with large or moderate pooled effect sizes: ΔHR -14 (10) bt. min-1 (d: -1.19); ΔfR -8 (7) br. min-1 (d: -0.78); ΔVe, -21.3 (9.8) L. min-1 (d: -1.64); ΔVt -0.4 (0.3) L -1. Variation was greatest in Ve (control vs comparator immersion: 32.5&24.7%) compared to Vt (11.8&12.1%). Repeated CWI induces CSR habituation potentially reducing drowning risk. We consider the neurophysiological and behavioural consequences.


Assuntos
Resposta ao Choque Frio , Habituação Psicofisiológica , Humanos , Frequência Cardíaca , Imersão , Temperatura Baixa
4.
Exp Physiol ; 104(9): 1384-1397, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31192502

RESUMO

NEW FINDINGS: What is the central question of this study? What are the mechanisms responsible for the decline in cognitive performance following exposure to acute normobaric hypoxia? What are the main findings and their importance? We found that (1) performance of a complex central executive task (n-back) was reduced at FIO2 0.12; (2) there was a strong correlation between performance of the n-back task and reductions in SpO2 and cerebral oxygenation; and (3) plasma adrenaline, noradrenaline, cortisol and copeptin were not correlated with cognitive performance. ABSTRACT: It is well established that hypoxia impairs cognitive function; however, the physiological mechanisms responsible for these effects have received relatively little attention. This study examined the effects of graded reductions in fraction of inspired oxygen ( FIO2 ) on oxygen saturation ( SpO2 ), cerebral oxygenation, cardiorespiratory variables, activity of the sympathoadrenal system (adrenaline, noradrenaline) and hypothalamic-pituitary-adrenal axis (cortisol, copeptin), and cognitive performance. Twelve healthy males [mean (SD), age: 22 (4) years, height: 178 (5) cm, mass: 75 (9) kg, FEV1 /FVC ratio: 85 (5)%] completed a four-task battery of cognitive tests to examine inhibition, selective attention (Eriksen flanker), executive function (n-back) and simple and choice reaction time (Deary-Liewald). Tests were completed before and following 60 min of exposure to FIO2 0.2093, 0.17, 0.145 and 0.12. Following 60 min of exposure, response accuracy in the n-back task was significantly reduced in FIO2 0.12 compared to baseline [82 (9) vs. 93 (5)%; P < 0.001] and compared to all other conditions at the same time point [ FIO2 0.2093: 92 (3)%; FIO2 0.17: 91 (6)%; FIO2 0.145: 85 (10)%; FIO2 12: 82 (9)%; all P < 0.05]. The performance of the other tasks was maintained. Δaccuracy and Δreaction time of the n-back task was correlated with both Δ SpO2 [r(9) = 0.66, P < 0.001 and r(9) = -0.36, P = 0.037, respectively] and Δcerebral oxygenation [r(7) = 0.55, P < 0.001 and r(7) = -0.38, P = 0.045, respectively]. Plasma adrenaline, noradrenaline, cortisol and copeptin were not significantly elevated in any condition or correlated with any of the tests of cognitive performance. These findings suggest that reductions in peripheral oxygen saturation and cerebral oxygenation, and not increased activity of the sympathoadrenal system and hypothalamic-pituitary-adrenal axis, as previously speculated, are responsible for a decrease in cognitive performance during normobaric hypoxia.


Assuntos
Encéfalo/metabolismo , Encéfalo/fisiologia , Catecolaminas/sangue , Cognição/fisiologia , Hipóxia/fisiopatologia , Oxigênio/metabolismo , Adulto , Atenção/fisiologia , Epinefrina/sangue , Glicopeptídeos/sangue , Humanos , Hidrocortisona/sangue , Sistema Hipotálamo-Hipofisário/fisiologia , Masculino , Norepinefrina/sangue , Sistema Hipófise-Suprarrenal/fisiologia , Troca Gasosa Pulmonar/fisiologia , Tempo de Reação/fisiologia , Adulto Jovem
5.
Br J Sports Med ; 53(10): 640-647, 2019 May.
Artigo em Inglês | MEDLINE | ID: mdl-30061304

RESUMO

OBJECTIVE: To summarise the current evidence on the effects of physical activity (PA) interventions on cognitive and academic performance in children, and formulate research priorities and recommendations. DESIGN: Systematic review (following PRISMA guidelines) with a methodological quality assessment and an international expert panel. We based the evaluation of the consistency of the scientific evidence on the findings reported in studies rated as of high methodological quality. DATA SOURCES: PubMed, PsycINFO, Cochrane Central, Web of Science, ERIC, and SPORTDiscus. ELIGIBILITY CRITERIA FOR SELECTING STUDIES: PA-intervention studies in children with at least one cognitive or academic performance assessment. RESULTS: Eleven (19%) of 58 included intervention studies received a high-quality rating for methodological quality: four assessed effects of PA interventions on cognitive performance, six assessed effects on academic performance, and one on both. All high-quality studies contrasted the effects of additional/adapted PA activities with regular curriculum activities. For cognitive performance 10 of 21 (48%) constructs analysed showed statistically significant beneficial intervention effects of PA, while for academic performance, 15 of 25 (60%) analyses found a significant beneficial effect of PA. Across all five studies assessing PA effects on mathematics, beneficial effects were reported in six out of seven (86%) outcomes. Experts put forward 46 research questions. The most pressing research priority cluster concerned the causality of the relationship between PA and cognitive/academic performance. The remaining clusters pertained to PA characteristics, moderators and mechanisms governing the 'PA-performance' relationship and miscellaneous topics. CONCLUSION: There is currently inconclusive evidence for the beneficial effects of PA interventions on cognitive and overall academic performance in children. We conclude that there is strong evidence for beneficial effects of PA on maths performance.The expert panel confirmed that more 'high-quality' research is warranted. By prioritising the most important research questions and formulating recommendations we aim to guide researchers in generating high-quality evidence. Our recommendations focus on adequate control groups and sample size, the use of valid and reliable measurement instruments for physical activity and cognitive performance, measurement of compliance and data analysis. PROSPERO REGISTRATION NUMBER: CRD42017082505.


Assuntos
Desempenho Acadêmico , Cognição , Exercício Físico , Adolescente , Criança , Humanos
6.
Behav Brain Res ; 466: 114982, 2024 05 28.
Artigo em Inglês | MEDLINE | ID: mdl-38582412

RESUMO

Creatine supplementation has been put forward as a possible aid to cognition, particularly for vegans, vegetarians, the elderly, sleep deprived and hypoxic individuals. However, previous narrative reviews have only provided limited support for these claims. This is despite the fact that research has shown that creatine supplementation can induce increased brain concentrations of creatine, albeit to a limited extent. We carried out a systematic review to examine the current state of affairs. The review supported claims that creatine supplementation can increases brain creatine content but also demonstrated somewhat equivocal results for effects on cognition. It does, however, provide evidence to suggest that more research is required with stressed populations, as supplementation does appear to significantly affect brain content. Issues with research design, especially supplementation regimens, need to be addressed. Future research must include measurements of creatine brain content.


Assuntos
Encéfalo , Cognição , Creatina , Suplementos Nutricionais , Creatina/metabolismo , Creatina/administração & dosagem , Creatina/farmacologia , Humanos , Cognição/efeitos dos fármacos , Cognição/fisiologia , Encéfalo/metabolismo , Encéfalo/efeitos dos fármacos , Animais
7.
Physiol Behav ; 274: 114409, 2024 Feb 01.
Artigo em Inglês | MEDLINE | ID: mdl-37977251

RESUMO

INTRODUCTION: Both sleep deprivation and hypoxia have been shown to impair executive function. Conversely, moderate intensity exercise is known to improve executive function. In a multi-experiment study, we tested the hypotheses that moderate intensity exercise would ameliorate any decline in executive function after i) three consecutive nights of partial sleep deprivation (PSD) (Experiment 1) and ii) the isolated and combined effects of a single night of total sleep deprivation (TSD) and acute hypoxia (Experiment 2). METHODS: Using a rigorous randomised controlled crossover design, 12 healthy participants volunteered in each experiment (24 total, 5 females). In both experiments seven executive function tasks (2-choice reaction time, logical relations, manikin, mathematical processing, 1-back, 2-back, 3-back) were completed at rest and during 20 min semi-recumbent, moderate intensity cycling. Tasks were completed in the following conditions: before and after three consecutive nights of PSD and habitual sleep (Experiment 1) and in normoxia and acute hypoxia (FIO2 = 0.12) following one night of habitual sleep and one night of TSD (Experiment 2). RESULTS: Although the effects of three nights of PSD on executive functions were inconsistent, one night of TSD (regardless of hypoxic status) reduced executive functions. Significantly, regardless of sleep or hypoxic status, executive functions are improved during an acute bout of moderate intensity exercise. CONCLUSION: These novel data indicate that moderate intensity exercise improves executive function performance after both PSD and TSD, regardless of hypoxic status. The key determinants and/or mechanism(s) responsible for this improvement still need to be elucidated. Future work should seek to identify these mechanisms and translate these significant findings into occupational and skilled performance settings.


Assuntos
Função Executiva , Privação do Sono , Feminino , Humanos , Cognição , Hipóxia , Sono , Exercício Físico , Estudos Cross-Over , Masculino
8.
Trends Mol Med ; 30(8): 708-712, 2024 Aug.
Artigo em Inglês | MEDLINE | ID: mdl-38719712

RESUMO

While the dopaminergic system is important for cognitive processes, it is also sensitive to the influence of physical activity (PA). We summarize current evidence on whether PA-related changes in the human dopaminergic system are associated with alterations in cognitive performance, discuss recent advances, and highlight challenges and opportunities for future research.


Assuntos
Cognição , Dopamina , Exercício Físico , Humanos , Cognição/fisiologia , Exercício Físico/fisiologia , Dopamina/metabolismo , Animais
9.
Int J Clin Health Psychol ; 24(3): 100498, 2024.
Artigo em Inglês | MEDLINE | ID: mdl-39290876

RESUMO

Objective: There is evidence that complex relationships exist between motor functions, brain structure, and cognitive functions, particularly in the aging population. However, whether such relationships observed in older adults could extend to other age groups (e.g., younger adults) remains to be elucidated. Thus, the current study addressed this gap in the literature by investigating potential associations between motor functions, brain structure, and cognitive functions in a large cohort of young adults. Methods: In the current study, data from 910 participants (22-35 yr) were retrieved from the Human Connectome Project. Interactions between motor functions (i.e., cardiorespiratory fitness, gait speed, hand dexterity, and handgrip strength), brain structure (i.e., cortical thickness, surface area, and subcortical volumes), and cognitive functions were examined using linear mixed-effects models and mediation analyses. The performance of different machine-learning classifiers to discriminate young adults at three different levels (related to each motor function) was compared. Results: Cardiorespiratory fitness and hand dexterity were positively associated with fluid and crystallized intelligence in young adults, whereas gait speed and handgrip strength were correlated with specific measures of fluid intelligence (e.g., inhibitory control, flexibility, sustained attention, and spatial orientation; false discovery rate [FDR] corrected, p < 0.05). The relationships between cardiorespiratory fitness and domains of cognitive function were mediated by surface area and cortical volume in regions involved in the default mode, sensorimotor, and limbic networks (FDR corrected, p < 0.05). Associations between handgrip strength and fluid intelligence were mediated by surface area and volume in regions involved in the salience and limbic networks (FDR corrected, p < 0.05). Four machine-learning classifiers with feature importance ranking were built to discriminate young adults with different levels of cardiorespiratory fitness (random forest), gait speed, hand dexterity (support vector machine with the radial kernel), and handgrip strength (artificial neural network). Conclusions: In summary, similar to observations in older adults, the current study provides empirical evidence (i) that motor functions in young adults are positively related to specific measures of cognitive functions, and (ii) that such relationships are at least partially mediated by distinct brain structures. Furthermore, our analyses suggest that machine-learning classifier has a promising potential to be used as a classification tool and decision support for identifying populations with below-average motor and cognitive functions.

10.
Brain Cogn ; 80(3): 338-51, 2012 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-23064033

RESUMO

The primary purpose of this study was to examine, using meta-analytical techniques, the differential effects of differing intensities of acute exercise on speed and accuracy of cognition. Overall, exercise demonstrated a small, significant mean effect size (g=0.14, p<0.01) on cognition. Examination of the comparison between speed and accuracy dependent variables showed that speed accounted for most of the effect. For speed, moderate intensity exercise demonstrated a significantly larger mean effect size than those for low and high intensities. For speed of processing during moderate intensity exercise, central executive tasks showed a larger effect size than recall and alertness/attention tasks; and mean effect size for counterbalanced or randomized studies was significantly greater than for studies in which a pre-exercise followed by during or post-exercise protocol was used. There was no significant difference between mean effect sizes when testing took place post-exercise compared to during exercise for speed but accuracy studies demonstrated a significantly larger mean effect size post-exercise. It was concluded that increased arousal during moderate intensity exercise resulted in faster speed of processing. The very limited effect on accuracy may be due to the failure to choose tests which are complex enough to measure exercise-induced changes in accuracy of performance.


Assuntos
Cognição/fisiologia , Exercício Físico/fisiologia , Esforço Físico/fisiologia , Tempo de Reação/fisiologia , Adolescente , Adulto , Idoso , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Resolução de Problemas , Reprodutibilidade dos Testes , Adulto Jovem
11.
Front Behav Neurosci ; 16: 957677, 2022.
Artigo em Inglês | MEDLINE | ID: mdl-36212191

RESUMO

It is well established that acute moderate-intensity exercise improves cognitive performance. However, the effects of acute high-intensity aerobic exercise on cognitive performance have not been well characterized. In this review, we summarize the literature investigating the exercise-cognition interaction, especially focusing on high-intensity aerobic exercise. We discuss methodological and physiological factors that potentially mediate cognitive performance in response to high-intensity exercise. We propose that the effects of high-intensity exercise on cognitive performance are primarily affected by the timing of cognitive task (during vs. after exercise, and the time delay after exercise). In particular, cognitive performance is more likely to be impaired during high-intensity exercise when both cognitive and physiological demands are high and completed simultaneously (i.e., the dual-task paradigm). The effects may also be affected by the type of cognitive task, physical fitness, exercise mode/duration, and age. Second, we suggest that interactions between changes in regional cerebral blood flow (CBF), cerebral oxygenation, cerebral metabolism, neuromodulation by neurotransmitters/neurotrophic factors, and a variety of psychological factors are promising candidates that determine cognitive performance in response to acute high-intensity exercise. The present review has implications for recreational, sporting, and occupational activities where high cognitive and physiological demands are required to be completed concurrently.

12.
Hum Brain Mapp ; 32(1): 71-9, 2011 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-20336685

RESUMO

It was recently observed that dehydration causes shrinkage of brain tissue and an associated increase in ventricular volume. Negative effects of dehydration on cognitive performance have been shown in some but not all studies, and it has also been reported that an increased perceived effort may be required following dehydration. However, the effects of dehydration on brain function are unknown. We investigated this question using functional magnetic resonance imaging (fMRI) in 10 healthy adolescents (mean age = 16.8, five females). Each subject completed a thermal exercise protocol and nonthermal exercise control condition in a cross-over repeated measures design. Subjects lost more weight via perspiration in the thermal exercise versus the control condition (P < 0.0001), and lateral ventricle enlargement correlated with the reduction in body mass (r = 0.77, P = 0.01). Dehydration following the thermal exercise protocol led to a significantly stronger increase in fronto-parietal blood-oxygen-level-dependent (BOLD) response during an executive function task (Tower of London) than the control condition, whereas cerebral perfusion during rest was not affected. The increase in BOLD response after dehydration was not paralleled by a change in cognitive performance, suggesting an inefficient use of brain metabolic activity following dehydration. This pattern indicates that participants exerted a higher level of neuronal activity in order to achieve the same performance level. Given the limited availability of brain metabolic resources, these findings suggest that prolonged states of reduced water intake may adversely impact executive functions such as planning and visuo-spatial processing.


Assuntos
Encéfalo/patologia , Encéfalo/fisiopatologia , Desidratação/patologia , Desidratação/fisiopatologia , Adolescente , Análise de Variância , Temperatura Corporal , Mapeamento Encefálico , Cognição/fisiologia , Estudos Cross-Over , Função Executiva/fisiologia , Exercício Físico/fisiologia , Feminino , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Testes Neuropsicológicos , Tempo de Reação/fisiologia
14.
Percept Mot Skills ; 113(2): 662-70, 2011 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-22185080

RESUMO

The effect of different sources of external attentional focus on learning a motor skill was assessed in the present study. 30 students (12 men, 18 women) participated voluntarily and were divided, according to type of external focus, into target, club swing, and target-club swing groups. The task was a golf putting skill. The target focus group attended to the target (hole), the club swing focus group attended to the execution of the club's swing, and the target-club swing focus group attended to both. All participants performed 50 trials of the putting skill in the acquisition phase and 10 trials in the 24-hr. delayed retention phase. The dependent variable was the error in the putting skill measured as the distance from the hole to the ball after each strike. Results showed the target-club swing focus group had better scores in the acquisition and retention phases than the other groups. It was concluded that external focus instruction helped the learners to integrate target cue with action cue and is more effective in skill learning than other external-focus instructions. These results support the claims of ecological psychology theorists concerning the effects of external focus of attention.


Assuntos
Atenção , Fixação Ocular , Golfe/educação , Golfe/psicologia , Prática Psicológica , Desempenho Psicomotor , Meio Social , Desempenho Atlético , Sinais (Psicologia) , Feminino , Humanos , Masculino , Retenção Psicológica , Adulto Jovem
15.
Int J Psychophysiol ; 170: 75-88, 2021 12.
Artigo em Inglês | MEDLINE | ID: mdl-34666105

RESUMO

An interoception model for the acute exercise-cognition interaction is presented. During exercise following the norepinephrine threshold, interoceptive feedback induces increased tonic release of extracellular catecholamines, facilitating phasic release hence better cognitive performance of executive functions. When exercise intensity increases to maximum, the nature of task-induced norepinephrine release from the locus coeruleus is dependent on interaction between motivation, perceived effort costs and perceived availability of resources. This is controlled by interaction between the rostral and dorsolateral prefrontal cortices, orbitofrontal cortex, anterior cingulate cortex and anterior insula cortex. If perceived available resources are sufficient to meet predicted effort costs and reward value is high, tonic release from the locus coeruleus is attenuated thus facilitating phasic release, therefore cognition is not inhibited. However, if perceived available resources are insufficient to meet predicted effort costs or reward value is low, tonic release from the locus coeruleus is induced, attenuating phasic release. As a result, cognition is inhibited, although long-term memory and tasks that require switching to new stimuli-response couplings are probably facilitated.


Assuntos
Catecolaminas , Interocepção , Cognição , Córtex Pré-Frontal Dorsolateral , Exercício Físico , Humanos
16.
Percept Mot Skills ; 110(2): 479-87, 2010 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-20499558

RESUMO

Expert performers in sports that include a high proportion of closed skills have often been found to score relatively high in field independence tests; a field-independent cognitive style may be advantageous for learning and performance of closed skills. The relationship between field dependence-independence (measured on a Portable Rod and Frame Test) and the acquisition of a kayak skill was examined. Undergraduates (6 men, 11 women; M age=21.6 yr., SD=3.2) who had no previous kayaking experience participated. Participants completed a structured teaching session (2 hr.) designed to develop three key subskills necessary for the kayak roll. Number of trials taken to consistently perform the underwater orientation and paddle movement subskills and duration of practice taken to develop the upper/lower body separation subskill as well as participants' ability to complete the roll were assessed. Field independence was associated with better performance of subskills and skill acquisition tests. Learners with greater field independence may have an advantage when acquiring sport skills that require cognitive restructuring and a strong reliance on kinesthetic and proprioceptive feedback.


Assuntos
Desempenho Atlético , Área de Dependência-Independência , Testes Neuropsicológicos/estatística & dados numéricos , Equilíbrio Postural , Prática Psicológica , Navios , Adolescente , Retroalimentação Sensorial , Feminino , Humanos , Cinestesia , Masculino , Orientação , Propriocepção , Adulto Jovem
17.
Sports Med ; 50(10): 1703-1708, 2020 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-32661840

RESUMO

The consensus of opinion, with regard to the effect of cognitive fatigue on subsequent physical performance, is that there is a small, negative effect, but there is no consensus regarding the mechanisms involved. When glucose levels are normal, undertaking cognitive tasks does not induce energy or neurotransmitter depletion. The adenosine hypothesis is questioned as cognitively induced increases in adenosine release are phasic and transient, while persistent effects of adenosine are tonic. Thus, the most likely explanation for a negative effect of cognitive fatigue would appear to be changes in perceptions of effort, for which there is some evidence from subjective participant feedback, while interoceptive theory would suggest a role for motivation levels. Cognitive fatigue and physical fatigue are dependent on interoceptive mechanisms, in particular the interactions between top-down predictions of effort from the dorsolateral prefrontal cortex (PFC) to the insula cortex, anterior cingulate cortex, ventromedial and ventrolateral PFC, and bottom-up feedback from the lamina I spinothalamic pathway, and the vagal and glossopharyngeal medullothalamic pathway. The dopaminergic mesocorticolimbic and the locus coeruleus-noradrenaline pathways are also vital. It would appear that cognitive fatigue leads to different predictions of the expected sensory consequences of undertaking the exercise than in the control condition and there is some evidence that motivation can overcome this. Much more research, in which motivation levels are manipulated, is necessary as the effects are small and the reasons for cognitive fatigue causing changes in predictions of sensory consequences are not clear.


Assuntos
Exercício Físico/fisiologia , Interocepção/fisiologia , Fadiga Mental/fisiopatologia , Motivação/fisiologia , Córtex Pré-Frontal/fisiologia , Humanos
18.
Hum Brain Mapp ; 30(1): 291-8, 2009 Jan.
Artigo em Inglês | MEDLINE | ID: mdl-18064587

RESUMO

Dehydration can affect brain structure which has important implications for human health. In this study, we measured regional changes in brain structure following acute dehydration. Healthy volunteers received a structural MRI scan before and after an intensive 90-min thermal-exercise dehydration protocol. We used two techniques to determine changes in brain structure: a manual point counting technique using MEASURE, and a fully automated voxelwise analysis using SIENA. After the exercise regime, participants lost (2.2% +/- 0.5%) of their body mass. Using SIENA, we detected expansion of the ventricular system with the largest change occurring in the left lateral ventricle (P = 0.001 corrected for multiple comparisons) but no change in total brain volume (P = 0.13). Using manual point counting, we could not detect any change in ventricular or brain volume, but there was a significant correlation between loss in body mass and third ventricular volume increase (r = 0.79, P = 0.03). These results show ventricular expansion occurs following acute dehydration, and suggest that automated longitudinal voxelwise analysis methods such as SIENA are more sensitive to regional changes in brain volume over time compared with a manual point counting technique.


Assuntos
Encefalopatias Metabólicas/fisiopatologia , Encéfalo/fisiopatologia , Ventrículos Cerebrais/fisiopatologia , Desidratação/fisiopatologia , Doença Aguda , Adulto , Peso Corporal/fisiologia , Encéfalo/patologia , Encefalopatias Metabólicas/etiologia , Encefalopatias Metabólicas/patologia , Tamanho Celular , Ventrículos Cerebrais/patologia , Desidratação/complicações , Exercício Físico/fisiologia , Terapia por Exercício/efeitos adversos , Humanos , Processamento de Imagem Assistida por Computador , Imageamento por Ressonância Magnética , Masculino , Tamanho do Órgão/fisiologia , Aptidão Física/fisiologia , Valor Preditivo dos Testes , Terceiro Ventrículo/patologia , Terceiro Ventrículo/fisiopatologia , Equilíbrio Hidroeletrolítico/fisiologia , Adulto Jovem
19.
Brain Cogn ; 69(3): 565-70, 2009 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-19138814

RESUMO

The main issue of this study was to determine whether cognitive control is affected by acute moderate exercise. Twelve participants [4 females (VO(2 max)=42 ml/kg/min) and 8 males (VO(2 max) = 48 ml/kg/min)] performed a Simon task while cycling at a carefully controlled workload intensity corresponding to their individual ventilatory threshold. The distribution-analytical technique and the delta plot analysis [Ridderinkhof, K. R. (2002). Activation and suppression in conflict tasks: Empirical clarification through distributional analyses. In W. Prinz & B. Hommel (Eds.), Common mechanisms in perception and action. Attention and performance (Vol. 19, pp. 494-519). Oxford: Oxford University Press.] were used to assess the role of selective response inhibition in resolving response conflict. Results showed that cognitive processes appeared to be differently affected by acute moderate exercise. Reaction time results confirmed that performance is better (faster without change in accuracy) when the cognitive task is performed simultaneously with exercise. Between-trial adjustments (post-conflict and post-error) highlighted that cognitive control adjustments are also fully efficient during exercise. However, the effect of congruency (Simon effect) appeared to be more pronounced during exercise compared to rest which suggests that the response inhibition is deteriorated during exercise. The present findings suggest that acute moderate exercise differently affects some specific aspects of cognitive functions.


Assuntos
Cognição , Exercício Físico/psicologia , Adulto , Análise de Variância , Ciclismo , Feminino , Humanos , Masculino , Desempenho Psicomotor , Tempo de Reação
20.
Brain Cogn ; 71(1): 14-9, 2009 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-19346049

RESUMO

This research aimed to investigate the time course effect of a moderate steady-state exercise session on response execution and response inhibition using a stop-task paradigm. Ten participants performed a stop-signal task whilst cycling at a carefully controlled workload intensity (40% of maximal aerobic power), immediately following exercise and 30min after exercise cessation. Results showed that moderate exercise enhances a subjects' ability to execute responses under time pressure (shorter Go reaction time, RT without a change in accuracy) but also enhances a subjects' ability to withhold ongoing motor responses (shorter stop-signal RT). The present outcomes reveal that the beneficial effect of exercise is neither limited to motor response tasks, nor to cognitive tasks performed during exercise. Beneficial effects of exercise remain present on both response execution and response inhibition performance for up to 52min after exercise cessation.


Assuntos
Cognição , Exercício Físico/psicologia , Desempenho Psicomotor , Análise de Variância , Feminino , Humanos , Masculino , Atividade Motora , Testes Neuropsicológicos , Tempo de Reação , Análise e Desempenho de Tarefas , Fatores de Tempo , Adulto Jovem
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