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BACKGROUND: Interlimb transfer of sequential motor learning (SML) refers to the positive influence of prior experiences in performing the same sequential movements using different effectors. Despite evidence from intermanual SML, and while most daily living activities involve interlimb cooperation and coordination between the four limbs, nothing is known about bilateral SML transfer between the upper and lower limbs. RESEARCH QUESTION: We examined the transfer of bilateral SML from the upper to the lower limbs and vice versa. METHODS: Twenty-four participants had to learn an initial bilateral SML task using the upper limbs and then performed the same sequence using the lower limbs during a transfer SML task. They performed the reversed situation 1 month apart. The performance was evaluated at the beginning and the end of both initial and transfer SML practice phases. RESULTS: Significant and reciprocal transfer gains in performance were observed regardless of the effectors. Greater transfer gains in performance were observed at the beginning of the transfer SML from the lower to the upper limbs (44â¯%) but these gains vanished after practice with the transfer effectors (5â¯%). Although smaller gains were initially achieved in the transfer of SML from the upper to the lower limbs (15â¯%), these gains persisted and remained significant (9â¯%) after practice with the transfer effectors. SIGNIFICANCE: Our results provide evidence of a reciprocal and asymmetrical interlimb transfer of bilateral SML between the upper and lower limbs. These findings could be leveraged as a relevant strategy in the context of sports and functional rehabilitation.
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PURPOSE: Personality traits are associated with psychophysiological stress, but few studies focus on medical students. This study aimed to better understand the association of personality traits with the efficacy of stress management interventions for medical students. METHOD: A randomized controlled trial was conducted with fourth-year students who took the objective structured clinical examination at Bernard University Lyon 1 in December 2021. Students were randomized in cardiac biofeedback, mindfulness, and control groups. Each intervention was implemented for 6 minutes before the examination. Physiological stress levels were collected during the intervention. Psychological stress levels were rated by students at baseline and after the intervention. Personality traits were assessed via the Big-Five Inventory. Interactions between personality traits and the efficacy of the interventions were analyzed using multivariable linear regression models. RESULTS: Four hundred eighty-one students participated. Higher baseline psychological stress levels were associated with higher neuroticism and agreeableness ( ß = 10.27 [95% confidence interval {CI}, 7.40-13.13; P < .001] and ß = 3.42 [95% CI, 0.98-5.85; P = .006], respectively) and lower openness ( ß = -4.95; 95% CI, -7.40 to -2.49; P < .001). As compared with the control intervention, both stress management interventions led to lower levels of psychological ( P < .001 for both) and physiological stress levels (biofeedback: P < .001 and mindfulness: P = .009). Biofeedback efficacy varied by extraversion score for psychological ( ß = -5.66; 95% CI, -10.83 to -0.50; P = .03) and physiological stress reduction ( ß = -0.002; 95% CI, -0.003 to -0.00004; P = .045). Mindfulness efficacy varied by agreeableness score for psychological stress reduction ( ß = -7.87; 95% CI, -13.05 to -2.68; P = .003). CONCLUSIONS: Students with a high score in extraversion may benefit more from biofeedback interventions, while students with high scores in agreeableness may benefit more from mindfulness interventions.
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Biorretroalimentación Psicológica , Atención Plena , Personalidad , Estrés Psicológico , Estudiantes de Medicina , Humanos , Estudiantes de Medicina/psicología , Estudiantes de Medicina/estadística & datos numéricos , Femenino , Masculino , Estrés Psicológico/terapia , Estrés Psicológico/psicología , Atención Plena/métodos , Biorretroalimentación Psicológica/métodos , Adulto , Adulto JovenRESUMEN
To optimise the relationship between exercise and sleep quality, the intensity of exercise and its proximity to sleep are key factors to manage. Although low-to-moderate exercises promote sleep quality, late-evening vigorous exercise instead of morning should still be avoided. It potentially impacts the objective and subjective markers of sleep quality. In the present study, we investigated the effects of vigorous morning and evening exercise on objective and subjective sleep features in an ecological context. A total of 13 recreational runners (mean [SD] age 27.7 [7.2] years, four females) performed a 45-60 min run (70% maximal aerobic velocity) either in the MORNING (30 min to 2 h after waking-up) or in the EVENING (2 h to 30 min before sleep). The two exercise conditions were separated by a REST day. After each condition, sleep was objectively assessed using an electroencephalographic headband and subjectively using the Spiegel Sleep Inventory. Compared with REST, both MORNING and EVENING exercise increased the time spent in non-rapid eye movement (NREM, +24.9 min and +22.7 min; p = 0.01, η2 = 0.11, respectively). Longer NREM duration was mainly due to sleep stage 2 extension after both MORNING (+20.8 min) and EVENING (+22.8 min) exercise relative to REST (p = 0.02, η2 = 0.12). No other effect of exercise on either objective or subjective sleep could be observed. Exercise, independently of the time at which it takes place, leads to extended NREM sleep without other effects on sleep quality. Considering the crucial role of exercise in achieving good health, sleep hygiene guidelines should be updated to promote exercise at any time of the day.
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Calidad del Sueño , Sueño de Onda Lenta , Femenino , Humanos , Adulto , Ejercicio Físico , Sueño , Higiene del Sueño , Ritmo CircadianoRESUMEN
Motor imagery can, similarly to physical practice, improve motor performance through experience-based plasticity. Using magnetoencephalography, we investigated changes in brain activity associated with offline consolidation of motor sequence learning through physical practice or motor imagery. After an initial training session with either physical practice or motor imagery, participants underwent overnight consolidation. As control condition, participants underwent wake-related consolidation after training with motor imagery. Behavioral analyses revealed that overnight consolidation of motor learning through motor imagery outperformed wake-related consolidation (95% CI [0.02, 0.07], P < 0.001, RP2 = 0.05). As regions of interest, we selected the generators of event-related synchronization/desynchronization of alpha (8-12 Hz) and beta (15-30 Hz) oscillations, which predicted the level of performance on the motor sequence. This yielded a primary sensorimotor-premotor network for alpha oscillations and a cortico-cerebellar network for beta oscillations. The alpha network exhibited increased neural desynchronization after overnight consolidation compared to wake-related consolidation. By contrast, the beta network exhibited an increase in neural synchronization after wake-related consolidation compared to overnight consolidation. We provide the first evidence of parallel brain plasticity underlying behavioral changes associated with sleep-dependent consolidation of motor skill learning through motor imagery and physical practice.
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Consolidación de la Memoria , Desempeño Psicomotor , Humanos , Aprendizaje , Destreza Motora , Sueño , Plasticidad NeuronalRESUMEN
Sleep benefits the consolidation of motor skills learned by physical practice, mainly through periodic thalamocortical sleep spindle activity. However, motor skills can be learned without overt movement through motor imagery or action observation. Here, we investigated whether sleep spindle activity also supports the consolidation of non-physically learned movements. Forty-five electroencephalographic sleep recordings were collected during a daytime nap after motor sequence learning by physical practice, motor imagery, or action observation. Our findings reveal that a temporal cluster-based organization of sleep spindles underlies motor memory consolidation in all groups, albeit with distinct behavioral outcomes. A daytime nap offers an early sleep window promoting the retention of motor skills learned by physical practice and motor imagery, and its generalizability toward the inter-manual transfer of skill after action observation. Findings may further have practical impacts with the development of non-physical rehabilitation interventions for patients having to remaster skills following peripherical or brain injury.
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Descriptive and functional anatomy is one of the most important sciences for kinesiology students. Anatomy learning requires spatial and motor imagery abilities. Learning anatomy is complex when teaching methods and instructional tools do not appropriately develop spatial and motor imagery abilities. Recent technological developments such as three-dimensional (3D) digital tools allow to overcome those difficulties, especially when 3D tools require strong interactions with the learners. Besides interactive digital tools, embodied learning or learning in motion is an effective method for a wide variety of sciences including anatomy. The aim of this study was to explore the impact of combining movement execution with 3D animation visualization on anatomy learning in a real classroom teaching context. To do so, the results of two groups of kinesiology students during three official assessments were compared. The experimental group (n = 60) learned functional anatomy by combining movement execution with traditional knowledge acquisition (e.g., 3D animations visualization, problem-based learning exercises). The control group (n = 61) had the same material but did not execute the movements during problem-solving exercises. Although no differences were found between both groups on early and mid-semester examinations, significant difference appeared at the end of the semester with an advantage for the experimental group. This exploratory study suggests that embodied learning is beneficial in improving functional anatomy learning. Therefore, it would be interesting to integrate such type of pedagogical approach within the kinesiology curriculum.
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Anatomía , Evaluación Educacional , Humanos , Anatomía/educación , Estudiantes , Aprendizaje , CurriculumRESUMEN
The present study aimed at investigating the influence of personality on both anticipatory stress vulnerability and the effectiveness of coping strategies in an occupational stressful context. Following assessment of individual personality traits (Big Five Inventory), 147 volunteers were exposed to the anticipation of a stressful event. Anxiety and cardiac reactivity were assessed as markers of vulnerability to anticipatory stress. Participants were then randomly assigned to three groups and subjected to a 5-min intervention: relaxation breathing, relaxation breathing combined with cardiac biofeedback, and control. The effectiveness of coping interventions was determined through the cardiac coherence score achieved during the intervention. Higher neuroticism was associated with higher anticipatory stress vulnerability, whereas higher conscientiousness and extraversion were related to lower anticipatory stress vulnerability. Relaxation breathing and biofeedback coping interventions contributed to improve the cardiac coherence in all participants, albeit with greater effectiveness in individuals presenting higher score of openness to experience. The present findings demonstrated that personality traits are related to both anticipatory stress vulnerability and effectiveness of coping interventions. These results bring new insights into practical guidelines for stress prevention by considering personality traits. Specific practical applications for health professionals, who are likely to manage stressful situations daily, are discussed.
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Adaptación Psicológica , Personalidad , Humanos , Extraversión Psicológica , Neuroticismo , Cuidados CríticosRESUMEN
BACKGROUND: Active participation in high-fidelity simulation remains stressful for residents. Increased stress levels elicited during such simulation impacts performance. We tested whether relaxing breathing, paired or not with cardiac biofeedback, could lead to enhanced performance of residents during simulation. METHODS: This randomized pilot study involved the fifth-year anesthesiology and critical care residents who participated in high-fidelity at Lyon medical simulation center in 2019. Residents were randomized into three parallel interventions: relaxing breathing, relaxing breathing paired with cardiac biofeedback, and control. Each intervention was applied for five minutes immediately after the scenario briefing. The primary endpoint was the overall performance during the simulation rated by two blinded independent investigators. The secondary endpoints included component scores of overall performance and changes in psychological states. RESULTS: Thirty-four residents were included. Compared to the control group, residents in the relaxing breathing (+ 7%, 98.3% CI: 0.3 to 13.7, P = 0.013) and relaxing breathing paired with cardiac biofeedback (+ 8%, 98.3% CI: 0.82 to 14.81, P = 0.009) groups had a higher overall performance score. Following the interventions, compared to the control group, stress level was lower when participants had performed relaxing breathing alone (P = 0.029) or paired with biofeedback (P = 0.035). The internal relaxation level was higher in both the relaxing breathing alone (P = 0.016) and paired with biofeedback groups (P = 0.035). CONCLUSIONS: Performing five minutes of relaxing breathing before the scenario resulted in better overall simulation performance. These preliminary findings suggest that short breathing interventions are effective in improving performance during simulation. TRIAL REGISTRATION: The study protocol was retrospectively registered on clinicaltrials.gov ( NCT04141124 , 28/10/2019).
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Biorretroalimentación Psicológica , Corazón , Simulación por Computador , Humanos , Proyectos Piloto , Estudios ProspectivosRESUMEN
Covert speech is accompanied by a subjective multisensory experience with auditory and kinaesthetic components. An influential hypothesis states that these sensory percepts result from a simulation of the corresponding motor action that relies on the same internal models recruited for the control of overt speech. This simulationist view raises the question of how it is possible to imagine speech without executing it. In this perspective, we discuss the possible role(s) played by motor inhibition during covert speech production. We suggest that considering covert speech as an inhibited form of overt speech maps naturally to the purported progressive internalization of overt speech during childhood. We further argue that the role of motor inhibition may differ widely across different forms of covert speech (e.g., condensed vs. expanded covert speech) and that considering this variety helps reconciling seemingly contradictory findings from the neuroimaging literature.
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This systematic review and meta-analysis aims to identify and quantify the current available evidence of hypnosis efficacy to manage pain in patients with chronic musculoskeletal and neuropathic pain. Randomized Control Trials (RCTs) with hypnosis and/or self-hypnosis treatment used to manage musculoskeletal and/or neuropathic chronic pain in adults and assessing pain intensity were included. Reviews, meta-analyses, non-randomized clinical trials, case reports and meeting abstracts were excluded. Five databases, up until May 13th 2021, were used to search for RCTs using hypnosis to manage chronic musculoskeletal and/or neuropathic pain. The protocol is registered on PROSPERO register (CRD42020180298) and no specific funding was received for this review. The risk of bias asessement was conducted according to the revised Cochrane risk of bias tool for randomized control trials (RoB 2.0). Nine eligible RCTs including a total of 530 participants were considered. The main analyses showed a moderate decrease in pain intensity (Hedge's g: -0.42; p = 0.025 after intervention, Hedge's g: -0.37; p = 0.027 after short-term follow-up) and pain interference (Hedge's g: -0.39; p = 0.029) following hypnosis compared to control interventions. A significant moderate to large effect size of hypnosis compared to controls was found for at 8 sessions or more (Hedge's g: -0.555; p = 0.034), compared to a small and not statistically significant effect for fewer than 8 sessions (Hedge's g: -0.299; p = 0.19). These findings suggest that a hypnosis treatment lasting a minimum of 8 sessions could offer an effective complementary approach to manage chronic musculoskeletal and neuropathic pain. Future research is needed to delineate the relevance of hypnosis in practice and its most efficient prescription.
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Dolor Crónico , Hipnosis , Neuralgia , Adulto , Dolor Crónico/terapia , Humanos , Hipnosis/métodos , Neuralgia/terapia , Dimensión del DolorRESUMEN
BACKGROUND: Previous studies have identified the dorsolateral prefrontal cortex (dlPFC) as a core region in cognitive emotional regulation. Transcranial direct current stimulations of the dlPFC (tDCS) and heart-rate variability biofeedback (BFB) are known to regulate emotional processes. However, the effect of these interventions applied either alone or concomitantly during an anticipatory stress remains unexplored. OBJECTIVE: The study investigated the effect of anodal tDCS and BFB, alone or combined, on psychophysiological stress responses and cognitive functioning. METHODS: Following a stress anticipation induction, 80 participants were randomized into four groups and subjected to a 15-min intervention: neutral video viewing (ctrl), left dlPFC anodal tDCS (tdcs), heart-rate variability biofeedback (bfb), or a combined treatment (bfb + tdcs). Participants were then immediately confronted with the stressor, which was followed by an assessment of executive functions. Psychophysiological stress responses were assessed throughout the experiment (heart rate, heart-rate variability, salivary cortisol). RESULTS: The tdcs did not modulate stress responses. Compared with both ctrl and tdcs interventions, bfb reduced physiological stress and improved executive functions after the stressor. The main finding revealed that bfb + tdcs was the most effective intervention, yielding greater reduction in psychological and physiological stress responses than bfb. CONCLUSIONS: Combining preventive tDCS with BFB is a relevant interventional approach to reduce psychophysiological stress responses, hence offering a new and non-invasive treatment of stress-related disorders. Biofeedback may be particularly useful for preparing for an important stressful event when performance is decisive.
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Estimulación Transcraneal de Corriente Directa , Biorretroalimentación Psicológica , Cognición , Función Ejecutiva , Humanos , Corteza PrefrontalRESUMEN
Motor imagery (MI) is known to engage motor networks and is increasingly used as a relevant strategy in functional rehabilitation following immobilization, whereas its effects when applied during immobilization remain underexplored. Here, we hypothesized that MI practice during 11 h of arm-immobilization prevents immobilization-related changes at the sensorimotor and cortical representations of hand, as well as on sleep features. Fourteen participants were tested after a normal day (without immobilization), followed by two 11-h periods of immobilization, either with concomitant MI treatment or control tasks, one week apart. At the end of each condition, participants were tested on a hand laterality judgment task, then underwent transcranial magnetic stimulation to measure cortical excitability of the primary motor cortices (M1), followed by a night of sleep during which polysomnography data was recorded. We show that MI treatment applied during arm immobilization had beneficial effects on (1) the sensorimotor representation of hands, (2) the cortical excitability over M1 contralateral to arm-immobilization, and (3) sleep spindles over both M1s during the post-immobilization night. Furthermore, (4) the time spent in REM sleep was significantly longer, following the MI treatment. Altogether, these results support that implementing MI during immobilization may limit deleterious effects of limb disuse, at several levels of sensorimotor functioning.
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Brazo , Potenciales Evocados Motores , Imágenes en Psicoterapia , Inmovilización , Corteza Motora/fisiopatología , Estimulación Magnética Transcraneal , Adulto , Femenino , Humanos , MasculinoRESUMEN
Anticipating a stressful situation involves psychophysiological reactions before the occurrence of the overt stress event. The current challenge in the stress domain is to characterize anticipatory stress reactions and how to effectively modulate them. The present study aimed to characterize the anticipation period and evaluate the benefits of a heart-rate variability biofeedback (BFB) intervention designed to manage anticipatory stress. Healthy participants were exposed to an anticipation stress period (15 min) during which they either practised BFB (stress + bfb, n = 15) or watched a neutral video (stress + video, n = 14). Anticipatory stress was effectively induced by the Trier Social Anticipatory Stress (TSAS) protocol, specifically designed for this study. Control participants, without anticipation stress, practised BFB for an equivalent time (ctrl + bfb, n = 15). Subsequently, all participants performed a set of cognitive tasks assessing executive functions. Heart-rate variability (cardiac coherence, standard deviation of the R-R intervals, root mean square of successive difference measure) and the evolution of the perceived psychological state were measured during the anticipation period. Self-reported judgements of how the intervention influenced stress and performance were further assessed. The main result showed that BFB is a relevant proactive stress-coping method. Compared with the stress + video group, participants who practised BFB attained higher cardiac coherence scores. Post-intervention self-reported measures revealed that BFB contributed to reduce psychological stress and increase perceived levels of performance. Together, these findings provide practical guidelines for examining the stress anticipation period by means of the TSAS protocol.
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Adaptación Psicológica , Biorretroalimentación Psicológica , Frecuencia Cardíaca , Humanos , Autoinforme , Estrés Psicológico/terapiaRESUMEN
Sleep-dependent performance enhancement has been consistently reported after explicit sequential finger learning, even using motor imagery practice (MIP), but whether similar sleep benefits occur after explicit sequential gross motor learning with the lower limbs has been addressed less often. Here, we investigated both acquisition and consolidation processes in an innovative sequential footstep task performed either physically or mentally. Forty-eight healthy young participants were tested before and after physical practice (PP) or MIP on the footstep task, following either a night of sleep (PPsleep and MIPsleep groups) or an equivalent daytime period (PPday and MIPday groups). Results showed that all groups improved motor performance following the acquisition session, albeit the magnitude of enhancement in the MIP groups remained lower relative to the PP groups. Importantly, only the MIPsleep group further improved performance after a night of sleep, while the other groups stabilized their performance after consolidation. Together, these findings demonstrate a sleep-dependent gain in performance after MIP in a sequential motor task with the lower limbs but not after PP. Overall, the present study is of particular importance in the context of motor learning and functional rehabilitation.
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Imaginación , Extremidad Inferior/fisiología , Destreza Motora/fisiología , Práctica Psicológica , Sueño/fisiología , Adulto , Femenino , Pie/fisiología , Humanos , Masculino , Movimiento , Adulto JovenRESUMEN
Motor imagery (MI) is the capacity to mentally perform one or a set of movements without concomitant overt action. MI training has been show to enhance the subsequent motor performance. While the benefits of MI to manage stress have been extensively documented, the reverse impact of stress on MI received far less attention. The present study thus aimed to evaluate whether acute stress might influence MI abilities. Thirty participants were assigned either to a stress or a control group. The Socially Evaluated Cold Pressor Test (SECPT) was used to induce stress, with heart rate, electrodermal activity, salivary cortisol, and self-report perceived levels of stress being monitored during the experiment. Stress induction was followed by both implicit (laterality judgment) and explicit (sequential pointing) MI tasks. Main results showed a deleterious impact of stress on implicit MI, while explicit MI was not altered. These exploratory findings provide a deeper understanding of stress effects on cognition, and practically support that under stressful conditions, as during a sport competition or rehabilitation contexts, explicit MI should be prioritized.
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Imaginación/fisiología , Actividad Motora/fisiología , Práctica Psicológica , Desempeño Psicomotor/fisiología , Estrés Psicológico/fisiopatología , Adolescente , Adulto , Femenino , Humanos , Masculino , Proyectos Piloto , Adulto JovenRESUMEN
Limb disuse causes overt, measurable alterations in motor functions. Motor imagery (MI) practice has been used as a behavioral strategy to prevent motor impairments due to limb disuse or immobilization. Yet, how MI operates at the neural level in the context of short-term limb immobilization remains understudied. We hypothesized that MI treatment applied during 12 h of arm immobilization prevents immobilization-related changes in resting-state electroencephalographic (rsEEG) power and functional connectivity. Fourteen participants first underwent rsEEG after 12 h of normal motor activity (without immobilization). Then, rsEEG recording was performed after 12 h of arm immobilization either with MI treatment or without, each condition separated by 1 week, according to a randomized within-subjects design. MI treatment consisted in performing varied visual and kinaesthetic MI exercises (5 sessions of 15 min every two hours). The results showed that in the delta, theta, alpha and beta frequency bands, interhemispheric difference in sensors power over the motor cortex (i.e. C3 vs. C4) was reduced after arm immobilization, while it did not change when MI treatment was delivered during the immobilization period. Moreover, functional connectivity across the sensors-network in the delta (1-4 Hz) and alpha (8-12 Hz) frequency bands decreased after immobilization while it was restored by MI treatment. To conclude, MI counteracts functional neural changes within and between motor regions in the context of limb immobilization. Practical applications for motor rehabilitation strategies, particularly in stroke patients, are also discussed.
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Electroencefalografía , Corteza Motora , Trastornos Motores , Brazo , Humanos , Corteza Motora/fisiología , Accidente Cerebrovascular , Rehabilitación de Accidente CerebrovascularRESUMEN
Purpose: The ability to perform motor imagery (MI) might be impaired by the physical fatigue elicited during training. Interestingly, there is also theoretical support for a more limited influence of fatigue in the existing literature. Method: We evaluated MI ability before and after two exercise protocols: (i) a continuous exercise of 20 min performed on a cycle ergometer at 80% of the secondary ventilatory threshold (Continuous exercise), and (ii) an intermittent exercise of 20 min involving sprints at maximal intensity performed with regular intervals (Intermittent exercise). MI ability evaluations were performed using validated behavioral (mental chronometry) and psychometric (subjective reports) methods. MI ability evaluations included mental rehearsal of a motor sequence which involved the main effectors of the exercise protocols (walking), and mental rehearsal of a motor task which did not involve the main somatic effectors of the exercise protocols (pointing movements with the upper limbs). Results: Mental chronometry showed that MI ability was degraded only after Intermittent exercise, while self-report measures of MI vividness revealed that MI ability was primarily impaired during MI of the walking task. Conclusions: Present results suggest that Intermittent exercise engaging anaerobic processes of energy expenditure, but not Continuous exercise engaging aerobic processes of energy expenditure, impaired MI ability. Findings are discussed in relation to the internal models theory of motor simulation, specifically changes in current state of the motor system under the fatigued state-affecting motor predictions. Present findings may contribute to successful applications of MI training in sports and rehabilitation.
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Ejercicio Físico/fisiología , Ejercicio Físico/psicología , Imaginación , Fatiga Muscular/fisiología , Adulto , Metabolismo Energético , Femenino , Frecuencia Cardíaca/fisiología , Humanos , Ácido Láctico/sangre , Masculino , Consumo de Oxígeno/fisiología , Percepción/fisiología , Esfuerzo Físico/fisiología , Psicometría , Autoinforme , Adulto JovenRESUMEN
When you suddenly understand how to solve a problem through an original and efficient strategy, you experience the so-called "Eureka" effect. The appearance of insight usually occurs after setting the problem aside for a brief period of time (i.e. incubation), thereby promoting unconscious and novel associations on problem-related representations leading to a new and efficient solving strategy. The left posterior parietal cortex (lPPC) has been showed to support insight in problem solving, when this region is activated during the initial representations of the task. The PPC is further activated during the next incubation period when the mind starts to wander. The aim of this study was to investigate whether stimulating the lPPC, either during the initial training on the problem or the incubation period, might enhance representation change in problem solving. To address this question, participants performed the Number Reduction Task (NRT, convergent problem-solving), while excitatory or sham (placebo) transcranial direct current stimulation (tDCS) was applied over the lPPC. The stimulation was delivered either during the initial problem representation or during the subsequent incubation period. Impressively, almost all participants (94%) with excitatory tDCS during the initial training gained representational change in problem solving, compared to only 39% in the incubation period and 33% in the sham groups. We conclude that the lPPC plays a role during the initial problem representation, which may be considerably strengthened by means of short brain stimulation.
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Lóbulo Parietal/fisiología , Solución de Problemas , Adulto , Simulación por Computador , Femenino , Humanos , Masculino , Modelos Teóricos , Lóbulo Parietal/diagnóstico por imagen , Estimulación Transcraneal de Corriente Directa , Adulto JovenRESUMEN
BACKGROUND: Acquisition and consolidation of a new motor skill occurs gradually over long time span. Motor imagery (MI) and brain stimulation have been showed as beneficial approaches that boost motor learning, but little is known about the extent of their combined effects. OBJECTIVE: Here, we aimed to investigate, for the first time, whether delivering multiple sessions of transcranial direct current stimulation (tDCS) over primary motor cortex during physical and MI practice might improve implicit motor sequence learning in a young population. METHODS: Participants practiced a serial reaction time task (SRTT) either physically or through MI, and concomitantly received either an anodal (excitatory) or sham stimulation over the primary motor cortex during three successive days. The effect of anodal tDCS on the general motor skill and sequence specific learning were assessed on both acquisition (within-day) and consolidation (between-day) processes. We further compared the magnitude of motor learning reached after a single and three daily sessions of tDCS. RESULTS: The main finding showed that anodal tDCS boosted MI practice, but not physical practice, during the first acquisition session. A second major result showed that compared to sham stimulation, multiple daily session of anodal tDCS, for both types of practice, resulted in greater implicit motor sequence learning rather than a single session of stimulation. CONCLUSIONS: The present study is of particular importance in the context of rehabilitation, where we postulate that scheduling mental training when patients are not able to perform physical movement might beneficiate from concomitant and consecutive brain stimulation sessions over M1 to promote functional recovery.
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Imaginación/fisiología , Consolidación de la Memoria/fisiología , Corteza Motora/fisiología , Destreza Motora/fisiología , Práctica Psicológica , Adulto , Femenino , Humanos , Masculino , Tiempo de Reacción , Estimulación Transcraneal de Corriente Directa , Adulto JovenRESUMEN
Action observation (AO) alone or combined with motor imagery (AOâ¯+â¯MI) has been shown to engage the motor system. While recent findings support the potential relevance of both techniques to enhance muscle function, this issue has received limited scientific scrutiny. In the present study, we implemented a counterbalanced conditions design where 21 participants performed 10 maximal isometric contractions (12-s duration) of elbow flexor muscles against a force platform. During the inter-trial rest periods, participants completed i) AO of the same task performed by an expert athlete, ii) AOâ¯+â¯MI, i.e. observation of an expert athlete while concurrently imagining oneself performing the same task, and iii) watching passively a video documentary about basketball shooting (Control). During force trials, we recorded the total force and integrated electromyograms from the biceps brachii and anterior deltoideus. We also measured skin conductance from two finger electrodes as an index of sympathetic nervous system activity. Both AO and AOâ¯+â¯MI outperformed the Control condition in terms of total force (2.79-3.68%, pâ¯<â¯0.001). For all conditions, we recorded a positive relationship between the biceps brachii activation and the total force developed during the task. However, only during AO was a positive relationship observed between the activation of the anterior deltoideus and the total force. We interpreted the results with reference to the statements of the psycho-neuromuscular theory of mental practice. Present findings extend current knowledge regarding the priming effects of AO and AOâ¯+â¯MI on muscle function, and may contribute to the optimization of training programs in sports and rehabilitation.