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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.

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 towards 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.

Objective: The present study aimed at investigating the influence of personality on both anticipatory stress vulnerability and effectiveness of coping strategies in a real-life context. Methods: 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. Then, participants were randomly assigned to three groups and subjected to a 5-min intervention: relaxing breathing, relaxing breathing combined with cardiac biofeedback, and control. The effectiveness of coping interventions was determined through the cardiac coherence score achieved during the intervention. Results. Higher neuroticism was associated with higher anticipatory stress vulnerability, whereas lower conscientiousness and extraversion were related to lower anticipatory stress vulnerability. Relaxing 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.Conclusions. 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.

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.

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.

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.

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 ...

International audience; 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.

There is now ample evidence that motor imagery contributes to improve motor performance and promote motor learning and recovery. During the last decades, a large number of experimental studies and imagery frameworks were designed to determine the critical key components for effective imagery interventions. The extent to which athletes often move slightly during motor imagery has spawned specific interest in imagery research from a conceptual perspective, hence challenging the traditional idea that imagery requires to remain motionless. While a wealth of research has extensively decoupled motor imagery from action, more recent imagery theories specifically considered that athletes can perform a dynamic form of imagery, by adopting a congruent body position and embodying spatial and/or temporal features of the movement without entirely performing it. Spurred by the wide use of this form of imagery by athletes and the promising related experimental research, the present paper aims at reviewing the impact and predictive positive effects of dynamic motor imagery on motor performance. Direct implications for applied work, including specific instructions that dynamic motor imagery might have during different stages of the coaching process of athletes, are further considered. A framework for the appropriate timing for delivering dynamic imagery interventions is finally proposed.

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.

Limb disuse has substantial maladaptive behavioral consequences, suggesting that a sustained stream of sensory inputs and motor outputs is necessary for the maintenance of optimal motor functions. Besides the actual execution of movements, the activation of mental representation of movements alone, or Motor Imagery (MI), is known to significantly engage motor networks. Based in such observation, MI should, at least in part, compensate for maladaptive neuroplasticity elicited by immobilization. Although highly relevant for clinical conditions associated with transient (e.g. after orthopedic injury) or chronic (e.g. after stroke) limb immobilization, this hypothesis and associated underlying neural mechanisms remain underexplored. Moreover, durable changes due to immobilization may also implicate sleep processes. To address these questions, here we investigated the potential benefits of MI practice during 11 h of unilateral arm-immobilization on the sensorimotor and cortical representations of the arms, as well as on subsequent sleep characteristics. Using a within-subjects design, fourteen participants were first tested after a normal day of motor activity (without immobilization, Baseline), followed by two randomized 11-hr conditions of immobilization of the right (dominant) arm, either with concomitant MI practice (15 min every two hours; MI) or without MI training but a neutral task during an equivalent time (NoMI), one week apart. At the end of each condition (Baseline, MI, NoMI), participants were tested on a hand laterality judgment task to assess changes in the sensorimotor representation of the hands, followed by a measure of cortical excitability of the primary motor cortices (M1). Polysomnography recordings were acquired during the subsequent night to assess condition-dependent modulations of sleep features. Data revealed that MI practice prevented the following consequences of arm immobilization: (i) alteration of the sensorimotor representation of hands, (ii) decrease of cortical excitability over M1 contralateral to arm-immobilization, (iii) reduction of sleep spindles over both M1s, and (iv) decrease in total time spent in REM sleep. Altogether, these results provide strong evidence that implementing MI within the context of limb-immobilization can substantially limit the deleterious effects of limb disuse, at several levels of sensorimotor functioning. Highlights MI prevents the impairment of sensorimotor representation caused by immobilization M1 excitability contralateral to immobilization is preserved with MI practice REM sleep duration is prolonged following MI practice Reduced sleep spindles over both M1s after immobilization is counteracted by MI practice

Action observation (AO) alone or combined with motor imagery (AO + 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) AO + 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 AO + MI outperformed the Control condition in terms of total force (2.79–3.68%, p

We aimed at studying the effect of Motor Imagery (MI), i.e., the mental representation of a movement without executing it, on breath-holding performance. Classical guidelines for efficient MI interventions advocate for a congruent MI practice with regards to the requirements of the physical performance, specifically in terms of physiological arousal. We specifically aimed at studying whether an incongruent form of MI practice might enhance the breath-hold performance. In a counterbalanced design including three experimental sessions, participants engaged in maximal breath-hold trials while concomitantly performing i) MI of breathing, ii) MI of breath-hold, and iii) an "ecological" breath-hold trial, i.e., without specific instructions of MI practice. In addition to breath-hold durations, we measured the cardiac activity and blood oxygen saturation. Performance was improved during MI of breathing (73.06 s ± 24.53) compared to both MI of breath-hold (70.57 s ± 18.15) and the control condition (67.67 s ± 19.27) (p 0.05). The mechanisms underlying breath-hold performance improvements during MI of breathing remain uncertain. MI of breathing might participate to decrease the threat perception associated with breath-holding, presumably due to psychological and physiological effects associated with the internal simulation of a breathing body state.

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.

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.

Limb immobilization paradigms are increasingly used to investigate changes in brain plasticity and support potential rehabilitation techniques that might help counteract motor impairments. Yet, it remains unclear how unilateral arm immobilization may influence the sensorimotor representation and functional output for both arms. Using a randomized crossover design, 14 participants underwent a baseline test, followed by two experimental conditions separated by 1 week: a right (dominant) arm immobilization phase over a period of 8 hr and a no-immobilization (or control) phase also lasting 8 hr. Before and after each condition, participants were tested on a hand laterality judgment task to assess changes in sensorimotor representation of the hands, followed by an out-and-back reaching motor task measuring changes in spatiotemporal components of motor actions. Data from the hand laterality judgment task revealed that participants were faster at identifying right-hand pictures after the control phase, but such improvement was not observed after the immobilization phase, with no effect of immobilization for pictures depicting the overused left hand. Results from the reaching motor task revealed that the right-arm movement planning component was altered after immobilization, whereas there was no effect for the overused left arm. Altogether, these findings demonstrate that an 8-hr period of unilateral immobilization affects sensorimotor representation and functions of the corresponding limb, but not of the overused, nonimmobilized hand. (PsycINFO Database Record (c) 2018 APA, all rights reserved).

Motor imagery contributes to enhance the (re)learning of motor skills through remapping of cortical networks. Combining motor imagery with anodal transcranial direct-current stimulation (a-tDCS) over the primary motor cortex has further been shown to promote its beneficial effects on postural control. Whether motor imagery should be performed concomitantly to a-tDCS (over depolarized membrane) or consecutively (over changing neurotransmitters activity) remains to be elucidated. In the present study, we measured the performance in a postural control task before and after three experimental conditions. Participants received a-tDCS before (tDCSBefore), during (tDCSDuring), or both before and during motor imagery training (tDCSBefore + During). Performance was improved after tDCSDuring, but not after both the tDCSBefore and tDCSBefore + During conditions. These results support that homeostatic plasticity is likely to operate following a-tDCS through decreasing cortical excitability and that motor imagery should be performed during anodal stimulation for optimum gains.

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.

Il est desormais bien etabli que le sommeil joue un role benefique dans les mecanismes de consolidation de sequences motrices. Quelques etudes experimentales recentes ont commence a s’interesser aux gains potentiels de performance a la suite d’une pratique par imagerie motrice. Cet article synthetise l’ensemble de ces resultats, obtenus a l’aide de diverses approches methodologiques comprenant des mesures comportementales et des enregistrements polysomnographiques, ou utilisant des paradigmes interferentiels (comportementaux ou par stimulation magnetique transcrânienne). Les donnees demontrent que le sommeil, contrairement a la simple passation de temps au cours de la journee, favorise la consolidation de la trace mnesique apres un entrainement mental. Ces resultats sont discutes au regard des effets observes apres une pratique physique. Leur portee devrait contribuer a mieux planifier les seances d’imagerie motrice afin d’en augmenter l’efficacite dans les domaines de l’apprentissage et de la rehabilitation des fonctions motrices.

There is now compelling evidence that motor imagery (MI) promotes motor learning. While MI has been shown to influence the early stages of the learning process, recent data revealed that sleep also contributes to the consolidation of the memory trace. How such “online” and “offline” processes take place and how they interact to impact the neural underpinnings of movements has received little attention. The aim of the present review is twofold: i) providing an overview of recent applied and fundamental studies investigating the effects of MI practice on motor learning, and ii) detangling applied and fundamental findings in support of a sleep contribution to motor consolidation after MI practice. We conclude with an integrative approach of online and offline learning resulting from intense MI practice in healthy participants, and underline research avenues in the motor learning/clinical domains.

The present experiment investigated whether motor imagery (MI) performed at a faster speed might influence the actual motor performance duration by comparing real-time vs. fast MI of different finger movement sequences. Forty-eight participants were either asked to do real-time or fast MI practice of simple 8-digit (unimanual), complex 8-digit (bimanual), and long (16-digit) finger movement sequences. The main findings revealed that both fast and real-time MI resulted in actual speed gains in all experimental conditions, hence suggesting that performing fast MI did not systematically provide additional benefits as compared to real-time MI. Interestingly, the results suggested that the speed at which movements were performed following an increase in MI speed was selectively influenced by the complexity of the task. MI training at higher speed seemed to be more effective in changing complex motor sequences compared with real-time MI. Practical implications in motor learning and rehabilitation are also discussed. Copyright © 2010 John Wiley & Sons, Ltd. Language: en

THERE IS NOW COMPELLING EVIDENCE THAT SLEEP CONTRIBUTES TO THE CONSOLIDATION PROCESS OF PROCEDURAL TYPES OF MEMORY,1–3 AND OF MOTOR-sequence learning in particular.4–9 The term memory consolidation refers to a poorly defined set of processes that convert an initial unstable memory representation into a more stable and effective form.10 More specifically, Stickgold and Walker10 also proposed that this term should refer to the automatic postencoding processing occurring without intent or awareness but not to those requiring conscious and behavioral rehearsal. Practically, researchers have reported the existence of delayed gains in performance using a sequential finger-tapping task after a night of sleep but not after a comparable time interval during daytime.6,11–13 These findings support the role of sleep in the offline processing or reprocessing of memories,10 and some authors have even suggested that physical practice (PP) should ideally be followed by sleep to ensure long-lasting storage of a newly acquired motor skill.5,8,14–16 By contrast, research investigating the possibility of sleep-related improvements in motor learning following mental practice with motor imagery (MI) has been almost nonexistent (see1, for an exception). Motor imagery is a dynamic state during which one mentally simulates an action without any concomitant body movement.16 Studies looking at this learning-enhancing technique have shown that MI and PP of motor tasks show several parallel outcome characteristics, as shown by their degree of similarity at the temporal, behavioral, and neural levels.18–22 Findings from these experiments have provided evidence that the time course of mentally simulated actions is correlated with that taken to execute the same movement. Second, the analysis of the autonomic nervous system activity shows similar responses during imagined and actual movements. Finally, brain-mapping techniques have shown that goal-directed actions, whether executed or imagined, recruit similar (albeit nonidentical) neural substrates. Practically, MI has been found to be effective in the rehabilitation of patients with neurologic disorders affecting the motor system.23–25 In an attempt to explore whether mental practice with MI can also elicit consolidation processes similar to those observed following PP, we have recently tested young healthy subjects who were required to imagine that they were performing a kinematic motor-adaptation task before and after a night of sleep.1 Interestingly, practice with MI produced a significant increase in the subjects' speed to complete the target-reaching task following sleep, suggesting that this physiologic state plays a role in the consolidation of newly learned adapted movements. Our interpretation of such findings was limited, however, by the fact that we could not exclude the possibility that performance gains were also partially due to the speed at which movements were performed during the MI condition. Indeed, all participants strongly underestimated the time needed to reach each target, i.e., they imagined doing the task faster than when they were physically performing the movements. Such a lack of temporal congruence between the actual and imagined movements is known to result in a significant decrease in movement time.26–27 Changing MI speed (voluntarily or not) is sufficient to elicit changes in the timing of actual movements, and it was therefore difficult to determine the influence of such effect, as compared with the contribution of sleep, to explain performance gains. Second, our previous study did not include any group that was trained and retested during the daytime, and, thus, it was not possible to determine whether the gain in performance following MI was sleep dependent or was also due to the simple passage of time. The present study thus aimed to test further the hypothesis that mental practice of a motor sequence learning task with MI can elicit a consolidation process similar to that observed following PP of the same task. To do so, we used an adapted version of the sequential finger-tapping task first developed by Karni et al.28 This task was chosen because it is known that consolidation of this type of motor skill is sleep dependent,4,6,8 and because there is evidence of a temporal congruence between the physical and imagined conditions.29 Indeed, investigators have previously shown that the time necessary to imagine a sequence of finger movements does not differ from that needed to physically produce the same sequential movements29 and that MI is effective in improving the performance on this type of motor skill.30 In the present study, motor performance was evaluated before training, as well as before and after a night of sleep, or after a similar time interval without sleep during the daytime. Groups of young healthy participants were either asked to PP or to imagine an explicitly known motor sequence. Subjects in the MI condition were required to perform the sequence in real time (rtMI) or at a faster pace than usual (fMI) to control for possible effects of different mental representations on motor memory consolidation. Specifically, comparing 2 MI-speed conditions was a prerequisite to identify whether voluntary changes in MI speed play a specific and critical role in explaining performance gains. Last, a final NoSleep (control) group, in which subjects were trained and retested the same day (without any intervening sleep) after rtMI practice, was also included to test for the role of passage of time in consolidating this form of learning. We predicted that all groups would demonstrate a significant improvement in performance following the initial training session. Subjects in the PP, rtMI, and fMI conditions were also expected to show delayed gains in performance, whereas those in the NoSleep group were not. Finally, based on findings from our previous study,1 we hypothesized that greater offline delayed gains would be observed in the fMI group, compared with the rtMI group.

Prospective memory (PM) refers to a complex cognitive ability that underpins the delayed execution of previously formulated intentions. PM performance declines early in normal aging and this process is accentuated in Alzheimer's disease. The left frontopolar cortex (BA10) has been consistently assigned a major role in PM functioning, but whether it can be noninvasively modulated to enhance PM perfor- mance in aged people has not been addressed so far. Here, we investigated the effects of modulating left BA10 by means of theta burst stimulation (TBS), using either excitatory (intermittent TBS), inhibitory (continuous TBS) or control (vertex) TBS in healthy aged subjects. The behavioral effects were assessed using a reliable and ecological virtual reality PM task that included both event- and time-based retrievals. As compared with vertex stimulation, event-based PM performance significantly improved after excit- atory stimulation, whereas inhibitory stimulation had no significant effect. Additionally, and across the different types of stimulation, performance for congruent links between the event-based PM cue and the action to be performed was significantly better as compared with incongruent links. In conclusion, intermittent TBS might provide a relevant interventional strategy to counteract the decline of cognitive functions and memory abilities in normal aging.

Skill learning is the improvement in perceptual, cognitive, or motor performance following practice. Expert performance levels can be achieved with well-organized knowledge, using sophisticated and specific mental representations and cognitive processing, applying automatic sequences quickly and efficiently, being able to deal with large amounts of information, and many other challenging task demands and situations that otherwise paralyze the performance of novices. The neural reorganizations that occur with expertise reflect the optimization of the neurocognitive resources to deal with the complex computational load needed to achieve peak performance. As such, capitalizing on neuronal plasticity, brain modifications take place over time-practice and during the consolidation process. One major challenge is to investigate the neural substrates and cognitive mechanisms engaged in expertise, and to define “expertise” from its neural and cognitive underpinnings. Recent insights showed that many brain structures are recruited during task performance, but only activity in regions related to domain-specific knowledge distinguishes experts from novices. The present review focuses on three expertise domains placed across a motor to mental gradient of skill learning: sequential motor skill, mental simulation of the movement (motor imagery), and meditation as a paradigmatic example of “pure” mental training. We first describe results on each specific domain from the initial skill acquisition to the achieving of expert performance, including recent results on the corresponding underlying neural mechanisms. We then discuss differences and similarities between these domains with the aim to identify the highlights of the neurocognitive processes underpinning expertise, and conclude with suggestions for future research.

International audience; Motor-skill practice in repetitive or variable orders leads to better within-day acquisition and facilitates retention and transfer, respectively. This practice pattern effect has been robustly found for physical practice, but little is known about its effect after motor imagery (MI) practice. In the present study, we investigated the effect of constant or variable MI practice, and the consolidation following a day-time or a sleep interval. The physical performance was assessed before (pre-test) and after MI training (post-test), as well as after a night or day-time consolidation (retention test). Finally, a transfer test on an unpracticed task was further performed. Results revealed that in all participants, performance increased significantly in the post-test when compared with the pre-test, while only subjects in the variable MI training showed further gains in performance in the retention test following a night of sleep, and exhibited the best transfer of performance to a novel visuomotor sequence. In contrast, subjects in the constant MI training did not show any delayed performance gain following both day and sleep-consolidation. Overall, and for the first time, these findings partially support the practice pattern effect of motor learning with MI, and further highlight a new difference between mental and physical practice, especially on consolidation. To conclude, variable MI practice, rather than constant, seems to be the valuable condition that should be considered in the practical implications of mental training in motor learning and rehabilitation.

When people listen to music, they hear beat and a metrical structure in the rhythm; these perceived patterns enable coordination with the music. A clear correspondence between the tempo of actual movement (e.g., walking) and that of music has been demonstrated, but whether similar coordination occurs during motor imagery is unknown. Twenty participants walked naturally for 8m, either physically or mentally, while listening to slow and fast music, or not listening to anything at all (control condition). Executed and imagined walking times were recorded to assess the temporal congruence between physical practice (PP) and motor imagery (MI). Results showed a difference when comparing slow and fast time conditions, but each of these durations did not differ from soundless condition times, hence showing that body movement may not necessarily change in order to synchronize with music. However, the main finding revealed that the ability to achieve temporal congruence between PP and MI times was altered when listening to either slow or fast music. These data suggest that when physical movement is modulated with respect to the musical tempo, the MI efficacy of the corresponding movement may be affected by the rhythm of the music. Practical applications in sport are discussed as athletes frequently listen to music before competing while they mentally practice their movements to be performed.

Recent studies suggest that a night of sleep may play a similar functional role following motor imagery (MI) practice. Here we examined whether offline gains following MI of a finger tapping sequence depends on the degree of complexity of the motor sequence, and whether this improvement differentially affects the individual transitions of the motor-sequence pattern being learned. The data revealed greater delayed performance gains in motor skill procedures that were most difficult, with larger sleep-dependent overnight improvement for movements involving bimanual coordination. The analyses of single transitions between sequence elements further revealed greatest overnight improvement in speed for the slowest (i.e., most difficult) transitions at the re-test. These findings suggest that sleep-related performance gains for imagined movements depend on motor skill complexity, and that difficult transition movements are most effectively enhanced after a night of sleep.

Retroactive interference from a declarative memory can prevent the consolidation of motor skill memories over wakefulness, but not over a night of sleep. Recently, motor imagery (MI) learning has been showed to allow for a stronger resistance against procedural interference rather than physical practice, but whether declarative interference might impact sleep-dependent consolidation process of an explicit finger tapping task learned with MI remains unknown. To address this issue, 57 subjects mentally rehearsed an explicit finger tapping sequence, and half of them were then requested to practice an interferential declarative task. All participants were re-tested on the initial procedural task either after a night of sleep or a similar daytime interval. The main findings provided evidence that declarative interference affected MI consolidation both over the night- and wakefulness intervals. These results extend our previous findings by underlying that declarative interference might impact more strongly explicit MI practice than physical practice, hence suggesting that MI might rely on declarative memory rather than exclusively on procedural memory system. The relationship between declarative and procedural memories during MI practice, as well as during off-line consolidation, is discussed.

International audience; In this study, we examined the effect of circadian modulation on motor imagery (MI) time while also considering the effects of task complexity and duration. The ability to imagine in real time was influenced by circadian modulation in a simple walking condition, with longer MI times in the morning and evening sessions. By contrast, there was no effect of circadian rhythm in the complex, short or long walking conditions. We concluded that motor imagery time is modulated during the course of the day, but the effect of task difficulty is stronger than circadian modulation in altering the temporal congruence between physical practice and MI performance. Practical applications in motor learning and rehabilitation are discussed.

Sleep is known to contribute to motor memory consolidation. Recent studies have provided evidence that a night of sleep plays a similar functional role following motor imagery (MI), while the simple passage of time does not result in performance gains. Here, we examined the benefits of a daytime nap on motor memory consolidation after MI practice. Participants were trained by MI on an explicitly known sequence of finger movements at 11:00. Half of the participants were then subjected (at 14:00) to either a short nap (10 min of stage 2 sleep) or a long nap (60-90 min, including slow wave sleep and rapid eye movement sleep). We also collected data from both quiet and active rest control groups. All participants remained in the lab until being retested at 16:00. The data revealed that a daytime nap after imagery practice improved motor performance and, therefore, facilitated motor memory consolidation, as compared with spending a similar time interval in the wake state. Interestingly, the results revealed that both short and long naps resulted in similar delayed performance gains. The data might also suggest that the presence of slow wave and rapid eye movement sleep does not provide additional benefits for the sleep-dependent motor skill consolidation following MI practice.

International audience; Physical practice is known to enhance motor adaptation skills, which refer to the individual ability to compensate for environmental changes. So far, it is still unknown whether a similar effect can be observed following motor imagery (MI). Thirty-nine participants were tested during a joystick tracking task under both normal and mirror conditions (i.e., the inductive direction of the joystick was reversed), before and after a physical practice or MI training phase. Eye movements and electromyographic activity were recorded during MI. Motor performance was also evaluated after a 6 h interval during daytime. As compared to the control group, the results revealed that both MI and physical practice improved motor performance in the mirror condition, during the post-training test. Furthermore, the time to complete the task was further reduced after 6 hours, both in the normal and mirror conditions. These results demonstrate the effectiveness of MI for learning mirror-reversed movements, and for the consolidation process that follows motor adaptation.

The present study aimed to investigate whether an interference task might impact the sleep-dependent consolidation process of a mentally learned sequence of movements. Thirty-two participants were subjected to a first training session through motor imagery (MI) or physical practice (PP) of a finger sequence learning task. After 2 h, half of the participants were requested to perform a second interfering PP task (reversed finger sequence). All participants were finally re-tested following a night of sleep on the first finger sequence. The main findings revealed delayed performance gains following a night of sleep in the MI group, i.e. the interfering task did not alter the consolidation process, by contrast to the PP group. These results confirm that MI practice might result in less retroactive interference than PP, and further highlight the relevance of the first night of sleep for the consolidation process following MI practice. These data might thus contribute to determine in greater details the practical implications of mental training in motor learning and rehabilitation.

A wide range of experimental studies have provided evidence that a night of sleep may enhance motor performance following physical practice (PP), but little is known, however, about its effect after motor imagery (MI). Using an explicitly learned pointing task paradigm, thirty participants were assigned to one of three groups that differed in the training method (PP, MI, and control groups). The physical performance was measured before training (pre-test), as well as before (post-test 1) and after a night of sleep (post-test 2). The time taken to complete the pointing tasks, the number of errors and the kinematic trajectories were the dependent variables. As expected, both the PP and the MI groups improved their performance during the post-test 1. The MI group was further found to enhance motor performance after sleep, hence suggesting that sleep-related effects are effective following mental practice. Such findings highlight the reliability of MI in learning process, which is thought consolidated when associated with sleep.

A wide range of experimental studies have provided evidence that a night of sleep contributes to memory consolidation. Mental rotation (MR) skill is characterized by fundamental aspect of both cognitive and motor abilities which can be improved within practice sessions, but little is known about the effect of consolidation after MR practice. In the present study, we investigated the effect of MR training and the following corresponding day- and sleep-related time consolidations in taking into account the well-established gender difference in MR. Forty participants (20 women) practiced a computerized version of the Vandenberg and Kuse MR task. Performance was evaluated before MR training, as well as prior to, and after a night of sleep or a similar daytime interval. Data showed that while men outperformed women during the pre-training test, brief MR practice was sufficient for women to achieve equivalent performance. Only participants subjected to a night of sleep were found to enhance MR performance during the retest, independently of gender. These results provide first evidence that a night of sleep facilitates MR performance compared with spending a similar daytime interval, regardless gender of the participants. Since MR is known to involve motor processes, the present data might contribute to schedule relevant mental practice interventions for fruitful applications in rehabilitation and motor learning processes.

Recently, it has been suggested that the primary motor cortex (M1) plays a critical role in implementing the fast and transient post-training phase of motor skill consolidation, known to yield an early boost in performance. Whether a comparable early boost in performance occurs following motor imagery (MIM) training is still unknown. To address this issue, two groups of subjects learned a finger tapping sequence either by MIM or physical practice (PP). In both groups, performance increased significantly in the post-training phase when compared with the pre-training phase and further increased after a 30 min resting period, indicating that both MIM and PP trainings were equally efficient and induced an early boost in motor performance. This conclusion was corroborated by the results of an additional control group. In a second experiment, we then investigated the causal role of M1 in implementing the early boost process resulting from MIM training. To do so, we inhibited M1 by applying a continuous theta-burst stimulation (cTBS) in healthy volunteers just after they learnt, by MIM, the same finger-tapping task as in Experiment #1. As a control, cTBS was applied over the vertex of subjects who underwent the same experiment. We found that cTBS applied over M1 selectively abolished the early boost process subsequent to MIM training. Altogether, the present study provides evidence that MIM practice induces an early boost in performance and demonstrates that M1 is causally involved in this process. These findings further divulge some degree of behavioral and neuronal similitude between MIM and PP.