When an actor performs a rhythmic limb movement while observing a spatially incongruent movement he or she exhibits increased movement orthogonal to the instructed motion. Known as rhythmic movement interference, this phenomenon has been interpreted as a motor contagion effect, whereby observing the incongruent movement interferes with the intended movement and results in a motor production error. Here we test the hypothesis that rhythmic movement interference is an emergent property of rhythmic coordination. Participants performed rhythmic limb movements at a self-selected tempo while observing a computer stimulus moving in a congruent or incongruent manner. The degree to which participants visually tracked the stimulus was manipulated to influence whether participants became spontaneously entrained to the stimulus or not. Consistent with the rhythmic coordination hypothesis, participants only exhibited the rhythmic movement interference effect when they became spontaneously entrained to the incongruent stimulus.

Brain-computer interface (BCI) has been widely used in sports training and rehabilitation training. It is primarily based on action simulation, including movement imagery (MI) and movement observation (MO). However, the development of BCI technology is limited due to the challenge of getting an in-depth understanding of brain networks involved in MI, MO, and movement execution (ME). To better understand the brain activity changes and the communications across various brain regions under MO, ME, and MI, this study conducted the fist experiment under MO, ME, and MI. We recorded 64-channel electroencephalography (EEG) from 39 healthy subjects (25 males, 14 females, all right-handed) during fist tasks, obtained intensities and locations of sources using EEG source imaging (ESI), computed source activation modes, and finally investigated the brain networks using spectral Granger causality (GC). The brain regions involved in the three motor conditions are similar, but the degree of participation of each brain region and the network connections among the brain regions are different. MO, ME, and MI did not recruit shared brain connectivity networks. In addition, both source activation modes and brain network connectivity had lateralization advantages.

Background Morphine administration is a strong predictor of delayed onset of action of orally administered ticagrelor in patients with ST-segment-elevation myocardial infarction, likely because of impaired gastrointestinal motility. The aim of this study was to evaluate whether the peripheral opioid antagonist methylnaltrexone could improve pharmacodynamics and pharmacokinetics of orally administered ticagrelor in patients with ST-segment-elevation myocardial infarction receiving morphine. Methods and Results The MOVEMENT (Methylnaltrexone to Improve Platelet Inhibition of Ticagrelor in Morphine-Treated Patients With ST-Segment Elevation Myocardial Infarction) trial was a multicenter, prospective, randomized, controlled trial in patients with ST-segment-elevation myocardial infarction treated with morphine and ticagrelor. Upon arrival to the catheterization laboratory, patients were randomized to a blinded intravenous injection of either methylnaltrexone (8 or 12 mg according to weight) or 0.9% sodium chloride. The proportion of patients with high on-treatment platelet reactivity and plasma concentrations of ticagrelor and AR -C124910XX were assessed at baseline (arrival in the catheterization laboratory) and 1 and 2 hours later. A total of 82 patients received either methylnaltrexone (n=43) or placebo (n=39). Median (interquartile range) time from ticagrelor administration to randomization was 41 (31-50) versus 45.5 (37-60) minutes ( P=0.16). Intravenous methylnaltrexone administration did not significantly affect prevalence of high on-treatment platelet reactivity at 2 hours after inclusion, the primary end point, when compared with placebo (54% versus 51%, P=0.84). Plasma concentrations of ticagrelor and its active metabolite, the prespecified secondary end points, did not differ significantly between the groups over time. There was no significant difference in patient self-estimated pain between the groups. Conclusions Methylnaltrexone did not significantly improve platelet reactivity or plasma concentrations of orally administered ticagrelor in patients with ST-segment-elevation myocardial infarction receiving morphine. Clinical Trial Registration URL : http://www.clinicaltrials.gov . Unique identifier: NCT 02942550.

This paper highlights major developments over the past two to three decades in the neuropsychology of movement and its disorders. We focus on studies in healthy individuals and patients, which have identified cognitive contributions to movement control and animal work that has delineated the neural circuitry that makes these interactions possible. We cover advances in three major areas: (1) the neuroanatomical aspects of the "motor" system with an emphasis on multiple parallel circuits that include cortical, corticostriate, and corticocerebellar connections; (2) behavioral paradigms that have enabled an appreciation of the cognitive influences on the preparation and execution of movement; and (3) hemispheric differences (exemplified by limb praxis, motor sequencing, and motor learning). Finally, we discuss the clinical implications of this work, and make suggestions for future research in this area. (JINS, 2017, 23, 768-777).

This study aims to determine whether response inhibition shows the same degree of effectiveness for two sources of motor complexity: (1) Movement complexity, which is measured through two actions with different motor requirements (simple lifting action vs. complex reaching action), and (2) Movement type selection, which is measured in movements performed separately (no active-movement type selection) vs. selectively (active-movement type selection). Activation-suppression model was tested in three experiments to measure activation of the preponderant responses and subsequent suppression in a Simon task. More errors and higher magnitude of congruence effect (which reflects greater effectiveness of response suppression) were expected for more difficult motor conditions. Reaction time, movement time, kinematic errors, and movement errors were recorded. Results of Experiment 1, in which movement type selection was not active, showed that both movements did not differ in their activation and suppression, as they presented similar kinematic error rates and Simon effects. Experiment 2, in which movement type selection was active, resulted in a higher kinematic error rate and higher magnitude of Simon effect in lifting. These results were confirmed in Experiment 3, in which participants performed all experimental motor complexity conditions. Finally, Experiment 4 showed that responses with similar movement complexity did not differ in their activation and suppression, even when movement type selection was active. Thus, the present study provides evidence on the varying effectiveness of response inhibition as a function of movement complexity, but only in demanding situations in which movement type selection is active. These results can be attributed to a top-down strategy to minimize error for actions most prone to develop kinematic error.

Electroencephalographic (EEG) event-related desynchronization (ERD) induced by movement imagery or by observing biological movements performed by someone else has recently been used extensively for brain-computer interface-based applications, such as applications used in stroke rehabilitation training and motor skill learning. However, the ERD responses induced by the movement imagery and observation might not be as reliable as the ERD responses induced by movement execution. Given that studies on the reliability of the EEG ERD responses induced by these activities are still lacking, here we conducted an EEG experiment with movement imagery, movement observation, and movement execution, performed multiple times each in a pseudorandomized order in the same experimental runs. Then, independent component analysis (ICA) was applied to the EEG data to find the common motor-related EEG source activity shared by the three motor tasks. Finally, conditional EEG ERD responses associated with the three movement conditions were computed and compared. Among the three motor conditions, the EEG ERD responses induced by motor execution revealed the alpha power suppression with highest strengths and longest durations. The ERD responses of the movement imagery and movement observation only partially resembled the ERD pattern of the movement execution condition, with slightly better detectability for the ERD responses associated with the movement imagery and faster ERD responses for movement observation. This may indicate different levels of involvement in the same motor-related brain circuits during different movement conditions. In addition, because the resulting conditional EEG ERD responses from the ICA preprocessing came with minimal contamination from the non-related and/or artifactual noisy components, this result can play a role of the reference for devising a brain-computer interface using the EEG ERD features of movement imagery or observation.

While much is known about motor control during simple movements, corticomuscular communication profiles during compound movement control remain largely unexplored. Here, we aimed at examining frequency band related interactions between brain and muscles during different movement periods of a bipedal squat (BpS) task utilizing regression corticomuscular coherence (rCMC), as well as partial directed coherence (PDC) analyses. Participants performed 40 squats, divided into three successive movement periods (Eccentric (ECC), Isometric (ISO) and Concentric (CON)) in a standardized manner. EEG was recorded from 32 channels specifically-tailored to cover bilateral sensorimotor areas while bilateral EMG was recorded from four main muscles of BpS. We found both significant CMC and PDC (in beta and gamma bands) during BpS execution, where CMC was significantly elevated during ECC and CON when compared to ISO. Further, the dominant direction of information flow (DIF) was most prominent in EEG-EMG direction for CON and EMG-EEG direction for ECC. Collectively, we provide novel evidence that motor control during BpS is potentially achieved through central motor commands driven by a combination of directed inputs spanning across multiple frequency bands. These results serve as an important step toward a better understanding of brain-muscle relationships during multi joint compound movements.

Performance of voluntary behavior requires the selection of appropriate movements to attain a desired goal. We propose that the selection of voluntary movements is often contingent on the formation of a movement heuristic or set of internal rules governing movement selection. We used event-related potentials (ERPs) to identify the electrophysiological correlates of the formation of movement heuristics during movement-outcome learning. In two experiments, ERPs from non-learning control tasks were compared to a movement-learning task in which a movement heuristic was formed. We found that novelty P3 amplitude was negatively correlated with improved performance in the movement-learning task. Additionally, enhancement of novelty P3 amplitude was observed during learning even after controlling for memory, attentional and inter-stimulus interval parameters. The feedback correct-related positivity (fCRP) was only elicited by sensory effects following intentional movements. These findings extend previous studies demonstrating the role of the fCRP in performance monitoring and the role of the P3 in learning. In particular, the present study highlights an integrative role of the fCRP and the novelty P3 for the acquisition of movement heuristics. While the fCRP indicates that the goal of intentional movements has been attained, the novelty P3 engages stimulus-driven attentional mechanisms to determine the primary aspects of movement and context required to elicit the sensory effect.

Knee joint functional deficits are common after anterior cruciate ligament (ACL) injury, but different assessment methods of joint function seem to provide contradicting information complicating recovery monitoring. We previously reported improved perceived knee function and functional performance (forward lunge ground contact time) in patients with an ACL injury from pre to 10 months post ACL reconstruction without improvement in knee-specific biomechanics. To further investigate this discrepancy, we additionally analyzed knee extensor and flexor muscle strength, and movement quality in the forward lunge (subjective and objective evaluations) and performed a full lower limb biomechanical analysis of the forward lunge movement. We included 12 patients with an ACL injury (tested before and after ACL reconstructive surgery) and 15 healthy controls from the previous study to the current investigation. Outcome measures were obtained pre and ~11 months post ACL reconstruction for the patients and at a single time point for the controls. Objective movement quality in the patients with an ACL injury showed an improvement from their pre reconstruction surgery visit to the post reconstruction visit but this was not observable in the subjective evaluation. Knee extensor muscle strength declined after the ACL reconstruction by 29% (p = 0.002) and both knee extensors (p < 0.001) and flexors (p = 0.027) were weaker in the patients post ACL reconstruction compared to healthy controls. ACL injured patients had an altered movement strategy in the forward lunge with reduced knee extensors contribution and increased hip extensor contribution compared to the controls both before and after the reconstruction. The altered movement strategy was associated with knee extensor muscle strength. This explorative study with a limited sample size found that clinicians should be aware that significant functional deficits in the knee extensor muscles, both in isolated muscle strength testing and during a functional movement, may be present although patients perceive an improvement in their knee function and present good functional performance without obvious movement quality issues.

The aim of the study was to investigate the relationship between motor surround inhibition (mSI) and the modulation of somatosensory temporal discrimination threshold (STDT) induced by voluntary movement. Seventeen healthy volunteers participated in the study. To assess mSI, we delivered transcranial magnetic stimulation (TMS) single pulses to record motor evoked potentials (MEPs) from the right abductor digiti minimi (ADM; "surround muscle") during brief right little finger flexion. mSI was expressed as the ratio of ADM MEP amplitude during movement to MEP amplitude at rest. We preliminarily measured STDT values by assessing the shortest interval at which subjects were able to recognize a pair of electric stimuli, delivered over the volar surface of the right little finger, as separate in time. We then evaluated the STDT by using the same motor task used for mSI. mSI and STDT modulation were evaluated at the same time points during movement. mSI and STDT modulation displayed similar time-dependent changes during index finger movement. In both cases, the modulation was maximally present at the onset of the movement and gradually vanished over about 200 ms. Our study provides the first neurophysiological evidence about the relationship between mSI and tactile-motor integration during movement execution.

Prediction errors guide many forms of learning, providing teaching signals that help us improve our performance. Implicit motor adaptation, for instance, is thought to be driven by sensory prediction errors (SPEs), which occur when the expected and observed consequences of a movement differ. Traditionally, SPE computation is thought to require movement execution. However, recent work suggesting that the brain can generate sensory predictions based on motor imagery or planning alone calls this assumption into question. Here, by measuring implicit motor adaptation during a visuomotor task, we tested whether motor planning and well-timed sensory feedback are sufficient for adaptation. Human participants were cued to reach to a target and were, on a subset of trials, rapidly cued to withhold these movements. Errors displayed both on trials with and without movements induced single-trial adaptation. Learning following trials without movements persisted even when movement trials had never been paired with errors and when the direction of movement and sensory feedback trajectories were decoupled. These observations indicate that the brain can compute errors that drive implicit adaptation without generating overt movements, leading to the adaptation of motor commands that are not overtly produced.

Delay in initiation of rapid voluntary eye movements (saccades) in bradykinetic parkinsonian patients and normal subjects was recorded with and without postural disturbances (rotation of the body and head). Parkinsonian patients as a group exhibited longer delays in the initiation of saccades. The delay increased during postural disturbance in both the patients and the normal subjects. The study failed to substantiate the hypothesis that postural reflexes interfere with the initiation of voluntary movement in Parkinsonism.

The neural simulation theory predicts similarity for the neural mechanisms subserving overt (motor execution) and covert (movement imagination) actions. Here we tested this prediction for movement preparation, a key characteristic of motor cognition.

Gamma activity in the subthalamic nucleus (STN) is widely viewed as a pro-kinetic rhythm. Here we test the hypothesis that rather than being specifically linked to movement execution, gamma activity reflects dynamic processing in this nucleus. We investigated the role of gamma during fast stopping and recorded scalp electroencephalogram and local field potentials from deep brain stimulation electrodes in 9 Parkinson's disease patients. Patients interrupted finger tapping (paced by a metronome) in response to a stop-signal sound, which was timed such that successful stopping would occur only in ~50% of all trials. STN gamma (60-90 Hz) increased most strongly when the tap was successfully stopped, whereas phase-based connectivity between the contralateral STN and motor cortex decreased. Beta or theta power seemed less directly related to stopping. In summary, STN gamma activity may support flexible motor control as it did not only increase during movement execution but also during rapid action-stopping.

Do movement plans, like representations in working memory, share a limited pool of resources? If so, the precision with which each individual movement plan is specified should decrease as the total number of movement plans increases. To explore this, human participants made speeded reaching movements toward visual targets. We examined if preparing one movement resulted in less variability than preparing two movements. The number of planned movements was manipulated in a delayed response cueing procedure that limited planning to a single target (experiment 1) or hand (experiment 2) or required planning of movements toward two targets (or with two hands). For both experiments, initial movement direction variability was higher in the two-plan condition than in the one-plan condition, demonstrating a cost associated with planning multiple movements, consistent with the limited resource hypothesis. In experiment 3, we showed that the advantage in initial variability of preparing a single movement was present only when the trajectory could be fully specified. This indicates that the difference in variability between one and two plans reflects the specification of full motor plans, not a general preparedness to move. The precision cost related to concurrent plans represents a novel constraint on motor preparation, indicating that multiple movements cannot be planned independently, even if they involve different limbs.

Cerebellar climbing fibers convey sensorimotor information and their errors, which are used for motor control and learning. Furthermore, they represent reward-related information. Despite such functional diversity of climbing fiber signals, it is still unclear whether each climbing fiber conveys the information of single or multiple modalities and how the climbing fibers conveying different information are distributed over the cerebellar cortex. Here we perform two-photon calcium imaging from cerebellar Purkinje cells in mice engaged in a voluntary forelimb lever-pull task and demonstrate that climbing fiber responses in 68% of Purkinje cells can be explained by the combination of multiple behavioral variables such as lever movement, licking, and reward delivery. Neighboring Purkinje cells exhibit similar climbing fiber response properties, form functional clusters, and share noise fluctuations of responses. Taken together, individual climbing fibers convey behavioral information on multiplex variables and are spatially organized into the functional modules of the cerebellar cortex.

No abstract available

Functional movement disorders (FMDs) have been rarely described in the elderly population.

Coordination of bilateral movements is essential for a large variety of animal behaviors. The olivocerebellar system is critical for the control of movement, but its role in bilateral coordination has yet to be elucidated. Here, we examined whether Purkinje cells encode and influence synchronicity of left-right whisker movements. We found that complex spike activity is correlated with a prominent left-right symmetry of spontaneous whisker movements within parts, but not all, of Crus1 and Crus2. Optogenetic stimulation of climbing fibers in the areas with high and low correlations resulted in symmetric and asymmetric whisker movements, respectively. Moreover, when simple spike frequency prior to the complex spike was higher, the complex spike-related symmetric whisker protractions were larger. This finding alludes to a role for rebound activity in the cerebellar nuclei, which indeed turned out to be enhanced during symmetric protractions. Tracer injections suggest that regions associated with symmetric whisker movements are anatomically connected to the contralateral cerebellar hemisphere. Together, these data point toward the existence of modules on both sides of the cerebellar cortex that can differentially promote or reduce the symmetry of left and right movements in a context-dependent fashion.

Stroke often affects arm functions and thus impairs patients' daily activities. Recently, several studies have shown that additional movement acoustics can enhance motor perception and motor control. Therefore, a new method has been developed that allows providing auditory feedback about arm movement trajectories in real-time for motor rehabilitation after stroke. The present article describes the study protocol for a randomized, controlled, examiner, and patient blinded superiority trial (German Clinical Trials Register, www.drks.de, DRKS00011419), in which the method will be applied to 13 subacute stroke patients with hemiparesis during 12 sessions of 30 min each as additional feedback during the regular movement therapy. As primary outcome, a significant pre-post-change in the Box and Block Test is expected that exceeds the performance increase of 13 patients who will be provided with sham-acoustics. Possible limitations of the method as well as the study design are discussed.