Performance Of Motor Task Research Articles

Native learning ability and not age determines the effects of brain stimulation

Healthy aging often entails a decline in cognitive and motor functions, affecting independence and quality of life in older adults. Brain stimulation shows potential to enhance these functions, but studies show variable effects. Previous studies have tried to identify responders and non-responders through correlations between behavioral change and baseline parameters, but results lack generalization to independent cohorts. We propose a method to predict an individual’s likelihood of benefiting from stimulation, based on baseline performance of a sequential motor task. Our results show that individuals with less efficient learning mechanisms benefit from stimulation, while those with optimal learning strategies experience none or even detrimental effects. This differential effect, first identified in a public dataset and replicated here in an independent cohort, was linked to one’s ability to integrate task-relevant information and not age. This study constitutes a further step towards personalized clinical-translational interventions based on brain stimulation.

Characterizing practice-dependent motor learning after a stroke.

After stroke, patients must learn to use residual motor function correctly. Consistently, motor learning is crucial in stroke motor recovery. We assessed motor performance, practice-dependent on-line motor learning, and factors potentially affecting them in stroke patients. This is a cross-sectional observational study. Twenty-six patients with first brain stroke leading to upper limb motor deficit in the subacute or chronic timeframe were enrolled. They performed a Finger Tapping Task (FTT) with both the affected and unaffected limbs. We assessed how patients learn to perform motor tasks despite the motor deficit and the differences in performance between the unaffected and affected limbs. Furthermore, by randomizing the order, we evaluated the possible inter-limb transfer of motor learning (i.e. transfer of a motor skill learned in one limb to the opposite one). Moreover, sleep, attention, anxiety, and depression were assessed through specific tests and questionnaires. Improved FTT accuracy and completed sequences for the affected limb were observed, even if lower than for the unaffected one. Furthermore, when patients initially performed the FTT with the unaffected limb, they showed higher accuracy in subsequent task completion with the affected limb than subjects who started with the affected limb. Only anxiety and attentional abilities showed significant correlations with motor performance. This work provides relevant insights into motor learning in stroke. Practice-dependent on-line motor learning is preserved in stroke survivors, and an inter-limb transfer effect can be observed. Attentional abilities and anxiety can affect learning after stroke, even if the effect of other factors cannot be excluded.

FORMATION OF SENSIMOTOR FEELINGS IN CHILDREN OF YOUNGER SCHOOL AGE WITH DISORDERS OF INTELLECTUAL DEVELOPMENT

The article examines the features of sensorimotor development of children with intellectual disability (ID), who often face difficulties in coordination of movements, fine motor skills, sensory perception and spatial adaptation. Special attention is paid to how sensorimotor skills affect learning success, including writing, drawing, and performing everyday tasks. The generalization of literary sources confirms that sensorimotor development is important for cognitive activity, the formation of educational competencies and children’s behavior. The described motor assessment methods include aspects such as dynamic and reciprocal coordination, differentiation of movements, kinesthetic gnosis, optic-spatial coordination, rhythmicity, and praxis. Research results indicate significant difficulties in children with PIR, especially in the regulation of movements of fingers and hands, dynamic coordination and execution of serial movements. These problems can lead to significant difficulties in the performance of graphomotor skills, such as writing, drawing and other visual activities. Insufficiently developed motor skills negatively affect the overall development of the child and his ability to adapt in the educational environment. The article recommends a variety of remedial interventions, including finger gymnastics, art therapy techniques, and exercises with a variety of objects to improve sensorimotor skills. Special emphasis is placed on the need for a playful approach in working with children with PID, as well as speech support to facilitate the performance of complex motor tasks. A systematic approach, which takes into account the individual characteristics of each child and his personal immaturity, is the key to the successful correction of motor problems in children with impaired intellectual development.

Use your imagination for better performance. Effects of analogy instruction in motor skills. A systematic review and meta-analysis

This systematic review and meta-analysis examined the effects of analogy instruction (ANA) on motor performance and knowledge declared (KD) compared with explicit learning (EXP) and control conditions. Five databases were included. The study analyzed 16 randomized controlled trials. Subsequent analysis was performed for moderators variables as age, skill, retention, stress situations number of rules, specificity and number of trials. The ANA instruction demonstrated greater efficacy than the control (ES = 0.32, p = 0.03) or EXP condition (ES = 0.29, p = 0.02) in motor tasks performance in general terms. ANA instructions also showed superiority in motor performance when compared to control conditions in retention (ES = 5.72, p = 0.004), and a trend towards significance was found under stress (ES = 1.18, p = 0.05). ANA also showed superiority in motor performance when compared to EXP instruction (ES = 0.29, p = 0.02). ANA demonstrated greater effects than EXP in retention (ES = 7.25, p = 0.01), but not under stress (ES = 0.62, p = 0.18). Sub-analyses demonstrated that children (all p < 0.01) and novices (all p < 0.01) are more likely to benefit from ANA instruction when compared to control or EXP. A subgroup analysis based on quantity of information comparing ANA versus EXP condition shows that ANA is more effective for enhancing motor performance than EXP when the number of rules are similar. Sub-analyses comparing ANA versus CNT shows that as the number of repetitions increases and the task becomes less specific, ANA instruction significantly improves performance. A comparison between ANA and EXP indicates no significant differences in performance regarding the number of repetitions and task specificity. A secondary analysis examined KD of different instructions. KD was greater in EXP instructions (ES = −1.48, p < 0.001) when compared to ANA. Findings suggest that analogy instruction may improve motor performance, especially in novice and child populations. However, caution is needed due to concerns when comparing with other instructional types and environments, as well as due to high heterogeneity in most of the comparisons and high risk of bias in included studies.

The effect of motor dual-task training on gait and mobility performances in children with intellectual disabilities.

The study investigated the impact of motor dual-task training on gait and mobility in children with intellectual disabilities. Performance was assessed using the Timed Up and Go Test (TUGT) and the 10-Meter Walking Test (TMWT) before and after an 8-week training period, with participants divided into a Trained Group (n=12) and a Control Group (n=14). Results indicated that, across both groups and regardless of session, TUGT and TMWT scores were significantly higher (p < 0.001) in the motor dual-task condition compared to the single-task condition. Post-training, TUGT scores significantly decreased (p < 0.05) in the single-task condition. The Trained Group showed significant improvements in second motor-task performance on both TUGT (p < 0.05) and TMWT (p < 0.001) under dual-task conditions, while the Control Group showed no change. The study demonstrated the effectiveness of motor dual-task training in enhancing mobility in children with intellectual disabilities.

Obstacle negotiation while dual-tasking in children with Developmental Coordination Disorder (DCD): An augmented-reality approach

BackgroundChildren with Developmental Coordination Disorder (DCD) exhibit deficits in predictive motor control, balance, and aspects of cognitive control, which are important for safely negotiating obstacles while walking. As concurrent performance of cognitive and motor tasks (dual-tasking) may exacerbate these deficits, we examined motor and cognitive dual-tasking differences between children with DCD and their typically developing (TD) peers during obstacle negotiation. Methods34 children aged 6–12 years (16 TD, 18 DCD) walked along a 12 m path, stepping over an obstacle (30 % or 50 % of leg length) at its mid-point. On dual-task trials, participants completed a simple or complex (cognitive) visual discrimination task presented via an augmented reality headset. Proportional dual-task costs (pDTCs) were measured on cognitive and gait outcomes over three phases: pre-obstacle, obstacle step-over, and post-obstacle. ResultsDuring the obstacle step-over phase, both groups increased their leading leg clearance when dual-tasking, while the DCD group had larger pDTC than TD for the high obstacle under simple stimulus conditions (viz simple-high combination). The complex cognitive task produced larger pDTCs than the simple one on leading leg clearance and post-obstacle gait variability. ConclusionsIn general, both DCD and TD groups showed similar pDTCs under complex conditions, while the specific deficit in DCD under the simple-high combination suggests a (default) compensatory strategy during step-over when attention is diverted to a secondary task. Competing cognitive and motor demands during obstacle negotiation present a potential safety risk for children.

On court wingwave® coaching improves accuracy and confidence in basketball athletes

AbstractThe short-term oriented coaching method known as wingwave® (Besser-Siegmund Institute, Hamburg, Germany) has demonstrated efficacy in boosting individuals’ confidence related to future tasks, enhancing overall performance in sports motor tasks, and improving concentration abilities. Its procedure incorporates elements of eye movement and desensitization and reprocessing (EMDR) and adds a muscular strength test to reduce stress and anxiety for the athletes. In this study, amateurs and experts were observed performing a basketball-specific task. In two sets of 30 free throws, with a 1 h break between sets, 44 participants (aged 16–32), consisting of 22 experts and 22 novices in basketball, were randomly assigned to either the experimental or control group. The experimental group received one coaching session using the wingwave® method during the break. During coaching, specific emotional obstacles or blockades were identified and addressed using the wingwave® method by six qualified coaches. The findings reveal a statistically significant increase in accuracy, F(1.40) = 4.74, p = 0.036, η2 = 0.106, Wilk’s Λ = 0.894, in free throws as well as a notable boost in task-specific confidence (i.e., subjective perception; F(1.40) = 4.21, p = 0.047, η2 = 0.095, Wilk’s Λ = 0.905) in the experimental group compared to the control group. Based on these findings, it can be deduced that the wingwave® method holds promise as a valuable tool for mitigating stress and anxiety, while bolstering self-assurance and fostering confidence in one’s own capabilities within a defined sporting context.

Modulation of motor cortex inhibition during manual dexterity tasks: an adaptive threshold hunting study.

Background: The ability to perform intricate movements is crucial for human motor function. The neural mechanisms underlying precision and power grips are incompletely understood. Corticospinal output from M1 is thought to be modulated by GABAA-ergic intracortical networks within M1. Objectives: To investigate the contribution of M1 intracortical inhibition to fine motor control using adaptive threshold hunting with paired-pulse TMS during pinching and grasping tasks. We hypothesised that SICI could be assessed during voluntary activation, and that corticomotor excitability and SICI modulation would be greater during pinch than grasp reflecting corticospinal control. Methods: Seventeen healthy participants performed gradual pinch and grasp tasks. Using an adaptive threshold-hunting method, paired-pulse TMS was applied in the anterior-posterior current direction to assess cortical excitability and SICI in the dominant FDI muscle. SICI and corticomotor excitability were analysed using an LMM. MEP latencies were obtained in LM, PA and AP current directions and compared using paired t-tests. Results: MEP latencies were prolonged with PA and AP coil orientations compared to LM, with AP showing the largest latency. During single-pulse TMS, there was no difference in the TMS intensity required to reach the MEP target during pinching and grasping. Greater inhibition was found during pinching compared to grasping. Conclusion: ATH with paired-pulse TMS permits investigation of intracortical inhibitory networks and their modulation during the performance of dexterous motor tasks revealing a greater modulation of GABAA-ergic inhibition contributing to SICI during pinching compared to grasping.

Online stimulation of the prefrontal cortex during practice increases motor variability and modulates later cognitive transfer: a randomized, double-blinded and sham-controlled tDCS study

The benefits of learning a motor skill extend to improved task-specific cognitive abilities. The mechanistic underpinnings of this motor-cognition relationship potentially rely on overlapping neural resources involved in both processes, an assumption lacking causal evidence. We hypothesize that interfering with prefrontal networks would inhibit concurrent motor skill performance, long-term learning and associated cognitive functions dependent on similar networks (transfer). We conducted a randomised, double-blinded, sham-controlled brain stimulation study using transcranial direct current stimulation (tDCS) in young adults spanning over three weeks to assess the role of the prefrontal regions in learning a complex balance task and long-term cognitive performance. Balance training combined with active tDCS led to higher performance variability in the trained task as compared to the sham group, impacting the process of learning a complex task without affecting the learning rate. Furthermore, active tDCS also positively influenced performance in untrained motor and cognitive tasks. The findings of this study help ascertaining the networks directly involved in learning a complex motor task and its implications on cognitive function. Hence, opening up the possibility of harnessing the observed frontal networks involved in resource mobilization in instances of aging, brain lesion/injury or dysfunction.

Sense of Embodiment Supports Motor Learning and Adaptation in Tele-robotics

In this paper, we transition from the theoretical and experimental groundwork of manipulating and measuring Sense of Embodiment (SoE) to addressing a fundamental question: What is the purpose of optimizing the SoE in a teleoperation system? This exploration centers on investigating the potential positive effects of SoE on motor adaptation, the acceleration of motor learning, and the potential enhancement of task performance. The paper delves into this investigation by focusing on two critical research questions: 1) what is the effect of SoE on task performance in a perceptual-motor task? 2) What is the effect of SoE on the asymptote of the learning curve in a perceptual-motor task? Drawing insights from the existing literature, the hypothesis emerges that enhancing SoE yields positive effects, not only on task performance (H1) but also on the overall embodiment experience (H2). An additional layer of exploration is introduced through an exploratory research question: Are these results consistent across diverse scenarios and tasks? The study design encompasses two distinct user studies, each set in different applications and featuring various avatars, yet all anchored in similar tasks, specifically a modified peg-in-hole task: 1) in the first experiment, participants operated a robotic arm with a human-like hand as end-effector, and they were required to perform a classic peg-in-hole task; 2) in user study 2, the task is transformed into a variation that we called “peg-on-button”, wherein participants use a robotic arm with a gripper as the end-effector to press a lit button. In both studies, a consistent pattern emerges: a setup that fosters embodiment has a positive impact on motor learning and adaptation, resulting in improved task performance. A supportive setup also reduces the perception of the surrogate as a mere mediator between the operator and the remote environment, especially when contrasted with a setup that suppresses embodiment. The positive effects on motor learning and task performance advocate for the incorporation of embodiment-supportive designs in teleoperational setups. However, the nuanced relationship between SoE and long-term task performance prompts a call for further exploration and consideration of various factors influencing teleoperation outcomes across diverse scenarios and tasks.

The effectiveness of different attentional foci on the acquisition of sport-specific motor skills in healthy adults: a systematic review with network meta-analysis.

The acquisition of motor skills is a key element in many sports. A motor learning principle, which is frequently used to support skill acquisition is the application of different attentional foci. The effectiveness of different attentional foci on performance and the learning of motor skills has been investigated in various sports using randomised controlled trials. The aim of the present study was to investigate the effectiveness of different attentional foci (such as external (EFA) and internal attentional foci (IFA), but also holistic and switching foci) on the performance and learning of a sport-specific motor task in healthy individuals. This study was a systematic review with network meta-analysis. We followed the Prisma reporting guideline and the Cochrane handbook for systematic reviews. Cinahl, Embase, Medline and Cochrane Central were searched for eligible studies. Network meta-analyses were performed for the post-acquisition, retention and transfer test endpoints. Twelve studies were included in the review. At post-acquisition an EFA was the most effective intervention compared to the control intervention (SMD: 0.9855; 95% CI [0.4-1.57]; p: 0.001). At the retention and transfer test endpoints, a holistic focus of attention had the highest effectiveness compared to an IFA (SMD 0.75; 95% CI [-0.1 to 1.6]; p: 0.09) and (SMD 1.16; 95% CI [0.47-1.86]; p: 0.001). For all three endpoints, we analysed a greater effectiveness of an EFA and holistic focus compared to an IFA. Several promising different attentional focus interventions were identified. The largest effects were analysed for a holistic focus. However, only one study used this intervention and therefore there remains uncertainty about the effectiveness. With regard to the inconsistency observed, the analysis at post-acquisition should be interpreted with caution. Modified versions of the EFA were the imagined and the dynamic EFA. Both were only explored in single studies and should therefore be investigated in further follow-up studies that directly compare them.

Improvement of Motor Task Performance: Effects of Verbal Encouragement and Music-Key Results from a Randomized Crossover Study with Electromyographic Data.

External motivational stimuli have been shown to improve athletic performance. However, the neurophysiological mechanisms underlying this improvement remain poorly understood. This randomized crossover study investigated the effects of music and verbal encouragement on measures of muscle excitation and myoelectric manifestations of fatigue in the biceps brachii and brachioradialis muscles during an endurance task. Fifteen untrained (mean age 29.57 ± 2.77 years) and 13 trained individuals (mean age 32.92 ± 2.90 years) were included. The endurance task, performed to exhaustion, consisted of keeping the dominant arm flexed to 90 degrees while holding a dumbbell loaded to 80% of 1RM with a supine grip in three randomized conditions: standard, with self-selected music, and with verbal encouragement. The untrained subjects showed an increase in task duration of 15.26% (p < 0.003) with music and 15.85% (p < 0.002) with verbal encouragement compared to the condition without external stimuli. There were no significant differences in the myoelectric manifestations of fatigue between the different conditions. Regarding the muscle excitation metrics, although the mean amplitude, peak value, and area under the curve remained unchanged across conditions, a significant reduction in the trend coefficient, indicating motor unit recruitment over time, was observed with both music (biceps brachii: -10.39%, p < 0.001; brachioradialis: -9.40%, p < 0.001) and verbal encouragement (biceps brachii: -7.61%, p < 0.001; brachioradialis: -6.51%, p < 0.001) compared to the standard condition. For the trained participants, no significant differences were observed between conditions in terms of task duration and outcome measures related to muscle excitation and myoelectric manifestations of fatigue, suggesting the possible presence of a ceiling effect on motivation. These results highlight the important role of external motivational stimuli, such as music and verbal encouragement, in improving task performance in untrained subjects, probably through more effective and efficient recruitment of motor units.

A method for the synchronization of inertial sensor signals and local field potentials from deep brain stimulation systems

Objective. Recent innovative neurostimulators allow recording local field potentials (LFPs) while performing motor tasks monitored by wearable sensors. Inertial sensors can provide quantitative measures of motor impairment in people with subthalamic nucleus deep brain stimulation. To the best of our knowledge, there is no validated method to synchronize inertial sensors and neurostimulators without an additional device. This study aims to define a new synchronization method to analyze disease-related brain activity patterns during specific motor tasks and evaluate how LFPs are affected by stimulation and medication. Approach. Fourteen male subjects treated with subthalamic nucleus deep brain stimulation were recruited to perform motor tasks in four different medication and stimulation conditions. In each condition, a synchronization protocol was performed consisting of taps on the implanted neurostimulator, which produces artifacts in the LFPs that a nearby inertial sensor can simultaneously record. Main results. In 64% of the recruited subjects, induced artifacts were detected at least in one condition. Among those subjects, 83% of the recordings could be synchronized offline analyzing LFPs and wearables data. The remaining recordings were synchronized by video analysis. Significance. The proposed synchronization method does not require an external system (e.g., TENS electrodes) and can be easily integrated into clinical practice. The procedure is simple and can be carried out in a short time. A proper and simple synchronization will also be useful to analyze subthalamic neural activity in the presence of specific events (e.g., freezing of gait events) to identify predictive biomarkers.

Transcranial direct current stimulation enhances effort maintenance in ADHD

BackgroundYouth with attention-deficit/hyperactivity disorder (ADHD) exhibit increased effort aversion, likely due to deficits in anticipatory dopamine firing. Previous research has shown that transcranial direct current stimulation (tDCS) targeting the right prefrontal cortex can enhance activity in dopaminergic meso-striatal regions. However, the extent to which this specific tDCS configuration effectively modulates effort behavior in anticipation of rewards in ADHD remains uncertain. HypothesisWe expected an increase of effort maintenance and invigoration during and following our tDCS set-up compared to sham in subjects with ADHD. MethodsTwenty-four children and adolescents with ADHD (mean age: 11.6 years; 95 % CI [10.7, 12.4]) received 2 mA and sham tDCS for 20 min each. The anode was positioned over the ventromedial prefrontal cortex (PFC), while the cathode was placed over the right dorsolateral PFC, generating an electrical field with maximal strength in the right PFC. During and after the tDCS sessions, participants performed a button-pressing task aimed at earning delayed monetary rewards. Primary outcomes were effort maintenance (frequency of button presses) and invigoration (slopes of button presses), measuring motor task performance. ResultsWe observed a significant increase in effort maintenance both during (b = 2.66; p < 0.001) and after tDCS (b = 2.04; p= .007) compared to sham. No significant difference was found for invigoration during stimulation, while after bonferroni correction (p = 0.025) a non-significant decrease was found after tDCS compared to sham (b = −5.18; p = 0.041). ConclusiontDCS targeting the ventromedial PFC (anodal) and right dorsolateral PFC (cathodal) increases effort maintenance in children and adolescents with ADHD.

Decision-Making Time Analysis for Assessing Processing Speed in Athletes during Motor Reaction Tasks.

Reaction time (RT) is a widely used measure for testing physical performance in motor tasks. This study focused on assessing the processing speed in athletes. Twenty-five healthy volunteers were assigned to the control (n = 16) or athletes groups (n = 9). They were evaluated during motor reaction tasks based on visual stimuli and three difficulty conditions. Physiological measures were obtained from motion capture and electromyography recordings of several muscles. Two RT phases, decision-making (DMK) and electromechanical delay (EMD), were used to analyze the processing speed. The results show significant RT differences between groups. The athletes were ~30% faster compared to the control group. Despite the fact that all participants were right-handed, RT did not show any differences between hands performances in any group. However, DMK time revealed significant differences between the hands. Controls showed a longer DMK time for the right-hand election, ~20% more than the left, while athletes showed no such disparity. These findings reveal that quantifying the decision-making component of reaction time is crucial to assessing processing speed in sport. This approach could facilitate the monitoring of adaptations in both motor-cognitive and neuromuscular processes. The theoretical implications presented in this study offer perspectives on handedness research.

Perturbation-based dual task assessment in older adults with mild cognitive impairment.

Dual tasking (i.e., concurrent performance of motor and cognitive task) is significantly impaired in older adults with mild cognitive impairment (OAwMCI) compared to cognitively intact older adults (CIOA) and has been associated with increased fall risk. Dual task studies have primarily examined volitionally driven events, and the effects of mild cognitive impairment on reactive balance control (i.e., the ability to recover from unexpected balance threats) are unexplored. We examined the effect of cognitive tasks on reactive balance control in OAwMCI compared to CIOA. Adults >55 years were included and completed the Montreal Cognitive Assessment (MoCA) to categorize them as OAwMCI (MoCA: 18-24, n = 15) or CIOA (MoCA: ≥25, n = 15). Both OAwMCI [MoCA: 22.4 (2.2), 65.4 (6.1) years, 3 females] and CIOA [MoCA: 28.4 (1.3), 68.2 (5.5) years, 10 females] responded to large magnitude stance slip-like perturbations alone (single task) and while performing perceptual cognitive tasks targeting the visuomotor domain (target and tracking game). In these tasks, participants rotated their head horizontally to control a motion mouse and catch a falling target (target game) or track a moving object (track). Margin of stability (MOS) and fall outcome (harness load cell >30% body weight) were used to quantify reactive balance control. Cognitive performance was determined using performance error (target) and sum of errors (tracking). A 3 × 2 repeated measures ANOVA examined the effect of group and task on MOS, and generalized estimating equations (GEE) model was used to determine changes in fall outcome between groups and tasks. 2 × 2 repeated measures ANOVAs examined the effect of group and task on cognitive performance. Compared to CIOA, OAwMCI exhibited significantly deteriorated MOS and greater number of falls during both single task and dual task (p < 0.05), and lower dual task tracking performance (p < 0.01). Compared to single task, both OAwMCI and CIOA exhibited significantly deteriorated perceptual cognitive performance during dual task (p < 0.05); however, no change in MOS or fall outcome between single task and dual task was observed. Cognitive impairment may diminish the ability to compensate and provide attentional resources demanded by sensory systems to integrate perturbation specific information, resulting in deteriorated ability to recover balance control among OAwMCI.

Dissecting Bayes: Using influence measures to test normative use of probability density information derived from a sample.

Bayesian decision theory (BDT) is frequently used to model normative performance in perceptual, motor, and cognitive decision tasks where the possible outcomes of actions are associated with rewards or penalties. The resulting normative models specify how decision makers should encode and combine information about uncertainty and value-step by step-in order to maximize their expected reward. When prior, likelihood, and posterior are probabilities, the Bayesian computation requires only simple arithmetic operations: addition, etc. We focus on visual cognitive tasks where Bayesian computations are carried out not on probabilities but on (1) probability density functions and (2) these probability density functions are derived from samples. We break the BDT model into a series of computations and test human ability to carry out each of these computations in isolation. We test three necessary properties of normative use of pdf information derived from a sample-accuracy, additivity and influence. Influence measures allow us to assess how much weight each point in the sample is assigned in making decisions and allow us to compare normative use (weighting) of samples to actual, point by point. We find that human decision makers violate accuracy and additivity systematically but that the cost of failure in accuracy or additivity would be minor in common decision tasks. However, a comparison of measured influence for each sample point with normative influence measures demonstrates that the individual's use of sample information is markedly different from the predictions of BDT. We will show that the normative BDT model takes into account the geometric symmetries of the pdf while the human decision maker does not. An alternative model basing decisions on a single extreme sample point provided a better account for participants' data than the normative BDT model.

Motor, Cognitive, and Behavioral Impairment in TLR3 and TLR9 Deficient Male Mice: Insights into the Non-Immunological Roles of Toll-Like Receptors

Toll-like receptors (TLRs) play a critical role in initiating the innate immune response to infection or injury. Recent studies have uncovered their intriguing functions as moonlighting proteins involved in various biological processes, including development, learning, and memory. However, the specific functions of individual TLRs are still largely unknown. We investigated the effects of TLR3 and TLR9 receptor deficiency on motor, cognitive, and behavioral functions during development using genetically modified male mice of different ages. We evaluated the motor coordination, anxiety-like behavior, spatial learning, and working memory of male mice lacking the TLR3 and TLR9 genes at different ages (two, four, six, and eight months) using the rotarod, open field, water maze, and T-maze tests. We observed that the deletion of either TLR3 or TLR9 resulted in impaired motor performance. Furthermore, young TLR3-deficient mice exhibited reduced anxiety-like behavior and spatial learning deficits; however, their working memory was unaffected. In contrast, young TLR9-knockout mice showed hyperactivity and a tendency toward decreased working memory. These findings provide valuable insights into the broader roles of the TLR system beyond the innate immune response, revealing its involvement in pathways associated with the central nervous system. Importantly, our results establish a strong association between the endosomal receptors TLR3 and TLR9 and the performance of motor, cognitive, and behavioral tasks that change over time. This study contributes to the growing body of research on the multifaceted functions of TLRs and enhances our understanding of their participation in non-immune-related processes.

Using Electric Stimulation of the Spinal Muscles and Electromyography during Motor Tasks for Evaluation of the Role in Development and Progression of Adolescent Idiopathic Scoliosis.

Introduction: The role of the spinal muscles in scoliogenesis is not fully substantiated. Do they act scoliogenic (inducing scoliosis) or counteract scoliosis in adolescent idiopathic scoliosis (AIS)? In this study, we will examine this by using selectively placed Transcutaneous Electric Stimulation (TES) combined with a cinematic radiographic technique and by performing electromyographic (EMG) evaluations during various motor tasks. Method: This is a cross-sectional study of subjects with small-curve AIS. Using cinematic radiography, they were evaluated dynamically either under electrical stimulation or when performing motor tasks of left and right lateral bending and rotation whilst measuring the muscle activity by EMG. Results: Forty-five patients with AIS were included as subjects. Five subjects volunteered for TES and six subjects performed the motor tasks with EMG. At the initial visual evaluation, and when stimulated with TES, the frontal plane spatial positions of the vertebral bodies showed discrete changes without an apparent pattern. However, analyzing the spatial positions when calibrated, we found that the spinal muscles exert a compressive 'response' with a minor change in the Cobb angle (CA) in small-curve AIS (CA = 10-20°). In larger curves (CA > 20°), TES induced a 'larger deformity' with a relative four-fold change in the CA compared to small-curve AIS with a ratio of 0.6. When evaluating local amplitude (peak) or cumulative (mean) EMG signals, we were unable to find consistent asymmetries. However, one subject had rapid progression and one regressed to a straight spine. When adding the absolute EMG ratios for all four motor tasks, the subject with progression had almost 10-fold less summed EMG ratios, and the subject with regression had more than 3-fold higher summed EMG ratios. Discussion: Based on these findings, we suggest that the spinal muscles in small-curve AIS have a stabilizing function maintaining a straight spine and keeping it in the midline. When deformities are larger (CA > 20°), the spine muscle curve exerts a scoliogenic 'response'. This suggests that the role of the muscles converts from counteracting AIS and stabilizing the spine to being scoliogenic for a CA of more than 20°. Moreover, we interpret higher EMG ratios as heightened asymmetric spinal muscle activity when the spinal muscles try to balance the spine to maintain or correct the deformity. When progression occurs, this is preceded or accompanied by decreased EMG ratios. These findings must be substantiated by larger studies.

Previous motor task performance impacts phase-based EEG resting-state connectivity states

Abstract The resting human brain cycles through distinct states that can be analyzed using microstate analysis and electroencephalography (EEG) data. This approach classifies multichannel EEG data into spontaneously interchanging microstates based on topographic features. These microstates may be valuable biomarkers in neurodegenerative diseases since they reflect the resting brain’s state. However, microstates do not provide information about the active neural networks during the resting state. This article presents an alternative and complementary method for analyzing resting-state EEG data and demonstrates its reproducibility and reliability. This method considers cerebral connectivity states defined by phase synchronization and measured using the corrected imaginary phase-locking value (ciPLV) based on source-reconstructed EEG recordings. We analyzed resting-state EEG data from young, healthy participants acquired on five consecutive days before and after a motor task. We show that our data reproduce microstates previously reported. Further, we reveal four stable topographic patterns over the multiple recording sessions in the source connectivity space. While the classical microstates were unaffected by a preceding motor task, the connectivity states were altered, reflecting the suppression of frontal activity in the post-movement resting state.