Stages of motor skill learning

Children Predict Improvement on Novel Skill Learning Tasks

Learning takes time: Performance usually starts poorly and improves with practice. Do children intuit this basic phenomenon of skill learning? In preregistered Experiment 1 (n = 125; 54% female; 48% White; collected 2022-2023), US 7- to 8-year-old children predicted improved performance, 5- to 6-year-old children predicted flat performance, and 4-year-old children predicted near-instant success followed by worse performance on a novel skill learning task. In preregistered Experiment 2 (n = 75; 47% female; 69% White; collected 2023), on a task with lowered cognitive demands, US 4- to 6-year-old children predicted improved performance. Thus, although children expect to improve on novel tasks, younger children need scaffolding to form these predictions and grasp this fundamental aspect of learning.

Different delayed consequences of attaining a plateau phase in practicing a simple (finger-tapping sequence learning) and a complex (Tower of Hanoi puzzle) task

In practicing a new task, the initial performance gains, across consecutive trials, decrease; in the following phase, performance tends to plateau. However, after a long delay additional performance improvements may emerge (delayed/ "offline" gains). It has been suggested that the attainment of the plateau phase is a necessary condition for the triggering of skill consolidation processes that lead to the expression of delayed gains. Here we compared the effect of a long-delay (24-48 h) interval following each of the two within-session phases, on performance in a simple motor task, the finger-tapping sequence learning (FTSL), and in a conceptually complex task, the Tower of Hanoi puzzle (TOHP). In Experiment 1 we determined the amount of practice leading to the plateau phase within a single practice session (long practice), in each task. Experiment 2 consisted of three consecutive sessions with long-delay intervals in between; in the first session, participants underwent a short practice without attaining the plateau phase, but in the next two sessions, participants received long practice, attaining the plateau phase. In the FTSL, short practice resulted in no delayed gains after the long delay, but after 24-48 h following long practice, task performance was further improved. In contrast, no delayed gains evolved in the TOHP during the 24- to 48-h delay following long practice. We propose that the attainment of a plateau phase can indicate either the attainment of a comprehensive task solution routine (achievable for simple tasks) or a preservation of work-in-progress task solution routine (complex tasks); performance after a long post-practice interval can differentiate these two states.

Experience-driven competition in neural reorganization after stroke

Behavioural experiences interact with regenerative responses to shape patterns of neural reorganization after stroke. This review is focused on the competitive nature of these behavioural experience effects. Interactions between learning-related plasticity and regenerative reactions have been found to underlie the establishment of new compensatory behaviours and the efficacy of motor rehabilitative training in rodent stroke models. Learning in intact brains depends on competitive and cooperative mechanisms of synaptic plasticity. Synapses are added in response to learning and selectively maintained and strengthened via activity-dependent competition. Long-term memories for experiences that occur closely in time can be weakened or enhanced by competitive or cooperative interactions in the time-dependent process of stabilizing synaptic changes. Rodent stroke model findings suggest that compensatory reliance on the non-paretic hand after stroke can shape and stabilize synaptic reorganization patterns in both hemispheres, to compete with the capacity for experiences of the paretic side to do so. However, the competitive edge of the non-paretic side can be countered by overlapping experiences of the paretic hand, and might even be shifted in a cooperative direction with skilfully coordinated bimanual experience. Advances in the basic understanding of learning-related synaptic competition are helping to inform the basis of experience-dependent variations in stroke outcome.

Improving Medical Student Performance With Unsupervised Simulation and Remote Asynchronous Feedback

OBJECTIVE

This study aims to assess the effectiveness of training medical students to perform two clinical procedures using unsupervised simulation with remote asynchronous feedback, compared to an intensive workshop with in-person feedback.

DESIGN, SETTING, AND PARTICIPANTS

Third-year medical students were recruited and randomized into 2 groups: Thoracentesis or paracentesis. Within each group, participants were further randomized into either unsupervised simulation with remote asynchronous feedback (experimental group; EG) or a 2-hour workshop (control group; CG). The EG underwent two unsupervised 20-minute training sessions and received remote asynchronous feedback. The CG had a 2-hour workshop where they received in-person feedback. After training, students were assessed using the objective structured assessment of technical skills (OSATS) scale. Twenty students in thoracentesis and 23 in paracentesis training completed the 2 training sessions with remote and asynchronous feedback, and 30 students for both thoracentesis and paracentesis groups completed the 2-hour workshop.

RESULTS

The EG achieved a significantly higher passing rate than the CG on both procedures (thoracentesis 80% vs. 43%, paracentesis 91% vs. 67%, p-value< 0.05).

CONCLUSION

The asynchronous educational method allowed EG students to achieve higher performance than CG students. This novel modality allowed students and instructors to train and assess at their own pace.

Effect of habitual physical activity on motor performance and prefrontal cortex activity during implicit motor learning

Background

Acute bouts of exercise have been shown to improve motor learning. However, whether these benefits can be observed from habitual physical activity (PA) levels remains unclear and has important implications around PA guidelines to promote motor learning across the lifespan. This study investigated the effect of habitual PA levels on brain activity within the dorsolateral prefrontal cortex (DLPFC) during procedural motor skill acquisition.

Methods

Twenty-six right-handed healthy young adults had physical activity levels quantified by calculating the metabolic equivalent of task (METs) in minutes per week, derived from the International Physical Activity Questionnaire (IPAQ). Functional near-infrared spectroscopy (fNIRS) over the DLPFC was recorded to measure neural activation during a serial reaction time task (SRTT). Behavioural indicators of procedural motor skill acquisition were quantified as reaction time and accuracy of correct trials during the SRTT. DLPFC activation was characterised as task-related changes in oxyhaemoglobin (∆[HbO2]).

Results

Findings showed that higher PA levels were associated with improvements in reaction time during procedural motor skill acquisition (p = 0.03). However, no significant effects of PA levels on accuracy or ∆[HbO2] during procedural motor skill acquisition were observed. These findings show that while habitual PA may promote motor performance in young adults, this is not reflected by changes in the DLPFC area of the brain.

Enhancing motor skill learning through multiple sessions of online high-definition transcranial direct current stimulation in healthy adults: insights from EEG power spectrum

The purpose of this study was to evaluate the influence of high-definition transcranial direct current stimulation (HD-tDCS) on finger motor skill acquisition. Thirty-one healthy adult males were randomly assigned to one of three groups: online HD-tDCS (administered during motor skill learning), offline HD-tDCS (delivered before motor skill learning), and a sham group. Participants engaged in a visual isometric pinch task for three consecutive days. Overall motor skill learning and speed-accuracy tradeoff function were used to evaluate the efficacy of tDCS. Electroencephalography was recorded and power spectral density was calculated. Both online and offline HD-tDCS total motor skill acquisition was significantly higher than the sham group (P < 0.001 and P < 0.05, respectively). Motor skill acquisition in the online group was higher than offline (P = 0.132, Cohen's d = 1.46). Speed-accuracy tradeoff function in the online group was higher than both offline and sham groups in the post-test. The online group exhibited significantly lower electroencephalography activity in the frontal, fronto-central, and centro-parietal alpha band regions compared to the sham (P < 0.05). The findings suggest that HD-tDCS application can boost finger motor skill acquisition, with online HD-tDCS displaying superior facilitation. Furthermore, online HD-tDCS reduces the power of alpha rhythms during motor skill execution, enhancing information processing and skill learning efficiency.

A Randomized Controlled Trial of Treatment Distribution and Biofeedback Effects on Speech Production in School-Age Children With Apraxia of Speech

PURPOSE

This study examines how ultrasound biofeedback and intensive treatment distribution affect speech sound generalization during an evidence-based treatment, Speech Motor Chaining, for children with persisting speech errors associated with childhood apraxia of speech (CAS).

METHOD

In a 2 × 2 factorial randomized controlled trial, children ages 9-17 years meeting CAS criteria were randomized to receive (a) a distributed treatment (20 sessions twice weekly over 10 weeks) or intensive treatment (20 hr in 5 weeks, with 10 hr in Week 1) and (b) treatment with or without biofeedback. Due to the COVID pandemic, some participants were randomized to distributed/intensive telepractice treatment only. The primary outcome was percent target sounds correct on untreated phrases (i.e., generalization) at the 10-week time point. More than 50,000 narrow phonetic transcriptions were analyzed.

RESULTS

Forty-eight participants completed treatment. Intensive treatment significantly increased generalization at all time points. The effect of biofeedback was significant at 5 weeks from the start of treatment but not significant at the primary 10-week time point. However, when comparing each group immediately after their 20 hr of treatment finished, generalization was significantly greater in intensive over distributed treatment and greater in ultrasound over no-ultrasound treatment (with a significant interaction favoring intensive treatment with ultrasound). Only the advantage of intensive treatment remained significant 5 weeks after groups finished treatment. There was no significant difference between face-to-face and telepractice modalities.

CONCLUSIONS

When the number of treatment hours is fixed, an intensive schedule of Speech Motor Chaining facilitated greater improvement than a distributed schedule. Ultrasound biofeedback initially accelerated learning, but the benefits may dissipate as treatment continues or after it ends.

Feasibility of At-Home Hand Arm Bimanual Intensive Training in Virtual Reality: Case Study

This single-participant case study examines the feasibility of using custom virtual reality (VR) gaming software in the home environment for low-dose Hand Arm Bimanual Intensive Training (HABIT). A 10-year-old with right unilateral cerebral palsy participated in this trial. Fine and gross motor skills as well as personal goals for motor outcomes were assessed before and after the intervention using the Box and Blocks Test, Nine-Hole Peg Test, and Canadian Occupational Performance Measure. Movement intensities collected via the VR hardware accelerometers, VR game scores, and task accuracy were recorded via the HABIT-VR software as indices of motor performance. The child and family were instructed to use the HABIT-VR games twice daily for 30 minutes over a 14-day period and asked to record when they used the system. The child used the system and completed the 14-hour, low-dose HABIT-VR intervention across 22 days. There was no change in Box and Blocks Test and Nine-Hole Peg Test scores before and after the intervention. Canadian Occupational Performance Measure scores increased but did not reach the clinically relevant threshold, due to high scores at baseline. Changes in motor task intensities during the use of VR and mastery of the VR bimanual tasks suggested improved motor efficiency. This case study provides preliminary evidence that HABIT-VR is useful for promoting adherence to HABIT activities and for the maintenance of upper extremity motor skills in the home setting.

Identification of a Hippocampus-to-Zona Incerta Projection involved in Motor Learning

Motor learning (ML), which plays a fundamental role in growth and physical rehabilitation, involves different stages of learning and memory processes through different brain regions. However, the neural mechanisms that underlie ML are not sufficiently understood. Here, a previously unreported neuronal projection from the dorsal hippocampus (dHPC) to the zona incerta (ZI) involved in the regulation of ML behaviors is identified. Using recombinant adeno-associated virus, the projections to the ZI are surprisingly identified as originating from the dorsal dentate gyrus (DG) and CA1 subregions of the dHPC. Furthermore, projection-specific chemogenetic and optogenetic manipulation reveals that the projections from the dorsal CA1 to the ZI play key roles in the acquisition and consolidation of ML behaviors, whereas the projections from the dorsal DG to the ZI mediate the retrieval/retention of ML behaviors. The results reveal new projections from the dorsal DG and dorsal CA1 to the ZI involved in the regulation of ML and provide insight into the stages over which this regulation occurs.

Motor Learning in a Complex Motor Task Is Unaffected by Three Consecutive Days of Transcranial Alternating Current Stimulation

Transcranial alternating current stimulation (tACS) delivered to the primary motor cortex (M1) can increase cortical excitability, entrain neuronal firing patterns, and increase motor skill acquisition in simple motor tasks. The primary aim of this study was to assess the impact of tACS applied to M1 over three consecutive days of practice on the motor learning of a challenging overhand throwing task in young adults. The secondary aim was to examine the influence of tACS on M1 excitability. This study implemented a double-blind, randomized, SHAM-controlled, between-subjects experimental design. A total of 24 healthy young adults were divided into tACS and SHAM groups and performed three identical experimental sessions that comprised blocks of overhand throwing trials of the right dominant arm concurrent with application of tACS to the left M1. Performance in the overhand throwing task was quantified as the endpoint error. Motor evoked potentials (MEPs) were assessed in the right first dorsal interosseus (FDI) muscle with transcranial magnetic stimulation (TMS) to quantify changes in M1 excitability. Endpoint error was significantly decreased in the post-tests compared with the pre-tests when averaged over the three days of practice (p = 0.046), but this decrease was not statistically significant between the tACS and SHAM groups (p = 0.474). MEP amplitudes increased from the pre-tests to the post-tests (p = 0.003), but these increases were also not different between groups (p = 0.409). Overall, the main findings indicated that tACS applied to M1 over multiple days does not enhance motor learning in a complex task to a greater degree than practice alone (SHAM).

Cortico-cerebellar coordination facilitates neuroprosthetic control

Temporally coordinated neural activity is central to nervous system function and purposeful behavior. Still, there is a paucity of evidence demonstrating how this coordinated activity within cortical and subcortical regions governs behavior. We investigated this between the primary motor (M1) and contralateral cerebellar cortex as rats learned a neuroprosthetic/brain-machine interface (BMI) task. In neuroprosthetic task, actuator movements are causally linked to M1 "direct" neurons that drive the decoder for successful task execution. However, it is unknown how task-related M1 activity interacts with the cerebellum. We observed a notable 3 to 6 hertz coherence that emerged between these regions' local field potentials (LFPs) with learning that also modulated task-related spiking. We identified robust task-related indirect modulation in the cerebellum, which developed a preferential relationship with M1 task-related activity. Inhibiting cerebellar cortical and deep nuclei activity through optogenetics led to performance impairments in M1-driven neuroprosthetic control. Together, these results demonstrate that cerebellar influence is necessary for M1-driven neuroprosthetic control.

The effect of reward on motor learning: different stage, different effect

Motor learning is a prominent and extensively studied subject in rehabilitation following various types of neurological disorders. Motor repair and rehabilitation often extend over months and years post-injury with a slow pace of recovery, particularly affecting the fine movements of the distal extremities. This extended period can diminish the motivation and persistence of patients, a facet that has historically been overlooked in motor learning until recent years. Reward, including monetary compensation, social praise, video gaming, music, and virtual reality, is currently garnering heightened attention for its potential to enhance motor motivation and improve function. Numerous studies have examined the effects and attempted to explore potential mechanisms in various motor paradigms, yet they have yielded inconsistent or even contradictory results and conclusions. A comprehensive review is necessary to summarize studies on the effects of rewards on motor learning and to deduce a central pattern from these existing studies. Therefore, in this review, we initially outline a framework of motor learning considering two major types, two major components, and three stages. Subsequently, we summarize the effects of rewards on different stages of motor learning within the mentioned framework and analyze the underlying mechanisms at the level of behavior or neural circuit. Reward accelerates learning speed and enhances the extent of learning during the acquisition and consolidation stages, possibly by regulating the balance between the direct and indirect pathways (activating more D1-MSN than D2-MSN) of the ventral striatum and by increasing motor dynamics and kinematics. However, the effect varies depending on several experimental conditions. During the retention stage, there is a consensus that reward enhances both short-term and long-term memory retention in both types of motor learning, attributed to the LTP learning mechanism mediated by the VTA-M1 dopaminergic projection. Reward is a promising enhancer to bolster waning confidence and motivation, thereby increasing the efficiency of motor learning and rehabilitation. Further exploration of the circuit and functional connections between reward and the motor loop may provide a novel target for neural modulation to promote motor behavior.

Tapping into Efficient Learning: An Exploration of the Impact of Sequential Learning on Skill Gains and Learning Curves in Central Venous Catheterization Simulator Training

OBJECTIVE

Medical residents learn how to perform many complex procedures in a short amount of time. Sequential learning, or learning in stages, is a method applied to complex motor skills to increase skill acquisition and retention but has not been widely applied in simulation-based training (SBT). Central venous catheterization (CVC) training could benefit from the implementation of sequential learning. CVC is typically taught with task trainers such as the dynamic haptic robotic trainer (DHRT). This study aims to determine the impact of sequential learning on skill gains and learning curves in CVC SBT by implementing a sequential learning walkthrough into the DHRT.

METHODS

103 medical residents participated in CVC training in 2021 and 2022. One group (N = 44) received training on the original DHRT system while the other group (N = 59) received training on the DHRTsequential with interactive videos and assessment activities. All residents were quantitatively assessed on (e.g. first trial success rate, distance to vein center, overall score) the DHRT or DHRTsequential systems.

RESULTS

Residents in the DHRTsequential group exhibited a 3.58 times higher likelihood of successfully completing needle insertion on their first trial than those in the DHRT only group and required significantly fewer trials to reach a pre-defined mastery level of performance. The DHRTsequential group also had fewer significant learning curves compared to the DHRT only group.

CONCLUSION

Implementing sequential learning into the DHRT system significantly benefitted CVC training by increasing the efficiency of initial skill gain, reducing the number of trials needed to complete training, and flattening the slope of the subsequent learning curve.

Single Pedicle Advancement Flap Models for Teaching Veterinary Reconstructive Surgical Techniques

Reconstructive surgical techniques are used in both general and referral veterinary practice to facilitate closure of challenging wound defects. During veterinary studies, there are often limited opportunities for students to practice these techniques on live patients or cadavers. Surgical models, including suture pads and ovariohysterectomy models, have been successfully incorporated into veterinary teaching, providing students with additional practice. Models to simulate veterinary reconstructive surgical techniques are lacking. In the current study, a single pedicle advancement flap model was designed. The design consisted of a silicone model secured by a plate, providing tension. Fifth-year veterinary science students (n = 34) were surveyed to assess the model's impact on surgical technique and confidence. Students were also assessed to determine surgical technique using the models. It was hypothesized that students who had two additional practice sessions using the models (Trial group, n = 17) would show greater improvement in technique than students who had no practice sessions between assessments (Control group, n = 17). Students strongly agreed (median score 5/5) that using the model helped to reinforce the subdermal plexus flap technique and improved their confidence in performing a subdermal plexus flap. Students from both groups performed significantly better in the follow-up assessment compared with the initial assessment. No significantly greater improvement was observed in technique between the control and the trial groups. Results suggest that the students' reconstructive surgical technique improved after a single practice session and that the single pedicle advancement flap model can be used synergistically with other teaching methods.

The Role of Instructions in Motor Learning of Oral Versus Nasalized Speech Targets

PURPOSE

The purpose of this study was to investigate how general, implicit instructions with auditory-perceptual emphasis; specific, explicit instructions with biomechanical focus; or both affect learning of oral-nasal balance control in speech.

METHOD

Thirty healthy, vocally untrained participants were assigned to one of three instructional groups (i.e., implicit, explicit, and integrated) and learned to produce oral versus nasalized vowel-, syllable-, and phrase-level targets during once-weekly sessions over 4 weeks. Learning gains and performance variability were analyzed using nasometry.

RESULTS

We observed a significant main effect of instruction type on learning gains at phrase level (p = .016). Specifically, the integrated group (M = 59.8%) significantly outperformed the explicit group (M = 37.9%) and numerically outperformed the implicit group (M = 45.1%). For nasalized phrase targets, results revealed a significant main effect of instruction type on performance variability (p = .042), but pairwise comparisons between instruction groups were not significant.

CONCLUSIONS

The integration of implicit processes via auditory-perceptual modeling and explicit processes via relevant biomechanical directives resulted in larger motor learning gains, especially at higher levels of task complexity (i.e., phrase) compared to providing implicit or explicit instruction alone. The higher performance variability (i.e., less stable productions) that was sometimes induced by explicit instruction did not negatively impact learning when integrated with implicit instruction. Clinical implications for speech/voice therapy models are discussed.

Altered motor learning and coordination in mouse models of autism spectrum disorder

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with increasing prevalence. Over 1,000 risk genes have now been implicated in ASD, suggesting diverse etiology. However, the diagnostic criteria for the disorder still comprise two major behavioral domains - deficits in social communication and interaction, and the presence of restricted and repetitive patterns of behavior (RRBs). The RRBs associated with ASD include both stereotyped repetitive movements and other motor manifestations including changes in gait, balance, coordination, and motor skill learning. In recent years, the striatum, the primary input center of the basal ganglia, has been implicated in these ASD-associated motor behaviors, due to the striatum's role in action selection, motor learning, and habit formation. Numerous mouse models with mutations in ASD risk genes have been developed and shown to have alterations in ASD-relevant behaviors. One commonly used assay, the accelerating rotarod, allows for assessment of both basic motor coordination and motor skill learning. In this corticostriatal-dependent task, mice walk on a rotating rod that gradually increases in speed. In the extended version of this task, mice engage striatal-dependent learning mechanisms to optimize their motor routine and stay on the rod for longer periods. This review summarizes the findings of studies examining rotarod performance across a range of ASD mouse models, and the resulting implications for the involvement of striatal circuits in ASD-related motor behaviors. While performance in this task is not uniform across mouse models, there is a cohort of models that show increased rotarod performance. A growing number of studies suggest that this increased propensity to learn a fixed motor routine may reflect a common enhancement of corticostriatal drive across a subset of mice with mutations in ASD-risk genes.

A Systematic Review of the Learning Dynamics of Proprioception Training: Specificity, Acquisition, Retention, and Transfer

OBJECTIVE

We aimed to identify key aspects of the learning dynamics of proprioception training including: 1) specificity to the training type, 2) acquisition of proprioceptive skills, 3) retention of learning effects, and 4) transfer to different proprioceptive skills.

METHODS

We performed a systematic literature search using the database (MEDLINE, EMBASE, Cochrane Library, and PEDro). The inclusion criteria required adult participants who underwent any training program that could enhance proprioceptive function, and at least 1 quantitative assessment of proprioception before and after the intervention. We analyzed within-group changes to quantify the effectiveness of an intervention.

RESULTS

In total, 106 studies with 343 participant-outcome groups were included. Proprioception-specific training resulted in large effect sizes with a mean improvement of 23.4 to 42.6%, nonspecific training resulted in medium effect sizes with 12.3 to 22% improvement, and no training resulted in small effect sizes with 5.0 to 8.9% improvement. Single-session training exhibited significant proprioceptive improvement immediately (10 studies). For training interventions with a midway evaluation (4 studies), trained groups improved by approximately 70% of their final value at the midway point. Proprioceptive improvements were largely maintained at a delayed follow-up of at least 1 week (12 studies). Finally, improvements in 1 assessment were significantly correlated with improvements in another assessment (10 studies).

CONCLUSIONS

Proprioceptive learning appears to exhibit several features similar to motor learning, including specificity to the training type, 2 time constant learning curves, good retention, and improvements that are correlated between different assessments, suggesting a possible, common mechanism for the transfer of training.

The effects of a single bout of moderate-intensity aerobic exercise on visuomotor adaptation and its savings

Performing exercise before or after motor skill learning is thought to have a positive impact on acquisition and retention of motor memories stored in our nervous system. It has been shown that performing 25 min of moderate-intensity aerobic exercise prior to visuomotor adaptation can enhance both visuomotor adaptation and its retention compared to 25 min of rest before the adaptation. To determine whether a single bout of aerobic exercise could actually facilitate the formation of a neural representation associated with a novel visuomotor condition, we examined aftereffects and savings associated with a visuomotor adaptation task following either an exercise or a rest condition. Sixteen healthy young individuals (18-35 years) first experienced 25 min of moderate-intensity cycling or rest, and then adapted to a 30-degree visuomotor rotation condition. Immediately following that, participants experienced a washout session, which was followed by a readaptation session. Results indicated that all subjects adapted to the visuomotor rotation completely, although no difference was found between the cycling and rest conditions. Aftereffects and savings were also observed in both conditions, but with no difference between the conditions. These findings suggest that compared to a short rest session, a single bout of moderate-intensity cycling may not have a greater impact for enhancing visuomotor adaptation and its retention. Further research is needed, in which the effects of certain factors such as exercise intensity, duration and timing are more systematically investigated.

The (cognitive) future of motor control and learning

An ongoing debate exists regarding the compatibility of dynamic systems theory (DST) and symbol processing accounts (SPA), where SPA assume abstract representations and processing. Another aspect under discussion is if either one appropriately describes and explains motor control and the modification of motor skills. Both frameworks have their strengths and weaknesses. DST provides mechanistic explanations and takes system complexity and the environment into account without reference to mental entities. System behaviour is described mathematically and considered deterministic. In contrast, SPA propose that abstract content, that is, mental representations of the (own) body, and task requirements are critically important for movement control. It is argued that neither approach nor an (unaccomplished) unification of these frameworks can achieve a comprehensive understanding of motor control and learning. In this perspective article, it is argued that further effective sources of motor learning, such as emotional support and motivational guidance, have the potential to improve and preserve motor skills indirectly and should, thus, be recognised. Qualitative approaches focussing on understanding the athlete and the situation might be appropriate for applied work.

Implicit signatures of voluntary action reduce with repeated motor practice

The sense of controlling one's actions and their consequences is a critical aspect of successful motor activity. While motor performance typically improves with learning, it is unclear whether, how, and why higher order aspects of motor cognition are also affected. Here, we used an implicit measure of sense of agency-the 'intentional binding' effect-as participants learned to make a skilled action involving precise control of thumb adduction. These actions were predictably followed by a tone (the outcome). At pre-test, we showed the perceived time of the tone was shifted towards the thumb action, compared to a control condition in which tones occurred without actions. Next, a relevant training group learned to refine the direction of the thumb movement, while an irrelevant training group was trained on another movement. Manipulation checks demonstrated that, as expected, the relevant training group improved performance of the trained movement, while the irrelevant training group did not. Critically, while both groups still showed binding of the tone towards the thumb action at post-test, the relevant training group showed less binding than the irrelevant training group. Given the link between intentional binding and volitional control of action, we suggest our result demonstrates subjective agency over the outcome of a skilled action decreases as practice makes the skilled action more fluent. We suggest that this reduction in sense of agency over movement outcomes is consistent with the decreasing cognitive engagement, or automatization, that occurs during skill learning.

Optical neuroimaging and neurostimulation in surgical training and assessment: A state-of-the-art review

Introduction

Functional near-infrared spectroscopy (fNIRS) is a non-invasive optical neuroimaging technique used to assess surgeons' brain function. The aim of this narrative review is to outline the effect of expertise, stress, surgical technology, and neurostimulation on surgeons' neural activation patterns, and highlight key progress areas required in surgical neuroergonomics to modulate training and performance.

Methods

A literature search of PubMed and Embase was conducted to identify neuroimaging studies using fNIRS and neurostimulation in surgeons performing simulated tasks.

Results

Novice surgeons exhibit greater haemodynamic responses across the pre-frontal cortex than experts during simple surgical tasks, whilst expert surgical performance is characterized by relative prefrontal attenuation and upregulation of activation foci across other regions such as the supplementary motor area. The association between PFC activation and mental workload follows an inverted-U shaped curve, activation increasing then attenuating past a critical inflection point at which demands outstrip cognitive capacity Neuroimages are sensitive to the impact of laparoscopic and robotic tools on cognitive workload, helping inform the development of training programs which target neural learning curves. FNIRS differs in comparison to current tools to assess proficiency by depicting a cognitive state during surgery, enabling the development of cognitive benchmarks of expertise. Finally, neurostimulation using transcranial direct-current-stimulation may accelerate skill acquisition and enhance technical performance.

Conclusion

FNIRS can inform the development of surgical training programs which modulate stress responses, cognitive learning curves, and motor skill performance. Improved data processing with machine learning offers the possibility of live feedback regarding surgeons' cognitive states during operative procedures.

Towards best practice in developing motor skills: a systematic review on spacing in VR simulator-based psychomotor training for surgical novices

OBJECTIVE

Repeated practice, or spacing, can improve various types of skill acquisition. Similarly, virtual reality (VR) simulators have demonstrated their effectiveness in fostering surgical skill acquisition and provide a promising, realistic environment for spaced training. To explore how spacing impacts VR simulator-based acquisition of surgical psychomotor skills, we performed a systematic literature review.

METHODS

We systematically searched the databases PubMed, PsycINFO, Psychology and Behavioral Sciences Collection, ERIC and CINAHL for studies investigating the influence of spacing on the effectiveness of VR simulator training focused on psychomotor skill acquisition in healthcare professionals. We assessed the quality of all included studies using the Medical Education Research Study Quality Instrument (MERSQI) and the risk of bias using the Cochrane Collaboration's risk of bias assessment tool. We extracted and aggregated qualitative data regarding spacing interval, psychomotor task performance and several other performance metrics.

RESULTS

The searches yielded 1662 unique publications. After screening the titles and abstracts, 53 publications were retained for full text screening and 7 met the inclusion criteria. Spaced training resulted in better performance scores and faster skill acquisition when compared to control groups with a single day (massed) training session. Spacing across consecutive days seemed more effective than shorter or longer spacing intervals. However, the included studies were too heterogeneous in terms of spacing interval, obtained performance metrics and psychomotor skills analysed to allow for a meta-analysis to substantiate our outcomes.

CONCLUSION

Spacing in VR simulator-based surgical training improved skill acquisition when compared to massed training. The overall number and quality of available studies were only moderate, limiting the validity and generalizability of our findings.

Explicit benefits: Motor sequence acquisition and short-term retention in adults who do and do not stutter

Motor sequencing skills have been found to distinguish individuals who experience developmental stuttering from those who do not stutter, with these differences extending to non-verbal sequencing behaviour. Previous research has focused on measures of reaction time and practice under externally cued conditions to decipher the motor learning abilities of persons who stutter. Without the confounds of extraneous demands and sensorimotor processing, we investigated motor sequence learning under conditions of explicit awareness and focused practice among adults with persistent development stuttering. Across two consecutive practice sessions, 18 adults who stutter (AWS) and 18 adults who do not stutter (ANS) performed the finger-to-thumb opposition sequencing (FOS) task. Both groups demonstrated significant within-session performance improvements, as evidenced by fast on-line learning of finger sequences on day one. Additionally, neither participant group showed deterioration of their learning gains the following day, indicating a relative stabilization of finger sequencing performance during the off-line period. These findings suggest that under explicit and focused conditions, early motor learning gains and their short-term retention do not differ between AWS and ANS. Additional factors influencing motor sequencing performance, such as task complexity and saturation of learning, are also considered. Further research into explicit motor learning and its generalization following extended practice and follow-up in persons who stutter is warranted. The potential benefits of motor practice generalizability among individuals who stutter and its relevance to supporting treatment outcomes are suggested as future areas of investigation.

Motor learning and tDCS: A systematic review on the dependency of the stimulation effect on motor task characteristics or tDCS assembly specifications

TDCS is one of the most commonly used methods among studies with transcranial electrical stimulation and motor skills learning. Differences between study results suggest that the effect of tDCS on motor learning is dependent on the motor task performed or on the tDCS assembly specification used in the learning process. This systematic review aimed to analyze the tDCS effect on motor learning and verify whether this effect is dependent on the task or tDCS assembly specifications. Searches were performed in PubMed, SciELO, LILACS, Web of Science, CINAHL, Scopus, SPORTDiscus, Cochrane Central Register of Controlled Trials (CENTRAL), Embase, and PsycINFO. Articles were included that analyzed the effect of tDCS on motor learning through pre-practice, post-practice, retention, and/or transfer tests (period ≥24 h). The tDCS was most frequently applied to the primary motor cortex (M1) or the cerebellar cortex (CC) and the majority of studies found significant stimulation effects. Studies that analyzed identical or similar motor tasks show divergent results for the tDCS effect, even when the assembly specifications are the same. The tDCS effect is not dependent on motor task characteristics or tDCS assembly specifications alone but is dependent on the interaction between these factors. This interaction occurs between uni and bimanual tasks with anodal uni and bihemispheric (bilateral) stimulations at M1 or with anodal unihemispheric stimulations (unilateral and centrally) at CC, and between tasks of greater or lesser difficulty with single or multiple tDCS sessions. Movement time seems to be more sensitive than errors to indicate the effects of tDCS on motor learning, and a sufficient amount of motor practice to reach the "learning plateau" also seems to determine the effect of tDCS on motor learning.

The experience of sensorimotor integration of a lower limb sensory neuroprosthesis: A qualitative case study

Introduction

Lower limb prosthesis users often struggle to navigate uneven terrain or ambulate in low light conditions where it can be challenging to rely on visual cues for balance and walking. Sensory feedback about foot-floor interactions may allow users to reduce reliance on secondary sensory cues and improve confidence and speed when navigating difficult terrain. Our group has developed a Sensory Neuroprosthesis (SNP) to restore sensation to people with lower limb amputation by pairing electrical stimulation of nerves in the residual limb applied via implanted neurotechnology with pressure sensors in the insole of a standard prosthesis. Stimulation applied to the nerves evoked sensations perceived as originating on the missing leg and foot.

Methods

This qualitative case study reports on the experiences of a 68-year-old with a unilateral trans-tibial amputation who autonomously used the SNP at home for 31 weeks. Interview data collected throughout the study period was analyzed using a grounded theory approach with constant comparative methods to understand his experience with this novel technology and its impacts on his daily life.

Results

A conceptual model was developed that explained the experience of integrating SNP-provided sensory feedback into his body and motor plans. The model described the requirements of integration, which were a combination of a low level of mental focus and low stimulation levels. While higher levels of stimulation and focus could result in distinct sensory percepts and various phantom limb experiences, optimal integration was associated with SNP-evoked sensation that was not readily perceivable. Successful sensorimotor integration of the SNP resulted in improvements to locomotion, a return to a more normal state, an enhancement of perceived prosthesis utility, and a positive outlook on the experience.

Discussion

These outcomes emerged over the course of the nearly 8 month study, suggesting that findings from long-term home studies of SNPs may differ from those of short-term in-laboratory tests. Our findings on the experience of sensorimotor integration of the SNP have implications for the optimal training of SNP users and the future deployment of clinical SNP systems for long-term home use.

Body into Narrative: Behavioral and Neurophysiological Signatures of Action Text Processing After Ecological Motor Training

Embodied cognition research indicates that sensorimotor training can influence action concept processing. Yet, most studies employ isolated (pseudo)randomized stimuli and require repetitive single-effector responses, thus lacking ecological validity. Moreover, the neural signatures of these effects remain poorly understood. Here, we examined whether immersive bodily training can modulate behavioral and functional connectivity correlates of action-verb processing in naturalistic narratives. The study involved three phases. First, in the Pre-training phase, 32 healthy persons listened to an action text (rich in movement descriptions) and a non-action text (focused on its characters' perceptual and mental processes), completed comprehension questionnaires, and underwent resting-state electroencephalogram (EEG) recordings. Second, in the four-day Training phase, half the participants completed an exergaming intervention (eliciting full-body movements for 60 min a day) while the remaining half played static videogames (requiring no bodily engagement other than button presses). Finally, in the Post-training phase, all participants repeated the Pre-training protocol with different action and non-action texts and a new EEG session. We found that exergaming selectively reduced action-verb outcomes and fronto-posterior functional connectivity in the motor-sensitive ∼ 10-20 Hz range, both patterns being positively correlated. Conversely, static videogame playing yielded no specific effect on any linguistic category and did not modulate functional connectivity. Together, these findings suggest that action-verb processing and key neural correlates can be focally influenced by full-body motor training in a highly ecological setting. Our study illuminates the role of situated experience and sensorimotor circuits in action-concept processing, addressing calls for naturalistic insights on language embodiment.

Corticospinal Excitability Quantification During a Visually-Guided Precision Walking Task in Humans: Potential for Neurorehabilitation

The corticospinal tract has been shown to be involved in normal walking in humans. However, its contribution during more challenging locomotor tasks is still unclear. As the corticospinal tract can be a potential target to promote gait recovery after neurological injury, it is of primary importance to quantify its use during human walking. The aims of the current study were to: (1) quantify the effects of precision walking on corticospinal excitability as compared to normal walking; (2) assess if corticospinal modulation is related to task difficulty or participants' performance. Sixteen healthy participants walked on a treadmill during 2 tasks: regular walking (simple task) and stepping onto virtual targets (precision task). Virtual targets appeared randomly at 3 different step lengths: preferred, and ±20%. To assess corticospinal excitability, 25 motor evoked potentials (MEPs) were recorded from the tibialis anterior muscle in each task during walking. Performance for each participant (global success score; % of target hit) and task difficulty related to step length adjustments (success score for each step length) were also calculated. MEP size was larger during the precision task in all participants (mean increase of 93% ± 72%; P < .05) compared to the simple task. There was a correlation between MEP facilitation and individual performance (r = -.64; P < .05), but no difference in MEP size associated with task difficulty (P > .05). In conclusion, corticospinal excitability exhibits a large increase during the precision task. This effect needs to be confirmed in neurological populations to potentially provide a simple and non-invasive approach to increase corticospinal drive during gait rehabilitation.

Differences in implicit motor learning between adults who do and do not stutter

Implicit learning allows us to acquire complex motor skills through repeated exposure to sensory cues and repetition of motor behaviours, without awareness or effort. Implicit learning is also critical to the incremental fine-tuning of the perceptual-motor system. To understand how implicit learning and associated domain-general learning processes may contribute to motor learning differences in people who stutter, we investigated implicit finger-sequencing skills in adults who do (AWS) and do not stutter (ANS) on an Alternating Serial Reaction Time task. Our results demonstrated that, while all participants showed evidence of significant sequence-specific learning in their speed of performance, male AWS were slower and made fewer sequence-specific learning gains than their ANS counterparts. Although there were no learning gains evident in accuracy of performance, AWS performed the implicit learning task more accurately than ANS, overall. These findings may have implications for sex-based differences in the experience of developmental stuttering, for the successful acquisition of complex motor skills during development by individuals who stutter, and for the updating and automatization of speech motor plans during the therapeutic process.

Selective behavioural impairments in mice heterozygous for the cross disorder psychiatric risk gene DLG2

Mutations affecting DLG2 are emerging as a genetic risk factor associated with neurodevelopmental psychiatric disorders including schizophrenia, autism spectrum disorder, and bipolar disorder. Discs large homolog 2 (DLG2) is a member of the membrane-associated guanylate kinase protein superfamily of scaffold proteins, a component of the post-synaptic density in excitatory neurons and regulator of synaptic function and plasticity. It remains an important question whether and how haploinsuffiency of DLG2 contributes to impairments in basic behavioural and cognitive functions that may underlie symptomatic domains in patients that cross diagnostic boundaries. Using a heterozygous Dlg2 mouse model we examined the impact of reduced Dlg2 expression on functions commonly impaired in neurodevelopmental psychiatric disorders including motor co-ordination and learning, pre-pulse inhibition and habituation to novel stimuli. The heterozygous Dlg2 mice exhibited behavioural impairments in long-term motor learning and long-term habituation to a novel context, but not motor co-ordination, initial responses to a novel context, PPI of acoustic startle or anxiety. We additionally showed evidence for the reduced regulation of the synaptic plasticity-associated protein cFos in the motor cortex during motor learning. The sensitivity of selective behavioural and cognitive functions, particularly those dependent on synaptic plasticity, to reduced expression of DLG2 give further credence for DLG2 playing a critical role in specific brain functions but also a mechanistic understanding of symptom expression shared across psychiatric disorders.

Timescales of Local and Cross-Area Interactions during Neuroprosthetic Learning

How does the brain integrate signals with different timescales to drive purposeful actions? Brain-machine interfaces (BMIs) offer a powerful tool to causally test how distributed neural networks achieve specific neural patterns. During neuroprosthetic learning, actuator movements are causally linked to primary motor cortex (M1) neurons, i.e., "direct" neurons that project to the decoder and whose firing is required to successfully perform the task. However, it is unknown how such direct M1 neurons interact with both "indirect" local (in M1 but not part of the decoder) and across area neural populations (e.g., in premotor cortex/M2), all of which are embedded in complex biological recurrent networks. Here, we trained male rats to perform a M1-BMI task and simultaneously recorded the activity of indirect neurons in both M2 and M1. We found that both M2 and M1 indirect neuron populations could be used to predict the activity of the direct neurons (i.e., "BMI-potent activity"). Interestingly, compared with M1 indirect activity, M2 neural activity was correlated with BMI-potent activity across a longer set of time lags, and the timescale of population activity patterns evolved more slowly. M2 units also predicted the activity of both M1 direct and indirect neural populations, suggesting that M2 population dynamics provide a continuous modulatory influence on M1 activity as a whole, rather than a moment-by-moment influence solely on neurons most relevant to a task. Together, our results indicate that longer timescale M2 activity provides modulatory influence over extended time lags on shorter-timescale control signals in M1.SIGNIFICANCE STATEMENT A central question in the study of motor control is whether primary motor cortex (M1) and premotor cortex (M2) interact through task-specific subpopulations of neurons, or whether tasks engage broader correlated networks. Brain-machine interfaces (BMIs) are powerful tools to study cross-area interactions. Here, we performed simultaneous recordings of M1 and M2 in a BMI task using a subpopulation of M1 neurons (direct neurons). We found that activity outside of direct neurons in M1 and M2 was predictive of M1-BMI task activity, and that M2 activity evolved at slower timescales than M1. These findings suggest that M2 provides a continuous modulatory influence on M1 as a whole, supporting a model of interactions through broad correlated networks rather than task-specific neural subpopulations.

Default mode and dorsal attention network involvement in visually guided motor sequence learning

Motor sequence learning (MSL) paradigms are often used to investigate the neural processes underlying the acquisition of complex motor skills. Behavioral and neuroimaging studies have indicated an early stage in which spatial learning is prominent and a late stage of automatized performance after multiple training periods. Functional magnetic resonance imaging (fMRI) studies yielded both decreased and increased activations of the sensorimotor and association areas. However, task-negative and task-positive intrinsic connectivity networks (ICNs), the default mode (DMN) and dorsal attention (DAN) networks involved in governing attention demands during various task conditions were not specifically addressed in most studies. In the present fMRI study, a visually guided MSL (VMSL) task was used for bringing roles of visuospatial and motor attention into foreground in order to investigate the role of attention-related ICNs in MSL. Seventeen healthy, right-handed participants completed training and test sessions of VMSL during fMRI on the 1st day. Then, after daily training for three consecutive days outside the scanner, they were re-tested during the 5th day's scanning session. When test session after early learning period was compared with training session, activation decrease was observed in the occipito-temporal fusiform cortex, while task-related suppression of DMN was reduced. Reduced deactivation after early learning was correlated with decreased error rates. After late learning stage we observed activation decreases in bilateral superior parietal lobules of task-positive DAN, dorsal precunei, and cerebellum. Reduced activity in left posterior parietal and right cerebellar regions were correlated with gains in speed, error rate, respectively. This dissociation in activity changes of DMN and DAN related areas suggests that DAN shows high contribution during both early and late MSL stages, possibly due to attention requirement for automatization of spatial and temporal aspects of motor sequence. In contrast, spatial learning occurring during early MSL stage was sufficient for releasing DMN resources.

The Association between Physical Activity, Motor Skills and School Readiness in 4-5-Year-Old Children in the Northeast of England

The benefits of being physically active, possessing good motor skills and being school-ready are well documented in early years. Nevertheless, the association between physical activity and motor skills with school readiness remains unknown. Therefore, the aim of this cross-sectional study was to explore the relationship between these variables. We collected data on 326 four to five-year-old children from the northeast of England. Children's PA (ActiGraph GT1M accelerometers), motor skills (MABC-2 and the locomotor section of the TGMD-2) and school readiness (EYFSP) were measured, and associations between these variables were examined. This study found that, on average, children engaged in more MVPA (99.6 min/day) and less sedentary behaviour (261 min/day) than documented in previous research. Motor-skill scores were consistent with existing literature in early years. A higher percentage of children in the sample (79.6%) achieved school readiness than the average for England. Regression analyses found that motor-skill variables and sedentary behaviour were significantly predictive of school readiness, whereas physical activity was not. Motor skills and sedentary behaviour significantly predict school readiness. Therefore, promoting motor skills and developmentally appropriate sedentary behaviour activities may increase the number of children achieving school readiness.

Dendritic Spine Initiation in Brain Development, Learning and Diseases and Impact of BAR-Domain Proteins

Dendritic spines are small, bulbous protrusions along neuronal dendrites where most of the excitatory synapses are located. Dendritic spine density in normal human brain increases rapidly before and after birth achieving the highest density around 2-8 years. Density decreases during adolescence, reaching a stable level in adulthood. The changes in dendritic spines are considered structural correlates for synaptic plasticity as well as the basis of experience-dependent remodeling of neuronal circuits. Alterations in spine density correspond to aberrant brain function observed in various neurodevelopmental and neuropsychiatric disorders. Dendritic spine initiation affects spine density. In this review, we discuss the importance of spine initiation in brain development, learning, and potential complications resulting from altered spine initiation in neurological diseases. Current literature shows that two Bin Amphiphysin Rvs (BAR) domain-containing proteins, MIM/Mtss1 and SrGAP3, are involved in spine initiation. We review existing literature and open databases to discuss whether other BAR-domain proteins could also take part in spine initiation. Finally, we discuss the potential molecular mechanisms on how BAR-domain proteins could regulate spine initiation.

Noradrenaline in the aging brain: Promoting cognitive reserve or accelerating Alzheimer's disease?

Many believe that engaging in novel and mentally challenging activities promotes brain health and prevents Alzheimer's disease in later life. However, mental stimulation may also have risks as well as benefits. As neurons release neurotransmitters, they often also release amyloid peptides and tau proteins into the extracellular space. These by-products of neural activity can aggregate into the tau tangle and amyloid plaque signatures of Alzheimer's disease. Over time, more active brain regions accumulate more pathology. Thus, increasing brain activity can have a cost. But the neuromodulator noradrenaline, released during novel and mentally stimulating events, may have some protective effects-as well as some negative effects. Via its inhibitory and excitatory effects on neurons and microglia, noradrenaline sometimes prevents and sometimes accelerates the production and accumulation of amyloid-β and tau in various brain regions. Both α2A- and β-adrenergic receptors influence amyloid-β production and tau hyperphosphorylation. Adrenergic activity also influences clearance of amyloid-β and tau. Furthermore, some findings suggest that Alzheimer's disease increases noradrenergic activity, at least in its early phases. Because older brains clear the by-products of synaptic activity less effectively, increased synaptic activity in the older brain risks accelerating the accumulation of Alzheimer's pathology more than it does in the younger brain.

Reversal of motor-skill transfer impairment by trihexyphenidyl and reduction of dorsolateral striatal cholinergic interneurons in Dyt1 ΔGAG knock-in mice

DYT-TOR1A or DYT1 early-onset generalized dystonia is an inherited movement disorder characterized by sustained muscle contractions causing twisting, repetitive movements, or abnormal postures. The majority of the DYT1 dystonia patients have a trinucleotide GAG deletion in DYT1/TOR1A. Trihexyphenidyl (THP), an antagonist for excitatory muscarinic acetylcholine receptor M1, is commonly used to treat dystonia. Dyt1 heterozygous ΔGAG knock-in (KI) mice, which have the corresponding mutation, exhibit impaired motor-skill transfer. Here, the effect of THP injection during the treadmill training period on the motor-skill transfer to the accelerated rotarod performance was examined. THP treatment reversed the motor-skill transfer impairment in Dyt1 KI mice. Immunohistochemistry showed that Dyt1 KI mice had a significant reduction of the dorsolateral striatal cholinergic interneurons. In contrast, Western blot analysis showed no significant alteration in the expression levels of the striatal enzymes and transporters involved in the acetylcholine metabolism. The results suggest a functional alteration of the cholinergic system underlying the impairment of motor-skill transfer and the pathogenesis of DYT1 dystonia. Training with THP in a motor task may improve another motor skill performance in DYT1 dystonia.

Practice Mediates Bidirectional Dual-Task Interference When Performing a Novel Sequential Nonword Repetition Task

Introduction The current study examined the extent to which practice amount mediates dual-task interference patterns associated with concurrent performance of a novel speech task and attention-demanding visuomotor task. Method A Sequential Nonword Repetition Task was used to examine the effect of practice on interference associated with concurrent performance of a Visuomotor Pursuit Task. Twenty-five young adult participants were assigned to either an Extended Practice Group or a Limited Practice Group and performed a novel Sequential Nonword Repetition Task in isolation and while performing a concurrent visuomotor pursuit rotor task. Results Participants in the Limited Practice Group who were afforded a limited amount of practice exhibited dual-task interference (i.e., dual-task performance reductions) for both the speech and visuomotor tasks (i.e., bidirectional dual-task interference). Conversely, participants in the Extended Practice Group who were afforded extended practice exhibited little-to-no observable dual-task interference on the nonword repetition task. Conclusion Data from the current investigation suggest that the amount of initial practice mediates the degree of dual-task interference observed when a novel speech production task is performed with an attention-demanding Visuomotor Pursuit Task. Supplemental Material https://doi.org/10.23641/asha.14608071.

Resting Theta/Beta Ratios Mediate the Relationship Between Motor Competence and Inhibition in Children With Attention Deficit/Hyperactivity Disorder

Despite that previous studies have supported relationships between motor ability and inhibitory function, and between resting brain theta/beta power ratios (TBR) and inhibition in children with attention deficit/hyperactivity disorder (ADHD), little research has examined the mechanism within these relationships. The purpose of this study was to investigate whether TBR would mediate the relationship between motor ability and inhibitory function. A total of 71 children with ADHD were recorded resting electroencephalographic (EEG) data during eyes-open. Motor abilities were evaluated by Movement Assessment Battery for Children-2 (MABC-2) and inhibitory ability were assessed by a modified Eriksen’s flanker task. The results of mediation analyses revealed that TBR could completely mediate the relationship between motor competence and response speed (indirect effect = −0.0004, 95% CI [−0.0010, −0.0001]) and accuracy (indirect effect = 0.0003, 95% CI [0.0000, 0.0010]) in the incongruent condition of the flanker task. This study suggests that TBR may be one of the mechanisms between motor ability and inhibition function in children with ADHD.

Modulation of premotor cortex response to sequence motor learning during escitalopram intake

The contribution of selective serotonin reuptake inhibitors to motor learning by inducing motor cortical plasticity remains controversial given diverse findings from positive preclinical data to negative findings in recent clinical trials. To empirically address this translational disparity, we use functional magnetic resonance imaging in a double-blind, randomized controlled study to assess whether 20 mg escitalopram improves sequence-specific motor performance and modulates cortical motor response in 64 healthy female participants. We found decreased left premotor cortex responses during sequence-specific learning performance comparing single dose and steady escitalopram state. Escitalopram plasma levels negatively correlated with the premotor cortex response. We did not find evidence in support of improved motor performance after a week of escitalopram intake. These findings do not support the conclusion that one week escitalopram intake increases motor performance but could reflect early adaptive plasticity with improved neural processing underlying similar task performance when steady peripheral escitalopram levels are reached.

Experiment in a Box (XB): An Interactive Technology Framework for Sustainable Health Practices

This paper presents the Experiment in a Box (XB) framework to support interactive technology design for building health skills. The XB provides a suite of experiments—time-limited, loosely structured evaluations of health heuristics for a user-as-experimenter to select from and then test in order to determine that heuristic’s efficacy, and to explore how it might be incorporated into the person’s life and when necessary, to support their health and wellbeing. The approach leverages self-determination theory to support user autonomy and competence to build actionable, personal health knowledge skills and practice (KSP). In the three studies of XB presented, we show that with even the short engagement of an XB experiment, participants develop health practices from the interventions that are still in use long after the intervention is finished. To situate the XB approach relative to other work around health practices in HCI in particular, we contribute two design continua for this design space: insourcing to outsourcing and habits to heuristics. From this analysis, we demonstrate that XB is situated in a largely under-explored area for interactive health interventions: the insourcing and heuristic oriented area of the design space. Overall, the work offers a new scaffolding, the XB Framework, to instantiate time-limited interactive technology interventions to support building KSP that can thrive in that person, significantly both post-interventions, and independent of that technology.

RTP801 regulates motor cortex synaptic transmission and learning

BACKGROUND

RTP801/REDD1 is a stress-regulated protein whose upregulation is necessary and sufficient to trigger neuronal death in in vitro and in vivo models of Parkinson's and Huntington's diseases and is up regulated in compromised neurons in human postmortem brains of both neurodegenerative disorders. Indeed, in both Parkinson's and Huntington's disease mouse models, RTP801 knockdown alleviates motor-learning deficits.

RESULTS

We investigated the physiological role of RTP801 in neuronal plasticity and we found RTP801 in rat, mouse and human synapses. The absence of RTP801 enhanced excitatory synaptic transmission in both neuronal cultures and brain slices from RTP801 knock-out (KO) mice. Indeed, RTP801 KO mice showed improved motor learning, which correlated with lower spine density but increased basal filopodia and mushroom spines in the motor cortex layer V. This paralleled with higher levels of synaptosomal GluA1 and TrkB receptors in homogenates derived from KO mice motor cortex, proteins that are associated with synaptic strengthening.

CONCLUSIONS

Altogether, these results indicate that RTP801 has an important role modulating neuronal plasticity and motor learning. They will help to understand its role in neurodegenerative disorders where RTP801 levels are detrimentally upregulated.

White matter microstructural changes in short-term learning of a continuous visuomotor sequence

Efficient neural transmission is crucial for optimal brain function, yet the plastic potential of white matter (WM) has long been overlooked. Growing evidence now shows that modifications to axons and myelin occur not only as a result of long-term learning, but also after short training periods. Motor sequence learning (MSL), a common paradigm used to study neuroplasticity, occurs in overlapping learning stages and different neural circuits are involved in each stage. However, most studies investigating short-term WM plasticity have used a pre-post design, in which the temporal dynamics of changes across learning stages cannot be assessed. In this study, we used multiple magnetic resonance imaging (MRI) scans at 7 T to investigate changes in WM in a group learning a complex visuomotor sequence (LRN) and in a control group (SMP) performing a simple sequence, for five consecutive days. Consistent with behavioral results, where most improvements occurred between the two first days, structural changes in WM were observed only in the early phase of learning (d1-d2), and in overall learning (d1-d5). In LRNs, WM microstructure was altered in the tracts underlying the primary motor and sensorimotor cortices. Moreover, our structural findings in WM were related to changes in functional connectivity, assessed with resting-state functional MRI data in the same cohort, through analyses in regions of interest (ROIs). Significant changes in WM microstructure were found in a ROI underlying the right supplementary motor area. Together, our findings provide evidence for highly dynamic WM plasticity in the sensorimotor network during short-term MSL.

The Optimal Adaptive-Based Neurofuzzy Control of the 3-DOF Musculoskeletal System of Human Arm in a 2D Plane

Each individual performs different daily activities such as reaching and lifting with his hand that shows the important role of robots designed to estimate the position of the objects or the muscle forces. Understanding the body's musculoskeletal system's learning control mechanism can lead us to develop a robust control technique that can be applied to rehabilitation robotics. The musculoskeletal model of the human arm used in this study is a 3-link robot coupled with 6 muscles which a neurofuzzy controller of TSK type along multicritic agents is used for training and learning fuzzy rules. The adaptive critic agents based on reinforcement learning oversees the controller's parameters and avoids overtraining. The simulation results show that in both states of with/without optimization, the controller can well track the desired trajectory smoothly and with acceptable accuracy. The magnitude of forces in the optimized model is significantly lower, implying the controller's correct operation. Also, links take the same trajectory with a lower overall displacement than that of the nonoptimized mode, which is consistent with the hand's natural motion, seeking the most optimum trajectory.

Forelimb Motor Skills Deficits Following Thoracic Spinal Cord Injury: Underlying Dopaminergic and Neural Oscillatory Changes in Rat Primary Motor Cortex

The loss of spinal sensorimotor pathways following spinal cord injury (SCI) can induce retrograde neurodegeneration in the primary motor cortex (M1). However, the effect of thoracic SCI on forelimb motor skills has not been studied clearly. So, herein we aimed to examine the effects of the thoracic SCI model on forelimb motor skills learning, parallel with dopaminergic and oscillatory changes in hindlimb and forelimb areas (HLA and FLA) of M1 in rats. Male Wistar rats were randomly subjected to laminectomy (Control) or contusion SCI at the thoracic (T10) level. Oscillatory activity and motor skills performance were evaluated for six consecutive days using local field potential (LFP) recording and skilled forelimb reaching task, respectively. Dopamine (DA) levels and expression of dopamine receptors (D1R and D2R) were determined in HLA and FLA by ELISA and western blotting. LFP recording results showed a sustained increase of LFP power in SCI rats compared with uninjured rats through skilled reaching training. Also, the SCI group had a lower reaching performance and learning rate in contrast to the Control group. Biochemical analysis of HLA and FLA showed a reduction in DA levels and expression of D1R and D2R after SCI. According to these findings, thoracic SCI causes aberrant changes in the oscillatory activity and dopaminergic system of M1, which are not restricted to HLA but also found in FLA accompanied by a deficit in forelimb motor skills performance.Summary statement: The reorganization of the primary motor cortex, following spinal cord injury, is not restricted to the hind limb area, and interestingly extends to the forelimb limb area, which appears as a dysfunctional change in oscillations and dopaminergic system, associated with a deficit in motor skills learning of forelimb.

cAMP-Fyn signaling in the dorsomedial striatum direct pathway drives excessive alcohol use

Fyn kinase in the dorsomedial striatum (DMS) of rodents plays a central role in mechanisms underlying excessive alcohol intake. The DMS is comprised of medium spiny neurons (MSNs) that project directly (dMSNs) or indirectly (iMSNs) to the substantia nigra. Here, we examined the cell-type specificity of Fyn's actions in alcohol use. First, we knocked down Fyn selectively in DMS dMSNs or iMSNs of mice and measured the level of alcohol consumption. We found that downregulation of Fyn in dMSNs, but not in iMSNs, reduces excessive alcohol but not saccharin intake. D1Rs are coupled to Gαs/olf, which activate cAMP signaling. To examine whether Fyn's actions are mediated through cAMP signaling, DMS dMSNs were infected with GαsDREADD, and the activation of Fyn signaling was measured following CNO treatment. We found that remote stimulation of cAMP signaling in DMS dMSNs activates Fyn and promotes the phosphorylation of the Fyn substrate, GluN2B. In contract, remote activation of GαsDREADD in DLS dMSNs did not alter Fyn signaling. We then tested whether activation of GαsDREADD in DMS dMSNs or iMSNs alters alcohol intake and observed that CNO-dependent activation of GαsDREADD in DMS dMSNs but not iMSNs increases alcohol but not saccharin intake. Finally, we examined the contribution of Fyn to GαsDREADD-dependent increase in alcohol intake, and found that systemic administration of the Fyn inhibitor, AZD0503 blocks GαsDREADD-dependent increase in alcohol consumption. Our results suggest that the cAMP-Fyn axis in the DMS dMSNs is a molecular transducer of mechanisms underlying the development of excessive alcohol consumption.

Changes in attentional resources during the acquisition of laparoscopic surgical skills

Background

Increasing familiarity and practice might free up mental resources during laparoscopic surgical skills training. The aim of the study was to track changes in mental resource allocation during acquisition of laparoscopic surgical skills.

Methods

Medical students with no previous experience in laparoscopic surgery took part in a 5-week laparoscopic training curriculum. At the beginning and end of the training period, one of the training tasks was combined with a secondary auditory detection task that required pressing a foot switch for defined target tones, creating a dual-task situation. During execution of the two concurrent tasks, continuous electroencephalographic measurements were made, with special attention to the P300 component, an index of mental resources. Accuracy and reaction times of the secondary task were determined.

Results

All 14 participants successfully completed the training curriculum. Target times for successful completion of individual tasks decreased significantly during training sessions (P  <0.001 for all tasks). Comparing results before and after training showed a significant decrease in event-related brain potential amplitude at the parietal electrode cluster (P300 component, W = 67, P = 0.026), but there were no differences in accuracy (percentage correct responses: W = 48, P = 0.518) or reaction times (W = 42, P = 0.850) in the auditory detection task.

Conclusion

The P300 decrease in the secondary task over training demonstrated a shift of mental resources to the primary task: the surgical exercise. This indicates that, with more practice, mental resources are freed up for additional tasks.

Distribution of Practice Combined with Observational Learning Has Time Dependent Effects on Motor Skill Acquisition

Studies of the benefits of a distributed practice schedule on motor skill acquisition have typically found that distribution of practice results in better learning. However, less research has focused on how the benefits of distributed practice are impacted by timing during acquisition. To examine how timing of skill acquisition interacts with distribution of practice we had two groups of participants complete either an extensive massed or distributed training schedule to learn a speed stacking sequence across ten sessions. For participants in both groups, we provided observational learning to facilitate skill acquisition. Analysis of speed stacking time on a retention test revealed an overall benefit for the distributed relative to the massed practice group. Interestingly, our analysis of the benefits of distributed practice during training only showed performance benefits in the early session (session one) and later sessions (sessions eight, nine, and ten) of skill acquisition but not mid-way through it (sessions two through seven). Our results support previous findings highlighting the learning benefits of a distributed practice schedule but suggest that these benefits occur differentially throughout acquisition. Our work also replicates research demonstrating that observational learning is more beneficial when it is yoked to actual practice.

Chronic Physical Activity for Attention Deficit Hyperactivity Disorder and/or Autism Spectrum Disorder in Children: A Meta-Analysis of Randomized Controlled Trials

Purpose: To explore the effects of physical activity (PA) intervention on executive function (EF) and motor skills (MS) among children with attention deficit hyperactivity disorder and/or autism spectrum disorder (ASD).

Methods: Relevant studies were sourced from PubMed, Web of Science, EMBASE, Cochrane Library, CNKI and Wanfang Data. Only randomized controlled trials (RCT) were included based upon the following criteria: (1) participants were children and clinically diagnosed with ADHD/ASD, (2) intervention strategies were identified as chronic physical activity, and (3) EF (e.g., cognitive flexibility) and/or MS (e.g., gross motor skills) were measured at baseline and post-intervention and compared with an eligible control group.

Results: Eleven studies involving 346 participants were finally identified. PA elicited significant improvements in EF and MS in children with ADHD/ASD. Regarding changes in the EF of participants, PA showed a great improvement in overall EF [standardized mean difference (SMD): 0.90, 95% confidence interval (CI) 0.49–1.30, p < 0.00001], inhibitory control (SMD: 1.30, 95% CI 0.58–2.02, p = 0.0004) and cognitive flexibility (SMD: 0.85, 95% CI 0.42–1.29, p = 0.0001), but no significant improvement in working memory (SMD: 0.28, 95% CI −0.15–0.71, p = 0.20). Significant improvements were also found with respect to gross motor skills (SMD: 0.80, 95% CI 0.30–1.30, p = 0.002), but no significant changes were found in fine motor skills (SMD: 0.30, 95% CI −0.91–1.52, p = 0.62).

Conclusion: Chronic PA interventions may promote EF and MS in children with ADHD/ASD, especially in inhibitory control, cognitive flexibility, and gross motor skills. However, PA interventions seemed to have insignificant effects on working memory and fine motor skills to children with ADHD/ASD.

PROSPERO registration number: CRD42019118622

Training in a cooperative bimanual skilled reaching task, the popcorn retrieval task, improves unimanual function after motor cortical infarcts in rats

Disuse of the paretic hand after stroke is encouraged by compensatory reliance on the nonparetic hand, to exacerbate impairment and potentially constrain motor rehabilitation efficacy. Rodent stroke model findings support that learning new unimanual skills with the nonparetic forelimb diminishes functional improvements that can be driven by rehabilitative training of the paretic forelimb. The influence of learning new ways of skillfully using the two hands together on paretic side function is much less clear. To begin to explore this, we developed a new cooperative bimanual skilled reaching task for rats, the Popcorn Retrieval Task. After motor cortical infarcts impaired an established unimanual reaching skill in the paretic forelimb, rats underwent a 7 week period of de novo bimanual training (BiT) or no-training control procedures (Cont). Probes of paretic forelimb unimanual performance revealed significant improvements during and after the training period in BiT vs. Cont. We additionally observed a striking change in the bimanual task strategy over training days: a switch from the paretic to the nonparetic forelimb for initiating reach-to-grasp sequences. This motivated another study to test whether rats that established the bimanual skill prior to the infarcts would similarly switch handedness, which they did not, though paretic paw use for manipulative movements diminished. These results indicate that unimanual function of the paretic side can be improved by novel bimanual skill practice, even when it involves compensatory reliance on the nonparetic hand. They further support the suitability of the Popcorn Retrieval Task for studying bimanual skill learning effects in rats.