Motor System Function Research Articles

Combination of induced pluripotent stem cell-derived motor neuron progenitor cells with irradiated brain-derived neurotrophic factor over-expressing engineered mesenchymal stem cells enhanced restoration of axonal regeneration in a chronic spinal cord injury rat model

BackgroundSpinal cord injury (SCI) is a disease that causes permanent impairment of motor, sensory, and autonomic nervous system functions. Stem cell transplantation for neuron regeneration is a promising strategic treatment for SCI. However, selecting stem cell sources and cell transplantation based on experimental evidence is required. Therefore, this study aimed to investigate the efficacy of combination cell transplantation using the brain-derived neurotrophic factor (BDNF) over-expressing engineered mesenchymal stem cell (BDNF-eMSC) and induced pluripotent stem cell-derived motor neuron progenitor cell (iMNP) in a chronic SCI rat model.MethodA contusive chronic SCI was induced in Sprague-Dawley rats. At 6 weeks post-injury, BDNF-eMSC and iMNP were transplanted into the lesion site via the intralesional route. At 12 weeks post-injury, differentiation and growth factors were evaluated through immunofluorescence staining and western blot analysis. Motor neuron differentiation and neurite outgrowth were evaluated by co-culturing BDNF-eMSC and iMNP in vitro in 2-dimensional and 3-dimensional.ResultsCombination cell transplantation in the chronic SCI model improved behavioral recovery more than single-cell transplantation. Additionally, combination cell transplantation enhanced mature motor neuron differentiation and axonal regeneration at the injured spinal cord. Both BDNF-eMSC and iMNP played a critical role in neurite outgrowth and motor neuron maturation via BDNF expression.ConclusionsOur results suggest that the combined transplantation of BDNF- eMSC and iMNP in chronic SCI results in a significant clinical recovery. The transplanted iMNP cells predominantly differentiated into mature motor neurons. Additionally, BDNF-eMSC exerts a paracrine effect on neuron regeneration through BDNF expression in the injured spinal cord.Graphical

Defining the concept of reserve in the motor domain: a systematic review.

A reserve in the motor domain may underlie the capacity exhibited by some patients to maintain motor functionality in the face of a certain level of disease. This form of "motor reserve" (MR) could include cortical, cerebellar, and muscular processes. However, a systematic definition has not been provided yet. Clarifying this concept in healthy individuals and patients would be crucial for implementing prevention strategies and rehabilitation protocols. Due to its wide application in the assessment of motor system functioning, non-invasive brain stimulation (NIBS) may support such definition. Here, studies focusing on reserve in the motor domain and studies using NIBS were revised. Current literature highlights the ability of the motor system to create a reserve and a possible role for NIBS. MR could include several mechanisms occurring in the brain, cerebellum, and muscles, and NIBS may support the understanding of such mechanisms.

Recording Forelimb Muscle Activity in Head-Fixed Mice with Chronically Implanted EMG Electrodes.

Powerful genetic and molecular tools available in mouse systems neuroscience research have enabled researchers to interrogate motor system function with unprecedented precision in head-fixed mice performing a variety of tasks. The small size of the mouse makes the measurement of motor output difficult, as the traditional method of electromyographic (EMG) recording of muscle activity was designed for larger animals like cats and primates. Pending commercially available EMG electrodes for mice, the current gold-standard method for recording muscle activity in mice is to make electrode sets in-house. This article describes a refinement of established procedures for hand fabrication of an electrode set, implantation of electrodes in the same surgery as headplate implantation, fixation of a connector on the headplate, and post-operative recovery care. Following recovery, millisecond-resolution EMG recordings can be obtained during head-fixed behavior for several weeks without noticeable changes in signal quality. These recordings enable precise measurement of forelimb muscle activity alongside in vivo neural recording and/or perturbation to probe mechanisms of motor control in mice.

Regulation of insect behavior by non-coding RNAs.

The adaptation of insects to environments relies on a sophisticated set of behaviors controlled by molecular and physiological processes. Over the past several decades, accumulating studies have unveiled the roles of non-coding RNAs (ncRNAs) in regulating insect behaviors. ncRNAs assume particularly pivotal roles in the behavioral plasticity of insects by rapidly responding to environmental stimuli. ncRNAs also contribute to the maintenance of homeostasis of insects by fine-tuning the expression of target genes. However, a comprehensive review of ncRNAs' roles in regulating insect behaviors has yet to be conducted. Here, we present the recent progress in our understanding of how ncRNAs regulate various insect behaviors, including flight and movement, social behavior, reproduction, learning and memory, and feeding. We refine the intricate mechanisms by which ncRNAs modulate the function of neural, motor, reproductive, and other physiological systems, as well as gene expression in insects like fruit flies, social insects, locusts, and mosquitos. Furthermore, we discuss potential avenues for future studies in ncRNA-mediated insect behaviors.

Skeletal phenotypes and molecular mechanisms in aging mice.

Aging is an inevitable physiological process, often accompanied by age-related bone loss and subsequent bone-related diseases that pose serious health risks. Research on skeletal diseases caused by aging in humans is challenging due to lengthy study durations, difficulties in sampling, regional variability, and substantial investment. Consequently, mice are preferred for such studies due to their similar motor system structure and function to humans, ease of handling and care, low cost, and short generation time. In this review, we present a comprehensive overview of the characteristics, limitations, applicability, bone phenotypes, and treatment methods in naturally aging mice and prematurely aging mouse models (including SAMP6, POLG mutant, LMNA, SIRT6, ZMPSTE24, TFAM, ERCC1, WERNER, and KL/KL-deficient mice). We also summarize the molecular mechanisms of these aging mouse models, including cellular DNA damage response, senescence-related secretory phenotype, telomere shortening, oxidative stress, bone marrow mesenchymal stem cell (BMSC) abnormalities, and mitochondrial dysfunction. Overall, this review aims to enhance our understanding of the pathogenesis of aging-related bone diseases.

Transcranial Magnetic and Transcutaneous Spinal Cord Electrical Stimulation a Stroke-Patients Walking Correction: Blinded Clinical Randomised Study

INTRODUCTION. The impairment of motor system function due to stroke often leads to patients’ dependence on external assistance. The technique of rhythmic transcranial magnetic stimulation (rTMS) is now widely used in the restoration of impaired central nervous system (CNS) function. In recent years, there has been information about the use of transcutaneous electrical spinal cord stimulation (TSCS) in the correction of motor functions in CNS disorders of various genesis. AIM. To evaluate the possibilities of combined use of transcranial magnetic and transcutaneous electrical stimulation of the spinal cord in the correction of locomotor functions in patients after ischemic stroke. MATERIALS AND METHODS. The conducted blind clinical randomized study involved patients who had an ischemic stroke. Study participants were randomly divided into control (n = 12) and experimental (n = 9) groups. Patients in the control group received standardized neurorehabilitation techniques. The participants of the experimental group were offered standardized neurorehabilitation techniques combined with rTMS and TSCS. High-frequency rTMS was performed in the projection of the sensory-motor cortex on the side of the lesion, in the area of innervation of the lower limb. During TSCS, a stimulating electrode was placed between Th11–Th12, indifferent electrodes were placed in the region of the iliac crests, and the lumbar enlargement of the spinal cord was stimulated. The dynamics of neurological deficit was assessed using the rehabilitation routing scale, the Rivermead mobility index, the Berg balance scale, and a six-point scale for assessing muscle strength. The excitability of the neural networks of the spinal cord was determined using TSCS at the T11–T12 level, with electromyographic recording of the evoked motor responses of the muscles of the lower extremities. RESULTS AND DISCUSSION. The combined use of rTMS and TSCS in the rehabilitation of patients in the acute period after ischemic stroke leads to an increase in the excitability of neuronal networks of the lumbar thickening of the spinal cord, a decrease in the activation thresholds of the RF, BF, TA and GM muscles of the affected limb (by 7.7 ma, 18.3 ma, 24.8 ma and 14.2 ma, respectively). Inclusion of rTMS and TSCS in the rehabilitation course leads to a significant improvement in the rehabilitation routing scale (by 2 points), Rivermead mobility index (by 5.8 points), statokinetic control functions (balance-Berg by 12 points) and an increase in lower limb muscle strength (flexors by 5.1 points, extensors by 6.2 points). CONCLUSION. The use of rTMS and TSCS can be used as an additional effect within the framework of rehabilitation measures in the acute period after ischemic stroke.

An fMRI study of finger movements in children with and without dyslexia.

Developmental dyslexia is a language-based reading disability, yet some have reported motor impairments, usually attributed to cerebellar dysfunction. Using fMRI, we compared children with and without dyslexia during irregularly paced, left or right-hand finger tapping. Next, we examined seed-to-voxel intrinsic functional connectivity (iFC) using six seed regions of the motor system (left and right anterior lobe of the cerebellum, SM1 and SMA). A whole-brain task-evoked analysis revealed relatively less activation in the group with dyslexia in right anterior cerebellum during right hand tapping. For iFC, we found the group with dyslexia to have greater iFC between the right SM1 seed and a medial aspect of right postcentral gyrus for left hand tapping; and greater iFC between the left SM1 seed and left thalamus, as well as weaker local iFC around the left SM1 seed region for right hand tapping. Lastly, extracted activity and connectivity values that had been identified in these between-group comparisons were not correlated with measures of reading. We conclude that there are some aberrations in motor system function in children with dyslexia, but these are not tied to reading ability.

Can non-swallowing function assessment predict nasogastric tube removal in patients with poststroke dysphagia? A clinical study.

This study aimed to predict nasogastric tube (NGT) removal in patients with poststroke dysphagia (PSD) by non-swallowing function assessment. We enrolled 232 eligible patients and performed rehabilitation. The Fugl-Meyer assessment motor (FMM) and National Institute of Health Stroke Scale (NIHSS) scores were used to measure the motor and overall nervous system functions. Predictors for NGT removal in patients with PSD after rehabilitation were analyzed. Of the 232 included patients, the NGTs were removed from 78% of them, while 22% were dependent on a feeding tube after 4 weeks of rehabilitation. Compared to the preserved NGT group, older age, a higher rate of intubation or tracheostomy, and more severe baseline functions were found in the NGT removal group. Age [odds ratio (OR) = 0.907; 95% confidence interval (CI): 0.859-0.957; p = 0.000], difference in the FMM score after 4 weeks of rehabilitation (OR = 1.219; 95% CI: 1.145-1.299; p = 0.00), and item 9 of NIHSS (OR = 0.488; 95% CI: 0.252-0.946; p = 0.034) were predictors of NGT removal after rehabilitation. We established a predictive model in patients with PSD using a non-swallowing assessment, which enabled us to predict swallowing recovery based on the non-swallowing function.

Postpartum as the best time for physical recovery and health care

Aim: The current paper presents a subjective symptom survey regarding postpartum discomfort (Study 1) and a case study on postpartum care using the program developed based on the survey results (Study 2). Thereafter, health care during the postpartum period is discussed. Methods: Study 1 analyzed 1638 postpartum women who completed the Subjective Fatigue Symptom Scale (SFSS) over the period from June 2012 to December 2019. Study 2 detailed the case of a 33-year-old primiparous woman who answered questions regarding the rehabilitation care program. Results: The 1638 subjects included in Study 1 had a mean age of 32.4 ± 8.2 years and a mean postpartum duration of 4.3 ± 2.3 months. Subjective symptoms included lower back pain, shoulder stiffness, sleepiness, wanting to lie down, yawing, and eye strain. The case included in Study 2 showed certain psychological and physical changes following the exercise program. The results of Study 1 showed that motor system discomfort, such as stiff shoulders and lower back pain, occurred in women across all postpartum stages. Our results demonstrated that care and exercise geared toward improving motor system function are imperative after childbirth. Meanwhile, the results of Study 2 imply that our rehabilitation program based on postpartum physical conditions had positive psychological and physical effects. Conclusion: Taken together, our results suggest that continuing rehabilitative care based on the physical condition during each postpartum stage facilitates improvement in mothers’ physical and psychological discomfort.

Acute Effects of High Intensity Dual Task Training on Cognitive Workload in Young Adults

<h3>Research Objectives</h3> Dual tasking (DT) is necessary for daily living and requires intact cognitive and motor system functions. The cognitive workload is the combined mental and physical effort in response to the cognitive demand and time constraints of a task. The aim was to evaluate the short-term effects of high-intensity DT training on cognitive workload. <h3>Design</h3> Participants completed one session of high-intensity DT training. The training involved 6 bouts of 6 minutes of DT treadmill walking. <h3>Setting</h3> Laboratory for Advanced Rehabilitation Research in Simulation (LARRS), G042 of Olathe Pavilion at the University of Kansas Medical Center. <h3>Participants</h3> 40 healthy young adults with age = mean (Sd), 23.7 (1.4), 24 females (60%), The motor component of the DT program consisted of walking at 80% of self-selected overground speed and obstacle crossing on a virtual reality treadmill. <h3>Interventions</h3> The training involved 6 bouts of 6 minutes of DT treadmill walking. The motor component of the DT program consisted of walking at 80% of self-selected overground speed and obstacle crossing on a virtual reality treadmill. <h3>Main Outcome Measures</h3> The cognitive component consisted of working memory (2-back test). The cognitive workload was administered through self-report (NASA-TLX) and pupillometry (Index of Cognitive Activity; greater cognitive workload indexed by pupil dilation). <h3>Results</h3> Repeated Measures ANOVA showed significant improvements in walking speed, percentages of obstacles crossed, and the number of hits on the 2-back (p< 0.05). NASA-TLX scores decreased across training sessions, with the most significant changes observed in the first three bouts (p< 0.05). No changes in pupillary responses were observed. <h3>Conclusions</h3> Highly intense DT training on virtual reality treadmill training leads to decreased self-reported cognitive workload and improvements in motor and cognitive performance. Further studies should include more sessions of DT training to investigate whether short-term improvements in DT performance stem from decreased cognitive workload to attend to the tasks. <h3>Author(s) Disclosures</h3> Maryam Sadeghi, Joan Augustyn, Alexis Bieker, Erin Holtmeier, Kari Skinner, Jacob Sosnoff, Jeffrey Hausdorff, Hannes Devos

Variational and phase response analysis for limit cycles with hard boundaries, with applications to neuromechanical control problems

Motor systems show an overall robustness, but because they are highly nonlinear, understanding how they achieve robustness is difficult. In many rhythmic systems, robustness against perturbations involves response of both the shape and the timing of the trajectory. This makes the study of robustness even more challenging. To understand how a motor system produces robust behaviors in a variable environment, we consider a neuromechanical model of motor patterns in the feeding apparatus of the marine mollusk Aplysia californica (Shaw et al. in J Comput Neurosci 38(1):25–51, 2015; Lyttle et al. in Biol Cybern 111(1):25–47, 2017). We established in (Wang et al. in SIAM J Appl Dyn Syst 20(2):701–744, 2021. https://doi.org/10.1137/20M1344974) the tools for studying combined shape and timing responses of limit cycle systems under sustained perturbations and here apply them to study robustness of the neuromechanical model against increased mechanical load during swallowing. Interestingly, we discover that nonlinear biomechanical properties confer resilience by immediately increasing resistance to applied loads. In contrast, the effect of changed sensory feedback signal is significantly delayed by the firing rates’ hard boundary properties. Our analysis suggests that sensory feedback contributes to robustness in swallowing primarily by shifting the timing of neural activation involved in the power stroke of the motor cycle (retraction). This effect enables the system to generate stronger retractor muscle forces to compensate for the increased load, and hence achieve strong robustness. The approaches that we are applying to understanding a neuromechanical model in Aplysia, and the results that we have obtained, are likely to provide insights into the function of other motor systems that encounter changing mechanical loads and hard boundaries, both due to mechanical and neuronal firing properties.

"Xingnao Kaiqiao" Acupuncture Combined with Traditional Chinese Medicine for Delayed Encephalopathy after Carbon Monoxide Poisoning: A Case Report

Purpose: To explore the clinical effect of acupuncture combined with traditional Chinese medicine in the treatment of delayed encephalopathy of carbon monoxide poisoning, to provide basis for the treatment of delayed encephalopathy of carbon monoxide poisoning by traditional Chinese medicine. Method: "Xingnaokaiqiao" acupuncture combined with traditional Chinese medicine was used to treat delayed encephalopathy caused by carbon monoxide poisoning, and the evolution of the syndrome was observed in detail. Result: After 44 days of treatment, the general state, cognitive function, the function of motor system and sensory system of the patients were significantly improved. Conclusion: The results of this case show that acupuncture combined with traditional Chinese medicine is effective in the treatment of carbon monoxide poisoning delayed encephalopathy and has the advantages of short course of treatment and integration of treatment and prevention. It can significantly improve the prognosis of delayed encephalopathy and improve the quality of life of patients, which is of great significance to reduce the economic burden of societies and families. Key words: Delayed Encephalopathy after Carbon Monoxide poisoning; Xingnao Kaiqiao Acupuncture; Traditional Chinese Medicine; Medical Case Report.

Local and large-scale beta oscillatory dysfunction in males with mild traumatic brain injury.

Mild traumatic brain injury (mTBI) is impossible to detect with standard neuroradiological assessment such as structural magnetic resonance imaging (MRI). Injury does, however, disrupt the dynamic repertoire of neural activity indexed by neural oscillations. In particular, beta oscillations are reliable predictors of cognitive, perceptual, and motor system functioning, as well as correlating highly with underlying myelin architecture and brain connectivity-all factors particularly susceptible to dysregulation after mTBI. We measured local and large-scale neural circuit function by magnetoencephalography (MEG) with a data-driven model fit approach using the fitting oscillations and one-over f algorithm in a group of young adult men with mTBI and a matched healthy control group. We quantified band-limited regional power and functional connectivity between brain regions. We found reduced regional power and deficits in functional connectivity across brain areas, which pointed to the well-characterized thalamocortical dysconnectivity associated with mTBI. Furthermore, our results suggested that beta functional connectivity data reached the best mTBI classification performance compared with regional power and symptom severity [measured with Sport Concussion Assessment Tool 2 (SCAT2)]. The present study reveals the relevance of beta oscillations as a window into neurophysiological dysfunction in mTBI and also highlights the reliability of neural synchrony biomarkers in disorder classification.NEW & NOTEWORTHY Mild traumatic brain injury (mTBI) disrupts the dynamic repertoire of neural oscillations, but so far beta activity has not been studied. In mTBI, we found reductions in frontal beta and large-scale beta networks, indicative of thalamocortical dysconnectivity and disrupted information flow through cortico-basal ganglia-thalamic circuits. Relatively, connectivity more accurately classifies individual mTBI cases compared with regional power. We show the relevance of beta oscillations in mTBI and the reliability of these markers in classification.

CONCEPTUAL DESIGN OF AUTONOMOUS CART FOLLOWER FOR WHEELCHAIR USER

This paper focuses on kinematics of the cart follower and the system identification of propulsion system by using brushed DC motor. The cart follower uses Ackermann configuration as the steering system. The modeling of kinematics equation takes into account the instantaneous center of rotation (ICR), velocity of each tire, heading angle, and simple movement of the cart. The cart is propelled by transaxle brushed DC motor. It is important to approximate an accurate transfer function to represent the motor as the plant module is unavailable. The motor is simulated by using Arduino hardware package in MATLAB®. Rotary encoder is used to record the angular velocity of the shaft. MATLAB® code is created in order to calculate the linear velocity and tabulate the datasets. System Identification Toolbox determines the transfer function of the motor and its performance. The variables measured in experiment to identify the transfer function of the DC motor system are output angular velocity and input voltage. The parameters taken from the DC motor’s mathematical model are derived based on existing literatures. The graph of output velocity against time is plotted and the transfer function is estimated by using System Identification Toolbox in MATLAB®. From the results, it is demonstrated that the motor exhibits second order system.&#x0D; Keywords: Cart follower, wheel mobile robot, kinematics, system identification

Phase-Specific Motor Efference during a Rhythmic Motor Pattern.

Neuronal circuits that control motor behaviors orchestrate multiple tasks, including the inhibition of self-generated sensory signals. In the hermaphroditic leech, T and P mechanosensory neurons respond to light touch and pressure on the skin, respectively. We show that the low threshold T cells were also sensitive to topological changes of the animal surface, caused by contraction of the muscles that erect the skin annuli. P cells were unresponsive to this movement. Annuli erection is part of the contraction phase of crawling, a leech locomotive behavior. In isolated ganglia, T cells showed phase-dependent IPSPs during dopamine-induced fictive crawling, whereas P cells were unaffected. The timing and magnitude of the T-IPSPs were highly correlated with the activity of the motoneurons excited during the contraction phase. Together, the results suggest that the central network responsible for crawling sends a reafferent signal onto the T cells, concomitant with the signal to the motoneurons. This reafference is specifically targeted at the sensory neurons that are affected by the movements; and it is behaviorally relevant as excitation of T cells affected the rhythmic motor pattern, probably acting upon the rhythmogenic circuit. Corollary discharge is a highly conserved function of motor systems throughout evolution, and we provide clear evidence of the specificity of its targets and timing and of the benefit of counteracting self-generated sensory input.SIGNIFICANCE STATEMENT Neuronal circuits that control motor behaviors orchestrate multiple tasks, including inhibition of sensory signals originated by the animal movement, a phenomenon known as corollary discharge. Leeches crawl on solid surfaces through a sequence of elongation and contraction movements. During the contraction, the skin topology changes, affecting a subpopulation of mechanosensory receptors, T (touch) neurons, but not P (pressure) sensory neurons. In the isolated nervous system, T neurons were inhibited during the contraction but not during the elongation phase, whereas P cells were unaffected throughout crawling. Excitation of T cells during the contraction phase temporarily disrupted the rhythmic pattern. Thus, corollary discharge was target (T vs P) and phase (contraction vs elongation) specific, and prevented self-generated signals to perturb motor behaviors.

Psychological Interventions for Dissociative disorders.

Dissociative disorders as described by ICD 10 include a range of disorders and combine what are conversion disorders (assumed under somatoform disorders in Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition) and the cluster of dissociative disorders. The mutual idea shared by these disorders is a partial or complete loss of usual integration between memories, cognizance of identity, and immediate sensations and voluntary control of body movements. Conversion occurs when there are clinical symptoms representing alteration of functioning of motor or sensory systems and which do not follow a pattern of a known neurological or medical disease. Dissociation is a mechanism that allows the mind to compartmentalize certain memories or thoughts from normal consciousness. These split-off mental contents are available and may return to consciousness either by an event or spontaneously. Broadly, dissociative disorders may be viewed as shown in Table 1. Table 1 Types of dissociative disorders

Altered motor system function in post-concussion syndrome as assessed via transcranial magnetic stimulation

ObjectiveIt is unclear why specific individuals incur chronic symptoms following a concussion. This exploratory research aims to identify and characterize any neurophysiological differences that may exist in motor cortex function in post-concussion syndrome (PCS). MethodsFifteen adults with PCS and 13 healthy, non-injured adults were tested. All participants completed symptom questionnaires, and transcranial magnetic stimulation (TMS) was used to measure intracortical and transcallosal excitability and inhibition in the dominant motor cortex. ResultsCortical silent period (p = 0.02, g = 0.96) and ipsilateral silent period (p = 0.04, g = 0.78) were shorter in the PCS group compared to the control group which may reflect reduced GABA-mediated inhibition in PCS. Furthermore, increased corticomotor excitability was observed in the left hemisphere but not the right hemisphere. ConclusionsThese data suggest that persistent neurophysiological differences are present in those with PCS. The exact contributing factors to such changes remain to be investigated by future studies. SignificanceThis study provides novel evidence of lasting neurophysiological changes in PCS.

Probiotics for Parkinson's Disease.

Parkinson’s disease (PD) is a complex neurological disorder classically characterized by impairments in motor system function associated with loss of dopaminergic neurons in the substantia nigra. After almost 200 years since the first description of PD by James Parkinson, unraveling the complexity of PD continues to evolve. It is now recognized that an interplay between genetic and environmental factors influences a diverse range of cellular processes, reflecting on other clinical features including non-motor symptoms. This has consequently highlighted the extensive value of early clinical diagnosis to reduce difficulties of later stage management of PD. Advancement in understanding of PD has made remarkable progress in introducing new tools and strategies such as stem cell therapy and deep brain stimulation. A link between alterations in gut microbiota and PD has also opened a new line. Evidence exists of a bidirectional pathway between the gastrointestinal tract and the central nervous system. Probiotics, prebiotics and synbiotics are being examined that might influence gut-brain axis by altering gut microbiota composition, enteric nervous system, and CNS. This review provides status on use of probiotics for PD. Limitations and future directions will also be addressed to promote further research considering use of probiotics for PD.

Time-Frequency-Domain Copula-Based Granger Causality and Application to Corticomuscular Coupling in Stroke

The corticomuscular coupling (CMC) characterization between the motor cortex and muscles during motion control is a valid biomarker of motor system function after stroke, which can improve clinical decision-making. However, traditional CMC analysis is mainly based on the coherence method that can’t determine the coupling direction, whereas Granger Causality (GC) is limited in identifying linear cause–effect relationship. In this paper, a time-frequency domain copula-based GC (copula-GC) method is proposed to assess CMC characteristic. The 32-channel electroencephalogram (EEG) signals over brain scalp and electromyography (EMG) signals from upper limb were recorded during controlling and maintaining steady-state force output for five stroke patients and five healthy controls. Then, the time-frequency copula-GC analysis was applied to evaluate the CMC strength in both directions. Experimental results show that the CMC strength of descending direction is greater than that of ascending direction in the time domain for healthy controls. With the increase of grip strength, the bi-directional CMC strength has an increasing trend. Meanwhile, the bi-directional CMC strength of right hand is larger than that of left hand. In addition, the bi-directional CMC strength of stroke patients is lower than that of healthy controls. In the frequency domain, the strongest CMC is observed at the beta frequency band. Additionally, the CMC strength of descending direction is slightly larger than that of ascending direction in healthy controls, while the CMC strength of descending direction is lower than that of ascending direction in stroke patients. We suggest that the proposed time-frequency domain analysis approach based on copula-GC can effectively detect complex functional coupling between cortical oscillations and muscle activities, and provide a potential quantitative analysis measure for motion control and rehabilitation evaluation.

Motometrics: A Toolbox for Annotation and Efficient Analysis of Motor Evoked Potentials.

Stimulating the nervous system and measuring muscle response offers a unique opportunity to interrogate motor system function. Often, this is performed by stimulating motor cortex and recording muscle activity with electromyography; the evoked response is called the motor evoked potential (MEP). To understand system dynamics, MEPs are typically recorded through a range of motor cortex stimulation intensities. The MEPs increase with increasing stimulation intensities, and these typically produce a sigmoidal response curve. Analysis of MEPs is often complex and analysis of response curves is time-consuming. We created an MEP analysis software, called Motometrics, to facilitate analysis of MEPs and response curves. The goal is to combine robust signal processing algorithms with a simple user interface. Motometrics first enables the user to annotate data files acquired from the recording system so that the responses can be extracted and labeled with the correct subject and experimental condition. The software enables quick visual representations of entire datasets, to ensure uniform quality of the signal. It then enables the user to choose a variety of response curve analyses and to perform near real time quantification of the MEPs for quick feedback during experimental procedures. This is a modular open source tool that is compatible with several popular electrophysiological systems. Initial use indicates that Motometrics enables rapid, robust, and intuitive analysis of MEP response curves by neuroscientists without programming or signal processing expertise.