Motor Connectivity Research Articles

Structure, place, and clinical efficacy of the interactive brain therapy (stimulation) technology in cerebrovascular diseases

Highlights.Interactive brain stimulation is the next step in neurofeedback technology, it implies the possibility of volitional regulation of the hemodynamic response of specific brain region in order to transform entire brain network and obtain the desired clinical and behavioral dynamics in patients (subjects). One of the indications for using the technology is post-stroke movements disorders when the volitional influence is focused on the motor area of the brain.Background.Neurofeedback and closely related concepts of neural interface system and “interactive brain” are considered as the foundation for developing algorithms for controlling neuroplasticity. Interactive brain therapy (stimulation) is a recently developed type of neurofeedback therapy, which implies dependence of feedback on a hemodynamic response signal recorded by functional magnetic resonance imaging (fMRI). The technology focuses on the region of interest with good accuracy and enables teaching the subject to control the activity of both individual cerebral structures and the functional connectivity between them, causing behavioral metamorphoses.Aim.To demonstrate the study design involving interactive stimulation of secondary motor areas of the brain using a bimodal fMRI-electroencephalography platform, and to describe the dynamics of the motor networks during treatment in patients with hemiparesis in the early period of recovery from stroke.Methods.The study involved 11 patients who were trained to regulate the activity of the secondary motor area and premotor cortex of the affected hemisphere, receiving feedback on the fMRI signal and the activity of the mu- (8–13 Hz) and beta2 (18–26 Hz) EEG ranges of the areas of interest. The block-designed training consisted of 6 sessions (imagination of movement – rest) with an interval of 2–3 days. During treatment the dynamics of the hemodynamic response of the areas of interest was analyzed. In test sessions (before treatment, immediately after the end, and six months later) functional connections within the motor network were reconstructed and hand function was assessed (grip strength, Fugle-Meyer Assessment, Box and Blocks test).Results.Upon completion of treatment, an increase in grip strength and dexterity was achieved; there was an increase in the fMRI signal of the premotor cortex of the ipsilateral hemisphere, and a strengthening of the interhemispheric functional connectivity of the secondary motor areas.Conclusion.fMRI and the interactive brain therapy technology built on its basis, on the one hand, provide the technological foundation for the “interactive brain” and the transformation of spontaneous neuroplasticity into a controlled one, and on the other hand, serve as an important tool for monitoring the process of restructuring of cerebral networks after a stroke, providing the ability to record the emergence (or disappearance) of connectivity between brain regions, and to measure its strength in dynamics, that is, to give a numerical description of neuroplasticity.

Not a benign motor neuron disease: longitudinal imaging captures relentless motor connectome disintegration in primary lateral sclerosis.

Primary lateral sclerosis (PLS) is a progressive upper motor neuron disorder associated with considerable clinical disability. Symptoms are typically exclusively linked to primary motor cortex degeneration and the contribution of pre-motor, supplementary motor, cortico-medullary and inter-hemispheric connectivity alterations are less well characterized. In a single-centre, prospective, longitudinal neuroimaging study 41 patients with PLS were investigated. Patients underwent standardized neuroimaging, genetic profiling with whole exome sequencing, and comprehensive clinical assessments including upper motor neuron scores, tapping rates, mirror movements, spasticity assessment, cognitive screening and evaluation for pseudobulbar affect. Longitudinal neuroimaging data from 108 healthy controls were used for image interpretation. A standardized imaging protocol was implemented including 3D T1-weighted structural, diffusion tensor imaging and resting-state functional magnetic resonance imaging. Following somatotopic segmentation, cortical thickness analyses, probabilistic tractography, blood oxygenation level dependent signal analyses and brainstem volumetry were conducted to evaluate cortical, brainstem, cortico-medullary and inter-hemispheric connectivity alterations both cross-sectionally and longitudinally. Our data confirm progressive primary motor cortex degeneration, considerable supplementary motor and pre-motor area involvement, progressive brainstem atrophy, cortico-medullary and inter-hemispheric disconnection, and close associations between clinical upper motor neuron scores and somatotopic connectivity indices in PLS. Primary lateral sclerosis is associated with relentlessly progressive motor connectome degeneration. Clinical disability in PLS is likely to stem from a combination of intra- and inter-hemispheric connectivity decline and primary, pre- and supplementary motor cortex degeneration. Simple 'bedside' clinical tools, such as tapping rates, are excellent proxies of the integrity of the relevant fibres of the contralateral corticospinal tract.

Biomarkers for prognostic functional recovery poststroke: A narrative review.

Background and objective: Prediction of poststroke recovery can be expressed by prognostic biomarkers that are related to the pathophysiology of stroke at the cellular and molecular level as well as to the brain structural and functional reserve after stroke at the systems neuroscience level. This study aimed to review potential biomarkers that can predict poststroke functional recovery. Methods: A narrative review was conducted to qualitatively summarize the current evidence on biomarkers used to predict poststroke functional recovery. Results: Neurophysiological measurements and neuroimaging of the brain and a wide diversity of molecules had been used as prognostic biomarkers to predict stroke recovery. Neurophysiological studies using resting-state electroencephalography (EEG) revealed an interhemispheric asymmetry, driven by an increase in low-frequency oscillation and a decrease in high-frequency oscillation in the ipsilesional hemisphere relative to the contralesional side, which was indicative of individual recovery potential. The magnitude of somatosensory evoked potentials and event-related desynchronization elicited by movement in task-related EEG was positively associated with the quantity of recovery. Besides, transcranial magnetic stimulation (TMS) studies revealed the potential values of using motor-evoked potentials (MEP) and TMS-evoked EEG potentials from the ipsilesional motor cortex as prognostic biomarkers. Brain structures measured using magnetic resonance imaging (MRI) have been implicated in stroke outcome prediction. Specifically, the damage to the corticospinal tract (CST) and anatomical motor connections disrupted by stroke lesion predicted motor recovery. In addition, a wide variety of molecular, genetic, and epigenetic biomarkers, including hemostasis, inflammation, tissue remodeling, apoptosis, oxidative stress, infection, metabolism, brain-derived, neuroendocrine, and cardiac biomarkers, etc., were associated with poor functional outcomes after stroke. However, challenges such as mixed evidence and analytical concerns such as specificity and sensitivity have to be addressed before including molecular biomarkers in routine clinical practice. Conclusion: Potential biomarkers with prognostic values for the prediction of functional recovery after stroke have been identified; however, a multimodal approach of biomarkers for prognostic prediction has rarely been studied in the literature. Future studies may incorporate a combination of multiple biomarkers from big data and develop algorithms using data mining methods to predict the recovery potential of patients after stroke in a more precise way.

Reproducibility of primary motor cortex cortico-cortical connectivity for changes in TMS current direction and pulse waveform

Reproducibility of primary motor cortex cortico-cortical connectivity for changes in TMS current direction and pulse waveform

Physics Informed Neural Network-based High-frequency Modeling of Induction Motors

The high-frequency (HF) modeling of induction motors plays a key role in predicting the motor terminal overvoltage and conducted emissions in a motor drive system. In this study, a physics informed neural network-based HF modeling method, which has the merits of high accuracy, good versatility, and simple parameterization, is proposed. The proposed model of the induction motor consists of a three-phase equivalent circuit with eighteen circuit elements per phase to ensure model accuracy. The per phase circuit structure is symmetric concerning its phase-start and phase-end points. This symmetry enables the proposed model to be applicable for both star- and delta-connected induction motors without having to recalculate the circuit element values when changing the motor connection from star to delta and vice versa. Motor physics knowledge, namely per-phase impedances, are used in the artificial neural network to obtain the values of the circuit elements. The parameterization can be easily implemented within a few minutes using a common personal computer (PC). Case studies verify the effectiveness of the proposed HF modeling method.

Motor cortex functional connectivity is associated with underlying neurochemistry in ALS

ObjectiveTo identify structural and neurochemical properties that underlie functional connectivity impairments of the primary motor cortex (PMC) and how these relate to clinical findings in amyotrophic lateral sclerosis (ALS).Methods52 patients...

Cytoplasmic pool of U1 spliceosome protein SNRNP70 shapes the axonal transcriptome and regulates motor connectivity

Regulation of pre-mRNA splicing and polyadenylation plays a profound role in neurons by diversifying the proteome and modulating gene expression in response to physiological cues. Although most of the pre-mRNA processing is thought to occur in the nucleus, numerous splicing regulators are also found in neurites. Here, we show that U1-70K/SNRNP70, a component of the major spliceosome, localizes in RNA-associated granules in zebrafish axons. We identify the extra-nuclear SNRNP70 as an important regulator of motor axonal growth, nerve-dependent acetylcholine receptor (AChR) clustering, and neuromuscular synaptogenesis. This cytoplasmic pool has a protective role for a limited number of transcripts regulating their abundance and trafficking inside axons. Moreover, non-nuclear SNRNP70 regulates splice variants of transcripts such as agrin, thereby controlling synapse formation. Our results point to an unexpected, yet essential, function of non-nuclear SNRNP70 in axonal development, indicating a role of spliceosome proteins in cytoplasmic RNA metabolism during neuronal connectivity.

Large-scale all-optical dissection of motor cortex connectivity shows a segregated organization of mouse forelimb representations

Large-scale all-optical dissection of motor cortex connectivity shows a segregated organization of mouse forelimb representations

Promoting regeneration while blocking cell death preserves motor neuron function in a model of ALS.

Amyotrophic lateral sclerosis (ALS) is a devastating and fatal neurodegenerative disease of motor neurons with very few treatment options. We had previously found that motor neuron degeneration in a mouse model of ALS can be delayed by deleting the axon damage sensor MAP3K12 or dual leucine zipper kinase (DLK). However, DLK is also involved in axon regeneration, prompting us to ask whether combining DLK deletion with a way to promote axon regeneration would result in greater motor neuron protection. To achieve this, we used a mouse line that constitutively expresses ATF3, a master regulator of regeneration in neurons. Although there is precedence for each individual strategy in the SOD1G93A mouse model of ALS, these have not previously been combined. By several lines of evidence including motor neuron electrophysiology, histology and behaviour, we observed a powerful synergy when combining DLK deletion with ATF3 expression. The combinatorial strategy resulted in significant protection of motor neurons with fewer undergoing cell death, reduced axon degeneration and preservation of motor function and connectivity to muscle. This study provides a demonstration of the power of combinatorial therapy to treat neurodegenerative disease.

The pathobiological basis of depression in Parkinson disease: challenges and outlooks.

Depression, with an estimated prevalence of about 40% is a most common neuropsychiatric disorder in Parkinson disease (PD), with a negative impact on quality of life, cognitive impairment and functional disability, yet the underlying neurobiology is poorly understood. Depression in PD (DPD), one of its most common non-motor symptoms, can precede the onset of motor symptoms but can occur at any stage of the disease. Although its diagnosis is based on standard criteria, due to overlap with other symptoms related to PD or to side effects of treatment, depression is frequently underdiagnosed and undertreated.DPD has been related to a variety of pathogenic mechanisms associated with the underlying neurodegenerative process, in particular dysfunction of neurotransmitter systems (dopaminergic, serotonergic and noradrenergic), as well as to disturbances of cortico-limbic, striato-thalamic-prefrontal, mediotemporal-limbicnetworks, with disruption in the topological organization of functional mood-related, motor and other essential brain network connections due to alterations in the blood-oxygen-level-dependent (BOLD) fluctuations in multiple brain areas. Other hypothetic mechanisms involve neuroinflammation, neuroimmune dysregulation, stress hormones, neurotrophic, toxic or metabolic factors. The pathophysiology and pathogenesis of DPD are multifactorial and complex, and its interactions with genetic factors, age-related changes, cognitive disposition and other co-morbidities awaits further elucidation.

Large-scale all-optical dissection of motor cortex connectivity shows a segregated organization of mouse forelimb representations.

In rodent motor cortex, the rostral forelimb area (RFA) and the caudal forelimb area (CFA) are major actors in orchestrating the control of complex forelimb movements. However, their intrinsic connectivity and reciprocal functional organization are still unclear, limiting our understanding of how the brain coordinates and executes voluntary movements. Here, we causally probe cortical connectivity and activation patterns triggered by transcranial optogenetic stimulation of ethologically relevant complex movements exploiting a large-scale all-optical method in awake mice. Results show specific activation features for each movement class, providing evidence for a segregated functional organization of CFA and RFA. Importantly, we identify a second discrete lateral grasping representation area, namely the lateral forelimb area (LFA), with unique connectivity and activation patterns. Therefore, we propose the LFA as a distinct forelimb representation in the mouse somatotopic motor map.

Effects of aging on cognitive and brain inter-network integration patterns underlying usual and dual-task gait performance.

IntroductionAging affects the interplay between cognition and gait performance. Neuroimaging studies reported associations between gait performance and structural measures; however, functional connectivity (FC) analysis of imaging data can help to identify dynamic neural mechanisms underlying optimal performance. Here, we investigated the effects on divergent cognitive and inter-network FC patterns underlying gait performance during usual (UW) and dual-task (DT) walking.MethodsA total of 115 community-dwelling, healthy participants between 20 and 80 years were enrolled. All participants underwent comprehensive cognitive and gait assessments in two conditions and resting state functional MRI (fMRI) scans. Inter-network FC from motor-related to 6 primary cognitive networks were estimated. Step-wise regression models tested the relationships between gait parameters, inter-network FC, neuropsychological scores, and demographic variables. A threshold of p < 0.05 was adopted for all statistical analyses.ResultsUW was largely associated with FC levels between motor and sustained attention networks. DT performance was associated with inter-network FC between motor and divided attention, and processing speed in the overall group. In young adults, UW was associated with inter-network FC between motor and sustained attention networks. On the other hand, DT performance was associated with cognitive performance, as well as inter-network connectivity between motor and divided attention networks (VAN and SAL). In contrast, the older age group (> 65 years) showed increased integration between motor, dorsal, and ventral attention, as well as default-mode networks, which was negatively associated with UW gait performance. Inverse associations between motor and sustained attention inter-network connectivity and DT performance were observed.ConclusionWhile UW relies on inter-network FC between motor and sustained attention networks, DT performance relies on additional cognitive capacities, increased motor, and executive control network integration. FC analyses demonstrate that the decline in cognitive performance with aging leads to the reliance on additional neural resources to maintain routine walking tasks.

Sensorimotor and Frontoparietal Network Connectivity Are Associated With Subsequent Maintenance of Gait Speed and Episodic Memory in Older Adults.

Slow gait is predictive of functional impairments in older adults, while concomitant slow gait and cognitive complaints are associated with a greater risk for cognitive decline and dementia. However, functional neural correlates for gait speed maintenance are unclear. As the sensorimotor network (SMN) and frontoparietal network (FPN) are integral components of these functions, this study investigated differences in SMN and FPN in older adults with/without gait speed decline over 24 months; and whether these networks were associated with the maintenance of cognitive function. We included 42 community-dwelling older adults aged >70 years from the MOBILIZE Boston Study. Resting-state fMRI was performed at the study baseline. Participant characteristics, gait speed, Mini-Mental State Examination, and Hopkins Verbal Learning Test (HVLT) were assessed at baseline and at 24-month follow-up. Decliners were identified as individuals with >0.05 meters/second decline in gait speed from baseline to 24 months. Of the 26 decliners and 16 maintainers, decliners exhibited a significant decline in delayed-recall performance on the HVLT over 24 months. Controlling for baseline age and multiple comparisons, contrary to initial hypothesis, maintainers exhibited lower baseline primary motor and premotor connectivity (p = .01) within the SMN, and greater baseline ventral visual-supramarginal gyrus connectivity within the FPN (p = .02) compared to decliners. Lower primary motor-premotor connectivity was correlated with maintenance of delayed-recall performance on the HVLT (p = .04). These findings demonstrated a potential compensatory mechanism involved in the link between the decline in gait speed and episodic memory, whereby baseline connectivity of the SMN and FPN may underlie subsequent maintenance of gait speed and cognitive function in old age.

DC Motor Drive Powered by Solar Photovoltaic Energy: An FPGA-Based Active Disturbance Rejection Control Approach

This paper presents an experimental platform for regulating the DC motor angular speed powered by photovoltaic cells. The experimental platform comprises an Eco Green Energy EGE-260P-60 solar panel, DC/DC SEPIC converter, DC bus, DC/DC buck converter, DC motor and Nexys 4 board with an Artix-7 100T FPGA. The DC/DC SEPIC converter is used for harvesting the maximum amount of energy from the PV cells using the perturb and observe algorithm to track the maximum power point. The DC/DC buck converter is used as the motor drive using the active disturbance rejection control to regulate the angular speed of the DC motor. In addition, the FPGA architecture design is presented using a hierarchical top-down methodology with the VHDL hardware description language and Xilinx System Generator tool. The software takes advantage of the FPGA’s concurrency to simultaneously evaluate the different processes, which is the main reason for choosing this digital device. Several tests were performed on the platform such as irradiance changes, DC bus variations, DC motor connection and load torque variations applied in the motor shaft. The results indicate that the maximum power is obtained from the photovoltaic cells, establishing the minimum operating conditions. In addition, the control approach estimates and cancels the effects of disturbances caused by variations in the environmental conditions, photovoltaic system, DC bus, and load changes in order to regulate DC motor speed.

A 90-channel triaxial magnetoencephalography system using optically pumped magnetometers.

Magnetoencephalography (MEG) measures the small magnetic fields generated by current flow in neural networks, providing a noninvasive metric of brain function. MEG is well established as a powerful neuroscientific and clinical tool. However, current instrumentation is hampered by cumbersome cryogenic field-sensing technologies. In contrast, MEG using optically pumped magnetometers (OPM-MEG) employs small, lightweight, noncryogenic sensors that provide data with higher sensitivity and spatial resolution, a natural scanning environment (including participant movement), and adaptability to any age. However, OPM-MEG is new and the optimum way to design a system is unknown. Here, we construct a novel, 90-channel triaxial OPM-MEG system and use it to map motor function during a naturalistic handwriting task. Results show that high-precision magnetic field control reduced background fields to ∼200 pT, enabling free participant movement. Our triaxial array offered twice the total measured signal and better interference rejection compared to a conventional (single-axis) design. We mapped neural oscillatory activity to the sensorimotor network, demonstrating significant differences in motor network activity and connectivity for left-handed versus right-handed handwriting. Repeatability across scans showed that we can map electrophysiological activity with an accuracy ∼4mm. Overall, our study introduces a novel triaxial OPM-MEG design and confirms its potential for high-performance functional neuroimaging.

Transient beta activity and cortico-muscular connectivity during sustained motor behaviour.

Neural oscillations are thought to play a central role in orchestrating activity states between distant neural populations. For example, during isometric contraction, 13-30Hz beta activity becomes phase coupled between the motor cortex and the contralateral muscle. This and related observations have led to the proposal that beta activity and connectivity sustain stable cognitive and motor states - or the 'status quo' - in the brain. Recently, however, beta activity at the single-trial level has been shown to be short-lived - though so far this has been reported for regional beta activity in tasks without sustained motor demands. Here, we measured magnetoencephalography (MEG) and electromyography (EMG) in 18 human participants performing a sustained isometric contraction (gripping) task. If cortico-muscular beta connectivity is directly responsible for sustaining a stable motor state, then beta activity within single trials should be (or become) sustained in this context. In contrast, we found that motor beta activity and connectivity with the downstream muscle were transient. Moreover, we found that sustained motor requirements did not prolong beta-event duration in comparison to rest. These findings suggest that neural synchronisation between the brain and the muscle involves short 'bursts' of frequency-specific connectivity, even when task demands - and motor behaviour - are sustained.

Assessing the Capabilities of Transcranial Magnetic Stimulation (TMS) to Aid in the Removal of Brain Tumors Affecting the Motor Cortex: A Systematic Review.

IntroductionThe brain tumor is frequently related to severe motor impairment and impacts the quality of life. The corticospinal tract can sometimes be affected depending on the type and size of the neoplasm, so different tools can evaluate motor function and connections. It is essential to organize surgical procedures and plan the approach. Functional motor status is mapped before, during, and after surgery. Studying corticospinal tract status can help map the functional areas, predict postoperative outcomes, and help the decision, reducing neurological deficits, aiming to preserve functional networks, using the concepts of white matters localization and fibbers connections. Nowadays, there are new techniques that provide functional information regarding the motor cortex, such as transcranial magnetic stimulation (TMS), direct cortical stimulation (DCS), and navigated TMS (nTMS). These tools can be used to plan a customized surgical strategy and the role of motor evoked potentials (MEPs) is well described during intra-operative, using intraoperative neuromonitoring. MEPs can help to localize primary motor areas and delineate the cut-off point of resection in real-time, using direct stimulation. In the post-operative, the MEP has increased your function as a predictive marker of permanent or transitory neurological lesion marker.MethodsSystematic review performed in MEDLINE via PUBMED, EMBASE, and SCOPUS databases regarding the post-operative assessment of MEP in patients with brain tumors. The search strategy included the following terms: ((“Evoked Potentials, Motor”[Mesh]) AND “Neoplasms”[Mesh]) AND “Transcranial Magnetic Stimulation”[Mesh] AND “Brain Tumor”[Mesh]), the analysis followed the PRISMA guidelines for systematic reviews, the review spanned until 06/04/2021, inclusion criteria were studies presenting confirmed diagnosis of brain tumor (primary or metastatic), patients >18 y/o, using TMS, Navigated TMS, and/or Evoked Potentials as tools in preoperative planning or at the intra-operative helping the evaluation of the neurological status of the motor cortex, articles published in peer-reviewed journals, and written in English or Portuguese.ResultsA total of 38 studies were selected for this review, of which 14 investigated the potential of nTMS to predict the occurrence of motor deficits, while 25 of the articles investigated the capabilities of the nTMS technique in performing pre/intraoperative neuro mapping of the motor cortex.ConclusionFurther studies regarding motor function assessment are needed and standardized protocols for MEPs also need to be defined.

A Neuroanatomy of Positive Affect Display - Subcortical Fiber Pathways Relevant for Initiation and Modulation of Smiling and Laughing.

BackgroundWe here report two cases of stimulation induced pathological laughter (PL) under thalamic deep brain stimulation (DBS) for essential tremor and interpret the effects based on a modified neuroanatomy of positive affect display (PAD).Objective/HypothesisThe hitherto existing neuroanatomy of PAD can be augmented with recently described parts of the motor medial forebrain bundle (motorMFB). We speculate that a co-stimulation of parts of this fiber structure might lead to a non-volitional modulation of PAD resulting in PL.MethodsWe describe the clinical and individual imaging workup and combine the interpretation with normative diffusion tensor imaging (DTI)-tractography descriptions of motor connections of the ventral tegmental area (VTA) (n = 200 subjects, HCP cohort), [[18F] fluorodeoxyglucose (18FDG)] positron emission tomography (PET), and volume of activated tissue simulations. We integrate these results with literature concerning PAD and the neuroanatomy of smiling and laughing.ResultsDBS electrodes bilaterally co-localized with the MB-pathway (“limiter pathway”). The FDG PET activation pattern allowed to explain pathological PAD. A conceptual revised neuroanatomy of PAD is described.ConclusionEliciting pathological PAD through chronic thalamic DBS is a new finding and has previously not been reported. PAD is evolution driven, hard wired to the brain and realized over previously described branches of the motorMFB. A major relay region is the VTA/mammillary body complex. PAD physiologically undergoes conscious modulation mainly via the MB branch of the motorMFB (limiter). This limiter in our cases is bilaterally disturbed through DBS. The here described anatomy adds to a previously described framework of neuroanatomy of laughter and humor.

Transcranial Direct Current Stimulation Enhances Neuroplasticity and Accelerates Motor Recovery in a Stroke Mouse Model.

More effective strategies are needed to promote poststroke functional recovery. Here, we evaluated the impact of bihemispheric transcranial direct current stimulation (tDCS) on forelimb motor function recovery and the underlying mechanisms in mice subjected to focal ischemia of the motor cortex. Photothrombotic stroke was induced in the forelimb brain motor area, and tDCS was applied once per day for 3 consecutive days, starting 72 hours after stroke. Grid-walking, single pellet reaching, and grip strength tests were conducted to assess motor function. Local field potentials were recorded to evaluate brain connectivity. Western immunoblotting, ELISA, quantitative real-time polymerase chain reaction, and Golgi-Cox staining were used to uncover tDCS-mediated stroke recovery mechanisms. Among our results, tDCS increased the rate of motor recovery, anticipating it at the early subacute stage. In this window, tDCS enhanced BDNF (brain-derived neurotrophic factor) expression and dendritic spine density in the peri-infarct motor cortex, along with increasing functional connectivity between motor and somatosensory cortices. Treatment with the BDNF TrkB (tropomyosin-related tyrosine kinase B) receptor inhibitor, ANA-12, prevented tDCS effects on motor recovery and connectivity as well as the increase of spine density, pERK (phosphorylated extracellular signal-regulated kinase), pCaMKII (phosphorylated calcium/calmodulin-dependent protein kinase II), pMEF (phosphorylated myocyte-enhancer factor), and PSD (postsynaptic density)-95. The tDCS-promoted rescue was paralleled by enhanced plasma BDNF level, suggesting its potential role as circulating prognostic biomarker. The rate of motor recovery is accelerated by tDCS applied in the subacute phase of stroke. Anticipation of motor recovery via vicariate pathways or neural reserve recruitment would potentially enhance the efficacy of standard treatments, such as physical therapy, which is often delayed to a later stage when plastic responses are progressively lower.

Analisis Kegagalan Permukaan Kontak Rail dan Wheel pada Overhead Travelling Crane

For the sake of the smooth process of cement production, it is necessary to maintain each component of the production. One of the tools that play an important role in the maintenance and production of cement is the Overhead Traveling Crane, which is a combination of a separate lifting mechanism with a frame to lift and move loads that can be hung freely or attached to the crane itself. The problems that arise in the Overhead Traveling Crane include the reverse direction of the motor rotation due to an error in the motor connection, the motor cannot start due to a disconnected power supply, the occurrence of bending (curving) on ​​the girder due to lifting operations that exceed the maximum capacity which can also accelerate service life. of the girder, wear on the wheel due to high workload during operation. Due to the need for very long use, periodic maintenance is needed so that it can be in normal condition for a long time. The main parts that support the overall weight of the crane are rails and wheels. This journal discusses the analysis of failures that occur due to contact between rails and wheels that occur in a cement factory. Failure analysis is done by testing the hardness of both the wheel and the rely which is considered to have failed or is no longer suitable for use. Then review the results of direct field observations with data from hardness tests and literature studies related to wheels and rails. after that it was concluded that the company considered for the procurement of rails and wheels. The conclusion obtained is that the hardness value on the rail is lower than on the wheel. Resulting in failure of the rail so that the rail must be replaced.