Nerve root magnetic stimulation improves locomotor function following spinal cord injury with electrophysiological improvements and cortical synaptic reconstruction

Following a spinal cord injury,there are usually a number of neural pathways that remain intact in the spinal cord.These residual nerve fibers are important,as they could be used to reconstruct the neural circuits that enable motor function.Our group previously designed a novel magnetic stimulation protocol,targeting the motor cortex and the spinal nerve roots,that led to significant improvements in locomotor function in patients with a chronic incomplete spinal cord injury.Here,we investigated how nerve root magnetic stimulation contributes to improved locomotor function using a rat model of spinal cord injury.Rats underwent surgery to clamp the spinal cord at T10;three days later,the rats were treated with repetitive magnetic stimulation(5 Hz,25 pulses/train,20 pulse trains)targeting the nerve roots at the L5-L6 vertebrae.The treatment was repeated five times a week over a period of three weeks.We found that the nerve root magnetic stimulation improved the locomotor function and enhanced nerve conduction in the injured spinal cord.In addition,the nerve root magnetic stimulation promoted the recovery of synaptic ultrastructure in the sensorimotor cortex.Overall,the results suggest that nerve root magnetic stimulation may be an effective,noninvasive method for mobilizing the residual spinal cord pathways to promote the recovery of locomotor function.

Habitual physical activity levels and sedentary time of children in different childcare arrangements from a nationally representative sample of Canadian preschoolers

Background:Children spend substantial time in childcare,and the reasons parents choose a particular childcare type may differ by family.However,little is known about how childcare type influences habitual(full day)activity levels among children.Therefore,exploring patterns between childcare type and habitual physical activity(PA)(i.e.,light,moderate-to-vigorous PA(MVPA),and total PA)and sedentary time(ST)in young Canadian children is needed.Methods:A nationally representative sample of preschoolers from Cycles 3 and 4 of the Canadian Health Measures Survey was used in this cross-sectional study.Childcare type(e.g.,center-based childcare,home-based childcare,home with parent,kindergarten)was reported by parents.Preschoolers wore an Actical accelerometer for 7 days.Device and population-spcific cut-points were applied to delineate PA intensities and ST.Population means and sample totals were calculated to examine average daily and hourly rates of activity.Results:Preschoolers’rates of MVPA and total PA from the 4 childcare arrangements ranged from 65.99 min/day to 74.62 min/day(5.48-6.18 min/h)and 274.20 min/day to 281.66 min/day (22.69-23.21 min/h),respectively,while ST ranged from 443.13 min/day to 460.57 min/day(36.80-37.31 min/h).No significant differences were observed in daily or hourly rates of activity.Conclusion:This study provides a snapshot of the levels of PA and ST among preschoolers in various childcare settings at a national level,with no differences observed in habitual activity levels based on childcare enrollment.Additional research is needed to clarify the relationship between young children’s PA and childcare type,with consideration given to the quality of the childcare settings.

Practice of Physical Activity and Its Relationship with Lipid Profile of Adolescents

In order to assess the prevalence of physical activity (PA) and its relationship with lipid profile among adolescents, a cross-sectional study with a quantitative approach was conducted with 102 adolescents aged 15 to 19 years from public schools of Campina Grande, Paraiba, Brazil. The following variables were analyzed: age, gender, ethnicity, maternal education, socioeconomic status, nutritional status, the practice of PA and lipid profile. The variables were obtained through validated form, anthropometry (weight and height) and blood collection by contract laboratory. Double entry and SPSS (Statistical Package for Social Sciences) 22.0 were performed. First, a descriptive analysis of all variables was conducted, as well as measures of central tendency and dispersion for continuous variables. Accordingly, distribution was tested for normality using the Kolmogorov-Smirnov test. According to results, correlation was evaluated by Pearson/Spearman tests. Significance level of 5% was adopted for all analyses. The study was approved by the Ethics Approach Committee (EAC) of the State University of Paraíba. The most prevalent sex in the sample was female and regarding maternal education, 35.4% had complete high school. Regarding serum lipoproteins, 16% showed elevated total cholesterol and HDL (High Density Lipoprotein) 66% below the desired value. With regard to physical activity, 60.8% had insufficient PA levels. The sample showed changes in lipid profile and insufficiently active life style, besides having overpowered the eutrophic nutritional status. No statistically significant correlations between variables of the lipid profile and the time of PA were observed. These findings highlight the importance of physical exercise for maintaining health and suggest studies with larger populations in order to check the scientific literature regarding this topic.

Disappearance of unaffected motor cortex activation by repetitive transcranial magnetic stimulation in a patient with cerebral infarct

The ipsilateral motor pathway from the unaffected motor cortex to the affected extremity is one of the motor recovery mechanisms following stroke （Jang, 2011）. Because stroke patients who had shown recovery by this mechanism usually showed poorer motor function, compared with patients who showed recovery by other mechanisms, several researchers have considered this mechanism as a maladaptive plasticity （]ang, 2013）.

Botulinum toxin type A plus rehabilitative training for improving the motor function of the upper limbs and activities of daily life in patients with stroke and brain injury

BACKGROUND: Botulinum toxin type A (BTX-A) is mostly to be used to treat various diseases of motor disorders, whereas its effect on muscle spasm after stroke and brain injury needs further observation. OBJECTIVE: To observe the effect of BTX-A plus rehabilitative training on treating muscle spasm after stroke and brain injury. DESIGN: A randomized controlled observation. SETTINGS: Department of Rehabilitation, Department of Neurology and Department of Neurosurgery, the Second Hospital of Hebei Medical University. PARTICIPANTS: Sixty inpatients with brain injury and stroke were selected from the Department of Rehabilitation, Department of Neurology and Department of Neurosurgery, the Second Hospital of Hebei Medical University from January 2001 to August 2006. They were all confirmed by CT and MRI, and had obvious increase of spastic muscle strength in upper limbs, their Ashworth grades were grade 2 or above. The patients were randomly divided into treatment group (n =30) and control group (n =30). METHODS: ① Patients in the treatment group undertook comprehensive rehabilitative trainings, and they were administrated with domestic BTX-A, which was provided by Lanzhou Institute of Biological Products, Ministry of Health (S10970037), and the muscles of flexion spasm were selected for upper limbs, 20-25 IU for each site. ② Patients in the treatment group were assessed before injection and at 1 and 2 weeks, 1 and 3 months after injection respectively, and those in the control group were assessed at corresponding time points. The recovery of muscle spasm was assessed by modified Ashworth scale (MAS, grade 0-Ⅳ; Grade 0 for without increase of muscle strength; Grade Ⅳ for rigidity at passive flexion and extension); The recovery of motor function of the upper limbs was evaluated with Fugl-Meyer Assessment (FMA, total score was 226 points, including 100 for exercise, 14 for balance, 24 for sense, 44 for joint motion, 44 for pain and 66 for upper limb); The ADL were evaluated with Barthel index, the total score was 100 points, 60 for mild dysfunction, 60-41 for moderate dysfunction, < 40 for severe dysfunction). MAIN OUTCOME MEASURES: Changes of MAS grade, FMA scores and Barthel index before and after BTX-A injection. RESULTS: All the 60 patients with brain injury and stroke were involved in the analysis of results. ① FMA scores of upper limbs: The FMA score in the treatment group at 2 weeks after treatment was higher than that before treatment [(14.98±10.14), (13.10±9.28) points, P < 0.05], whereas there was no significant difference at corresponding time point in the control group. The FMA scores at 1 and 3 months in the treatment group [(23.36±10.69), (35.36±11.36) points] were higher than those in the control group [(20.55±10.22), (30.33±10.96) points, P < 0.01]. ② MAS grades of upper limbs: There were obviously fewer cases of grade Ⅲ in MAS at 2 weeks after treatment than before treatment in the treatment group (0, 9 cases, P < 0.05), whereas there was no obvious difference in the control group. There were obviously fewer cases of grade Ⅲ in MAS at 2 weeks and 1 month after treatment in the treatment group (0, 0 case) than the control group (5, 2 cases, P < 0.01). ③ Barthel index of upper limbs: The Barthel index at 2 weeks after treatment was higher than that before treatment in the treatment group [(30.36±22.25), (28.22±26.21) points, P < 0.05], whereas there was no significant difference in the control group. The Barthel indexes at 1 and 3 months after treatment in the treatment group were obviously higher than those in the control group [(20.55±10.22), (30.33±10.96) points, P < 0.01]. CONCLUSION: BTX-A has obvious efficacy on decreasing muscle tension after stroke and brain injury, and relieving muscle spasm; Meanwhile, the combination with rehabilitative training can effectively ameliorate the motor function of upper limbs and ADL of the patients.

Automated monitoring of early neurobehavioral changes in mice following traumatic brain injury

Traumatic brain injury often causes a variety of behavioral and emotional impairments that can develop into chronic disorders. Therefore, there is a need to shift towards identifying early symptoms that can aid in the prediction of traumatic brain injury outcomes and behavioral endpoints in patients with traumatic brain injury after early interventions. In this study, we used the Smart Cage system, an automated quantitative approach to assess behavior alterations in mice during an early phase of traumatic brain injury in their home cages. Female C57BL/6 adult mice were subjected to moderate controlled cortical impact（CCI） injury. The mice then received a battery of behavioral assessments including neurological score, locomotor activity, sleep/wake states, and anxiety-like behaviors on days 1, 2, and 7 after CCI. Histological analysis was performed on day 7 after the last assessment. Spontaneous activities on days 1 and 2 after injury were significantly decreased in the CCI group. The average percentage of sleep time spent in both dark and light cycles were significantly higher in the CCI group than in the sham group. For anxiety-like behaviors, the time spent in a light compartment and the number of transitions between the dark/light compartments were all significantly reduced in the CCI group than in the sham group. In addition, the mice suffering from CCI exhibited a preference of staying in the dark compartment of a dark/light cage. The CCI mice showed reduced neurological score and histological abnormalities, which are well correlated to the automated behavioral assessments. Our findings demonstrate that the automated Smart Cage system provides sensitive and objective measures for early behavior changes in mice following traumatic brain injury.

Axonal remodeling in the corticospinal tract after stroke： how does rehabilitative training modulate it？

Stroke causes long-term disability, and rehabilitative training is commonly used to improve the consecutive functional recovery. Following brain damage, surviving neurons undergo morphological alterations to reconstruct the remaining neural network. In the motor system, such neural network remodeling is observed as a motor map reorganization. Because of its significant correlation with functional recovery, motor map reorganization has been regarded as a key phenomenon for functional recovery after stroke. Although the mechanism underlying motor map reorganization remains unclear, increasing evidence has shown a critical role for axonal remodeling in the corticospinal tract. In this study, we review previous studies investigating axonal remodeling in the corticospinal tract after stroke and discuss which mechanisms may underlie the stimulatory effect of rehabilitative training. Axonal remodeling in the corticospinal tract can be classified into three types based on the location and the original targets of corticospinal neurons, and it seems that all the surviving corticospinal neurons in both ipsilesional and contralesional hemisphere can participate in axonal remodeling and motor map reorganization. Through axonal remodeling, corticospinal neurons alter their output selectivity from a single to multiple areas to compensate for the lost function. The remodeling of the corticospinal axon is influenced by the extent of tissue destruction and promoted by various therapeutic interventions, including rehabilitative training. Although the precise molecular mechanism underlying rehabilitation-promoted axonal remodeling remains elusive, previous data suggest that rehabilitative training promotes axonal remodeling by upregulating growth-promoting and downregulating growth-inhibiting signals.

The cortical activation pattern during bilateral arm raising movements

Bilateral arm raising movements have been used in brain rehabilitation for a long time. However, no study has been reported on the effect of these movements on the cerebral cortex. In this study, using functional near infrared spectroscopy（f NIRS）, we attempted to investigate cortical activation generated during bilateral arm raising movements. Ten normal subjects were recruited for this study. f NIRS was performed using an f NIRS system with 49 channels. Bilateral arm raising movements were performed in sitting position at the rate of 0.5 Hz. We measured values of oxyhemoglobin and total hemoglobin in five regions of interest： the primary sensorimotor cortex, premotor cortex, supplementary motor area, prefrontal cortex, and posterior parietal cortex. During performance of bilateral arm raising movements, oxyhemoglobin and total hemoglobin values in the primary sensorimotor cortex, premotor cortex, supplementary motor area, and prefrontal cortex were similar, but higher in these regions than those in the prefrontal cortex. We observed activation of the arm somatotopic areas of the primary sensorimotor cortex and premotor cortex in both hemispheres during bilateral arm raising movements. According to this result, bilateral arm raising movements appeared to induce large-scale neuronal activation and therefore arm raising movements would be good exercise for recovery of brain functions.

Pharmacogenetic activation of midbrain dopaminergic neurons induces hyperactivity

Dopaminergic neurons regulate and organize numerous important behavioral processes including motor activity.Consistently,manipulation of brain dopamine concentrations changes animal activity levels.Dopamine is synthesized by several neuronal populations in the brain.This study was carried out to directly test whether selective activation of dopamine neurons in the midbrain induces hyperactivity.A pharmacogenetic approach was used to activate midbrain dopamine neurons,and behavioral assays were conducted to determine the effects on mouse activity levels.Transgenic expression of the evolved hM3Dq receptor was achieved by infusing Creinducible AAV viral vectors into the midbrain of DATCre mice.Neurons were excited by injecting the hM3Dq ligand clozapine-N-oxide（CNO）.Mouse locomotor activity was measured in an open field.The results showed that CNO selectively activated midbrain dopaminergic neurons and induced hyperactivity in a dose-dependent manner,supporting the idea that these neurons play an important role in regulating motor activity.

Towards semi-supervised myoelectric finger motion recognition based on spatial motor units activation

It is vital to recognize the intention of finger motions for human-machine interaction(HMI).The latest research focuses on fine myoelectric control through the decoding of neural motor unit action potential trains(MUAPt) from high-density surface electromyographic(sEMG) signals.However,the existing EMG decoding algorithms rarely obtain the spatial matching relationship between decoded motion units(MU) and designated muscles,and the control interface can only recognize the trained hand gestures.In this study,a semi-supervised HMI based on MU-muscle matching(MMM) is proposed to recognize individual finger motions and even the untrained combined multi-finger actions.Through automatic channel selection from high-density s EMG signals,the optimal spatial positions to monitor the MU activation of finger muscles are determined.Finger tapping experiment is carried out on ten subjects,and the experimental results show that the proposed s EMG decomposition algorithm based on MMM can accurately identify single finger motions with an accuracy of 93.1%±1.4%,which is comparable to that of state-of-the-art pattern recognition methods.Furthermore,the MMM allows unsupervised recognizing the untrained combined multi-finger motions with an accuracy of 73%±3.8%.The outcomes of this study benefit the practical applications of HMI,such as controlling prosthetic hand and virtual keyboard.

Evaluation of the anxiolytic effect of the methanol stem extracts of Cissus quadrangularis

Objective:To investigate the potentials of the stem of Cissus quadrangularis(C.quadrangularis)in the control of anxiety and related motor coordination effects in mice using experimental models.Methods:The methanol extract of the stem of C.quadrangularis was studied in mice using elevated plus maze,hole board,open field and stair case tests.Acute toxicity and phytochemical analysis were also carried out.Results:The methanol extract(100,200,300 and 400 mg/kg)exhibited significant anxiolytic effects,as evident by significant(P<0.05)increase in the number of crossings at 100,200 and 300 mg/kg dose and number of rearing at 200,300 and 400 mg/kg dose in open field behavior test.Time spent in the open arms and number of entrances in the open arms increased significantly(P<0.05,P<0.01)at the dose of 200 and 300 mg/kg in elevated plus maze test.Post hoc analysis showed that C.quadrangularis at the dose of 200 and 300 mg/kg significantly(P<0.05)increased the number of steps taken and number of head dips.Significant(P<0.05)reduction in time duration on the bar and number of rearing were observed at the dose of 200,300 and 400 mg/kg.The acute toxicity test revealed an oral LD_(50)above 5000 mg/kg,while phytochemical studies showed the presence of phytosterols,terpenoids,saponins,flavanoids,tannins,carbohydrates and aminoacids.Conclusions:The stem extracts of C.quadrangularis is anxiolytic in nature,which contribute to its use in traditional medicine as anxiolytic.