腹直肌肌电图运动单位电位正常值的建立

目的:建立腹直肌肌电图(EMG)运动单位动作电位(MUAP)各参数正常值。方法:测定109例正常人腹直肌EMG的MUAP的时限、波幅及多相波。结果:腹直肌EMG的MUAP参数分别为:波幅373．78±56．46μV,时限9．95±1．13 ms,多相波19．40％±1．52％。结论:腹直肌EMG各参数能可靠、稳定地测出,有助于脊髓胸段下运动神经元病变的检测。     

运动相关皮层电位研究的知识图谱分析

运动相关皮层电位是一种事件相关电位,可以反映运动前的策划、准备和早期的运动执行过程,近年来多受关注。以Web of Science^TM核心合集收录2000年至今“运动相关皮层电位”为研究主题的498篇文献为数据来源,利用Cite SpaceⅤ可视化技术绘制图谱分析相关问题。分析表明,研究热点主要集中于运动关联电位、运动皮层、脑电图、运动等方向。运动相关皮层电位的研究发展按照时间可以分为3个阶段：第一阶段主要以大脑额叶、诱发电位、吞咽诱发运动相关皮层电位的研究为主;第二阶段以脑机接口、运动想象、运动检测电位与帕金森综合征为主;第三阶段研究趋势逐渐向着康复性研究方向发展,主要以脑电图学、注意力、以及抓握分析为主。通过对运动相关皮层电位的研究热点以及发展历程进行分析,有助于对体育训练和运动康复等领域提供理论和应用研究方面的参考。     

精神分裂症患者的事件相关电位研究——词意分类与 N400

本文利用词意分类作业对19例精神分裂症病人的事件相关电位进行对照研究。结果表明,词意分类作业中,虽然无关刺激在精神分裂症病人中诱发 ERPs 在300—600ms 内负性活动也显著高于相关刺激诱发的 ERPs,但精神分裂症组相关刺激诱发的 ERPs 在以上时间窗内的负性活动显著高于正常对照组。这种差异提示精神分裂症病人的语言信息处理过程可能存在某种程度的障碍。     

运动单位电位多参数分析在肌原性损害中的诊断价值

目的 :探讨运动单位电位 (MUP)多项参数对肌原性损害的诊断价值。方法 :对 10例肌原性病变患者 ,采用棘波触发平均技术 ,得到股四头肌MUP 2 30个 ,肱二头肌MUP 190个 ,胫骨前肌MUP172个 ,对MUP多项参数进行定量分析 ,并与正常对照进行对比。结果 :各项参数与正常对照相比均有显著意义 (P <0 0 0 1～ 0 0 0 0 1) ,经 5 %可信限和均数 - 2 0标准差界值水平的显著性检验和相关性分析 ,证明时限与面积 /波幅比较大小指数、宽度高度指数和面积具有较高的诊断敏感性。结论 :时限与面积 /波幅比对肌原性损害的诊断作用最敏感 ,大小指数、宽高度指数与面积的诊断作用次之 ,波幅的诊断作用最小     

六周虚拟现实运动对大学生认知能力影响的事件相关电位测评

评价虚拟现实运动对人体认知能力的影响.随机招募30名健康大学生,实验组(20人)利用爱动运动王Ⅱ进行六周的虚拟现实运动(伸展运动、射箭运动与平衡运动),每次30 min,每周三次.对照组(10人)正常作息.采用德国BP公司生产的32导Brain Vision Analyzer分别测量受试者实验前和六周实验结束后安静状态下的事件相关电位(event-related potential,ERP) P300,选用改良版的Flanker刺激范式.采用SPSS15.0 for windows对数据分别进行描述性统计和推断性统计分析.六周前后组内配对t检验显示,实验组额叶区(F3、F4)和中央区(C3)电极点在一致性刺激时(S1和S2)ERP P300潜伏期较实验前显著延长(P<0.05),额叶区表现更为显著.实验组中顶区(P3)S1刺激下ERP P300波幅较实验前显著增加(P<0.05).对照组和实验组其他电极点和其他刺激方式下未见有显著性改变(P>0.05).六周虚拟现实运动(伸展运动、射箭运动与平衡运动)对大学生认知能力有一定的选择性影响,体现于ERP P300潜伏期和波幅指标显著性改变仅出现在特定的脑区和刺激方式.P300潜伏期改变只出现于额叶区和中央区,P300波幅改变只出现在顶区,且上述改变仅发生在一致性刺激的条件下.这些选择性改变应是对该运动方式的适应性改变.     

平面运动与深度运动差异的直接证据——ERP研究

平面运动(MIP)与深度运动(MID)是自然界两种最基本的运动形式,但关于人类大脑对它们的感知机制上的差异,目前还不清楚.本研究采用一种比较接近人视觉经验的实验范式,采集了这两种运动情况下的128导脑电数据,对其ERP数据进行了较详细的时-空分析,结果显示MIP与MID在激活脑区、时间过程等方面均表现出了一定的差异,同时运动方向也对运动感知具有显著的影响.同时还发现MIP与MID的感知都是多脑区信息整合的结果.     

单纤维肌电图中多电位对颤抖值的影响

目的：确定单纤维肌电图（SFEMG）中最佳的颤抖（jitter）值数目。方法：选择39例重症肌无力患者进行眼轮匝肌SFEMG检测,重新计算多电位的颤抖值并比较差异性。结果：来自异常终板的多电位可以增大颤抖值,该值在不同的Ossermann分型之间无差异。结论：在SFEMG操作中,应采用一个颤抖值的描记,以防止假阳性的结果。     

基于数学形态学与核主成分分析的峰电位检测与分类方法

目的 为抑制高强度背景噪声及信号叠加的干扰,提高峰电位的检出率和分类的正确性,本文提出一种新的无监督方法.方法 首先,应用数学形态学的复合操作对信号进行降噪,采用定阈值提取峰电位.然后,小波变换和核主成分分析法（kernel principal components analysis,KPCA）相结合,对已提取的峰电位波形进行特征提取.最后,用改进的最小距离法实现峰电位分类.结果 仿真实验结果表明,此方法对于不同噪声强度的信号,峰电位检出率达94%,总分类正确率91%以上,其中大量叠加信号的分类正确率88%以上.结论 本方法能在有效抑制噪声的基础上,准确提取峰电位并有效分类.     

自动分解肌电图运动单位动作电位各参数的分析和临床意义

目的：探讨运动单位动作电位（ＭＵＡＰ）各参数评价神经肌肉疾病的临床意义。方法：采用肌电图仪,以常规同心圆针电极记录,对７１例健康成人和４３例神经肌肉疾病患者的肱二头肌或／和胫前肌进行自动分解肌电图（ＡＤＥＭＧ）检测,共收集ＭＵＡＰ８３５６个,测定ＭＵＡＰ的５个参数：波幅、时限、转折数、发放率、棘波间隔变异系数（ＣＩＶ）。结果：１５例肌源性疾病患者表现为每一记录部位的ＭＵＡＰ数目增加;肱二头肌ＭＵＡＰ的波幅、时限、转折数减低、发放率增加,ＣＩＶ无改变;胫前肌ＭＵＡＰ的各参数无显著性改变。２８例神经源性疾病患者表现为每一记录部位的ＭＵＡＰ数目减少;ＭＵＡＰ的波幅、转折数及ＣＩＶ增加,时限及发放率无显著性增加。结论：ＡＤＥＭＧ检测的ＭＵＡＰ各参数对于评价神经肌肉疾病有重要的临床意义。     

癫痫大鼠听觉事件相关电位P3样波的研究

目的：研究正常大鼠听觉事件相关电位（ERP）的P3样波（下简称听觉P3样电位）特点及癫痫大鼠P3样电位变化。方法：癫痫组大鼠每日予戊四氮腹腔注射，直至达到点燃标准，正常组大鼠每日注射生理盐水。记录并分析两组动物听觉ERP特点及其P3样电位的变化。结果：（1）在大鼠可发现与人类听觉ERP的P3电位波形、潜伏期及反应特点相似的ERP；（2）癫痫大鼠与正常大鼠相比，其P3样电位的听觉ERP的P3电位潜伏期明显延长（P＜0．01），波幅相对降低（P＞0．05），波形分化不清。结论：P3样电位的产生具有跨越种属的相似性，提示P3样电位在哺乳动物中可能具有共同的神经回路。     

The Effects of Sensory Perceptual Isolation on Single Motor Unit Conditioning

Forty male volunteers were injected with bipolar fine-wire electrodes into the tibialis anterior muscle and trained to isolate and cunt nil a single motor unit. A light panel indicated trial onsets and correct and incorrect responses. Subjects were randomly assigned to the isolation or non-isolation condition for both sessions. Isolation condition was produced In an air-fluidized. ceramic-bead bed in a light attenuating chamber. A relearning session followed the initial session after a two week interim rest. The hypodynamic effects of sensory isolation increased the speed of learning to isolate and control an SMU. The results. suggested that subjects were better able to attend to the relatively weak proprioceptive information provided by the SMU through the reduction of the amount and/or variety of competing stimuli.     

Auditory Feedback and Conditioning of the Single Motor Unit

The effects of direct auditory feedback of the electromyogram (EMG) on learning to control a single motor unit (SMU) were investigated. Seventeen human subjects were injected with bipolar fine-wire electrodes into the tibialis anterior muscle. A trial light indicated the onset of a trial. If the subject activated an SMU, a correct light appeared. A non-SMU response was followed by an incorrect light. All subjects received an initial training series with auditory EMG feedback followed by a retest at 2 weeks without EMG feedback. Speed of initial learning was substantially improved by direct EMG feedback. The nature and amount of learning, including the ability to use proprioceptive cues in controlling an SMU, were not affected, nor was retention of learning.     

电极配置对MUAP检测影响的仿真研究

本研究采用模型的方法,研究了电极配置对运动单位动作电位检测的影响.根据肌肉的形态结构和生理特征,从细胞内动作电位开始,仿真了运动单位动作电位序列.在此基础上,研究了电极的配置对运动单位动作电位的波形和统计特征的影响.结果表明:尺寸较小的电极选择性较好;差分电极的选择性优于单电极,适当调整其电极间距离和角度,可提高检测质量.     

Synthesising of a motor unit potential based on the sequential firing of muscle fibres

A model for the summation of the fibre potentials in a motor unit is presented. A possible mechanism for the recruitment sequence of the various fibres of a motor unit is developed on the basis of anatomical and physiological findings supplemented with a mathematical approach making it possible to take into consideration the spatial and temporal distribution of various fibre potentials. In addition to the commonly accepted parameters of a motor unit potential, stress is laid on the relative position of the recording electrode with respect to the structure of the motor unit and the location of the motor point of the muscle. The model is evaluated both with dipole and dielectric attenuation approaches. The sub-unit concept of a motor unit is critically examined in the light of the results of the model. Attention has been focused on the motor units of the brachial biceps, but the flexibility of the approach also makes it possible to consider motor units of other muscles. The procedure for such generalisations and the respective limitations are discussed. The model provides a unified approach to the diversity of the parameters of the motor unit potential.     

Attention to Color: An Analysis of Selection, Controlled Search, and Motor Activation, Using Event-Related Potentials

In this study the organization of information processing in a selective search task was examined by analyzing event-related potentials. This task consisted of searching for target letters in a relevant (attended) color. The ERPs revealed two different effects of attention: an early occipital negativity (+/- 150 ms) reflecting feature-specific attention, and a later, central N2b component (+/- 240 ms) reflecting covert orienting of attention. A later, prolonged negativity (search-related negativity) (+/- 300 ms), maximal at Cz, was related to controlled search to letters in the attended color. Detection of relevant targets resulted in a parietal P3b component. Depending on stimulus presentation conditions an earlier response to both attended and unattended targets was found: an N2 component (+/- 250 ms). In these same conditions, C'3-C'4 asymmetries (Corrected Motor Asymmetries--CMA) suggested motor activation at +/- 300 ms, in the same time range as search-related negativity. It was argued that N2 and CMA suggest the existence of a preattentive target detection system, operating in parallel with a slower serial attentive system, as reflected by N2b and search negativity.     

Motor unit recruitment strategy changes with skill acquisition

The modifications of motor unit recruitment strategy due to skill acquisition was determined in the elbow flexor-extensor muscles of normal human subjects. The median frequency of the power density spectra of the electromyograms recorded from the biceps and triceps muscles during a 3-s linear increase in flexion force in the range of 0–100% maximal voluntary contraction (MVC) was calculated for each subject, every 2 weeks over a total 6-week period during which subjects practiced linear flexion force increase three times a week. Electromyograms were recorded with two pairs of electrodes of different size and electrode spacing. It was shown that skill acquisition due to the 360 practice trials over the 6-week period caused an increase in the initial motor unit recruitment phase of the agonist's force generation cycle from about 0–65% MVC to about 0–85% MVC. The increase in the recruitment range was gradual and statistically significant for the measurements made every 2 weeks. The reccruitment range of the antagonist triceps demonstrated a minor, but statistically insignificant, decrease over the same training period. There was a minor, but statistically significant, advantage of using small electrodes and inter-electrode spacing. It was concluded that skill acquisition, due to repeated functional use of a muscle in the same contraction mode, results in a slower, prolonged recruitment of motor units in the initial segment of the force generation cycle, thereby allowing a more precise and accurate control of the increments of force increase. Such conclusions reinforce the concept advocating the plasticity of motor unit control according to the functional demands imposed on the muscle. The results have significant implications in the design of various athletic, occupational and rehabilitation training modalities for optimal performance of various movement functions.     

Selectivity of electromyographic recording techniques: simulation study

A modified line source model was used to simulate single muscle fibre action potentials and their radial decline as measured using a single fibre (SF), concentric needle (CN) and macroelectromyography (EMG) electrode. The 90 per cent attenuation distance, defined as the distance from the fibre at which the peak-to-peak amplitude of the action potential declines to 10 per cent of its value measured near the fibre, was determined. For the CN and macro electrode this distance was 1·4 and 4·1 times, respectively, the distance measured for the SF electrode Based on the decline characteristics obtained from our simulations and experimental data reported in the literature, we inferred that in a normal human biceps muscle the spike component of CN MUAPs is produced mainly by the action potentials of the closest one-six muscle fibres. This inference was used to interpret the changes in MUAP amplitude seen by clinical EMG in neuromuscular diseases. The decline of action potential amplitude with distance from the electrode was least when recordings were made by the macro-EMG electrode. The three electrodes differed in their uptake area and thus recordings made with them provided complementary information about the motor unit architecture and the way it changes in neuromuscular diseases.     

Motor unit properties after operant conditioning of rat H-reflex

Operant conditioning of the H-reflex produces plasticity at several sites in the spinal cord, including the motoneuron. This study assessed whether this spinal cord plasticity is accompanied by changes in motor unit contractile properties. Thirty-one adult male Sprague-Dawley rats implanted for chronic recording of triceps surae electromyographic activity and H-reflex elicitation were exposed for at least 40 days to HRup or HRdown training, in which reward occurred when the H-reflex was greater than (12 HRup rats) or less than (12 HRdown rats) a criterion value, or continued under the control mode in which the H-reflex was simply measured (7 HRcon rats). At the end of H-reflex data collection, rats were anesthetized and the contractile properties of 797 single triceps surae motor units activated by intraaxonal (or intramyelin) current injection were determined. Motor units were classified as S, FR, Fint, or FF on the basis of sag and fatigue properties. Maximum tetanic force and twitch contraction time were also measured. HRdown rats exhibited a significant increase in the fatigue index of fast-twitch motor units. This resulted in a significant decrease in the percentage of Fint motor units and a significant increase in that of FR motor units. HRup conditioning had no effect on fatigue index. Neither HRup nor HRdown conditioning affected maximum tetanic force or twitch contraction time. These data are consistent with the hypothesis that conditioning mode-specific change in motoneuron firing patterns causes activity-dependent change in muscle properties.     

The Topography of Event-Related Slow Potentials During Reflex Movement (Ankle Jerk) Conditioning

The morphology and scalp distribution of slow negative potentials elicited in type I conditioning, requiring no instruction, were studied. The paradigm involved the presentation of a conditioned stimulus (S1), followed 1500 msec later by an unconditioned stimulus (H), the electrical stimulation of the popliteal nerve evoking an ankle jerk (Hoffmann reflex). Our topographical data showed that two components develop in the interstimulus interval S1-H: a large fronto-central early component followed by a late centro-parietal negative component which precedes the H-reflex movement. This negative shift terminates abruptly in a positivity post-H-reflex. These anticipatory components show similarities, particularly at the parietal site, to slow waves elicited in a CNV paradigm involving the presentation of an indicative stimulus (S1) followed by an imperative stimulus (S2) requiring an operant motor response. These results are discussed in terms of conditioning, arousal, and early preparatory and time estimation processes.