基于表面肌电非负矩阵分解与一致性的肌间协同耦合关系研究

肌肉协同模型是神经产生并控制运动的低维度结构,探讨不同动作任务下的表面肌电信号(sEMG)间的相干性分析,可以体现相应肌群的协同耦合关系,进而能从神经控制运动与肌肉相互配合协调的角度揭示运动产生与执行规律。组织8名年轻健康受试者(男女均半、20～24岁)进行上肢腕部屈、伸实验,采集动作时相应肌群的sEMG数据,引入非负矩阵分解(NMF)方法分析肌间协同性,并进一步对协同性较高的肌群采用一致性分析方法,研究信号beta(15~35 Hz)和gamma(35～60 Hz)频段的耦合强度关系,探讨腕部伸屈动作下不同受试者之间的协同耦合性差异。结果表明:腕伸动作下,主动肌桡侧腕短伸肌(ECR)、指伸肌(ED)、尺侧腕伸肌(ECU)、肱桡肌(B)在协同模块W₅中具有协同关系,且肌间耦合强度显著(P<0.05),beta频段与gamma频段一致性显著面积相差较大(1.261±0.966);腕屈动作下,分别在协同模块公式中存在具有协同关系的肌肉对,且肌肉间耦合强度显著(P<0.001),在beta和gamma频段一致性显著面积相差较小(0.412±0.163),但主动肌桡侧腕屈肌、指浅屈肌间不具有协同性,耦合关系较弱。以上说明:神经控制运动的方式不同,体现为肌肉协同耦合关系有所差异;在同一协同模块中,协同性较高的肌肉间耦合关系较强,揭示神经控制运动规律与肌肉相互配合方式;运用此方法进行肌间协同耦合联合分析,可望深入揭示中枢神经模块化协同控制运动机制,进一步为运动障碍患者功能分析和评价提供科学依据。     

右前臂正中尺动脉型掌浅弓变异1例

近期,我们在解剖1具约65岁的男性尸体时,发现其右前臂正中尺动脉型掌浅弓变异。肱动脉沿肱二头肌下行至肘窝平桡骨颈高度分成桡动脉和尺动脉。尺动脉起始处的最大外径为4.0mm。尺动脉全程286.0mm。从肱动脉起始后,斜向内下方,行经旋前圆肌深头与屈肌深层之后,即下行于由指浅屈肌(外侧)和尺侧腕屈肌(内侧)所形成的尺侧沟内,并被尺侧腕屈肌覆盖。下行至腕部时,转向豌豆骨的桡侧,经腕横韧带的浅面到达手掌,于掌腱膜的深面,横行经过指浅屈肌腱的浅面,与正中动脉吻合成掌浅弓。尺动脉自起始处以下25.0mm分支出尺侧返动脉。以下10.0mm分支出骨间总…     

尺侧浅动脉一例

制作教学标本时,发现右侧尺侧浅动脉一例,此种变异较少见。女性标本,14岁左右,身高156cm,体形略胖,四肢无畸形。左侧尺、桡动脉及骨间总动脉未见异常。变异的尺浅动脉,在右侧髁间线上,离桡骨颈约4.0cm处,从肱动脉发出。尺浅动脉外径2.3mm,穿肱二头肌腱膜,于旋前圆肌、桡侧腕屈肌、掌长肌、指浅屈肌浅面与深筋膜下之间下行,沿尺侧腕屈肌的桡侧,伴尺神经至腕部,沿途发出数支皮支,肱动     

膝关节骨性关节炎推拿手法的力学特征和上肢核心肌群的疲劳研究

探讨膝关节骨性关节炎推拿手法的生物力学特征和生理学(表面肌电)特征,定量分析推拿手法的力学指标,建立一种客观评价推拿医生上肢核心肌群的疲劳状况的方法。招募10位推拿科医生,实时采集推拿医生拇指垂直压力和上肢表面肌电信号,研究垂直强度、次做功期与主做功期的时间比;研究操作该推拿手法时的上肢核心肌群;研究核心肌群的疲劳状况。结果表明,该推拿手法1 min内按压4次,平均垂直强度为(228±13)N,主做功期持续时间为(4.83±0.88)s,次做功期持续时间为(11.43±1.94)s,有效做功时间比为2.37±0.63。由上肢各肌肉群的平均积分肌电值(iEMG)和贡献率的降序可知,手法涉及上肢的核心肌群为拇短展肌(8.32±0.29,21.65%)、尺侧腕屈肌(5.67±0.32,14.74%)、肱三头肌(4.79±0.36,12.46%)、桡侧腕屈肌(4.60±0.12,11.96%)。在4 min的推拿过程中,拇短展肌的平均中值频率(MF)和平均功率频率(MPF)的下降程度是最大的,分别为30%和22%,即拇短展肌更易发生疲劳。因此,所研究的膝关节骨性关节炎推拿手法的生物力学特征和生理学(表面肌电)特征,为后续的人因工程研究和研制可替代推拿医生手法的自动化装置奠定良好的基础。     

健康人手部不同动作的脑电-肌电相干性分析

运动皮层和肌肉之间的功能连接直接关系到上肢功能障碍者的康复,神经肌肉的活动状态可以通过脑电-肌电(EEG-EMG)相干性来分析。本文通过在进行手抓、握及手腕屈、伸4组动作时,采集皮层运动区的9导联EEG信号和前臂4导联的EMG信号,进行相干性分析处理。结果表明在β频段,右手做屈指、伸指动作时相应的右前臂指屈肌(FD)、指伸肌(ED)与大脑左侧C3导联相干系数值较大(P0.05);右手做屈腕、伸腕动作时相应的尺侧腕屈肌(FCU)、桡侧腕伸肌(ECR)与大脑左侧C3导联相干系数值较大(P0.01)。研究结果为探索基于皮层肌肉相干性(CMC)的手部运动信息解码提供了依据。     

双侧正中神经、肌皮神经变异一例

正笔者在解剖1具女性尸体时,发现双侧肌皮神经、正中神经存在变异(图1),现报道如下。右侧正中神经在臂部伴肱血管走行,位于肱二头肌内侧沟,约在臂部上段与中下段正中神经由外侧发出2个分支,近侧分支沿前外下方走行,到达肱二头肌与喙肱肌并支配上述2肌;远侧分支由正中神经外侧发出,行向外下方到达肱肌并支配该肌。正常情况下正中神经在臂部无分支,在前臂发出肌支,支配除肱桡肌、尺侧腕屈肌和指深屈肌尺侧半以外的前臂所有屈肌;而肱二头肌、喙肱肌与肱肌均受来至臂丛外侧束的肌皮神经支配,但该侧肌皮神经未出现。左侧正中神经由来自外侧束的内侧根与来自内侧束的外侧     

双侧下腔静脉伴肝后段缺如变异一例*

<正>笔者在解剖一成年男性右上肢过程中发现正中动脉自腋动脉第3段发出,分支形成掌浅弓和变异拇主要动脉,报道如下。此标本正中动脉自腋动脉第3段(外径6.68 mm)距离旋肱后动脉(外径4.00 mm)10.10 mm处发出,此处正中动脉外径为2.82 mm;跨过正中神经起始部,在臂部于肱动脉和正中神经之间经肱二头肌内侧至肘窝,臂部长度227.00mm,后跨过旋前圆肌和桡侧腕屈肌,行于桡侧腕屈肌和掌     

行于前臂屈肌浅面的尺动脉一例

制作离体上肢标标本中,发现行于前臂屈肌浅面的尺动脉一例,报告如下:材料为一男性成人离体左上肢,发育正常。尺动脉在肘窝稍下,距背阔肌下缘19厘米处发自肱动脉,挠动脉也在此同时发出。尺动脉发出后,经旋前圆肌、挠侧腕屈肌、掌长肌、指浅屈肌的浅面,由外上向内下斜行,至前臂中下三分之一交界处,与行于尺侧腕屈肌和指浅屈肌间的尺神经接近,接近处距肱骨内上髁约18厘米。然后,两者伴行经腕横韧带浅面达手掌,参与形成掌浅弓。尺动脉的全     

肱二头肌腱膜止点变异一例

<正>笔者在一男性左上肢标本肘部操作时,发现该肱二头肌腱膜止点存在变异(图1),该腱膜起于肱二头肌肌腹下端的内侧份,起始处明显有肌丝附着,从形态上观察类似于肱二头肌的另一肌腱。该腱膜平行于肱二头肌肌腱内侧132 mm处走行,其位置较肱二头肌肌腱略浅。止于桡侧腕屈肌上份肌腹,与肱二头肌之间形成类似于"二腹肌"样的结构。腱膜中间宽度7.65mm,厚度0.43mm,其深面有肱动脉和肱静脉穿行,而正中神经未穿其深面。用手触摸该腱膜,其强度较肱二头肌肌腱差。     

基于小波包-交叉频率相干性的肌间耦合特性

人体运动控制系统具有高度的非线性特性,通过量化评价表面肌电(sEMG)信号间的非线性耦合强度,可以得到运动相关肌肉的功能状态,进而探究人体运动控制的机制。本文将小波包分解和n∶m相干性分析相结合,构建基于小波包-n∶m相干性的肌间交叉频率耦合分析模型,探究肌电信号间的非线性耦合关系。在维持30%最大自主收缩力(MVC)的肘部屈伸状态下,采集20名健康成年人的sEMG信号,首先基于小波包分解获取子带分量,然后将子带信号进行n∶m相干性计算,分析肌间耦合特征。结果表明:30%MVC的肘部屈曲运动下,协同肌对和拮抗肌对的线性耦合(频率比为1∶1时)强度高于非线性耦合(频率比为1∶2、2∶1和1∶3、3∶1时);对于肌间非线性耦合,随着频率比的增大,耦合强度随之降低,且频率比为n∶m和m∶n之间没有明显的耦合强度差异;beta和gamma频段内的肌间耦合主要体现在协同肌对之间的线性耦合(1∶1)和低频率比的非线性耦合(1∶2、2∶1)以及拮抗肌对之间的线性耦合上。以上说明:小波包-n∶m相干性方法可以定性、定量地描述肌间非线性耦合强度,为深入揭示人体运动控制机制和运动功能障碍患者的康复评价提供理论参考。     

Ballistic reactions under different motor sets

In preparation for performing task specific ballistic movements, subjects may choose among different possibilities for setting up their motor apparatus, ranging from quiet resting to different types of muscle activation. In the study presented here, we investigated whether differences in the motor set modify either the reaction time or the kinematic characteristics of the movement. Subjects wearing surface EMG recording electrodes in the wrist extensor (WE) and wrist flexor (WF) muscles were requested to react to the presentation of a visual stimulus by performing a ballistic wrist extension movement of an amplitude of about 50° in the following experimental conditions: resting quietly, which was considered as the control condition (CC); isometric contraction (IC), in which subjects were required to activate WE and WF muscles isometrically; rapid oscillations (RO), in which subjects were requested to make a fast oscillatory wrist movement; and slow oscillations (SO), in which subjects were maintaining a slow oscillatory motion of the wrist. To constrain the movement to the wrist joint and limit the action of postural muscles, the subjects forearm and hand were attached to joined non-resistive metallic platforms, allowing for free non-frictional displacement. In the EMG recordings, we measured the size of the EMG bursts in agonist and antagonist muscles, and the inter-burst intervals. In movement recordings, we measured movement onset latency and the velocity profile. Movement onset was delayed in SO with respect to all other conditions. Conversely, peak velocity was larger in all test conditions in comparison to CC. There were no differences in the size of the first EMG burst of the agonist muscle, but significant changes occurred in the subsequent bursts recorded in the agonist and antagonist muscles. Our study indicates that the motor program used to execute a ballistic voluntary movement is influenced by the conditions of the motor system. The configuration of the motor set should be specifically considered in the search for improving the speed of the reaction and the kinematics of ballistic movements.JMC and MTS were funded by the Spanish Ministry of Education, Culture and Sport, with grant numbers PR 2003-0212 and AP2000-0913     

Changes in cortically related intermuscular coherence accompanying improvements in locomotor skills in incomplete spinal cord injury

In human spinal cord injury, the neuronal mechanisms mediating the improvement of locomotor function in response to intensive treadmill training are not well understood. In this study, we examined if such recovery is mediated, in part, by increases in residual corticospinal drive to muscles of the leg during walking. To do this, we measured the coherence of electromyogram (EMG) activity between two antagonist muscles (intermuscular coherence), specifically at frequencies between 24 and 40 Hz, which is thought to indicate common drive to two muscles from corticospinal inputs. In 12 subjects with incomplete spinal cord injury, intermuscular coherence was measured between hamstrings and vastus lateralis EMG that was activated during walking on a motorized treadmill. Before training, appreciable coherence in the 24-40 Hz frequency band was only present in subjects with moderate volitional motor strength in their leg muscles (n = 8 subjects) compared with subjects with little or no leg muscle strength (n = 4 subjects), reconfirming that 24-40 Hz frequency coherence is likely mediated by common supraspinal inputs. After training, increases in 24-40 Hz coherence only occurred in the eight subjects with moderate leg muscle strength who also exhibited improvements in locomotor recovery as assessed by the 21 point WISCI II scale (termed responders). In contrast, development of intermuscular coherence in the 24-40 Hz frequency band did not occur in the four subjects with absent or weak muscle strength. These subjects also did not improve in their locomotor ability as reflected in unchanging WISCI II scores (termed nonresponders). Lower-frequency coherence (5-18 Hz), which is thought to contain common drive from spinal inputs, did not change in either group. In a subset of subjects that were previously assessed with transcranial magnetic stimulation (TMS) before and after training (n = 5 responders and 3 nonresponders), there was a significant and positive relationship between increases in 24-40 Hz coherence and increases in evoked muscle responses to TMS of the primary motor cortex. Taken together, increases in higher-frequency EMG coherence in subjects with residual voluntary muscle strength and its parallel relation to changes in TMS-evoked responses provides further evidence that improvements in locomotor function from treadmill training are mediated, in part, by increases in corticospinal drive to muscles of the leg during walking.     

Modulation of EMG power spectrum frequency during motor imagery

To provide evidence that motor imagery (MI) is accompanied by improvement of intramuscular conduction velocity (CV), we investigated surface electromyographic (EMG) activity of 3 muscles during the elbow flexion/extension. Thirty right-handed participants were asked to lift or to imagine lifting a weighted dumbbell under 3 types of muscular contractions, i.e. concentric, isometric and eccentric, taken as independent variables. The EMG activity of the agonist (long and short heads of biceps brachii) and the antagonist (long portion of triceps brachii) muscles was recorded and processed to determine the median frequency (MF) of EMG power spectrum as dependant variable. The MF was significantly higher during the MI sessions than during the resting condition while the participants remained strictly motionless. Moreover, the MF during imagined concentric contraction was significantly higher than during the eccentric. Thus, the MF variation was correlated to the type of contraction the muscle produced. During MI, the EMG patterns corresponding to each type of muscle contraction remained comparable to those observed during actual movement. In conclusion, specific motor programming is hypothesized to be performed as a function of muscle contraction type during MI.     

Myocyte production of nitric oxide in response to AChR-reactive antibodies in two inbred rat strains may influence disease outcome in experimental myasthenia gravis

In an attempt to identify mechanisms that explain the difference in susceptibility of two rat strains to the induction of experimental autoimmune myasthenia gravis (EAMG), acetylcholine receptor (AChR)-reactive antibodies were tested for their ability to up-regulate levels of inducible nitric oxide synthase (iNOS) in skeletal muscles of disease-sensitive Lewis rats and disease-resistant Wistar Furth (WF) rats. Initially, the WF muscle cell line, WE1, appeared to be more sensitive to antibody-stimulated iNOS induction and NO production than did the Lewis muscle cell line, LE1. Next, AChR-reactive antibody induced widespread iNOS production in skeletal muscles of WF rats, while iNOS production in muscles of Lewis rats was much less pronounced. Finally, inhibition of iNOS activity by administration of a specific iNOS inhibitor resulted in increased susceptibility to the induction of impaired muscle function in EAMG-resistant WF rats. It is speculated that nitric oxide production plays a protective immunomodulating role in WF rats.     

Developmental profile of slow hand movement oscillation coupling in humans

In adults, slow hand and finger movements are characterized by 6- to 12-Hz discontinuities visible in the raw records and spectra of motion signals such as acceleration. This pulsitile behavior is correlated with motor unit synchronization at 6-12 Hz as shown by significant coherence at these frequencies between pairs of motor units and between the motor units and the acceleration recorded from the limb part controlled by the muscle, suggesting that it has a central origin. In this study, we examined the correlation between this 6- to 12-Hz pulsatile behavior and muscle activity as a function of childhood development. Sixty-eight participants (ages 4-25 yr) performed static wrist extensions against gravity or slow wrist extension and flexion movements while extensor carpi radialis muscle electromyographic (EMG) and wrist acceleration signals were simultaneously recorded. Coherence between EMG and acceleration within the 6- to 12-Hz frequency band was used as an index of the strength of the relation between central drive and the motor output. The main findings of the study are 1) EMG-acceleration coherence increased with increases in age, with the age differences being greater under movement conditions and the difference between conditions increasing with age; 2) the EMG signal showed increases in normalized power with increases in age under both conditions; and 3) coherence under movement conditions was moderately positively correlated with manual dexterity. These findings indicate that the strength of the 6- to 12-Hz central oscillatory drive to the motor output increases through childhood development and may contribute to age-related improvements in motor skills.     

肱三头肌的解剖特点及其在臂后中部桡神经显露中的意义

目的观察肱三头肌与桡神经的位置关系,改进臂中后部桡神经的显露方法。方法尸体标本31具(62侧),在臂中部将肱三头肌外侧头自臂外侧肌间隔上钝性剥离达肱骨,继续向内侧钝性分离肱三头肌外侧头,显露桡神经,观察肱三头肌外侧头和内侧头融合的位置、融合前二者分界是否清晰,观察肱三头肌内侧头起点和外侧头起点与桡神经的位置关系。结果肱三头肌内、外侧头融合近端与桡神经穿过臂外侧肌间隔处距离(6.7±2.6)cm,约在鹰嘴窝上缘水平,融合前肱三头肌内、外侧头分界清晰。肱三头肌外侧头全部起自桡神经沟近端肱骨骨面的为79%(49侧),部分起自桡神经沟以远肱骨骨面的为21%(13侧),其中腱性的9例,肌性的4例。结论利用臂中部肱三头肌内、外侧头的解剖特点,可使臂后中部桡神经的显露更安全、合理。     

基于Gabor小波和格兰杰因果的脑-肌电同步性分析

手部运动功能神经肌肉调节机制的研究在假肢控制、康复治疗和评价等方面具有重要意义。基于Gabor小波和格兰杰因果(WT-GC)实现皮层肌肉耦合(CMC)分析,并定义GC峰值频率和显著性面积指标,定量描述不同频段的脑-肌电耦合及信息流向特征。同步采集10名健康被试在10%和60%最大自主收缩力(MVC)下的脑电(EEG)与肌电(EMG)信号,运用脑-肌电同步性分析方法进行手部不同力量下的脑-肌电同步耦合特征分析。结果显示:与10%MVC相比,在60%MVC握力输出下,EEG→EMG和EMG→EEG方向GC峰值频率均向高频段转移;EEG→EMG方向上beta频段的GC显著性面积降低,并具有统计性差异(P<0.05)。研究结果验证,所提出方法能够有效刻画不同频段的皮层肌肉间能量耦合特征,可描述不同信息传递方向上的神经元同步振荡强度,也可揭示皮层肌肉运动系统通过调节神经元同步振荡强度、频段与流向来控制手部力量输出的神经机制,为探索手部运动控制与反馈信息解码提供了依据。     

癫痫发作脑电信号的相位幅度调制研究

脑电图是癫痫诊治中一种最为重要的工具,而大数据量的脑电记录给人工分析带来困难,计算机分类则可减轻此负担。从相位幅度调制角度研究癫痫脑电低频节律相位与高频节律幅度间的耦合关系,利用归一化后的调制指数(MI)来量化各频段间的耦合强度。基于波恩癫痫发作间期和发作期脑电的200个样本数据集,提出依据高低频节律范围对MI图进行分区,再利用分区后的耦合系数对不同状态下的脑电进行分类。结果显示,发作期Gamma节律与Delta(2～4 Hz)节律的MI值(0.009 9±0.009 6)相比发作间期(0.003 6±0.008 7)显著增加(P<0.01)。Gamma节律与Theta(4～8 Hz)节律的发作期MI值(0.008 7±0.006 2)相比发作间期(0.001 4±0.003 2)也有显著增加(P<0.01);Theta Beta节律间耦合强度在发作期(0.002 2±0.001 3)与发作间期(0.000 5±0.000 7)也存在显著差异。利用支持向量机在五折交叉验证下,波恩癫痫脑电数据MI特征对发作期和间期数据分类准确率达到97%;采用随机森林分类方法,同样得到一致结果。所提出方法的应用可有效提高对临床视频脑电图分析的效率。