Primary motor cortex

初级运动皮层
  • 文章类型: Journal Article
    胶质瘤,最常见的原发性脑肿瘤,由于影响患者生活质量(QOL)和死亡风险增加的潜在缺陷,在雄辩的皮质区域提出了手术挑战。这项研究调查了40例Rolandic皮质胶质瘤切除术后的运动和感觉恢复,除了癫痫发作结果和清醒开颅手术等术中技术的疗效。
    这是一项为期10年的单中心回顾性研究,基于神经外科医生在2011年至2020年期间切除Rolandic胶质瘤的经验及其对40名患者生活质量的影响。主要结果是肿瘤复发和手术疗效定义为生存状态,癫痫发作状态,感觉和运动神经缺陷。数据收集包括人口统计,肿瘤,和手术结果变量。切除范围(EOR)分为全切除(GTR)(EOR≥95%)或次全切除(EOR<95%)。统计分析涉及描述性统计和结果比较的推论检验。
    患者平均年龄为42.3±14岁,男性占72.5%,女性占27.5%。最常见的表现是癫痫发作(65%)。肿瘤位于额叶的65%,电机在75%,肿瘤病理最高的是少突胶质细胞瘤(42.5%)。研究中的复发率为20%(40个中的8个),1年生存率为92.5%。切除后,Karnofsky的表现状态显着改善(P=0.007),在正常的日常活动中(P=0.001),在精细运动技能方面(P=0.020),和工作爱好(P=0.046)。癫痫发作和赤字率没有统计学上的显着改善。复发与人口统计学特征无关,临床表现,肿瘤相关特征(位置,area,侧面,和突变),肿瘤切除,辅助治疗(P>0.05)。
    使用细致的刺激图可以实现Rolandic胶质瘤的GTR,尽管有共同的信念,但完全的功能恢复是可以实现的。
    UNASSIGNED: Gliomas, the most common primary brain tumors, pose surgical challenges in eloquent cortex regions due to potential deficits affecting patients\' quality of life (QOL) and increased mortality risk. This study investigates motor and sensory recovery postresection of Rolandic cortex gliomas in 40 patients, alongside seizure outcomes and the efficacy of intraoperative techniques such as awake craniotomy.
    UNASSIGNED: This was a 10-year monocentric retrospective study based on the experience of a neurosurgeon in the resection of Rolandic gliomas and its impact on 40 patients\' QOL in a period from 2011 to 2020. The primary outcomes were tumor recurrence and the efficacy of the surgery defined as survival status, seizure status, and sensory and motor neurological deficits. Data collection included demographic, tumor, and surgical outcome variables. The extent of resection (EOR) was classified as gross total resection (GTR) (EOR ≥95%) or subtotal resection (EOR <95%). Statistical analysis involved descriptive statistics and inferential tests for outcome comparisons.
    UNASSIGNED: Patients were aged an average of 42.3 ± 14 years and distributed between 72.5% of males and 27.5% of females. The most common presentation was seizures (65%). The tumor was located in the frontal lobe at 65%, the motor at 75%, and the top tumor pathology was oligodendroglioma (42.5%). The recurrence rate in the study was 20% (8 of 40), and the 1-year survival rate was 92.5%. After the resection, significant improvement was shown in Karnofsky\'s performance status (P = 0.007), in normal daily activities (P = 0.001), in fine motor skills (P = 0.020), and work hobbies (P = 0.046). No statistically significant improvement was shown in seizures and deficit rates. Recurrence was not associated with the demographic characteristics, clinical presentation, tumor-related characteristics (location, area, side, and mutation), tumor resection, and adjuvant treatment (P > 0.05).
    UNASSIGNED: GTR of Rolandic gliomas can be achieved with the use of meticulous stimulation mapping, and complete functional recovery is attainable despite common belief.
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  • 文章类型: Journal Article
    I波周期性重复配对脉冲经颅磁刺激(iTMS)可以改变对新型运动技能的获取,但相关的神经生理效应仍不清楚。因此,当前的研究使用TMS-脑电图联合(TMS-EEG)来研究iTMS对随后的视觉运动训练(VT)的神经生理学影响。16名年轻人(26.1±5.1岁)参加了三个会议,包括真正的iTMS和VT(iTMSVT),控制iTMS和VT(iTMSControl+VT),或者单独的iTMS。测量iTMS前后的运动诱发电位(MEPs)和TMS诱发电位(TEPs),在VT之后,评估神经可塑性变化。无论干预如何,iTMS或VT后MEP振幅无变化。与基线相比,运动技能有所提高,但是在刺激条件之间没有发现差异。相比之下,在对照iTMS之前,P30峰值被VT改变(P<0.05),但当在iTMS之前或单独在iTMS之后进行VT时,这种效果并不明显(所有P>0.15)。与期望相反,iTMS无法调节MEP振幅或影响运动学习。尽管如此,P30振幅的变化表明运动学习与皮质反应性的改变有关。此外,通过启动iTMS消除了这种影响,表明启动的影响未能影响学习。
    I-wave periodicity repetitive paired-pulse transcranial magnetic stimulation (iTMS) can modify acquisition of a novel motor skill, but the associated neurophysiological effects remain unclear. The current study therefore used combined TMS-electroencephalography (TMS-EEG) to investigate the neurophysiological effects of iTMS on subsequent visuomotor training (VT). Sixteen young adults (26.1 ± 5.1 years) participated in three sessions including real iTMS and VT (iTMS + VT), control iTMS and VT (iTMSControl + VT), or iTMS alone. Motor-evoked potentials (MEPs) and TMS-evoked potentials (TEPs) were measured before and after iTMS, and again after VT, to assess neuroplastic changes. Irrespective of the intervention, MEP amplitude was not changed after iTMS or VT. Motor skill was improved compared with baseline, but no differences were found between stimulus conditions. In contrast, the P30 peak was altered by VT when preceded by control iTMS (P < 0.05), but this effect was not apparent when VT was preceded by iTMS or following iTMS alone (all P > 0.15). In contrast to expectations, iTMS was unable to modulate MEP amplitude or influence motor learning. Despite this, changes in P30 amplitude suggested that motor learning was associated with altered cortical reactivity. Furthermore, this effect was abolished by priming with iTMS, suggesting an influence of priming that failed to impact learning.
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  • 文章类型: Journal Article
    放置经颅直流电刺激(tDCS)电极的常规方法恰好在目标大脑区域上方。然而,这种电极放置策略通常无法改善运动功能和调节皮质兴奋性.我们研究了优化电极放置的效果,以在M1和SMA的腿部区域诱导最大电场,通过T1和T2加权MRI解剖模型中的电场模拟进行估计,健康个体的运动表现和皮质兴奋性。
    共有36名健康志愿者参加了这项随机研究,三盲,假对照实验。他们按性别分层,并根据刺激范式随机分配到三组中的一组,包括tDCS,其中(1)阳极和阴极电极位于FCz和POz上,分别,(A-PtDCS),(2)阳极和阴极电极位于POz和FCz上,分别,(P-AtDCS),和(3)假tDCS。tDCS(2毫安,10分钟)在3周内每3或4天进行一次(总共5个疗程)。
    与假tDCS相比,A-PtDCS导致3周训练后坐到站的数量显着增加,而P-AtDCS在3周训练后显着增加了膝关节屈肌峰值扭矩,并在第一次训练后立即降低了短期皮质内抑制(SICI),并在训练后保持了这种抑制作用。
    这些结果表明,通过电场模拟估算的最大EF的优化电极放置可增强电机性能,并根据电流流动的方向调节皮质兴奋性。
    UNASSIGNED: The conventional method of placing transcranial direct current stimulation (tDCS) electrodes is just above the target brain area. However, this strategy for electrode placement often fails to improve motor function and modulate cortical excitability. We investigated the effects of optimized electrode placement to induce maximum electrical fields in the leg regions of both M1 and SMA, estimated by electric field simulations in the T1and T2-weighted MRI-based anatomical models, on motor performance and cortical excitability in healthy individuals.
    UNASSIGNED: A total of 36 healthy volunteers participated in this randomized, triple-blind, sham-controlled experiment. They were stratified by sex and were randomly assigned to one of three groups according to the stimulation paradigm, including tDCS with (1) anodal and cathodal electrodes positioned over FCz and POz, respectively, (A-P tDCS), (2) anodal and cathodal electrodes positioned over POz and FCz, respectively, (P-A tDCS), and (3) sham tDCS. The sit-to-stand training following tDCS (2 mA, 10 min) was conducted every 3 or 4 days over 3 weeks (5 sessions total).
    UNASSIGNED: Compared to sham tDCS, A-P tDCS led to significant increases in the number of sit-to-stands after 3 weeks training, whereas P-A tDCS significantly increased knee flexor peak torques after 3 weeks training, and decreased short-interval intracortical inhibition (SICI) immediately after the first session of training and maintained it post-training.
    UNASSIGNED: These results suggest that optimized electrode placement of the maximal EF estimated by electric field simulation enhances motor performance and modulates cortical excitability depending on the direction of current flow.
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  • 文章类型: Journal Article
    肌肉骨骼损伤后,经常有皮质脊髓失去控制。当前的肌腱康复可能无法充分解决皮质脊髓对肌肉的控制,这可能导致症状复发的顽抗。这篇综述提供了关于节奏控制阻力训练(TCRT)在(1)促进皮质脊髓可塑性方面的有效性的现有文献的总结,(2)提高物理性能,(3)改善健康成年人的力量结果。使用电子数据库(PubMed,CINAHL,Embase,和谷歌学者),以确定2010年至2023年发表的相关研究。随机对照(RCT)研究包括18至60岁之间的娱乐性训练和未经训练的健康成年人,并将TCRT干预措施与对照条件进行了比较。最初搜索中确定的1255项研究中有12项被纳入最终分析。在所有纳入的研究中,与传统的阻力训练方法相比,TCRT被证明能引起更大的神经适应(即,自定进度的力量训练)。这些结果表明,TCRT有望成为调节健康成人皮质脊髓可塑性的有效方法,并可能增强神经肌肉适应。包括CSE的改进,降低SICI,增强电机单元同步,和自愿性肌肉激活。
    After musculoskeletal injuries, there is often a loss of corticospinal control. Current tendon rehabilitation may not adequately address the corticospinal control of the muscle which may contribute to the recalcitrance of symptom recurrence. This review provides a summary of the current literature regarding the effectiveness of tempo-controlled resistance training (TCRT) in (1) promoting corticospinal plasticity, (2) improving physical performance, and (3) improving strength outcomes in healthy adults. A comprehensive literature search was conducted using electronic databases (PubMed, CINAHL, Embase, and Google Scholar) to identify relevant studies published between 2010 and 2023. Randomized control (RCT) studies that included recreationally trained and untrained healthy adults between 18 and 60 years of age and that compared a TCRT intervention to a control condition were included. Twelve of the 1255 studies identified in the initial search were included in the final analysis. Throughout all included studies, TCRT was shown to elicit greater neural adaptations compared to traditional resistance training methods (i.e., self-paced strength training). These results indicate that TCRT holds promise as an effective method for modulating corticospinal plasticity in healthy adults and may enhance neuromuscular adaptations, including improvements in CSE, decreased SICI, enhanced motor unit synchronization, and voluntary muscle activation.
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  • 文章类型: Journal Article
    衰老诱导GABA能皮质内抑制的下降,这似乎不仅与幸福感的下降有关,睡眠质量,认知和疼痛管理,但也有运动控制受损。到目前为止,关于有针对性的干预措施是否可以防止老年人初级运动皮质皮质内抑制的下降,目前尚不清楚.因此,本研究调查了在6个月的平衡学习后,年龄相关的皮质去抑制是否可以逆转,以及姿势控制的改善是否与逆转去抑制的程度相关.结果表明,长期平衡学习后,老年受试者的皮质内抑制可以上调,并揭示了平衡表现的变化与皮质内抑制之间的相关性。这是第一项研究表明,在慢性抑制障碍人群中,与身体活动相关的GABA能抑制上调,因此可能对许多抑制性和兴奋性神经递质之间的平衡受到干扰的病理具有开创性意义。关键点:衰老诱导GABA能皮质内抑制的下降。到目前为止,关于有针对性的干预措施是否可以防止老年人初级运动皮质皮质内抑制的下降,目前尚不清楚.经过6个月的平衡学习,皮质内抑制可以在老年受试者中上调。这项研究的结果还揭示了平衡性能的变化与皮质内抑制之间的相关性。这是第一项研究显示在慢性抑制障碍人群中与身体活动相关的GABA能抑制上调。
    Ageing induces a decline in GABAergic intracortical inhibition, which seems to be associated not only with decremental changes in well-being, sleep quality, cognition and pain management but also with impaired motor control. So far, little is known regarding whether targeted interventions can prevent the decline of intracortical inhibition in the primary motor cortex in the elderly. Therefore, the present study investigated whether age-related cortical dis-inhibition could be reversed after 6 months of balance learning and whether improvements in postural control correlated with the extent of reversed dis-inhibition. The results demonstrated that intracortical inhibition can be upregulated in elderly subjects after long-term balance learning and revealed a correlation between changes in balance performance and intracortical inhibition. This is the first study to show physical activity-related upregulation of GABAergic inhibition in a population with chronic dis-inhibition and may therefore be seminal for many pathologies in which the equilibrium between inhibitory and excitatory neurotransmitters is disturbed. KEY POINTS: Ageing induces a decline in GABAergic intracortical inhibition. So far, little is known regarding whether targeted interventions can prevent the decline of intracortical inhibition in the primary motor cortex in the elderly. After 6 months of balance learning, intracortical inhibition can be upregulated in elderly subjects. The results of this study also revealed a correlation between changes in balance performance and intracortical inhibition. This is the first study to show physical activity-related upregulation of GABAergic inhibition in a population with chronic dis-inhibition.
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  • 文章类型: Journal Article
    背景:心率变异性(HRV)是评估心血管自主神经系统(ANS)功能的有用工具。这项系统评价和荟萃分析研究了经颅直流电刺激(tDCS)方案对HRV参数的潜在影响。
    方法:本研究从24个合格的数据综合研究中获得了97个比较。使用标准化平均差(SMD),估计个体和总体效应大小,以显示活动性tDCS和假刺激条件之间HRV变量的差异.更积极的效应大小值表明,与假刺激相比,活性tDCS引起的HRV增加更大。此外,进行调节变量分析以确定HRV变量的变化是否取决于(a)任务类型(身体压力与心理压力与静息状态),(b)目标大脑区域,(c)刺激极性,(d)参与者的特点,和(e)特定的HRV变量。最后,我们使用元回归分析来确定不同的tDCS参数(即,tDCS会话的数量,刺激持续时间,和密度)与HRV模式的变化有关。
    结果:随机效应模型荟萃分析表明,tDCS方案显著改善了HRV变量(SMD=0.400;P<0.001)。此外,在物理压力任务期间增加HRV(SMD=1.352;P=0.001),M1的阳极刺激是有效的,而PFC上的联合极性刺激改善了心理应激任务(SMD=0.550;P<0.001)和静息状态(SMD=0.192;P=0.012)期间的HRV。其他调节变量和荟萃回归分析未能表明tDCS协议在某些条件下具有积极作用,例如不同的刺激极性,参与者的特点,特定的HRV变量,和tDCS参数。
    结论:这些发现初步表明,使用tDCS方案刺激最佳目标脑区可能有效改善与心血管ANS功能相关的HRV模式。
    BACKGROUND: Heart rate variability (HRV) is a useful tool for evaluating cardiovascular autonomic nervous system (ANS) functions. This systematic review and meta-analysis examined the potential effects of transcranial direct current stimulation (tDCS) protocols on HRV parameters.
    METHODS: This study acquired 97 comparisons from 24 qualified studies for data synthesis. Using standardized mean difference (SMD), individual and overall effect sizes were estimated to show differences in HRV variables between active tDCS and sham stimulation conditions. More positive effect size values indicated that active tDCS caused greater increases in HRV than sham stimulation. Furthermore, moderator variable analyses were performed to determine whether changes in HRV variables differed depending on (a) task types (physical stress versus psychological stress versus resting condition), (b) targeted brain regions, (c) stimulation polarity, (d) characteristics of participants, and (e) specific HRV variables. Finally, we used meta-regression analyses to determine whether different tDCS parameters (i.e., the number of tDCS sessions, stimulation duration, and density) were associated with changes in HRV patterns.
    RESULTS: The random-effects model meta-analysis showed that tDCS protocols significantly improved HRV variables (SMD = 0.400; P < 0.001). Moreover, for increasing HRV during the physical stress task (SMD = 1.352; P = 0.001), anodal stimulation on the M1 was effective, while combined polarity stimulation on the PFC improved HRV during the psychological stress task (SMD = 0.550; P < 0.001) and resting condition (SMD = 0.192; P = 0.012). Additional moderator variables and meta-regression analyses failed to show that tDCS protocols had positive effects in certain conditions, such as different stimulus polarity, characteristics of participants, specific HRV variables, and tDCS parameters.
    CONCLUSIONS: These findings tentatively suggest that using tDCS protocols to stimulate optimal targeted brain areas may be effective in improving HRV patterns potentially related to cardiovascular ANS functions.
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  • 文章类型: Journal Article
    背景:重复经颅磁刺激(rTMS)可引起皮质兴奋性改变并促进神经可塑性。为了精确量化这些影响,功能近红外光谱(fNIRS),一种光学神经成像模式,擅长检测皮质血液动力学反应的变化,已与rTMS同时使用,以测量和调整各种rTMS协议对大脑皮层的影响。
    目的:本系统综述和荟萃分析旨在阐明rTMS对fNIRS检测到的初级运动皮质(M1)皮质血流动力学反应的影响。
    方法:在PubMed中系统地搜索了利用rTMS刺激M1皮质并结合fNIRS来评估皮质活动的原始文章,Embase,和Scopus数据库。搜索包括从这些数据库开始到4月的记录,2024.还进行了偏见风险评估。在具有可提取原始数据的研究中也进行了荟萃分析。
    结果:在312项研究中,14篇文章有资格进行定性审查。7项研究符合荟萃分析的条件。在M1皮质上采用了多种rTMS方案。在抑制性rTMS中,多项研究观察到同侧M1的氧合血红蛋白[HbO]浓度降低,与对侧M1的升高形成对比.荟萃分析也证实了这种一致的趋势。然而,某些调查显示,双边M1中的[HbO]减少。一些研究还描绘了不同皮质区域之间复杂的抑制性或兴奋性相互作用。
    结论:不同的rTMS方案导致fNIRS检测到的皮质活动模式不同。Meta分析显示,低频抑制性rTMS后,对侧皮质[HbO]升高,同侧皮质[HbO]降低。然而,由于研究之间的异质性,需要进一步的研究来全面了解rTMS诱导的大脑活动改变。
    BACKGROUND: Repeated transcranial magnetic stimulation (rTMS) could induce alterations in cortical excitability and promote neuroplasticity. To precisely quantify these effects, functional near-infrared spectroscopy (fNIRS), an optical neuroimaging modality adept at detecting changes in cortical hemodynamic responses, has been employed concurrently alongside rTMS to measure and tailor the impact of diverse rTMS protocols on the brain cortex.
    OBJECTIVE: This systematic review and meta-analysis aimed to elucidate the effects of rTMS on cortical hemodynamic responses over the primary motor cortex (M1) as detected by fNIRS.
    METHODS: Original articles that utilized rTMS to stimulate the M1 cortex in combination with fNIRS for the assessment of cortical activity were systematically searched across the PubMed, Embase, and Scopus databases. The search encompassed records from the inception of these databases up until April, 2024. The assessment for risk of bias was also conducted. A meta-analysis was also conducted in studies with extractable raw data.
    RESULTS: Among 312 studies, 14 articles were eligible for qualitative review. 7 studies were eligible for meta-analysis. A variety of rTMS protocols was employed on M1 cortex. In inhibitory rTMS, multiple studies observed a reduction in the concentration of oxygenated hemoglobin [HbO] at the ipsilateral M1, contrasted by an elevation at the contralateral M1. Meta-analysis also corroborated this consistent trend. Nevertheless, certain investigations unveiled diminished [HbO] in bilateral M1. Several studies also depicted intricate inhibitory or excitatory interplay among distinct cortical regions.
    CONCLUSIONS: Diverse rTMS protocols led to varied patterns of cortical activity detected by fNIRS. Meta-analysis revealed a trend of increasing [HbO] in the contralateral cortices and decreasing [HbO] in the ipsilateral cortices following low frequency inhibitory rTMS. However, due to the heterogeneity between studies, further research is necessary to comprehensively understand rTMS-induced alterations in brain activity.
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  • 文章类型: Journal Article
    背景:经颅磁刺激(TMS),当应用于初级运动皮层时,在从外周肌肉测量的肌电图中引发运动诱发电位(MEP)。经常观察到MEP振幅在试验之间波动,即使有持续的刺激。许多因素导致TMS中的MEP波动。其中一个主要因素是大脑皮层活动的平稳性和不稳定性弱,我们假设MEP波动源于此。我们假设,当在头皮上测得的几个脑电图(EEG)通道在频域中高度相似时,将TMS传递到初级运动皮层时,MEP波动受到抑制。
    目的:我们开发了一种TMS触发系统,使用EEG相干分析来抑制MEP波动,在频域中检测2个通道之间的脑电信号相似性。
    方法:七个健康的成年人参加了实验,以确认TMS触发系统是否能够正常工作,记录MEP变化的平均幅度和系数,并与控制任务期间获得的值进行比较。我们还确定了每种条件下的实验时间,并验证了它是否在预测时间内。
    结果:7名参与者中有5名MEP振幅的变异系数下降,根据F检验,在2名参与者中确认了显着差异(P=.02)。阈值修改后每个刺激所需的实验时间的变异系数小于不进行阈值修改时的变异系数。并且通过进行F检验证实了显着差异(P<.001)。
    结论:我们发现使用本研究中开发的系统可以抑制MEP,并且TMS触发系统还可以通过自动改变触发阈值来稳定实验时间。
    BACKGROUND: Transcranial magnetic stimulation (TMS), when applied over the primary motor cortex, elicits a motor-evoked potential (MEP) in electromyograms measured from peripheral muscles. MEP amplitude has often been observed to fluctuate trial to trial, even with a constant stimulus. Many factors cause MEP fluctuations in TMS. One of the primary factors is the weak stationarity and instability of cortical activity in the brain, from which we assumed MEP fluctuations originate. We hypothesized that MEP fluctuations are suppressed when TMS is delivered to the primary motor cortex at a time when several electroencephalogram (EEG) channels measured on the scalp are highly similar in the frequency domain.
    OBJECTIVE: We developed a TMS triggering system to suppress MEP fluctuations using EEG coherence analysis, which was performed to detect the EEG signal similarity between the 2 channels in the frequency domain.
    METHODS: Seven healthy adults participated in the experiment to confirm whether the TMS trigger system works adequately, and the mean amplitude and coefficient of the MEP variation were recorded and compared with the values obtained during the control task. We also determined the experimental time under each condition and verified whether it was within the predicted time.
    RESULTS: The coefficient of variation of MEP amplitude decreased in 5 of the 7 participants, and significant differences (P=.02) were confirmed in 2 of the participants according to an F test. The coefficient of variation of the experimental time required for each stimulus after threshold modification was less than that without threshold modification, and a significant difference (P<.001) was confirmed by performing an F test.
    CONCLUSIONS: We found that MEP could be suppressed using the system developed in this study and that the TMS trigger system could also stabilize the experimental time by changing the triggering threshold automatically.
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  • 文章类型: Journal Article
    中风是成人残疾的主要原因,导致运动障碍和独立性下降。恢复独立依赖于运动恢复,特别是恢复手和手臂的功能。这篇综述提供了来自人类研究的证据,这些研究使用经颅磁刺激(TMS)来确定中风后早期上肢运动恢复的神经生理机制。在中风后亚急性阶段进行的TMS研究已经确定了几种可导致运动障碍的神经生理因素。包括膜兴奋性,皮质醇神经元的募集,以及谷氨酸能和GABA能神经传递。然而,运动诱发电位(MEP)测量的固有变异性和随后的低可靠性限制了TMS在个体患者水平的预后中的应用.目前,为卒中后早期患者提供最准确的上肢运动结果信息的预测工具将临床测量与基于MEP存在或不存在的简单神经生理学生物标志物相结合,即MEP状态。这里,我们提出了一个新的组成框架,以检查阈值矩阵内多条上肢肌肉的MEP。通过成分分析量化亚阈值和超阈值MEP的演变,该矩阵可以提供中风后皮质运动功能和恢复的更全面视图。我们的论点是,亚阈值反应可能对皮质运动性神经元的输出减少最敏感,剩余神经元的非同步放电,和中风后早期发生的髓鞘形成过程。定量亚阈值反应可能为中风后神经生理学提供新的见解,并提高上肢运动结果预测的准确性。
    Stroke is a leading cause of adult disability that results in motor deficits and reduced independence. Regaining independence relies on motor recovery, particularly regaining function of the hand and arm. This review presents evidence from human studies that have used transcranial magnetic stimulation (TMS) to identify neurophysiological mechanisms underlying upper limb motor recovery early after stroke. TMS studies undertaken at the subacute stage after stroke have identified several neurophysiological factors that can drive motor impairment, including membrane excitability, the recruitment of corticomotor neurons, and glutamatergic and GABAergic neurotransmission. However, the inherent variability and subsequent poor reliability of measures derived from motor evoked potentials (MEPs) limit the use of TMS for prognosis at the individual patient level. Currently, prediction tools that provide the most accurate information about upper limb motor outcomes for individual patients early after stroke combine clinical measures with a simple neurophysiological biomarker based on MEP presence or absence, i.e. MEP status. Here, we propose a new compositional framework to examine MEPs across several upper limb muscles within a threshold matrix. The matrix can provide a more comprehensive view of corticomotor function and recovery after stroke by quantifying the evolution of subthreshold and suprathreshold MEPs through compositional analyses. Our contention is that subthreshold responses might be the most sensitive to reduced output of corticomotor neurons, desynchronized firing of the remaining neurons, and myelination processes that occur early after stroke. Quantifying subthreshold responses might provide new insights into post-stroke neurophysiology and improve the accuracy of prediction of upper limb motor outcomes.
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  • 文章类型: Journal Article
    一种称为试验水平偏差评分(TL-BS)的相对较新的计算方法表明,吸烟者对吸烟相关刺激的注意力偏差在时间上波动,通过审判进行审判,注意任务。这里,我们调查了使用TL-BS值评估注意偏差的可靠性,以及吸烟者注意偏差波动的电生理学机制.
    总共,26名男性吸烟者和26名男性非吸烟者在实验1中执行了点探针任务。在实验2中,另外23名男性吸烟者和23名男性非吸烟者在进行单脉冲经颅磁刺激时执行了相同的任务,用于研究皮质脊髓兴奋性。
    它表明评估反应时间(RT)的TL-BS参数比计算传统的平均注意偏差分数更可靠;但是,在控制了一般RT变异性后,这种优越的可靠性不再明显.在RT和运动诱发电位(MEP)振幅计算的TL-BS参数中,吸烟者和非吸烟者之间存在显着差异。然而,RT和MEP振幅的TL-BS参数与一般RT变异性和一般MEP变异性密切相关,分别。
    我们的发现表明,TL-BS参数可能不是测量行为或电生理水平的注意偏差的理想选择;然而,非吸烟者的一般RT和MEP振幅变化较大可能表明吸烟者的认知过程失调。
    UNASSIGNED: A relatively new computational approach called trial-level bias score (TL-BS) has shown that attentional bias to smoking-related stimuli in smokers fluctuates temporally, trial by trial, during attention tasks. Here, we investigated the reliability of using TL-BS values to assess attentional bias and the electrophysiology mechanisms undergirding fluctuations in attentional bias among smokers.
    UNASSIGNED: In total, 26 male smokers and 26 male non-smokers performed a dot-probe task in Experiment 1. In Experiment 2, an additional 23 male smokers and 23 male non-smokers performed the same task while undergoing single-pulse transcranial magnetic stimulation, which was used to investigate corticospinal excitability.
    UNASSIGNED: It showed that assessing TL-BS parameters for reaction time (RT) was more reliable than calculating the traditional mean attentional bias score; however, this superior reliability was no longer apparent after controlling for general RT variability. There was a significant difference between smokers and non-smokers in TL-BS parameters calculated for both RT and motor-evoked potential (MEP) amplitude. However, TL-BS parameters for RT and MEP amplitude were strongly correlated with general RT variability and general MEP variability, respectively.
    UNASSIGNED: Our findings indicated that TL-BS parameters may not be ideal for measuring attentional bias at either the behavioral or electrophysiology level; however, larger general RT and MEP amplitude variabilities in non-smokers may indicate dysregulation of cognitive processing in smokers.
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