这项研究得到瑞士国家科学基金会（316030_128826）的资助。

该协议经当地道德委员会批准，实验符合赫尔辛基宣言（1964年）。 主题准备 注意:主题说明 - 在开始实验之前，指导每个受试者了解研究的目的和潜在的危险因素。对于经颅磁刺激（TMS），医疗风险包括任何癫痫发作史 ，眼睛和/或头部精神植入物，心血管系统疾病和怀孕。排除所有确认其中一个风险因素的科目。此外，在测试健康个体的实验中，排除所有患有神经和/或骨科疾病的受试者。 <ol><li> 主题放置 <ol><li>将主体放在支撑腿，躯干和头部的椅子上。确保双腿伸展，使膝盖分开并且周围神经更接近皮肤，使得神经更容易并且更可靠地通过电刺激兴奋。 </li><li>确保受试者的头部弯曲，搁置在稳定的支撑表面（如桌子）上，并用垫子固定。确保颈部和寰枢椎弯曲，以刺激皮质脊髓通路。 </li><li>定位双锥形磁性线圈，使其中心部分放置在接近或接近的位置，感应电流的一阶导数被引导为19,26。在头部和躯干上使用弹性带，以确保在整个实验过程中保持这一位置。 </li></ol></li><li>使用表面电极测量外周神经刺激（PNS）和TMS的电生理反应。 <ol><li>通过剃须，用丙醇消毒和轻微磨损来准备皮肤在比目鱼肌肉的腹部ñ。 <ol><li>将自粘EMG电极放在肌肉腹部的肌肤上。比目鱼。将参考电极放在骨骼上的皮肤上， 例如在髌骨或内踝上。 </li><li>将所有电极连接到EMG放大器，最后连接模拟数字转换器。放大EMG信号（×1000），带通滤波器（10 - 1000 Hz）和4 kHz采样。 </li></ol></li><li> PNS <ol><li>对于H反射调理，通过刺激po窝中的胫后神经来记录比目鱼肌中的H反射。用持续1 ms的方波脉冲进行刺激。对于刺激，用胶带将5×5cm的阳极固定在膝盖正前方的髌骨下方。 注意:稳定的H反射幅度是成功的H反射调理的先决条件，并且从比目鱼肌记录时可以发现所有肌肉的最小变异性。 </li><li>移动阴极在popliteal窝，直到找到刺激的最佳位置。 注意:最佳位置是指在比目鱼肌中以最小的刺激强度记录H反射，在这些低刺激强度下在EMG记录中没有可见的M波，而在拮抗剂m中没有接收任何反应。胫骨。 </li><li>避免在m中的回应。胫骨肌，因为那些可能通过n的Ia传入的相互抑制影响结果。腓肠肌与比目鱼肌的脊柱运动神经元。找到最佳位置后，将自粘电极放在皮肤上，用胶带固定电极，以确保刺激条件一致。 </li></ol></li><li> TMS <ol><li>用图8线圈刺激对侧半球的运动皮质区域，以在比目鱼肌肌电图记录中引发运动诱发电位（MEPs）。 </li><li>为了找到最佳的刺激点，pla首先在顶点和1厘米正面线圈。线圈的手柄应向后指向，引起线圈中心的感应电流的后向通量。 </li><li>以最低刺激物输出的约20-30％的低强度开始刺激，使受试者习惯于磁刺激。选择连续刺激之间的暂停为4秒。 </li><li>经过几次试验，将刺激强度提高到最大刺激物输出的40-60％左右，并将线圈移动到前额叶和中外侧方向，以找到m的热点。比目鱼。热点被定义为m中的MEP的位置。可以以最小的刺激强度诱发比目鱼肌。 </li><li>在找到比目鱼的热点后，确定静息电动机阈值（1.0 MT）作为在十个连续试验中的六次中使EMG大于50μV的MEP峰 - 峰值振幅所需的最小强度30。在背景EMG已经在50μV附近的受试者中，使用100μV作为阈值。 </li></ol></li><li> 固定线圈 <ol><li>将受试者的头部放在桌子上（请参阅"主题放置"），并使用硬质泡沫来防止头部朝四面八方移动。将线圈固定在支架上，将受试者的头部固定在椅子上。 </li><li>使用魔术贴将线圈固定到头部，并使用图像引导的TMS导航系统来监控整个实验中的线圈和头部位置。避免线圈相对于受试者头部的小的运动，因为这改变了神经元由TMS的募集。 </li></ol></li><li> 颈动脉结的磁刺激 <ol><li>使用放置在颈髓髓结的双锥形磁性线圈激发皮质脊髓束的轴突。 </li><li>定位线圈，使感应电流的一阶导数i并且其中心部分位于或靠近入口处。以最大刺激物输出（100％）施加刺激。 注意:即使具有这种高刺激强度，刺激太弱，无法充分招募脊髓运动神经元，并激活大多数受试者的小腿肌肉（ 即比目鱼肌和胫前肌）。因此，在颈髓刺激下，小腿肌肉表面EMG无复合潜力。因此，将颈髓模拟与H反射相结合（参见"3.1"）来提高脊髓运动神经元的兴奋性。 </li></ol></li></ol></li></ol> 2.预测<ol><li>调整H反射的大小（周围神经刺激） <ol><li>对于H反射调理，通过改变电刺激器的刺激强度，将H反射的尺寸调整到最大M波（Mmax） 31的20％。要获得Mmax，请记录H反射招聘曲线。为此，应用不同刺激强度的刺激。连续试验之间的暂停是4秒。 </li><li>将H反射和M波作为记录软件在线的EMG（mV）峰 - 峰幅度计算。注意控制H反射的大小在整个实验期间保持恒定在Mmax的20％，并检查其在每次试验中的大小。当检测H反射大小的系统偏差（控制H反射总是小于或者更大的目标大小）时，在连续试验之前调整刺激强度。 </li></ol></li><li>在实验前调整TMS的刺激强度。 <ol><li>对于休息时的H反射调理，将运动皮质上的TMS的刺激强度设置为MT的90-100％。确保在没有PNS的试验中没有观察到MEP。 注意:模拟强度应接近MT的100％，以确保对r条件下的H反射具有很大的影响以便容易地检测到早期便利化。 </li><li>在实验前调整颈髓刺激强度。与皮层刺激不同，始终将刺激强度调整为颈部刺激的最大刺激输出的100％。 </li></ol></li><li>通过运动皮层的磁刺激来调节H反射。 <ol><li>通过改变两个刺激之间的时间（H反射调节）来应用TMS和PNS，以允许评估皮质类神经元传播的变化。为了检测早期便利化，以-5毫秒的间激间隔（ISI）启动调理协议，并以-5毫秒为单位改变ISI，从-5 - +1 ms（ 图1B ）。 注意:负ISI表示在TMS之前引发PNS，正ISI表示相反。 </li><li> TMS和PNS之间的ISI随机从刺激试验到刺激试验，使得由于一定的顺序没有偏差的刺激可能会出现。 注意:在运动皮层上应用TMS时，"早期促进"应发生在ISI周围-4毫秒至-2毫秒。这意味着最快的（单突触皮质脊髓通路）在此时由PNS在脊髓运动神经元的传入排阻中碰撞（见5.2检测早期促进）。 </li><li>将连续刺激试验之间的暂停设置为4秒。 </li></ol></li><li>通过磁刺激来调节颈部髓核结合处的H反射。 注意:使用颈髓刺激进行调理，皮质脊髓通路的激发在空间上更接近脊柱运动神经元，而不是刺激运动皮质。因此，对应于早期促进的ISI移位约3-4毫秒。作为一个例子，在-4毫秒的初级运动皮层上TMS的早期促进将对应于-7 - -8毫秒与宫颈髓核刺激之间的ISI。 <ol><li&gt;使用ISI -9 - -3 ms之间的ISI，以1 ms为间隔进行宫颈髓核调理。在一次试验中总是一起应用在运动皮层和TMS上的TMS施加ISI，并在本试验中记录控制H反射和对照MEP。使用控制H反射作为条件H反射和对照MEP的参考，以确保类似的刺激条件。在测量前记录（至少）十个试验。 </li></ol></li><li> 在运动皮质和颈椎结节交替刺激 <ol><li>在同一试验期间，通过磁刺激运动皮层（M1调理;参见2.1）和磁性颈髓刺激（CMS-调节;参见2.2）来调节SOL H反射。 注意:建议在同一个试验中交替应用M1-和CMS调理，以将调节的H反射参考到相同的对照H反射样品（see 图1 ）。 </li></ol></li></ol> 3.干预 - 慢速重复TMS <ol><li>将刺激强度设置为1.2 MT，其诱导长期持续的32,33抑制皮质脊髓兴奋性，因为H反射调节需要数分钟的时间才能完成。在rTMS干预过程中，应用TMS在主动脉皮质上以1Hz进行20分钟。 </li></ol> 4.测量<ol><li>干预后直接使用与测量中使用的ISI相同的H反射调理。 </li><li>使用相同的刺激强度用于M1和颈髓髓结的磁刺激比预测量。 </li><li>确保控制H反射具有与预测量相同的尺寸。如果检测到系统偏差，则调整刺激强度。 </li></ol>大卫ta处理<ol><li>计算所有生理反应，如H反射，MEPs和调节H反射作为未修正EMG的峰 - 峰幅度。 <ol><li>对于每个ISI，平均十个条件H反射a）皮质和b）子宫颈髓母细胞刺激。此外，平均十个控制（ 即无条件）H反射作为调节H反射的参考（ 即 100％）。 </li><li>因此，在测量之前和之后，将每个ISI的调节H反射的平均振幅表示为对照H反射的平均幅度的百分比。确定早期便利化时要小心，因为这是至关重要的: 注意:由于早期促进发生的发生之间存在个体间变异性，因此分别确定每个受试者的预测量的早期促进。 </li></ol></li><li>使用非参数Wilcoxon测试来确定e第一次上升的条件H反射。对于CMS调节，开始ISI -9 ms的测试，M1调节搜索从ISI -5 ms开始的早期促进。将预测中获得的早期促进的幅度与使用相同ISI的后测量中获得的早期促进的振幅进行比较。 </li><li>另外，通过目视检查来验证早期便利化。 注意:M1调理后，早期促进最有可能发生在ISI -3毫秒左右。在调节H反射的第一次上升之后不久， 即 1至2ms后，在再次升高之前，调节的H反射有下降。 CMS调理后，早期易于发生可能发生在ISI -7毫秒左右，因此比M1调理后早4毫秒。 </li></ol>

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Physiol. 484, 791-802 (1995).</li><li>Leukel, C., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Changes+in+corticospinal+transmission+following+8weeks+of+ankle+joint+immobilization.">Changes in corticospinal transmission following 8weeks of ankle joint immobilization.</a> Clin neurophysiol. , (2014).</li><li>Schubert, M., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Balance+training+and+ballistic+strength+training+are+associated+with+task-specific+corticospinal+adaptations.">Balance training and ballistic strength training are associated with task-specific corticospinal adaptations.</a> Eur J Neurosci. 27, 2007-2018 (2008).</li><li>Taube, W., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Cortical+and+spinal+adaptations+induced+by+balance+training:+correlation+between+stance+stability+and+corticospinal+activation.">Cortical and spinal adaptations induced by balance training: correlation between stance stability and corticospinal activation.</a> Acta Physiol (Oxf). 189, 347-358 (2007).</li><li>Di Lazzaro, V., et al. <a target="_blank" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed&cmd=Search&doptcmdl=Citation&defaultField=Title+Word&term=Effects+of+voluntary+contraction+on+descending+volleys+evoked+by+transcranial+stimulation+in+conscious+humans.">Effects of voluntary contraction on descending volleys evoked by transcranial stimulation in conscious humans.</a> J. 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作者没有什么可以披露的。

这里描述的H反射调节程序已经专门用于评估在重复激活皮质脊髓通路28之后的皮质类神经元突触的传播的急性变化。在这方面，H反射调理已经突出表明，rTMS不仅影响皮质结构的兴奋性，而且还对皮质类膜转移突触的皮质转移传导有影响。然而，随着运动发育和衰老，运动学习，运动和训练，疲劳，不活动，从损伤恢复，神经生理学和治疗干预，病理学等方面发生皮质螺旋传播?...

在灵长类动物中，皮质脊髓束构成控制自愿行为的主要下降途径1 。皮质螺旋途径通过直接的单突触性皮质神经元连接和间接的寡聚和多突触连接2,3将运动皮质区域连接到脊髓α运动神经元。虽然运动皮质可以通过经颅磁刺激（TMS）非常侵入地很容易地被激发，但对这种刺激的诱发肌电图反应通常难以解释。其原因是复合运动诱发电位（MEP）可能受皮质和皮质脊髓神经元，脊髓中间神经元和脊髓α运动神经元4,5,6,7的兴奋性变化的影响。几种无创电生理学cal技术和刺激方案旨在确定皮质脊髓兴奋性和传播的变化是否由皮质或脊髓水平的变化引起。通常，电诱发H反射的振幅的变化被用作运动神经元池的兴奋性改变的"指示性"。然而，之前已经表明，H反射不仅依赖于运动神经元池的兴奋性，而且还受其他因素调节，例如突触前抑制8,9或同源突触后活化抑郁症5,10 。比较MEPs和H反射的另一个限制是检测11级12级神经元兴奋性变化的障碍。除了这些缺点，运动神经元可能不同于周围神经刺激而不是wi激活TMS使得运动神经元兴奋性的变化将以与通过皮质脊髓通路13,14,15介导的反应相比以不同的方式影响这些应答。 用于将脊柱与皮质作用分离的另一种方法代表运动皮质16的经颅电刺激（TES）。在低刺激强度下应用，TES被认为不受皮质兴奋性变化的影响。由于TES和TMS都通过皮质螺旋途径激活α运动神经元，所以磁诱发MEPs的比较提供了一种更有吸引力的方法来得出关于MEPs大小变化的皮层性质的结论，而不是H反射之间的比较和MEPs。然而，当刺激强度增加时，TES诱发的MEP也受皮层兴奋性变化的影响sup class ="xref"&gt; 17，18。当电刺激不施加到运动皮质但在颈髓髓结的时候，可以避免这个问题。然而，虽然电刺激可以引起上肢和下肢肌肉的颈动脉运动诱发电位（cMEP），但大多数受试者感觉到脑干（和皮层）的电刺激极其不愉快和痛苦。一个不那么痛苦的替代方案是通过使用磁刺激在宫颈髓核结合处激活皮质脊髓通路19 。通常接受的是，颈动脉磁刺激（CMS）激活许多与运动皮层TMS相同的下降纤维，并且通过将MEP与cMEP 19进行比较可以检测到皮质兴奋性的变化。皮层细胞和皮质神经元细胞的兴奋性增加被认为促进皮层诱发的MEP没有并发改变的宫颈诱发MEP。 然而，在大多数受试者中，不可能在休息20,21的下肢获得磁性诱发的cMEP。克服这个问题的一个方法是通过自愿预先收缩目标肌肉来提高脊柱运动神经元的兴奋性。然而，众所周知，收缩强度的轻微变化影响cMEP的尺寸。因此，难以比较不同的任务。此外，由于预收缩引起的运动神经元兴奋性的变化将影响MEPs和cMEP，但不一定在相同程度上。最后，通过比较化合物MEP和化合物cMEP，一些信息包含在下降的波浪中。通过研究包括通过磁力马达皮层刺激调节比目鱼肌，胫前肌和桡侧肌的H反射的研究揭示了这一点12日 ， 22日 。通过结合外周神经刺激和TMS在运动皮质上具有特异的刺激间期（ISI），可以研究不同下降球对H反射的促进和抑制作用。这种技术受到动物实验中用于确定神经通路传播的空间促进技术的极大启发，可被视为该技术的非侵入性间接版本23 。虽然H反射不仅对于区分皮质脊髓通路的不同部分（快速与较慢的皮质脊髓投射）是重要的，但是也必须以受控和可比较的方式提高脊柱兴奋性。因此，在休息和活动期间，这种刺激技术的组合允许以高时间分辨率评估皮质螺旋途径的不同部分的变化， 即在t他最快，可能是单突触性皮质神经元连接和慢性低聚和多突触通路12,22,24,25。最近，这种技术不仅通过运动皮质（M1调节）调节TMS的H反射，而且通过在宫颈髓核结合处（CMS-调节） 26进行额外的调理刺激来延长。通过比较M1-和CMS调节之间的效应，该技术允许具有高时间分辨率的途径特异性分化，并且允许对皮质与脊髓机制进行解释。此外，最重要的是，关于目前的研究，这种技术允许在考虑早期促进时评估皮质转移突触的传播。 H反射的早期促进很可能是由激活引起的对脊柱运动神经元12,26的直接，单突触性皮质转移瘤投射。为了测试最快的皮质脊髓途径，因此，早期促进，H反射必须在TMS之前2至4 ms引出。其原因是与H反射（约34ms;见25 ）相比，MEP的等待时间略短（约32ms;见27 ）。在应用TMS之前不久就引发H反射，导致脊柱运动神经元水平上升和最快下降兴奋的趋同。当TMS施加在颈髓髓结上时，下降排卵将在脊髓运动神经元游泳池的3〜4毫秒之前比在M1刺激之后达到。对于CMS调理，因此周围神经刺激应在磁脉冲前6 - 8 ms引起。 CMS调节后的早期促进变化表明差异tr在皮质脊髓束和α-运动神经元之间的突触28 。在目前的研究中，最近开发的技术用于区分脊髓与低频重复TMS（rTMS）后的皮层效应。更具体地说，我们假设，如果在rTMS干预之后，如果M1调节的早期促进减少，但CMS调节之后的早期促进不是，其效果应该是纯皮层的起源。相比之下，如果早期促进CMS调理也发生变化，这种改变应该与脊髓水平发生的机制有关。更具体地说，由于H反射的早期促进被认为是由对直接的脊髓运动神经元12,29的直接的皮质类神经元突起的激活引起的，所以在时间上改变了CMS-和M1-调节的H反射早期促进应该指示改变的皮质类神经元传播即突触功效28 。

<table border="1" fo:keep-together.within-page="1" fo:keep-with-next.within-page="always">
	<tbody>
		<tr>
			<td>Self-adhesive EMG electrodes</td>
			<td>Blue sensor N, Ambu, Ballerup, Denmark</td>
			<td></td>
			<td>Used to record EMG signals</td>
		</tr>
		<tr>
			<td>Electrical stimulator</td>
			<td>Digitimer DS7A, Hertfordshire, UK</td>
			<td></td>
			<td>Used to elicit the soleus H-reflex</td>
		</tr>
		<tr>
			<td>Stimulating electrode</td>
			<td>Blue sensor N, Ambu, Ballerup, Denmark</td>
			<td></td>
			<td>Used to elicit the soleus H-reflex</td>
		</tr>
		<tr>
			<td>Magnetic stimulator no1</td>
			<td>Magstim Rapid2 TMS stimulator, Magstim Company Ltd., Whitland, UK</td>
			<td></td>
			<td>Used to elicit contralateral motor evoked potentials in the soleus muscle</td>
		</tr>
		<tr>
			<td>Coil no1: 90 mm figure-of-eight coil&#160;</td>
			<td>Magstim Company Ltd., Whitland, UK</td>
			<td></td>
			<td>Used to elicit contralateral motor evoked potentials in the soleus muscle</td>
		</tr>
		<tr>
			<td>&#160; &#160;</td>
			<td>&#160; &#160;</td>
			<td>&#160; &#160;</td>
			<td>Stimulator no1 and coil no1 were used in the original publication (Taube et al. 2014; Cerebral Cortex)</td>
		</tr>
		<tr>
			<td>Magnetic stimulator no2</td>
			<td>MagPro X100 with MagOption, MagVenture A/S, Farum, Denmark</td>
			<td></td>
			<td>Used to elicit contralateral motor evoked potentials in the soleus muscle</td>
		</tr>
		<tr>
			<td>Coil no2: 95-mm focal &#8220;butterfly-shaped&#8221; coil (D-B80)&#160;</td>
			<td>MagVenture A/S, Farum, Denmark</td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td></td>
			<td></td>
			<td></td>
			<td>Stimulator no2 and coil no2 were used in the video session</td>
		</tr>
		<tr>
			<td>Magnetic stimulator no3</td>
			<td>Magstim Company Ltd., Whitland, UK</td>
			<td></td>
			<td>Used to stimulate at the cervicomedullary junction</td>
		</tr>
		<tr>
			<td>Coil no3: double-cone magnetic coil</td>
			<td>Magstim Company Ltd., Whitland, UK</td>
			<td></td>
			<td>Used to stimulate at the cervicomedullary junction</td>
		</tr>
		<tr>
			<td>Image-guided TMS navigational system no1</td>
			<td>Brainsight 2, Rouge Research, Montreal, Canada</td>
			<td></td>
			<td>Used in the original publication (Taube et al. 2014; Cerebral Cortex) to monitor coil position throughout the experiment</td>
		</tr>
		<tr>
			<td>Image-guided TMS navigational system no2</td>
			<td colspan="2">TMS Navigator SW-Version 2.0, LOCALITE GmbH, Sankt Augustin, Germany</td>
			<td>Used for the video session</td>
		</tr>
		<tr>
			<td>Literature:&#160;</td>
			<td><a name="RANGE!B15"></a></td>
			<td></td>
			<td></td>
		</tr>
		<tr>
			<td>Taube et al. 2014</td>
			<td colspan="3">Taube, W., Leukel, C., Nielsen, J. B. &#38; Lundbye-Jensen, J. Repetitive Activation of the Corticospinal Pathway by Means of rTMS may Reduce the Efficiency of Corticomotoneuronal Synapses. Cerebral cortex, doi:10.1093/cercor/bht359 (2014).</td>
		</tr>
	</tbody>
</table>

non-invasive assessment of changes in corticomotoneuronal transmission in humans

皮质脊髓通路是连接大脑与肌肉的主要途径，因此对运动控制和运动学习非常重要。存在一些研究该途径的兴奋性和可塑性的无创电生理方法。然而，大多数方法是基于化合物电位的定量，并忽略皮质螺旋途径由许多或多或少直接的不同连接组成。在这里，我们提出一种允许测试皮质脊髓传播的不同部分的兴奋性的方法。这种所谓的H反射调节技术允许评估最快（单突触）和多突触皮质螺旋途径的兴奋性。此外，通过使用两个不同的刺激部位，运动皮层和颈椎管连接处，它不仅允许皮层和脊柱效应之间的分化，还允许评估皮质的传播耳聋突触在这份手稿中，我们描述了这种方法如何用于评估低频重复经颅磁刺激后的皮质类固醇传播，这是先前显示的减少皮层细胞兴奋性的方法。在这里我们证明，不仅皮质细胞受到这种重复刺激的影响，而且在脊髓水平的皮质类神经元突触期间的传播。这一发现对于了解神经可塑性的基本机制和部位很重要。除了基本机制的调查之外，H反射调理技术可以用于测试行为（ 例如 ，训练）或治疗干预，病理学或老化后皮质脊髓传播的变化，因此可以更好地理解运动控制和运动的基础的神经过程学习。

<html> 在M1-和CMS调理之后发生早期促进 在TMS上的H反射调理导致早期促进发生在ISI -3和-4毫秒周围。 CMS调理后的早期促进发生在3毫秒前（分别为ISI -6和-7毫秒）。 图1中显示了一个对象的示例性ISI曲线。在本研究中，早期的促进是在其发生的第一个毫秒内进行评估，同时使用M1-和CMS-调理（参见<strong c...

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Non-invasive Assessment of Changes in Corticomotoneuronal Transmission in Humans

本研究的目的是评估重复经颅磁刺激后人类皮质类神经元突触的变化。为此目的，引入电生理方法，其允许评估途径特异性皮质脊髓传播， 即快速，直接皮质螺旋途径从多突触连接的分化。

非侵入性评估人类皮质神经元传播的变化

The corticospinal pathway is the major pathway connecting the brain with the muscles and is therefore highly relevant for movement control and motor ...

non-invasive-assessment-changes-corticomotoneuronal-transmission

Research

JoVE Journal

Neuroscience

7.7K 次观看.  University of Fribourg (Switzerland). 本研究的目的是评估重复经颅磁刺激后人类皮质类神经元突触的变化。为此目的，引入电生理方法，其允许评估途径特异性皮质脊髓传播， 即快速，直接皮质螺旋途径从多突触连接的分化。 

视频: Non-invasive Assessment of Changes in Corticomotoneuronal Transmission in Humans

Dual Electrophysiological Recordings of Synaptically-evoked Astroglial and Neuronal Responses in Acute Hippocampal Slices

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs through activation of their ion channels and neurotransmitter receptors, and process information in part through activity-dependent release of gliotransmitters. Furthermore, astrocytes constitute the main uptake system for glutamate, contribute to potassium spatial buffering, as well as to GABA clearance. These cells therefore constantly monitor synaptic activity, and are thereby sensitive indicators for alterations in synaptically-released glutamate, GABA and extracellular potassium levels. Additionally, alterations in astroglial uptake activity or buffering capacity can have severe effects on neuronal functions, and might be overlooked when characterizing physiopathological situations or knockout mice. Dual recording of neuronal and astroglial activities is therefore an important method to study alterations in synaptic strength associated to concomitant changes in astroglial uptake and buffering capacities. Here we describe how to prepare hippocampal slices, how to identify stratum radiatum astrocytes, and how to record simultaneously neuronal and astroglial electrophysiological responses. Furthermore, we describe how to isolate pharmacologically the synaptically-evoked astroglial currents.

The preparation of acute brain slices from isolated hippocampi, as well as the simultaneous electrophysiological recordings of astrocytes and neurons in stratum radiatum during stimulation of schaffer collaterals is described. The pharmacological isolation of astroglial potassium and glutamate transporter currents is demonstrated.

双突触诱发的星形胶质细胞和神经元的反应，在急性海马脑片电生理记录

Astrocytes form together with neurons tripartite synapses, where they integrate and modulate neuronal activity. Indeed, astrocytes sense neuronal inputs ...

科研

神经科学

Assessment of Dopaminergic Homeostasis in Mice by Use of High-performance Liquid Chromatography Analysis and Synaptosomal Dopamine Uptake

Dopamine (DA) is a modulatory neurotransmitter controlling motor activity, reward processes and cognitive function. Impairment of dopaminergic (DAergic) neurotransmission is strongly associated with several central nervous system-associated diseases such as Parkinson&#39;s disease, attention-deficit-hyperactivity disorder and drug addiction1,2,3,4. Delineating disease mechanisms involving DA imbalance is critically dependent on animal models to mimic aspects of the diseases, and thus protocols that assess specific parts of the DA homeostasis are important to provide novel insights and possible therapeutic targets for these diseases.
Here, we present two useful experimental protocols that when combined provide a functional read-out of the DAergic system in mice. Biochemical and functional parameters on DA homeostasis are obtained through assessment of DA levels and dopamine transporter (DAT) functionality5. When investigating the DA system, the ability to reliably measure endogenous levels of DA from adult brain is essential. Therefore, we present how to perform high-performance liquid chromatography (HPLC) on brain tissue from mice to determine levels of DA. We perform the experiment on tissue from dorsal striatum (dStr) and nucleus accumbens (NAc), but the method is also suitable for other DA-innervated brain areas.
DAT is essential for reuptake of DA into the presynaptic terminal, thereby controlling the temporal and spatial activity of released DA. Knowing the levels and functionality of DAT in the striatum is of major importance when assessing DA homeostasis. Here, we provide a protocol that allows to simultaneously deduce information on surface levels and function using a synaptosomal6 DA uptake assay.
Current methods combined with standard immunoblotting protocols provide the researcher with relevant tools to characterize the DAergic system.

Synaptosomal dopamine uptake and high-performance liquid chromatography analysis represent experimental tools to investigate dopamine homeostasis in mice by assessing the function of the dopamine transporter and levels of dopamine in striatal tissue, respectively. Here we present protocols to measure dopamine tissue content and assess the functionality of the dopamine transporter.

高效液相色谱分析和触多巴胺摄取对小鼠多巴胺能稳态的评价

Dopamine (DA) is a modulatory neurotransmitter controlling motor activity, reward processes and cognitive function. Impairment of dopaminergic (DAergic) ...

Visual Evoked Potential Recordings in Mice Using a Dry Non-invasive Multi-channel Scalp EEG Sensor

For scalp EEG research environments with laboratory mice, we designed a dry-type 16 channel EEG sensor which is non-invasive, deformable, and re-usable because of the plunger-spring-barrel structural facet and mechanical strengths resulting from metal materials. The whole process for acquiring the VEP responses in vivo from a mouse consists of four steps: (1) sensor assembly, (2) animal preparation, (3) VEP measurement, and (4) signal processing. This paper presents representative measurements of VEP responses from multiple mice with a submicro-voltage signal resolution and sub-hundred millisecond temporal resolution. Although the proposed method is safer and more convenient compared to other previously reported animal EEG acquiring methods, there are remaining issues including how to enhance the signal-to-noise ratio and how to apply this technique with freely moving animals. The proposed method utilizes easily available resources and shows a repetitive VEP response with a satisfactory signal quality. Therefore, this method could be utilized for longitudinal experimental studies and reliable translational research exploiting non-invasive paradigms.

We designed a dry-type 16 channel EEG sensor which is non-invasive, deformable, and re-usable. This paper describes the whole process from manufacturing the proposed EEG electrode to signal processing of visual evoked potential (VEP) signals measured on a mouse scalp using a dry non-invasive multi-channel EEG sensor.

干无创多通道头皮脑电传感器在小鼠视觉诱发电位记录中的应用

For scalp EEG research environments with laboratory mice, we designed a dry-type 16 channel EEG sensor which is non-invasive, deformable, and re-usable ...

The Power of Interstimulus Interval for the Assessment of Temporal Processing in Rodents

Temporal processing deficits have been implicated as a potential elemental dimension of higher-level cognitive processes, commonly observed in neurocognitive disorders. Despite the popularization of prepulse inhibition (PPI) in recent years, many current protocols promote using a percent of control measure, thereby precluding the assessment of temporal processing. The present study used cross-modal PPI and gap prepulse inhibition (gap-PPI) to demonstrate the benefits of employing a range of interstimulus intervals (ISIs) to delineate effects of sensory modality, psychostimulant exposure, and age. Assessment of sensory modality, psychostimulant exposure, and age reveals the utility of an approach varying the interstimulus interval (ISI) to establish the shape of the ISI function, including increases (sharper curve inflections) or decreases (flattening of the response amplitude curve) in startle amplitude. Additionally, shifts in peak response inhibition, suggestive of a differential sensitivity to the manipulation of ISI, are often revealed. Thus, the systematic manipulation of ISI affords a critical opportunity to evaluate temporal processing, which may reveal the underlying neural mechanisms involved in neurocognitive disorders.

Temporal processing, a preattentive process, may underlie deficits in higher-level cognitive processes, including attention, commonly observed in neurocognitive disorders. Using prepulse inhibition as an exemplar paradigm, we present a protocol for manipulating interstimulus interval (ISI) to establish the shape of the ISI function to provide an assessment of temporal processing.

间刺激间隔对啮齿类动物时间处理评估的力量

Temporal processing deficits have been implicated as a potential elemental dimension of higher-level cognitive processes, commonly observed in ...

Non-invasive Strategies for Chronic Manipulation of DREADD-controlled Neuronal Activity

Chemogenetic strategies have emerged as reliable tools for remote control of neuronal activity. Among these, designer receptors exclusively activated by designer drugs (DREADDs) have become the most popular chemogenetic approach used in modern neuroscience. Most studies deliver the ligand clozapine-N-oxide (CNO) using a single intraperitoneal injection, which is suitable for the acute activation/inhibition of the targeted neuronal population. There are, however, only a few examples of strategies for chronic modulation of DREADD-controlled neurons, the majority of which rely on the use of delivery systems that require surgical intervention. Here, we expand on two non-invasive strategies for delivering the ligand CNO to chronically manipulate neural population in mice. CNO was administered either by using repetitive (daily) eye-drops, or chronically through the animal&#39;s drinking water. These non-invasive paradigms result in robust activation of the designer receptors that persisted throughout the CNO treatments. The methods described here offer alternatives for the chronic DREADD-mediated control of neuronal activity and may be useful for experiments designed to evaluate behavior in freely moving animals, focusing on less-invasive CNO delivery methods.

Here we describe two non-invasive methods to chronically control neuronal activity using chemogenetics in mice. Eye-drops were used to deliver clozapine-N-oxide (CNO) daily. We also describe two methods for prolonged administration of CNO in drinking water. These strategies for chronic neuronal control require minimal intervention reducing animals&#8217; stress.

DREADD控制神经活动慢性操作的非侵入性策略

Chemogenetic strategies have emerged as reliable tools for remote control of neuronal activity. Among these, designer receptors exclusively activated by ...

Non-Invasive Modulation and Robotic Mapping of Motor Cortex in the Developing Brain

Mapping the motor cortex with transcranial magnetic stimulation (TMS) has potential to interrogate motor cortex physiology and plasticity but carries unique challenges in children. Similarly, transcranial direct current stimulation (tDCS) can improve motor learning in adults but has only recently been applied to children. The use of tDCS and emerging techniques like high&#8211;definition tDCS (HD-tDCS) require special methodological considerations in the developing brain. Robotic TMS motor mapping may confer unique advantages for mapping, particularly in the developing brain. Here, we aim to provide a practical, standardized approach for two integrated methods capable of simultaneously exploring motor cortex modulation and motor maps in children. First, we describe a protocol for robotic TMS motor mapping. Individualized, MRI-navigated 12x12 grids centered on the motor cortex guide a robot to administer single-pulse TMS. Mean motor evoked potential (MEP) amplitudes per grid point are used to generate 3D motor maps of individual hand muscles with outcomes including map area, volume, and center of gravity. Tools to measure safety and tolerability of both methods are also included. Second, we describe the application of both tDCS and HD-tDCS to modulate the motor cortex and motor learning. An experimental training paradigm and sample results are described. These methods will advance the application of non-invasive brain stimulation in children.

We demonstrate protocols for the modulation (tDCS, HD-tDCS) and mapping (robotic TMS) of the motor cortex in children.

发育中大脑运动皮质的非侵入性调制和机器人映射

Mapping the motor cortex with transcranial magnetic stimulation (TMS) has potential to interrogate motor cortex physiology and plasticity but carries ...

Statistical Modelling of Cortical Connectivity Using Non-invasive Electroencephalograms

Non-invasive electrophysiological recordings are useful for the evaluation of nervous system function. These techniques are inexpensive, fast, replicable, and less resource-intensive than imaging. Further, the functional data produced have excellent temporal resolution, which is not achievable with structural imaging.
Current applications of electroencephalograms (EEG) are limited by data processing methods. Standard analysis techniques using raw time series data at individual channels are very limited methods of interrogating nervous system activity. More detailed information about cortical function can be achieved by examining relationships between channels and deriving statistical models of how areas are interacting, allowing visualization of connectivity between networks.
This manuscript describes a method for deriving statistical models of cortical network activity by recording EEG in a standard manner, then examining the interelectrode coherence measures to assess relationships between the recorded areas. Higher order interactions can be further examined by assessing the covariance between the coherence pairs, producing high-dimensional &#34;maps&#34; of network interactions. These data constructs can be examined to assess cortical network function and its relationship to pathology in ways not achievable with traditional techniques.
This approach offers greater sensitivity to network level interactions than is achievable with raw time series analysis. It is, however, limited by the complexity of drawing specific mechanistic conclusions about the underlying neural populations and the high volumes of data generated, requiring more advanced statistical techniques for evaluation, including dimensionality reduction and classifier-based approaches.

Standard EEG analysis techniques offer limited insight into nervous system function. Deriving statistical models of cortical connectivity offers far greater ability to investigate underlying network dynamics. Improved functional assessment opens new possibilities for diagnosis, prognostication, and outcome prediction in nervous system diseases.

使用非侵入性脑电图的皮质连通性统计建模

Non-invasive electrophysiological recordings are useful for the evaluation of nervous system function. These techniques are inexpensive, fast, replicable, ...

Targeted Neuronal Injury for the Non-Invasive Disconnection of Brain Circuitry

Surgical intervention can be quite effective for treating certain types of medically intractable neurological diseases. This approach is particularly useful for disorders in which identifiable neuronal circuitry plays a key role, such as epilepsy and movement disorders. Currently available surgical modalities, while effective, generally involve an invasive surgical procedure, which can result in surgical injury to non-target tissues. Consequently, it would be of value to expand the range of surgical approaches to include a technique that is both non-invasive and neurotoxic.
Here, a method is presented for producing focal, neuronal lesions in the brain in a non-invasive manner. This approach utilizes low-intensity focused ultrasound together with intravenous microbubbles to transiently and focally open the Blood Brain Barrier (BBB). The period of transient BBB opening is then exploited to focally deliver a systemically administered neurotoxin to a targeted brain area. The neurotoxin quinolinic acid (QA) is normally BBB-impermeable, and is well-tolerated when administered intraperitoneally or intravenously. However, when QA gains direct access to brain tissue, it is toxic to the neurons. This method has been used in rats and mice to target specific brain regions. Immediately after MRgFUS, successful opening of the BBB is confirmed using contrast enhanced T1-weighted imaging. After the procedure, T2 imaging shows injury restricted to the targeted area of the brain and the loss of neurons in the targeted area can be confirmed post-mortem utilizing histological techniques. Notably, animals injected with saline rather than QA do demonstrate opening of the BBB, but dot not exhibit injury or neuronal loss. This method, termed Precise Intracerebral Non-invasive Guided surgery (PING) could provide a non-invasive approach for treating neurological disorders associated with disturbances in neural circuitry.

The goal of the protocol is to provide a method for producing non-invasive neuronal lesions in the brain. The method utilizes Magnetic Resonance-guided Focused Ultrasound (MRgFUS) to open the Blood Brain Barrier in a transient and focal manner, in order to deliver a circulating neurotoxin to the brain parenchyma.

脑回路非侵入性断开的靶向神经元损伤

Surgical intervention can be quite effective for treating certain types of medically intractable neurological diseases. This approach is particularly ...

Construction and Implementation of Carbon Fiber Microelectrode Arrays for Chronic and Acute In Vivo Recordings

Multichannel electrode arrays offer insight into the working brain and serve to elucidate neural processes at the single-cell and circuit levels. Development of these tools is crucial for understanding complex behaviors and cognition and for advancing clinical applications. However, it remains a challenge to densely record from cell populations stably and continuously over long time periods. Many popular electrodes, such as tetrodes and silicon arrays, feature large cross-diameters that produce damage upon insertion and elicit chronic reactive tissue responses associated with neuronal death, hindering the recording of stable, continuous neural activity. In addition, most wire bundles exhibit broad spacing between channels, precluding simultaneous recording from a large number of cells clustered in a small area. The carbon fiber microelectrode arrays described in this protocol offer an accessible solution to these concerns. The study provides a detailed method for fabricating carbon fiber microelectrode arrays that can be used for both acute and chronic recordings in vivo. The physical properties of these electrodes make them ideal for stable and continuous long-term recordings at high cell densities, enabling the researcher to make robust, unambiguous recordings from single units across months.

Construction and Implementation of Carbon Fiber Microelectrode Arrays for Chronic and Acute In Vivo Recordings

This protocol describes a procedure for constructing carbon fiber microelectrode arrays for chronic and acute in vivo electrophysiological recordings in mouse (Mus musculus) and ferret (Mustela putorius furo) from multiple brain regions. Each step, following the purchase of raw carbon fibers to microelectrode array implantation, is described in detail, with emphasis on microelectrode array construction.

用于慢性和急性体内记录的碳纤维微电极阵列 的 构建和实现

Multichannel electrode arrays offer insight into the working brain and serve to elucidate neural processes at the single-cell and circuit levels. ...

Modeling Neonatal Intraventricular Hemorrhage Through Intraventricular Injection of Hemoglobin

Neonatal intraventricular hemorrhage (IVH) is a common consequence of premature birth and leads to brain injury, posthemorrhagic hydrocephalus (PHH), and lifelong neurological deficits. While PHH can be treated by temporary and permanent cerebrospinal fluid (CSF) diversion procedures (ventricular reservoir and ventriculoperitoneal shunt, respectively), there are no pharmacological strategies to prevent or treat IVH-induced brain injury and hydrocephalus. Animal models are needed to better understand the pathophysiology of IVH and test pharmacological treatments. While there are existing models of neonatal IVH, those that reliably result in hydrocephalus are often limited by the necessity for large-volume injections, which may complicate modeling of the pathology or introduce variability in the clinical phenotype observed.
Recent clinical studies have implicated hemoglobin and ferritin in causing ventricular enlargement after IVH. Here, we develop a straightforward animal model that mimics the clinical phenotype of PHH utilizing small-volume intraventricular injections of the blood breakdown product hemoglobin. In addition to reliably inducing ventricular enlargement and hydrocephalus, this model results in white matter injury, inflammation, and immune cell infiltration in periventricular and white matter regions. This paper describes this clinically relevant, simple method for modeling IVH-PHH in neonatal rats using intraventricular injection and presents methods for quantifying ventricle size post injection.

We present a model of neonatal intraventricular hemorrhage using rat pups that mimics the pathology seen in humans.

通过脑室内注射血红蛋白模拟新生儿脑室内出血

Neonatal intraventricular hemorrhage (IVH) is a common consequence of premature birth and leads to brain injury, posthemorrhagic hydrocephalus (PHH), and ...