The synaptic connexions to intercostal motoneurones as revealed by the average common excitation potential.
The synaptic connexions to intercostal motoneurones as revealed by the average common excitation potential.
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平均共同兴奋电位揭示了突触与肋间运动神经元的连接。
DOI：
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发表时间：
1978
期刊：
影响因子：
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通讯作者：
T. Sears
中科院分区：
文献类型：
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作者：
P. Kirkwood;T. Sears
1. 提出了一种假设，即由共同干突触前纤维分支在运动神经元中引起的单一e.p.s.p.s的共同发生，平均而言，在同一池的另一个运动神经元放电时，一个运动神经元会发生短暂的去极化。2. 这一假设在被麻醉、瘫痪的猫身上进行了测试，方法是将胸部吸气运动神经元自然产生的交感噪声与其他吸气运动神经元的尖峰触发的平均值进行平均。这些尖峰是作为供应外肋间肌近端区域的神经丝的传出放电而获得的。3. 以触发尖峰时间为中心的瞬态去极化被一致地观察到，并被指定为平均共激发（a.c.e）电位。4. 相对于触发峰，峰值去极化在‐1.0到+4.6 msec（平均+0.7 msec）之间，其最突出的分量上升时间在4到16 msec（平均8.4 msec）之间。5. 当触发电位来源于与运动神经元在同一节段上的细丝时，其振幅范围为6 ~ 104 muV（平均32 muV）；当细丝位于运动神经元的两侧时，其振幅范围为3 ~ 42 muV（平均19 muV）。6. 支配肋间隙近端区域的细胞比支配远端区域的细胞具有更大的a.c.e.电位，中枢呼吸驱动电位也更大。7. 观察α或γ峰作为触发点的A.c.e.电位。γ峰的电位通常比α峰的电位小，平均比值约为0.6。来自伽马峰的a.c.e.电位的存在被认为是共同突触前轴突α - γ共激活的证据。8. 西尔斯和斯塔格（1976）所观察到的a.c.e.电势和短期同步的主要特征，已经发展出一种定量解释的理论。9. 该理论包括一个命题，即由于一个单一的e.p.s.p.引起的运动神经元放电概率的提高具有一个时间过程，这个时间过程可以用e.p.s.p.时间过程及其时间差的总和来描述。因此，通过测量，该理论至少在第一个近似上预测了由各种形状和大小的e.p.s.p.s引起的预期发射概率。
1. The hypothesis is advanced that the joint occurrence of unitary e.p.s.p.s evoked in motoneurones by branches of common stem presynaptic fibres causes, on average, transient depolarization in one motoneurone at the time of discharge in another motoneurone of the same pool. 2. The hypothesis was tested in anaesthetized, paralysed cats by averaging the naturally occurring synpatic noise of thoracic inspiratory motoneurones with an averager triggered by spikes from other inspiratory motoneurones. These spikes were obtained as efferent discharges in nerve filaments supplying the proximal regions of the external intercostal muscles. 3. A transient depolarization centred around the time of the trigger spikes was consistently observed and was designated the average common excitation (a.c.e.) potential. 4. The peak depolarization lay between ‐1.0 and +4.6 msec (mean +0.7 msec) with respect to the trigger spikes and the rise times of its most prominent component ranged from 4 to 16 msec (mean 8.4 msec). 5. The amplitudes of the a.c.e. potentials ranged from 6 to 104 muV (mean 32 muV) when the trigger spikes were derived from a filament in the same segment as the relevant motoneurones, and from 3 to 42 muV (mean 19 muV) when the filament was two segments rostral to the motoneurone. 6. Cells innervating the proximal region of the intercostal space gave larger a.c.e. potentials than those innervating more distal regions and also showed larger central respiratory drive potentials. 7. A.c.e. potentials were observed for either alpha or gamma spikes as triggers. The potentials were usually smaller for the gamma than for the alpha spikes, the mean ration being about 0.6. The presence of the a.c.e. potentials from the gamma spikes was taken as evidence for alpha‐gamma coactivation by common presynaptic axons. 8. A theory is developed which quantitatively accounts for the main features of both the a.c.e. potential and the short term synchrony observed by Sears & Stagg (1976). 9. The theory includes the proposition that the raised probability of firing of a motoneurone due to a unitary e.p.s.p. has a time course which may be described by the sum of the e.p.s.p. time course and its time differential. Thus, via the measurements, the theory predicts at least to a first approximation the expected probability of firing due to e.p.s.p.s of various shapes and sizes.