SYNAPTIC NOISE AND OTHER SOURCES OF RANDOMNESS IN MOTONEURON INTERSPIKE INTERVALS
SYNAPTIC NOISE AND OTHER SOURCES OF RANDOMNESS IN MOTONEURON INTERSPIKE INTERVALS
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DOI：
10.1152/jn.1968.31.4.574
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发表时间：
1968-01-01
影响因子：
2.5
通讯作者：
STEVENS, CF
中科院分区：
文献类型：
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作者：
CALVIN, WH;STEVENS, CF
猫脊髓运动神经元的细胞内记录被用来研究重复放电过程中动作电位间隔变异性的来源。这些记录揭示了一系列的尖峰、复极化和线性上升的去极化，当放电水平交叉时，接着是另一个尖峰。由于膜电位即使在静息状态下也有波动，这种叠加在线性去极化上的“突触噪声”可能会在达到放电水平的时间内引起变化。通过测量运动神经元的放电水平和去极化率，在计算机上建立实时工作模型，并将同一运动神经元的突触噪声加入到人工去极化序列中，对该模型进行了验证。人工放电水平交叉的时间被编译成一个直方图，然后与运动神经元的脉冲间隔直方图进行比较。突触噪声通常足以解释间隔变异性，无论是在放电水平不变的情况下，还是在观察到在前一个峰值之后随着时间的推移而增加的情况下。
Intra-cellular recordings from cat spinal motoneurons were used to investigate sources of variability in the interval between action potentials during repetitive firing. These records reveal a sequence of spike, repolarization, and linearly rising depolarization, followed by another spike when the firing level is crossed. Since the membrane potential fluctuated even in the resting state, such "synaptic noise" superimposed upon the otherwise linear depolarization might be expected to cause variations in the time when the firing level is reached. This model is tested by measuring the firing level and depolarization rate from a motoneuron, setting up a real-time working model on a computer, and adding synaptic noise from the same motoneuron to the artificial depolarization sequence. Times at which the artificial firing level is crossed are compiled into a histogram which is then compared to that motoneuron''s interspike interval histogram. Synaptic noise is often sufficient to account for the interval variability, both when the firing level is constant and when it is observed to increase with time following the preceding spike.