Stevens C F
Fed Proc. 1975 Apr;34(5):1364-9.
The mechanisms underlying many of the processes studied by membrane biophysicists are inherently probabilistic, and therefore exhibit random fluctuations around the mean of behavior. These fluctuations reflect the underlying probabilistic mechanism and therefore can sometimes provide information, not otherwise available, about these mechanisms. Fluctuations may be characterized by their spectra which are obtained from a Fourier analysis of the experimental records. When a theory for membrane processes is available, it makes predictions about fluctuation spectra and therefore may be tested by examining these spectra. Theories about gating behavior at the frog neuromuscular junction have been tested in this way, and it has been possible, in addition, to estimate the conductance of one open channel, a quantity not susceptible to direct measurements. Various physical pictures are capable of yielding the same macroscopic behavior for axon membranes, that is, the Hodgkin-Huxley equations, but these various mechanisms predict that the current fluctuations around their mean values should have different characteristics. Fluctuation analysis may, then be of value in elucidating the physical basis for axon conductance changes.
膜生物物理学家所研究的许多过程背后的机制本质上是概率性的，因此在行为均值周围表现出随机波动。这些波动反映了潜在的概率机制，因此有时可以提供关于这些机制的、以其他方式无法获得的信息。波动可以通过其频谱来表征，频谱是从实验记录的傅里叶分析中获得的。当有关于膜过程的理论时，它会对波动频谱做出预测，因此可以通过检查这些频谱来进行检验。关于青蛙神经肌肉接头处门控行为的理论就是通过这种方式进行检验的，此外，还能够估计单个开放通道的电导，这是一个不易直接测量的量。各种物理模型都能够产生与轴突膜相同的宏观行为，即霍奇金 - 赫胥黎方程，但这些不同的机制预测，围绕其均值的电流波动应该具有不同的特征。那么，波动分析可能有助于阐明轴突电导变化的物理基础。
