Buño W, Bustamante J, Fuentes J
J Physiol. 1984 May;350:55-80. doi: 10.1113/jphysiol.1984.sp015188.
Input-output relations were investigated in the slowly adapting stretch receptor organ of crayfish using a Gaussian white noise length input with a 0.03-12.5 Hz band width and the resulting action potential output. The noise input was presented to the de-efferented receptor in situ, at three mean elongations and at four different amplitudes. The three mean elongations were set within the normal range in vivo, two at the extremes close to the minimum and maximum physiological lengths and the other in the mid-range. With white noise inputs there is a finite probability that the system will be tested in all possible conditions within the chosen band width because white noise has the advantage that it contains, with a finite probability, all possible stimulus wave forms at random. The analysis indicated similarities between the effects of the input variables, namely white noise amplitude and mean elongation. With low input variables the activity was periodic. With larger inputs, impulse rates were higher and irregular. The average length trajectories leading to a spike (i.e. the average stimulus) were either biphasic with high inputs or multiphasic and periodic with lower input variables. The frequency of periodicity increased with mean elongation. Although for a given length and noise amplitude a variety of individual length trajectories preceded spikes, the final biphasic shortening-lengthening average stimulus sequence before a spike was similar in all cases irrespective of the input variables. The number of possible trajectories decreased with increments in the input variables. The standard deviation of length values for each average stimulus was computed and displayed as a function of time relative to the spike. It was first constant, and decreased gradually to a minimum value at the spike reference. Standard deviation values were lower for higher white noise amplitudes and mean elongation. Simple, short-lasting stimulus wave forms in the white noise were isolated and the corresponding responses were computed. Responses were periodic at low input variables and aperiodic with larger inputs and also asymmetric, being larger and briefer for lengthenings than for shortenings. Asymmetries augmented with input increments. Investigation of the interactions between the pace-maker and the white noise effects showed that lengthenings were more effective when they occurred just after a spike while the effectiveness of shortenings was greater just before a spike.(ABSTRACT TRUNCATED AT 400 WORDS)
利用带宽为0.03 - 12.5 Hz的高斯白噪声长度输入以及由此产生的动作电位输出，对小龙虾的慢适应性牵张感受器器官的输入 - 输出关系进行了研究。将噪声输入施加于原位去传入神经的感受器，设置了三个平均伸长量和四个不同的幅度。这三个平均伸长量设定在体内的正常范围内，两个处于接近最小和最大生理长度的极端值，另一个处于中间范围。对于白噪声输入，系统在所选带宽内的所有可能条件下进行测试存在有限的概率，因为白噪声的优点是它以有限的概率随机包含所有可能的刺激波形。分析表明输入变量（即白噪声幅度和平均伸长量）的影响之间存在相似性。输入变量较低时，活动是周期性的。输入较大时，冲动频率较高且不规则。导致动作电位发放的平均长度轨迹（即平均刺激）在高输入时是双相的，在低输入变量时是多相且周期性的。周期性频率随平均伸长量增加。尽管对于给定的长度和噪声幅度，动作电位发放之前有各种不同的个体长度轨迹，但在所有情况下，动作电位发放之前最终的双相缩短 - 延长平均刺激序列与输入变量无关，都是相似的。随着输入变量的增加，可能的轨迹数量减少。计算每个平均刺激的长度值的标准差，并将其作为相对于动作电位发放的时间的函数显示出来。它最初是恒定的，然后逐渐减小到动作电位发放参考点处的最小值。对于较高的白噪声幅度和平均伸长量，标准差的值较低。从白噪声中分离出简单、持续时间短的刺激波形，并计算相应的反应。在低输入变量时反应是周期性的，在较大输入时是非周期性的，并且也是不对称的，伸长时的反应比缩短时更大且更短暂。不对称性随着输入增加而增强。对起搏器和白噪声效应之间相互作用的研究表明，伸长在动作电位发放后立即发生时更有效，而缩短在动作电位发放前立即发生时效果更大。（摘要截断于400字）
