Moradmand K, Goldfinger M D
Department of Physiology and Biophysics, Wright State University, Dayton, OH 401-0927, USA.
J Neurosci Methods. 1995 Dec;63(1-2):113-20. doi: 10.1016/0165-0270(95)00096-8.
This work describes a simple circuit which generated a highly Poisson-like sequence of pulses. Resistor noise was amplified in three series stages followed by rectification through a relatively large shunt resistance. This yielded a sequence of variable-amplitude transients, which were inverted, amplified with DC adjustment, and fed into a Schmitt trigger/multivibrator chip for pulse generation. The pulse generation frequency was modulated by the amplification of the rectified transients. The stochastic characteristics of the output pulse train were Poisson-like over a wide frequency range, as assessed using the intervent interval distribution and expectation density as steady-state and real-time estimators, respectively. In separate tests, the output pulse train was applied to forelimb cutaneous axons of the anesthetized cat; trains of elicited propagating action potentials were recorded extracellularly from individual G1 axons in the cuneate fasciculus. The stochastic properties of the action potential train differed from those of the stimulus, with longer deadtime, lower mean rate, and an early expectation density peak. These physiological responses to circuit output were similar to those elicited by other generators of Poisson-like stimulation.
这项工作描述了一个简单电路，该电路能产生高度类似泊松分布的脉冲序列。电阻噪声在三个串联级中被放大，随后通过一个相对较大的并联电阻进行整流。这产生了一系列幅度可变的瞬态信号，这些瞬态信号被反相、经直流调整放大，然后馈入一个施密特触发器/多谐振荡器芯片以产生脉冲。脉冲产生频率通过整流后的瞬态信号的放大进行调制。使用间隔时间分布和期望密度分别作为稳态和实时估计器评估发现，输出脉冲序列的随机特性在很宽的频率范围内类似泊松分布。在单独的测试中，将输出脉冲序列施加到麻醉猫的前肢皮肤轴突上；从楔束中单个G1轴突细胞外记录诱发的传播动作电位序列。动作电位序列的随机特性与刺激的随机特性不同，具有更长的死区时间、更低的平均速率和一个早期期望密度峰值。这些对电路输出的生理反应与其他类似泊松分布刺激发生器引发的反应相似。
