Kember G C, Fenton G A, Collier K, Armour J A
Department of Engineering Mathematics, Dalhousie University, P. O. Box 1000, Halifax, Nova Scotia, Canada B3J 2X4.
Phys Rev E Stat Phys Plasmas Fluids Relat Interdiscip Topics. 2000 Feb;61(2):1816-24. doi: 10.1103/physreve.61.1816.
Aperiodic stochastic resonance (ASR) is studied for a densely interconnected population of excitatory and inhibitory neurons that exhibit hysteresis. Switching between states in the presence of noisy external forcing is represented as a "competition between averages" and this is further explained through a semianalytical model. In contrast to energy-based approaches where only the timing of a switch between states is represented, the competition between averages also identifies the input history responsible for a switch. This last point leads to some interesting conclusions regarding cause and effect in the presence of noisy forcing of a hysteretic system. For example, at subthreshold inputs, it is found that the input history causing a switch between states is primarily dependent upon the noise level even though the corresponding time to switch is sensitive to both the distance from the threshold and the noise level. Since the application considered here is to cardiac neuronal control, control performance is considered over the full input range. Noise tuning for adequate control performance is found to be unnecessary if the noise level is high enough. This is consistent with studies of ASR for sensory neurons. Another observation made here that may be of clinical significance is that at higher noise levels, constraints placed upon inputs to ensure adequate control performance are likely to depend upon the switching direction.
研究了具有滞后现象的兴奋性和抑制性神经元密集互连群体的非周期随机共振（ASR）。在存在噪声外部强迫的情况下，状态之间的切换被表示为“平均值之间的竞争”，并通过半解析模型进一步解释。与仅表示状态之间切换时间的基于能量的方法不同，平均值之间的竞争还确定了导致切换的输入历史。最后这一点导致了关于滞后系统在噪声强迫存在下的因果关系的一些有趣结论。例如，在亚阈值输入时，发现导致状态之间切换的输入历史主要取决于噪声水平，尽管相应的切换时间对与阈值的距离和噪声水平都很敏感。由于这里考虑的应用是心脏神经元控制，因此在整个输入范围内考虑控制性能。如果噪声水平足够高，发现为获得足够的控制性能而进行噪声调谐是不必要的。这与对感觉神经元的ASR研究一致。这里做出的另一个可能具有临床意义的观察结果是，在较高的噪声水平下，为确保足够的控制性能而对输入施加的约束可能取决于切换方向。
