Mechanisms of noise-induced improvement in light-intensity encoding in Hermissenda photoreceptor network.
Mechanisms of noise-induced improvement in light-intensity encoding in Hermissenda photoreceptor network.
复制标题
Hermissenda 光感受器网络中噪声引起的光强度编码改善机制。
DOI：
10.1152/jn.01250.2006
复制
发表时间：
2008
影响因子：
2.5
通讯作者：
Clark,GregoryA
中科院分区：
文献类型：
--
作者：
Butson,ChristopherR;Clark,GregoryA
在一篇配套论文中，我们表明随机通道和突触噪声提高了生物现实的、基于 GENESIS 的 Hermissendaeye 计算模型编码光强度的能力。在本文中，我们通过检查光感受器网络中神经元之间的上下文尖峰时序关系来探索噪声引起的改善的机制。在其他系统中，突触连接的尖峰细胞对可以在特定的、明确定义的频率下形成锁相尖峰时序关系。因此，出现了稳定域（DOS），其中抑制性突触后电位频率的增加反而会增加而不是减少突触后细胞的放电率。我们扩展了这种分析，以检查 DOS 作为专门抑制性 Hermissenda 光感受器网络中噪声幅度的函数。在无噪声模拟中，DOS 出现在 B 型和 A 型光感受器的特定发射频率下，从而在它们的发射率和光强度之间产生非单调关系。相比之下，在添加噪声的条件下，噪声幅度的增加会导致给定细胞的峰间间隔分布的方差增加；反过来，这又阻止了锁相和 DOS 的出现。这些噪声引起的变化使眼睛能够更好地执行其基本任务之一：编码光强度。这种效应与随机共振无关，随机共振通常用于描述阈值刺激。噪声在生物信号处理中的建设性作用对于理解神经系统的动力学和神经接口设备的设计都有影响。
In a companion paper we showed that random channel and synaptic noise improve the ability of a biologically realistic, GENESIS-based computational model of theHermissendaeye to encode light intensity. In this paper we explore mechanisms for noise-induced improvement by examining contextual spike-timing relationships among neurons in the photoreceptor network. In other systems, synaptically connected pairs of spiking cells can develop phase-locked spike-timing relationships at particular, well-defined frequencies. Consequently, domains of stability (DOS) emerge in which an increase in the frequency of inhibitory postsynaptic potentials can paradoxically increase, rather than decrease, the firing rate of the postsynaptic cell. We have extended this analysis to examine DOS as a function of noise amplitude in the exclusively inhibitoryHermissendaphotoreceptor network. In noise-free simulations, DOS emerge at particular firing frequencies of type B and type A photoreceptors, thus producing a nonmonotonic relationship between their firing rates and light intensity. By contrast, in the noise-added conditions, an increase in noise amplitude leads to an increase in the variance of the interspike interval distribution for a given cell; in turn, this blocks the emergence of phase locking and DOS. These noise-induced changes enable the eye to better perform one of its basic tasks: encoding light intensity. This effect is independent of stochastic resonance, which is often used to describe perithreshold stimuli. The constructive role of noise in biological signal processing has implications both for understanding the dynamics of the nervous system and for the design of neural interface devices.