Research Group: Cortical function and dynamics, Max-Planck-Institute for Brain Research Frankfurt, Germany.
Front Comput Neurosci. 2011 Jul 12;5:34. doi: 10.3389/fncom.2011.00034. eCollection 2011.
Recently, it has been suggested that effective interactions between two neuronal populations are supported by the phase difference between the oscillations in these two populations, a hypothesis referred to as "communication through coherence" (CTC). Experimental work quantified effective interactions by means of the power correlations between the two populations, where power was calculated on the local field potential and/or multi-unit activity. Here, we present a linear model of interacting oscillators that accounts for the phase dependency of the power correlation between the two populations and that can be used as a reference for detecting non-linearities such as gain control. In the experimental analysis, trials were sorted according to the coupled phase difference of the oscillators while the putative interaction between oscillations was taking place. Taking advantage of the modeling, we further studied the dependency of the power correlation on the uncoupled phase difference, connection strength, and topology. Since the uncoupled phase difference, i.e., the phase relation before the effective interaction, is the causal variable in the CTC hypothesis we also describe how power correlations depend on that variable. For uni-directional connectivity we observe that the width of the uncoupled phase dependency is broader than for the coupled phase. Furthermore, the analytical results show that the characteristics of the phase dependency change when a bidirectional connection is assumed. The width of the phase dependency indicates which oscillation frequencies are optimal for a given connection delay distribution. We propose that a certain width enables a stimulus-contrast dependent extent of effective long-range lateral connections.
最近，有人提出，两个神经元群体之间的有效相互作用是由这两个群体的振荡之间的相位差支持的，这种假设被称为“相干传递通讯”（CTC）。实验工作通过两个群体之间的局部场电位和/或多单元活动的功率相关性来量化有效相互作用。在这里，我们提出了一个相互作用振荡器的线性模型，该模型考虑了两个群体之间的功率相关性的相位依赖性，并且可以作为检测非线性的参考，例如增益控制。在实验分析中，根据振荡器的耦合相位差对试验进行排序，而振荡之间的假定相互作用正在发生。利用建模，我们进一步研究了功率相关性对未耦合相位差、连接强度和拓扑结构的依赖性。由于未耦合相位差，即有效相互作用之前的相位关系，是 CTC 假设中的因果变量，我们还描述了功率相关性如何依赖于该变量。对于单向连接，我们观察到未耦合相位依赖性的宽度比耦合相位的宽度更宽。此外，分析结果表明，当假设存在双向连接时，相位依赖性的特征会发生变化。相位依赖性的宽度表明对于给定的连接延迟分布，哪些振荡频率是最佳的。我们提出，一定的宽度可以实现刺激对比度相关的有效远程横向连接的程度。
