Edmond and Lily Safra International Institute of Neuroscience of Natal and Federal University of Rio Grande do Norte, Natal, RN, Brazil.
J Neurophysiol. 2010 Aug;104(2):1195-210. doi: 10.1152/jn.00106.2010. Epub 2010 May 12.
Neuronal oscillations of different frequencies can interact in several ways. There has been particular interest in the modulation of the amplitude of high-frequency oscillations by the phase of low-frequency oscillations, since recent evidence suggests a functional role for this type of cross-frequency coupling (CFC). Phase-amplitude coupling has been reported in continuous electrophysiological signals obtained from the brain at both local and macroscopic levels. In the present work, we present a new measure for assessing phase-amplitude CFC. This measure is defined as an adaptation of the Kullback-Leibler distance-a function that is used to infer the distance between two distributions-and calculates how much an empirical amplitude distribution-like function over phase bins deviates from the uniform distribution. We show that a CFC measure defined this way is well suited for assessing the intensity of phase-amplitude coupling. We also review seven other CFC measures; we show that, by some performance benchmarks, our measure is especially attractive for this task. We also discuss some technical aspects related to the measure, such as the length of the epochs used for these analyses and the utility of surrogate control analyses. Finally, we apply the measure and a related CFC tool to actual hippocampal recordings obtained from freely moving rats and show, for the first time, that the CA3 and CA1 regions present different CFC characteristics.
不同频率的神经元振荡可以以多种方式相互作用。低频振荡的相位调制高频振荡的幅度特别引起了人们的兴趣，因为最近的证据表明这种类型的跨频耦合（CFC）具有功能作用。在大脑的局部和宏观水平上连续的电生理信号中已经报道了相位-幅度耦合。在本工作中，我们提出了一种新的用于评估相位-幅度 CFC 的度量方法。该度量方法是 Kullback-Leibler 距离的一种适应，Kullback-Leibler 距离是用于推断两个分布之间距离的函数，并计算经验幅度分布样函数在相位箱上偏离均匀分布的程度。我们表明，以这种方式定义的 CFC 度量非常适合评估相位-幅度耦合的强度。我们还回顾了其他七种 CFC 度量方法；我们表明，通过一些性能基准，我们的度量方法在这项任务中特别有吸引力。我们还讨论了与该度量方法相关的一些技术方面，例如用于这些分析的时间段的长度以及替代控制分析的实用性。最后，我们将该度量方法和相关的 CFC 工具应用于从自由移动的大鼠获得的实际海马记录，并首次表明 CA3 和 CA1 区域具有不同的 CFC 特征。
