Coulter Department of Biomedical Engineering, Georgia Institute of Technology and Emory University, Atlanta, United States.
School of Electrical and Computer Engineering, Georgia Institute of Technology, Atlanta, United States.
Elife. 2019 Jul 29;8:e44320. doi: 10.7554/eLife.44320.
Oscillatory brain activity reflects different internal brain states including neurons' excitatory state and synchrony among neurons. However, characterizing these states is complicated by the fact that different oscillations are often coupled, such as gamma oscillations nested in theta in the hippocampus, and changes in coupling are thought to reflect distinct states. Here, we describe a new method to separate single oscillatory cycles into distinct states based on frequency and phase coupling. Using this method, we identified four theta-gamma coupling states in rat hippocampal CA1. These states differed in abundance across behaviors, phase synchrony with other hippocampal subregions, and neural coding properties suggesting that these states are functionally distinct. We captured cycle-to-cycle changes in oscillatory coupling states and found frequent switching between theta-gamma states showing that the hippocampus rapidly shifts between different functional states. This method provides a new approach to investigate oscillatory brain dynamics broadly.
脑振荡活动反映了不同的内部脑状态，包括神经元的兴奋状态和神经元之间的同步性。然而，由于不同的振荡通常是耦合的，例如海马体中的θ内嵌套的γ振荡，因此对这些状态进行特征描述很复杂，并且耦合的变化被认为反映了不同的状态。在这里，我们描述了一种新的方法，该方法可以根据频率和相位耦合将单个振荡周期分离为不同的状态。使用这种方法，我们在大鼠海马 CA1 中鉴定出了四个θ-γ耦合状态。这些状态在行为、与其他海马亚区的相位同步性以及神经编码特性方面存在差异，表明这些状态在功能上是不同的。我们捕获了振荡耦合状态的周期到周期变化，并发现θ-γ状态之间的频繁切换，表明海马体在不同的功能状态之间快速切换。这种方法为广泛研究脑振荡动力学提供了一种新方法。
