Tiesinga Paul H, Sejnowski Terrence J
Donders Institute for Brain, Cognition and Behavior, Radboud University Nijmegen Nijmegen, Netherlands.
Front Hum Neurosci. 2010 Nov 2;4:196. doi: 10.3389/fnhum.2010.00196. eCollection 2010.
In the primate visual cortex, the phase of spikes relative to oscillations in the local field potential (LFP) in the gamma frequency range (30-80 Hz) can be shifted by stimulus features such as orientation and thus the phase may carry information about stimulus identity. According to the principle of communication through coherence (CTC), the relative LFP phase between the LFPs in the sending and receiving circuits affects the effectiveness of the transmission. CTC predicts that phase shifting can be used for stimulus selection. We review and investigate phase shifting in models of periodically driven single neurons and compare it with phase shifting in models of cortical networks. In a single neuron, as the driving current is increased, the spike phase varies systematically while the firing rate remains constant. In a network model of reciprocally connected excitatory (E) and inhibitory (I) cells phase shifting occurs in response to both injection of constant depolarizing currents and to brief pulses to I cells. These simple models provide an account for phase-shifting observed experimentally and suggest a mechanism for implementing CTC. We discuss how this hypothesis can be tested experimentally using optogenetic techniques.
在灵长类动物的视觉皮层中，相对于伽马频率范围（30 - 80赫兹）的局部场电位（LFP）振荡，尖峰的相位会因诸如方向等刺激特征而发生偏移，因此该相位可能携带有关刺激特性的信息。根据通过相干性进行通信的原理（CTC），发送和接收回路中LFP之间的相对相位会影响传输的有效性。CTC预测相位偏移可用于刺激选择。我们回顾并研究了周期性驱动的单个神经元模型中的相位偏移，并将其与皮层网络模型中的相位偏移进行比较。在单个神经元中，随着驱动电流增加，尖峰相位会系统性变化，而放电率保持恒定。在由相互连接的兴奋性（E）和抑制性（I）细胞组成的网络模型中，相位偏移会因注入恒定去极化电流以及对I细胞施加短暂脉冲而发生。这些简单模型解释了实验中观察到的相位偏移，并提出了一种实现CTC的机制。我们讨论了如何使用光遗传学技术通过实验来检验这一假设。
