Gu Xiaochun, Han Fang, Wang Zhijie
College of Information Science and Technology, Donghua University, Shanghai, 201620 China.
Cogn Neurodyn. 2021 Jun;15(3):501-515. doi: 10.1007/s11571-020-09622-5. Epub 2020 Jul 28.
It has been found that gamma oscillations and the oscillation frequencies are regulated by the properties of external stimuli in many biology experimental researches. To unveil the underlying mechanism, firstly, we reproduced the experimental observations in an excitatory/inhibitory (E/I) neuronal network that the oscillation became stronger and moved to a higher frequency band (gamma band) with the increasing of the input difference between E/I neurons. Secondly, we found that gamma oscillation was induced by the unbalance between positive and negative synaptic currents, which was caused by the input difference between E/I neurons. When this input difference became greater, there would be a stronger gamma oscillation (i.e., a higher peak power in the power spectrum of the population activity of neurons). Further investigation revealed that the frequency dependency of gamma oscillation on the input difference between E/I neurons could be explained by the well-known mechanisms of inter-neuron-gamma (ING) and pyramidal-interneuron-gamma (PING). Finally, we derived mathematical analysis to verify the mechanism of frequency regulations and the results were consistent with the simulation results. The results of this paper provide a possible mechanism for the external stimuli-regulated gamma oscillations.
在许多生物学实验研究中发现，γ振荡和振荡频率受外部刺激特性的调节。为揭示其潜在机制，首先，我们在兴奋性/抑制性（E/I）神经元网络中重现了实验观察结果，即随着E/I神经元之间输入差异的增加，振荡变强并移向更高频段（γ频段）。其次，我们发现γ振荡是由E/I神经元之间的输入差异导致的正负突触电流失衡所诱发的。当这种输入差异变得更大时，会有更强的γ振荡（即神经元群体活动功率谱中的峰值功率更高）。进一步研究表明，γ振荡对E/I神经元之间输入差异的频率依赖性可以用著名的神经元间γ（ING）和锥体神经元-中间神经元γ（PING）机制来解释。最后，我们进行了数学分析以验证频率调节机制，结果与模拟结果一致。本文的结果为外部刺激调节γ振荡提供了一种可能的机制。
