No Evidence for Entrainment: Endogenous Gamma Oscillations and Rhythmic Flicker Responses Coexist in Visual Cortex.
No Evidence for Entrainment: Endogenous Gamma Oscillations and Rhythmic Flicker Responses Coexist in Visual Cortex.
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DOI：
10.1523/jneurosci.3134-20.2021
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发表时间：
2021-08-04
期刊：
影响因子：
--
通讯作者：
Jensen O
中科院分区：
文献类型：
--
作者：
Duecker K;Gutteling TP;Herrmann CS;Jensen O
在过去的几十年里，大量研究将皮质伽玛振荡（∼30-100 Hz）与神经计算机制联系起来。然而，它们的功能相关性仍然存在激烈争论。在这里，我们询问人脑中的内源性伽马振荡是否可以通过 >50 Hz 的节律性光驱动来夹带。这种对内源性大脑节律的无创调节可以得出关于它们与神经认知的因果关系的结论。为此，我们使用脑磁图（MEG）结合高频投影仪系统地研究了在不存在和存在内源伽马振荡的情况下对快速正弦闪烁的振荡响应。光驱动在视觉皮层上对高达 80 Hz 的刺激频率产生强烈的反应。正如之前的研究中反复进行的那样，使用移动光栅刺激诱发强烈的内源伽马振荡。当叠加闪烁和光栅时，没有证据表明光驱动对内源伽马振荡产生相位或频率夹带。出乎意料的是，我们没有观察到参与者个体伽马频率（IGF）周围闪烁响应的放大；相反，响应的幅度随着频率的增加而单调下降。源重建表明闪烁响应和伽马振荡是由视觉皮层中单独的、共存的发生器产生的。所提出的发现挑战了皮质伽马振荡可以由有节奏的视觉刺激引起的观念。相反，产生内源伽马振荡的机制似乎对外部扰动具有弹性。意义声明 我们的目的是研究视觉闪烁会在多大程度上引起人脑伽玛波段（30-100 Hz）持续的高频振荡。长期以来，伽马振荡一直被认为可以协调神经元放电并实现区域间通信。我们的结果表明，有节奏的视觉刺激不能劫持正在进行的伽马振荡的动态；相反，闪烁响应和内源伽马振荡共存于不同的视觉区域。因此，虽然视觉闪烁即使在伽玛波段的高频下也会引起强烈的神经元反应，但它不会在视觉皮层中引起内源性伽玛振荡。这对于解释伽玛波段节律性感觉刺激的因果和神经保护作用的研究具有重要意义。
Over the past decades, numerous studies have linked cortical gamma oscillations (∼30–100 Hz) to neurocomputational mechanisms. Their functional relevance, however, is still passionately debated. Here, we asked whether endogenous gamma oscillations in the human brain can be entrained by a rhythmic photic drive >50 Hz. Such a noninvasive modulation of endogenous brain rhythms would allow conclusions about their causal involvement in neurocognition. To this end, we systematically investigated oscillatory responses to a rapid sinusoidal flicker in the absence and presence of endogenous gamma oscillations using magnetoencephalography (MEG) in combination with a high-frequency projector. The photic drive produced a robust response over visual cortex to stimulation frequencies of up to 80 Hz. Strong, endogenous gamma oscillations were induced using moving grating stimuli as repeatedly done in previous research. When superimposing the flicker and the gratings, there was no evidence for phase or frequency entrainment of the endogenous gamma oscillations by the photic drive. Unexpectedly, we did not observe an amplification of the flicker response around participants' individual gamma frequencies (IGFs); rather, the magnitude of the response decreased monotonically with increasing frequency. Source reconstruction suggests that the flicker response and the gamma oscillations were produced by separate, coexistent generators in visual cortex. The presented findings challenge the notion that cortical gamma oscillations can be entrained by rhythmic visual stimulation. Instead, the mechanism generating endogenous gamma oscillations seems to be resilient to external perturbation. SIGNIFICANCE STATEMENT We aimed to investigate to what extent ongoing, high-frequency oscillations in the gamma-band (30–100 Hz) in the human brain can be entrained by a visual flicker. Gamma oscillations have long been suggested to coordinate neuronal firing and enable interregional communication. Our results demonstrate that rhythmic visual stimulation cannot hijack the dynamics of ongoing gamma oscillations; rather, the flicker response and the endogenous gamma oscillations coexist in different visual areas. Therefore, while a visual flicker evokes a strong neuronal response even at high frequencies in the gamma-band, it does not entrain endogenous gamma oscillations in visual cortex. This has important implications for interpreting studies investigating the causal and neuroprotective effects of rhythmic sensory stimulation in the gamma-band.
影响因子：
1.8
作者：
Lobo T;Brookes MJ;Bauer M
通讯作者：
Bauer M