Stimulus Dependence of Gamma Oscillations in Human Visual Cortex
Stimulus Dependence of Gamma Oscillations in Human Visual Cortex
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DOI：
10.1093/cercor/bhu091
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发表时间：
2015-09-01
期刊：
影响因子：
3.7
通讯作者：
Winawer, J.
中科院分区：
文献类型：
--
作者：
Hermes, D.;Miller, K. J.;Winawer, J.
视觉皮质中一些场电位记录的一个显着特征是伽马频带（30-80 Hz）内的节律性振荡。这些振荡被认为是感知、注意力和信息传输计算的基础。最近对皮层场电位的研究，包括人类皮层电图（ECoG），强调了伽马波段内的另一种信号，一种跨越80-200 Hz的非振荡宽带信号。目前还不清楚在什么条件下伽马振荡引起的视觉皮层，他们是否是必要的和普遍存在的视觉编码，以及他们有什么关系，非振荡，宽带场电位。我们证明，ECoG在人类视觉皮层（V1/V2/V3）的反应可以包括强大的窄带伽马振荡，这些振荡是可靠的引起一些空间对比度模式（亮度光栅），但不是由其他人（噪声模式和许多自然图像）。伽马振荡可以是显著的和鲁棒的，但是因为它们对于观察者可以看到和识别的许多刺激是不存在的，所以振荡对于观看是不必要的。与此相反，所有的视觉刺激引起的ECoG反应的宽带频谱变化。在视觉皮层中的异步神经信号，反映在宽带ECoG响应中，可以在没有明显的伽马振荡的情况下支持用于感知和识别的信息的传输。
A striking feature of some field potential recordings in visual cortex is a rhythmic oscillation within the gamma band (30-80 Hz). These oscillations have been proposed to underlie computations in perception, attention, and information transmission. Recent studies of cortical field potentials, including human electrocorticography (ECoG), have emphasized another signal within the gamma band, a nonoscillatory, broadband signal, spanning 80-200 Hz. It remains unclear under what conditions gamma oscillations are elicited in visual cortex, whether they are necessary and ubiquitous in visual encoding, and what relationship they have to nonoscillatory, broadband field potentials. We demonstrate that ECoG responses in human visual cortex (V1/V2/V3) can include robust narrowband gamma oscillations, and that these oscillations are reliably elicited by some spatial contrast patterns (luminance gratings) but not by others (noise patterns and many natural images). The gamma oscillations can be conspicuous and robust, but because they are absent for many stimuli, which observers can see and recognize, the oscillations are not necessary for seeing. In contrast, all visual stimuli induced broadband spectral changes in ECoG responses. Asynchronous neural signals in visual cortex, reflected in the broadband ECoG response, can support transmission of information for perception and recognition in the absence of pronounced gamma oscillations.