Neural representations of individual stimuli in humans revealed by gamma-band electrocorticographic activity.
Neural representations of individual stimuli in humans revealed by gamma-band electrocorticographic activity.
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DOI：
10.1523/jneurosci.2187-09.2009
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发表时间：
2009-08-19
期刊：
影响因子：
--
通讯作者：
Kahana MJ
中科院分区：
文献类型：
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作者：
Jacobs J;Kahana MJ
神经科学中的一个基本问题是人类大脑如何表达感知和概念信息。传统上，研究人员通过识别单个神经元来探索这个问题，这些神经元在动物遇到某些刺激时会增加其放电率。在这里，我们提供了一个互补的方案，其中γ波段（25-128赫兹）皮层电图（ECoG）活动的现象，涉及大量的神经元编码的积极的认知表示的证据。我们分析了来自神经外科患者的颅内脑记录，同时他们研究了视觉呈现的字母列表，并发现伽马波段活动的幅度编码了当前字母的身份。这些字母特定的模式发生在伽马振幅整体增加的时期，并与同步θ（4-8 Hz）振荡的相位有关。在枕叶皮层，这些模式有时反映了所看到的字母的形状，但在其他大脑区域，这种现象与字母形式无关。我们的研究结果表明，γ-波段活动编码了一系列的感知和概念信息，这表明ECoG记录可以揭示特定人类认知表征的神经相关性。
A fundamental question in neuroscience concerns how the human brain represents perceptual and conceptual information. Traditionally researchers probed this issue by identifying single neurons that increased their firing rate when an animal encountered certain stimuli. Here we provide evidence of a complementary scheme in which gamma-band (25-128 Hz) electrocorticographic (ECoG) activity—a phenomenon involving large groups of neurons—encodes the active cognitive representation. We analyzed intracranial brain recordings from neurosurgical patients while they studied lists of visually presented letters, and found that the amplitude of gamma-band activity encoded the current letter’s identity. These letter-specific patterns occurred during periods of overall increased gamma amplitude and were linked to the phase of simultaneous theta (4-8 Hz) oscillations. In occipital cortex these patterns sometimes reflected the shape of the viewed letter, but in other brain regions this phenomenon was not related to letter form. Our findings show that gamma-band activity encodes a range of perceptual and conceptual information, suggesting that ECoG recordings can reveal neural correlates of specific human cognitive representations.