Oscillatory γ-Band (30–70 Hz) Activity Induced by a Visual Search Task in Humans
Oscillatory γ-Band (30–70 Hz) Activity Induced by a Visual Search Task in Humans
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DOI：
10.1523/jneurosci.17-02-00722.1997
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发表时间：
1997-01
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影响因子：
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通讯作者：
C. Tallon-Baudry;O. Bertrand;C. Delpuech;J. Pernier
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文献类型：
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作者：
C. Tallon-Baudry;O. Bertrand;C. Delpuech;J. Pernier
视觉系统中物体的相干表征被认为是通过分布的神经元集合在γ波段（30-70 Hz）的同步来实现的。在这里，我们测量人类头皮上高频活动的变化。这个实验的目的是比较对同一张图片的两种不同的看法。在第一种情况下，一个显然毫无意义的图片，其中包含一个隐藏的斑点狗，一个中性刺激，和一个目标刺激（旋转的斑点）。在训练受试者感知隐藏的狗及其镜像之后，进行记录的第二部分（条件2）。呈现相同的中性刺激，与狗的图片及其镜像（目标刺激）混合。早期（95 msec）锁相（或刺激锁定）γ波段振荡不随刺激类型而变化，但可细分为前分量（38 Hz）和后分量（35 Hz）。非锁相γ波段振荡在刺激开始后出现约280 msec的延迟抖动，并在平均数据中消失。它们对两种目标刺激的响应幅度增加。与第一种情况相比，在第二种情况下，它们也在全球范围内增加。这表明，这种γ-波段能量的增加反映了自下而上（基本特征的结合）和自上而下（寻找隐藏的狗）激活相同的神经组装编码的斑点狗。高频和低频分量的响应之间的关系进行了讨论，并建议每个组件的可能的功能作用。
The coherent representation of an object in the visual system has been suggested to be achieved by the synchronization in the γ-band (30–70 Hz) of a distributed neuronal assembly. Here we measure variations of high-frequency activity on the human scalp. The experiment is designed to allow the comparison of two different perceptions of the same picture. In the first condition, an apparently meaningless picture that contained a hidden Dalmatian, a neutral stimulus, and a target stimulus (twirled blobs) are presented. After the subject has been trained to perceive the hidden dog and its mirror image, the second part of the recordings is performed (condition 2). The same neutral stimulus is presented, intermixed with the picture of the dog and its mirror image (target stimulus). Early (95 msec) phase-locked (or stimulus-locked) γ-band oscillations do not vary with stimulus type but can be subdivided into an anterior component (38 Hz) and a posterior component (35 Hz). Non-phase-locked γ-band oscillations appear with a latency jitter around 280 msec after stimulus onset and disappear in averaged data. They increase in amplitude in response to both target stimuli. They also globally increase in the second condition compared with the first one. It is suggested that this γ-band energy increase reflects both bottom-up (binding of elementary features) and top-down (search for the hidden dog) activation of the same neural assembly coding for the Dalmatian. The relationships between high- and low-frequency components of the response are discussed, and a possible functional role of each component is suggested.