Tallon-Baudry C, Bertrand O, Delpuech C, Permier J
Brain Signals and Processes Laboratory, Institut National de la Santé et de la Recherche Médicale U280, Lyon, France.
J Neurosci. 1997 Jan 15;17(2):722-34. doi: 10.1523/JNEUROSCI.17-02-00722.1997.
The coherent representation of an object in the visual system has been suggested to be achieved by the synchronization in the gamma-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) gamma-band oscillations do not vary with stimulus type but can be subdivided into an anterior component (38 Hz) and a posterior component (35 Hz). Nonphase-locked gamma-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 gamma-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.
视觉系统中物体的连贯表征被认为是通过分布式神经元组件在伽马波段（30 - 70赫兹）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。该实验旨在比较对同一幅图片的两种不同感知。在第一种情况下，呈现一幅看似无意义的图片，其中包含一只隐藏的斑点狗、一个中性刺激和一个目标刺激（旋转的斑点）。在受试者经过训练能够感知隐藏的狗及其镜像后，进行记录的第二部分（条件2）。呈现相同的中性刺激，并与狗及其镜像的图片（目标刺激）混合。早期（95毫秒）锁相（或刺激锁相）的伽马波段振荡不随刺激类型变化，但可细分为前部成分（38赫兹）和后部成分（35赫兹）。非锁相伽马波段振荡在刺激开始后约280毫秒出现延迟抖动，并在平均数据中消失。它们对两种目标刺激的反应幅度都增加。与第一种情况相比，在第二种情况下它们在整体上也增加。有人认为，这种伽马波段能量增加反映了对编码斑点狗的同一神经组件的自下而上（基本特征的绑定）和自上而下（寻找隐藏的狗）的激活。讨论了反应的高频和低频成分之间的关系，并提出了每个成分可能的功能作用。
