Yuval-Greenberg Shlomit, Tomer Orr, Keren Alon S, Nelken Israel, Deouell Leon Y
Department of Psychology, The Hebrew University of Jerusalem, Jerusalem 91905, Israel.
Neuron. 2008 May 8;58(3):429-41. doi: 10.1016/j.neuron.2008.03.027.
The induced gamma-band EEG response (iGBR) recorded on the scalp is widely assumed to reflect synchronous neural oscillation associated with object representation, attention, memory, and consciousness. The most commonly reported EEG iGBR is a broadband transient increase in power at the gamma range approximately 200-300 ms following stimulus onset. A conspicuous feature of this iGBR is the trial-to-trial poststimulus latency variability, which has been insufficiently addressed. Here, we show, using single-trial analysis of concomitant EEG and eye tracking, that this iGBR is tightly time locked to the onset of involuntary miniature eye movements and reflects a saccadic "spike potential." The time course of the iGBR is related to an increase in the rate of saccades following a period of poststimulus saccadic inhibition. Thus, whereas neuronal gamma-band oscillations were shown conclusively with other methods, the broadband transient iGBR recorded by scalp EEG reflects properties of miniature saccade dynamics rather than neuronal oscillations.
头皮记录的诱发伽马波段脑电图反应（iGBR）被广泛认为反映了与物体表征、注意力、记忆和意识相关的同步神经振荡。最常报道的脑电图iGBR是刺激开始后约200-300毫秒在伽马范围内功率的宽带瞬态增加。这种iGBR的一个显著特征是刺激后潜伏期在每次试验中的变异性，这一点尚未得到充分研究。在这里，我们通过对同步脑电图和眼动追踪的单次试验分析表明，这种iGBR与非自愿微小眼动的开始紧密时间锁定，并反映了一种扫视“尖峰电位”。iGBR的时间进程与刺激后扫视抑制期后扫视速率的增加有关。因此，虽然用其他方法已确凿显示了神经元伽马波段振荡，但头皮脑电图记录的宽带瞬态iGBR反映的是微小扫视动力学的特性，而非神经元振荡。
