EEG oscillations induced by contour closure in a noisy visual field.
EEG oscillations induced by contour closure in a noisy visual field.
复制标题
嘈杂视野中轮廓闭合引起的脑电图振荡。
DOI：
10.1016/j.bbr.2008.07.026
复制
发表时间：
2009
影响因子：
2.7
通讯作者：
Tarokh,Leila
中科院分区：
文献类型：
--
作者：
Tarokh,Leila
本研究的目的是将与视觉对象的意识相关的神经反应与无意识的视觉输入的神经反应分开。向受试者呈现两类刺激：（1）随机定位和定向的Gabor贴片的场（无轮廓）或（2）相同的Gabor贴片场，其中Gabor贴片的子集以这样的方式定向，从而产生椭圆的概念（轮廓）。为了测量脑电图（EEG）对轮廓的反应，在没有意识的情况下，将存在轮廓但未感知到的试验与不存在轮廓且正确指示其不存在的试验进行比较。在β频率下，轮廓的存在降低了刺激后约130- 230 ms的诱发电位（EP）功率。当轮廓存在但未被感知时，θ波段的相干性也降低。因此，当轮廓出现时，即使受试者没有意识到，也会发生EP的调制。为了探索意识的相关性，将受试者正确指出轮廓存在的试验与未检测到物体的试验进行比较。受试者之间一致，意识导致刺激后130- 230 ms左右的β范围内的EP功率增加。这些结果表明，在EEG记录中，对物体的神经反应和对该物体的意识是分离的。
This study was designed to separate the neural response associated with awareness of a visual object from the neural responses to the visual input without awareness. Two classes of stimuli were presented to subjects: (1) a field of randomly positioned and oriented Gabor patches (no contour) or (2) the same field of Gabor patches in which a subset of the Gabor patches were oriented in such a way as to give rise to the percept of an ellipse (contour). To measure the electroencephalograph (EEG) responses to the contour without awareness, trials during which a contour was present but not perceived were compared to trials where no contour was present and its absence was correctly indicated. At beta frequencies, the presence of the contour reduced the evoked potential (EP) power approximately 130–230ms post-stimulus. Coherence in the theta band were also reduced when a contour was present but not perceived. Thus, modulations of the EP take place when a contour is presented even without the subjects’ awareness. To explore the correlates of awareness, trials during which the subject correctly indicated the presence of a contour were compared to trials in which the object was not detected. Consistent across subjects, awareness caused an increase in the EP power in the beta range around 130–230ms post-stimulus. These results suggest that the neural response to an object and awareness of that object are dissociable in EEG recordings.