Low-level and high-level modulations of fixational saccades and high frequency oscillatory brain activity in a visual object classification task.
Low-level and high-level modulations of fixational saccades and high frequency oscillatory brain activity in a visual object classification task.
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DOI：
10.3389/fpsyg.2013.00948
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发表时间：
2013
影响因子：
3.8
通讯作者：
Martinovic J
中科院分区：
文献类型：
--
作者：
Kosilo M;Wuerger SM;Craddock M;Jennings BJ;Hunt AR;Martinovic J
直到最近，诱发的γ-波段活动（GBA）被认为是皮质物体表征的神经标记。然而，诱发GBA在脑电图（EEG）是容易受到伪影所造成的微型固视扫视。最近的研究表明，注视扫视也反映了高层次的表征过程。高水平因素和低水平因素对注视性眼跳有影响吗？这些因素对无伪影GBA有什么影响？为了研究这一点，我们使用相同的设计进行了单独的眼动跟踪和EEG实验。参与者将线条画分为物体和非物体。为了引入低水平的差异，轮廓被定义为沿着沿着不同的方向在基数颜色空间：S锥隔离，中间等亮度，或全色刺激，后者包含一个额外的非彩色组件。在分类任务之前，测量物体辨别阈值，并将刺激缩放到匹配每个参与者的阈上水平。在这两个实验中，行为表现是最好的全色刺激和最差的S锥隔离刺激。眼跳率200-700毫秒刺激发作后调制独立的低和高层次的因素，是更高的全色刺激比S-锥隔离刺激和更高的对象。低振幅诱发GBA和总GBA观察到在极少数情况下，显示范例与等亮度刺激可能不是理想的引发这样的反应。我们的结论是，参与处理对象的皮质回路优先兴奋的刺激，包含无色信息。它们的激活可以导致相对早期的探索性眼球运动，即使是对于中央凹呈现的刺激。
Until recently induced gamma-band activity (GBA) was considered a neural marker of cortical object representation. However, induced GBA in the electroencephalogram (EEG) is susceptible to artifacts caused by miniature fixational saccades. Recent studies have demonstrated that fixational saccades also reflect high-level representational processes. Do high-level as opposed to low-level factors influence fixational saccades? What is the effect of these factors on artifact-free GBA? To investigate this, we conducted separate eye tracking and EEG experiments using identical designs. Participants classified line drawings as objects or non-objects. To introduce low-level differences, contours were defined along different directions in cardinal color space: S-cone-isolating, intermediate isoluminant, or a full-color stimulus, the latter containing an additional achromatic component. Prior to the classification task, object discrimination thresholds were measured and stimuli were scaled to matching suprathreshold levels for each participant. In both experiments, behavioral performance was best for full-color stimuli and worst for S-cone isolating stimuli. Saccade rates 200–700 ms after stimulus onset were modulated independently by low and high-level factors, being higher for full-color stimuli than for S-cone isolating stimuli and higher for objects. Low-amplitude evoked GBA and total GBA were observed in very few conditions, showing that paradigms with isoluminant stimuli may not be ideal for eliciting such responses. We conclude that cortical loops involved in the processing of objects are preferentially excited by stimuli that contain achromatic information. Their activation can lead to relatively early exploratory eye movements even for foveally-presented stimuli.
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DOI：
10.1126/science.1166112
发表时间：
2009-02-13
期刊：
Science (New York, N.Y.)
影响因子：
--
作者：
Hafed ZM;Goffart L;Krauzlis RJ
通讯作者：
Krauzlis RJ
影响因子：
3.4
作者：
Hassler, Uwe;Friese, Uwe;Gruber, Thomas
通讯作者：
Gruber, Thomas
影响因子：
--
作者：
CORNSWEET, TN
通讯作者：
CORNSWEET, TN
影响因子：
3.7
作者：
Fruend, Ingo;Busch, Niko A.;Herrmann, Christoph S.
通讯作者：
Herrmann, Christoph S.
影响因子：
3.7
作者：
Craddock M;Martinovic J;Müller MM
通讯作者：
Müller MM