Induced gamma-band activity elicited by visual representation of unattended objects.
Induced gamma-band activity elicited by visual representation of unattended objects.
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由无人看管物体的视觉表现引起的诱导伽马带活动。
DOI：
10.1162/jocn.2009.21004
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发表时间：
2009
影响因子：
3.2
通讯作者：
Martinovic J
中科院分区：
文献类型：
--
作者：
Martinovic J
物体识别是通过依赖于分布式神经组件活动的神经机制来实现的，这些神经组件被认为是通过伽玛波段范围（> 20 Hz）内的同步发射来协调的。一个悬而未决的问题集中在伽马振荡在物体识别中的作用在多大程度上依赖于注意力。注意力机制决定了复杂场景中物体的感知资源分配，从而影响了它们相互竞争相互作用的结果。当感知资源被权衡为并发视觉材料的处理时，无人值守的对象也会出现与对象相关的伽玛活动增强吗？目前的脑电图研究使用固定时低或高感知负荷的视觉辨别任务，研究了事件相关电位以及诱发（时间和相位锁定）和诱导（非时间和相位锁定刺激开始）伽玛带活动（GBA）。当与任务无关的熟悉或不熟悉的物体同时出现在周围的中心区域时执行任务。通过在试验之间改变感知负荷，将注意力集中在固定处；在这种情况下，人们认为只需要很少或根本不需要注意的整体对象处理或低级感知处理就会发生。尽管诱发的 GBA 仍未受到调节，但观察到诱发的 GBA 增强（特定于熟悉的物体呈现），从而为无人看管物体的皮层视觉表征提供了证据。此外，该效果主要是由低负载下特定于对象的活动驱动的，这意味着在杂乱或复杂的场景中，注意力选择可能在对象表示中发挥更重要的作用。
Object recognition is achieved through neural mechanisms reliant on the activity of distributed neural assemblies that are thought to be coordinated by synchronous firing in the gamma-band range (>20 Hz). An outstanding question focuses on the extent to which the role of gamma oscillations in object recognition is dependent on attention. Attentional mechanisms determine the allocation of perceptual resources to objects in complex scenes biasing the outcome of their mutual competitive interactions. Would object-related enhancements in gamma activity also occur for unattended objects when perceptual resources are traded off to the processing of concurrent visual material? The present electroencephalogram study investigated event-related potentials and evoked (time- and phase-locked) and induced (non-time- and phase-locked to stimulus onset) gamma-band activity (GBA) using a visual discrimination task of low or high perceptual load at fixation. The task was performed while task-irrelevant familiar or unfamiliar objects coappeared in the surrounding central area. Attentional focus was kept at fixation by varying perceptual load between trials; in such conditions, only holistic object processing or low-level perceptual processing, requiring little or no attention, are thought to occur. Although evoked GBA remained unmodulated, induced GBA enhancements, specific to familiar object presentations, were observed, thus providing evidence for cortical visual representation of unattended objects. In addition, the effect was mostly driven by object-specific activity under low load, implying that, in cluttered or complex scenes, attentional selection likely plays a more significant role in object representation.