Perceiving the Tree in the Woods: Segregating Brain Responses to Stimuli Constituting Natural Scenes
Perceiving the Tree in the Woods: Segregating Brain Responses to Stimuli Constituting Natural Scenes
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DOI：
10.1523/jneurosci.4743-11.2011
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发表时间：
2011-11
期刊：
影响因子：
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通讯作者：
Ulla Martens;N. Trujillo-Barreto;T. Gruber
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文献类型：
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作者：
Ulla Martens;N. Trujillo-Barreto;T. Gruber
传统的神经科学方法不足以分离与同时处理自然场景不同部分相关的大脑反应。在目前的人类脑电图（EEG）研究中，我们通过标记同时呈现的背景和具有不同呈现频率的对象来克服这一限制。结果，背景和物体引发了不同的稳态视觉诱发电位（SSVEP），这些电位在频域中单独量化。我们分析了背景和物体之间的语义一致性和不一致对 SSVEP 振幅、地形和断层扫描 [可变分辨率电磁断层扫描 (VARETA)] 的影响。结果显示，与背景处理相关的 SSVEP 在一致条件下显示出比不一致条件下更高的振幅，而与对象相关的 SSVEP 显示出相反的效果模式。鉴于 SSVEP 对视觉注意力的敏感性，结果表明语义不一致会导致更多的注意力集中在物体上。如果所有图像部分在语义上都是相关的，那么注意力就会集中在背景上。对场景中不一致对象的注意力优势可能是基于背景的期望与语义对象信息之间不匹配的结果。前颞叶一致性效应的明显偏侧表明在处理背景和物体相关语义信息时功能半球不对称。总之，本研究首次证明了 SSVEP 阐明背景和物体感知中涉及的并发神经元过程各自贡献的可行性。
Conventional neuroscientific methods are inadequate for separating the brain responses related to the simultaneous processing of different parts of a natural scene. In the present human electroencephalogram (EEG) study, we overcame this limitation by tagging concurrently presented backgrounds and objects with different presentation frequencies. As a result, background and object elicited different steady-state visual evoked potentials (SSVEPs), which were separately quantified in the frequency domain. We analyzed the effects of semantic consistency and inconsistency between background and object on SSVEP amplitudes, topography, and tomography [variable resolution electromagnetic tomography (VARETA)]. The results revealed that SSVEPs related to background processing showed higher amplitudes in the consistent as opposed to the inconsistent condition, whereas object-related SSVEPs showed the reversed pattern of effects. Given the SSVEPs' sensitivity to visual attention, the results indicate that semantic inconsistency leads to greater attention focused on the object. If all image parts are semantically related, attention is rather directed to the background. The attentional advantage to inconsistent objects in a scene is likely the result of a mismatch between background-based expectations and semantic object information. A clear lateralization of the consistency effect in the anterior temporal lobes indicates functional hemispheric asymmetries in processing background- and object-related semantic information. In summary, the present study is the first to demonstrate the feasibility of SSVEPs to unravel the respective contributions of concurrent neuronal processes involved in the perception of background and object.