Subthreshold facilitation and suppression in primary visual cortex revealed by intrinsic signal imaging.
Subthreshold facilitation and suppression in primary visual cortex revealed by intrinsic signal imaging.
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DOI：
10.1073/pnas.93.18.9869
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发表时间：
1996-09
影响因子：
11.1
通讯作者：
L. Toth;S. Rao;Dae-Shik Kim;D. Somers;Mriganka Sur
中科院分区：
文献类型：
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作者：
L. Toth;S. Rao;Dae-Shik Kim;D. Somers;Mriganka Sur
初级视皮层（17区）的神经元对感受野内的定向刺激反应强烈;然而，阈上感受野外的刺激也会影响它们的反应。在这里，我们描述了阈上中心和阈下周围的空间相互作用的一个基本特征。通过对区域17中响应于刺激边界的内在信号的光学成像，我们表明，给定的刺激主要在等取向域中产生活动，该等取向域以与区域17中的长距离水平连接的架构一致的方式在皮层表面上延伸几毫米。通过映射单个神经元的感受野和来自同一皮层的成像反应，包括或排除聚合阈上感受野的刺激，我们表明，内在信号强烈揭示了阈下环绕的贡献。光学成像和单单位记录都表明，中心和周围刺激的相对对比度调节周围的相互作用是促进还是抑制：相同的周围刺激促进反应时，中心对比度低，但抑制反应时，中心对比度高。区域17中的这种空间交互理想地适合于促成通常被认为是“高级”视觉处理的一部分的现象，诸如感知“弹出”和“填充”。"
Neurons in primary visual cortex (area 17) respond vigorously to oriented stimuli within their receptive fields; however, stimuli presented outside the suprathreshold receptive field can also influence their responses. Here we describe a fundamental feature of the spatial interaction between suprathreshold center and subthreshold surround. By optical imaging of intrinsic signals in area 17 in response to a stimulus border, we show that a given stimulus generates activity primarily in iso-orientation domains, which extend for several millimeters across the cortical surface in a manner consistent with the architecture of long-range horizontal connections in area 17. By mapping the receptive fields of single neurons and imaging responses from the same cortex to stimuli that include or exclude the aggregate suprathreshold receptive field, we show that intrinsic signals strongly reveal the subthreshold surround contribution. Optical imaging and single-unit recording both demonstrate that the relative contrast of center and surround stimuli regulates whether surround interactions are facilitative or suppressive: the same surround stimulus facilitates responses when center contrast is low, but suppresses responses when center contrast is high. Such spatial interactions in area 17 are ideally suited to contribute to phenomena commonly regarded as part of "higher-level" visual processing, such as perceptual "popout" and "filling-in."