Dynamics of spatial summation in primary visual cortex of alert monkeys
Dynamics of spatial summation in primary visual cortex of alert monkeys
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DOI：
10.1073/pnas.96.21.12073
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发表时间：
1999-10-12
影响因子：
11.1
通讯作者：
Gilbert, CD
中科院分区：
文献类型：
--
作者：
Kapadia, MK;Westheimer, G;Gilbert, CD
视觉皮层的基本任务之一是整合来自视网膜不同部分的输入，将图像解析为轮廓和表面，然后将这些特征组装成物体的连贯表示。为了研究初级视皮层在视觉信息整合中的作用，我们测量了神经元在不同刺激条件下的反应特性。令人惊讶的是，我们发现即使是最传统的感受野（RF）大小的测量也不是固定的，而是可以根据刺激对比度和前景-背景关系而变化。平均而言，兴奋性RF的长度是4倍，在高对比度的刺激比低对比度的刺激。在纹理背景中嵌入高对比度刺激往往会抑制神经元的反应，并产生类似于通过降低孤立刺激的对比度所观察到的RF大小的放大。结果表明，RF尺寸的调节在一个动态的方式，既取决于本地的刺激特性，如对比度，和刺激和它的周围环境之间的全球关系。
One of the fundamental tasks of the visual cortex is to integrate input from different parts of the retina, parsing an image into contours and surfaces, and then assembling these features into coherent representations of objects. To examine the role of the primary visual cortex in the integration of visual information, we measured the response properties of neurons under different stimulus conditions. surprisingly, we found that even the most conventional measures of receptive field (RF) size were not fixed, but could vary depending on stimulus contrast and foreground-background relationships. On average, the length of the excitatory RF was 4-fold greater for a low-contrast stimulus than for a stimulus at high contrast. Embedding a high-contrast stimulus in a textured background tended to suppress neuronal responses and produced an enlargement in RF size similar to that observed by decreasing the contrast of an isolated stimulus. The results show that RF dimensions are regulated in a dynamic manner that depends both on local stimulus characteristics, such as contrast, and on global relationships between a stimulus and its surroundings.