文章基本信息

标题：Novel neural circuit mechanism for visual edge detection
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作者：Charles F. Stevens
期刊名称：Proceedings of the National Academy of Sciences
印刷版ISSN：0027-8424
电子版ISSN：1091-6490
出版年度：2015
卷号：112
期号：3
页码：875-880
DOI：10.1073/pnas.1422673112
语种：English
出版社：The National Academy of Sciences of the United States of America
摘要：SignificanceThis paper is significant for three reasons. First, it proposes a new way that the visual cortex carries out a computation by simply having differing abundances of neurons that vary in a particular property (how large a piece of the visual world they report on). Second, it proposes a new use for population codes. Finally, it establishes the role for a quantitative anatomical feature of primary visual cortex: Abundances that differ in the way observed in experiment serve to apply an edge detection filter to the image. The primary visual cortex is organized in a way that assigns a specific collection of neurons the job of providing the rest of the brain with all of the information it needs about each small part of the image present on the retina: Neighboring patches of the visual cortex provide the information about neighboring patches of the visual world. Each one of these cortical patches--often identified as a "pinwheel"--contains thousands of neurons, and its corresponding image patch is centered on a particular location in the retina. For stimuli within their image patch, neurons respond selectively to lines or edges with a particular slope (orientation tuning) and to regions of the patch of different sizes (known as spatial frequency tuning). The same number of neurons is devoted to reporting each possible slope (orientation). For the cells that cover different-sized regions of their image patch, however, the number of neurons assigned depends strongly on their preferred region size. Only a few neurons report on large and small parts of the image patch, but many neurons report visual information from medium-sized areas. I show here that having different numbers of neurons responsible for image regions of different sizes actually carries out a computation: Edges in the image patch are extracted. I also explain how this edge-detection computation is done.
关键词：visual cortex ; neural computation ; population code ; theory