Mexican hats and pinwheels in visual cortex
Mexican hats and pinwheels in visual cortex
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DOI：
10.1073/pnas.0138051100
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发表时间：
2003-03-04
影响因子：
11.1
通讯作者：
Sompolinsky, H
中科院分区：
文献类型：
--
作者：
Kang, KJ;Shelley, M;Sompolinsky, H
许多模型的皮质功能假设，当地的横向连接是特定的相互作用的细胞的首选功能，他们是组织在一个墨西哥帽模式与强大的“中心”兴奋两侧的强大的“环绕”抑制。然而，初级视皮层的解剖学数据表明，局部连接是各向同性的，抑制的范围比兴奋的范围短。我们解决这个问题的神经元网络模型的局部皮层电路在初级视觉皮层的分析研究。在该模型中，由会聚的外侧膝状体核输入指定的方向列被安排在一个风车架构，而皮质连接是各向同性的。我们得到抑制的空间范围和它的时间常数之间的权衡。如果抑制是快速的，网络可以运行在一个墨西哥帽模式与各向同性的连接，即使在空间狭窄的抑制。如果抑制不快，墨西哥帽操作需要一个空间广泛的抑制。墨西哥帽操作可以产生一个尖锐的取向调谐，这在很大程度上是独立的细胞从风车中心的距离。
Many models of cortical function assume that local lateral connections are specific with respect to the preferred features of the interacting cells and that they are organized in a Mexican-hat pattern with strong "center" excitation flanked by strong "surround" inhibition. However, anatomical data on primary visual cortex indicate that the local connections are isotropic and that inhibition has a shorter range than excitation. We address this issue in an analytical study of a neuronal network model of the local cortical circuit in primary visual cortex. In the model, the orientation columns specified by the convergent lateral geniculate nucleus inputs are arranged in a pinwheel architecture, whereas cortical connections are isotropic. We obtain a trade-off between the spatial range of inhibition and its time constant. If inhibition is fast, the network can operate in a Mexican-hat pattern with isotropic connections even with a spatially narrow inhibition. If inhibition is not fast, Mexican-hat operation requires a spatially broad inhibition. The Mexican-hat operation can generate a sharp orientation tuning, which is largely independent of the distance of the cell from the pinwheel center.