The contribution of spike threshold to the dichotomy of cortical simple and complex cells
The contribution of spike threshold to the dichotomy of cortical simple and complex cells
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DOI：
10.1038/nn1310
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发表时间：
2004-10
影响因子：
25
通讯作者：
Nicholas J. Priebe;F. Mechler;M. Carandini;D. Ferster
中科院分区：
文献类型：
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作者：
Nicholas J. Priebe;F. Mechler;M. Carandini;D. Ferster
Hubel和Wiseel于1962年发现猫初级视皮层存在简单和复杂两类细胞，这是猫初级视皮层的基本特征之一。用来区分简单和复杂细胞的一个定量指标是对漂移的栅格的尖峰响应的调制和未调制分量之间的比率，这是一个形成双峰分布的指数。我们发现，当从亚阈值膜电势而不是由尖峰速率推导出的调制比是单峰分布的，但高度偏斜。进而，通过将尖峰阈值的非线性特性应用于亚阈值调制比的偏斜分布，可以定量地预测从尖峰速率导出的调制率的分布。阈值还增加了感受野的ON和OFF区域的空间分离，这是简单细胞的一个定义属性。因此，阈值增强了简单细胞和复杂细胞之间的区别，就像对方向和方向等刺激特征的选择性一样。然而，在这种情况下，突触输入的空间组织中的连续分布被转换为两类不同的细胞。
The existence of two classes of cells, simple and complex, discovered by Hubel and Wiesel in 1962, is one of the fundamental features of cat primary visual cortex. A quantitative measure used to distinguish simple and complex cells is the ratio between modulated and unmodulated components of spike responses to drifting gratings, an index that forms a bimodal distribution. We have found that the modulation ratio, when derived from the subthreshold membrane potential instead of from spike rate, is unimodally distributed, but highly skewed. The distribution of the modulation ratio as derived from spike rate can, in turn, be predicted quantitatively by the nonlinear properties of spike threshold applied to the skewed distribution of the subthreshold modulation ratio. Threshold also increases the spatial segregation of ON and OFF regions of the receptive field, a defining attribute of simple cells. The distinction between simple and complex cells is therefore enhanced by threshold, much like the selectivity for stimulus features such as orientation and direction. In this case, however, a continuous distribution in the spatial organization of synaptic inputs is transformed into two distinct classes of cells.