Priebe Nicholas J, Ferster David
Section of Neurobiology, University of Texas at Austin, 1 University Station C0920, Austin, TX 78712, USA.
Neuron. 2008 Feb 28;57(4):482-97. doi: 10.1016/j.neuron.2008.02.005.
Ever since Hubel and Wiesel described orientation selectivity in the visual cortex, the question of how precise selectivity emerges has been marked by considerable debate. There are essentially two views of how selectivity arises. Feed-forward models rely entirely on the organization of thalamocortical inputs. Feedback models rely on lateral inhibition to refine selectivity relative to a weak bias provided by thalamocortical inputs. The debate is driven by two divergent lines of evidence. On the one hand, many response properties appear to require lateral inhibition, including precise orientation and direction selectivity and crossorientation suppression. On the other hand, intracellular recordings have failed to find consistent evidence for lateral inhibition. Here we demonstrate a resolution to this paradox. Feed-forward models incorporating the intrinsic nonlinear properties of cortical neurons and feed-forward circuits (i.e., spike threshold, contrast saturation, and spike-rate rectification) can account for properties that have previously appeared to require lateral inhibition.
自从休伯尔和威塞尔描述了视觉皮层中的方向选择性以来，关于精确选择性是如何产生的问题一直存在着相当大的争论。关于选择性如何产生，本质上有两种观点。前馈模型完全依赖于丘脑皮质输入的组织。反馈模型则依靠侧向抑制来相对于丘脑皮质输入提供的微弱偏差来细化选择性。这场争论是由两条不同的证据线索驱动的。一方面，许多反应特性似乎需要侧向抑制，包括精确的方向和方向选择性以及交叉方向抑制。另一方面，细胞内记录未能找到侧向抑制的一致证据。在这里，我们展示了这个悖论的一个解决方案。结合皮层神经元和前馈回路的内在非线性特性（即 spike 阈值、对比度饱和和 spike 率整流）的前馈模型可以解释以前似乎需要侧向抑制的特性。
