Department of Neural Systems, Max Planck Institute for Brain Research, Frankfurt am Main, Hessen 60528, Germany.
Neural Comput. 2012 Aug;24(8):2033-52. doi: 10.1162/NECO_a_00304. Epub 2012 Apr 17.
Models of cortical neuronal circuits commonly depend on inhibitory feedback to control gain, provide signal normalization, and selectively amplify signals using winner-take-all (WTA) dynamics. Such models generally assume that excitatory and inhibitory neurons are able to interact easily because their axons and dendrites are colocalized in the same small volume. However, quantitative neuroanatomical studies of the dimensions of axonal and dendritic trees of neurons in the neocortex show that this colocalization assumption is not valid. In this letter, we describe a simple modification to the WTA circuit design that permits the effects of distributed inhibitory neurons to be coupled through synchronization, and so allows a single WTA to be distributed widely in cortical space, well beyond the arborization of any single inhibitory neuron and even across different cortical areas. We prove by nonlinear contraction analysis and demonstrate by simulation that distributed WTA subsystems combined by such inhibitory synchrony are inherently stable. We show analytically that synchronization is substantially faster than winner selection. This circuit mechanism allows networks of independent WTAs to fully or partially compete with other.
皮质神经元回路模型通常依赖于抑制性反馈来控制增益，提供信号归一化，并使用竞争型选择（winner-take-all，WTA）动态选择性地放大信号。这些模型通常假设兴奋性和抑制性神经元能够轻松地相互作用，因为它们的轴突和树突在同一小体积中局部化。然而，对新皮层中神经元的轴突和树突的维度的定量神经解剖学研究表明，这种局部化假设是不成立的。在这封信中，我们描述了对 WTA 电路设计的一个简单修改，该修改允许分布式抑制性神经元的影响通过同步来耦合，从而允许单个 WTA 在皮质空间中广泛分布，远远超出任何单个抑制性神经元的分支范围，甚至跨越不同的皮质区域。我们通过非线性收缩分析进行了证明，并通过模拟进行了演示，由这种抑制性同步组合的分布式 WTA 子系统是固有稳定的。我们分析表明，同步速度远远快于选择胜者的速度。这种电路机制允许独立 WTA 的网络完全或部分地与其他网络竞争。
