Digital selection and analogue amplification coexist in a cortex-inspired silicon circuit
Digital selection and analogue amplification coexist in a cortex-inspired silicon circuit
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DOI：
10.1038/35016072
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发表时间：
2000-06-22
期刊：
影响因子：
64.8
通讯作者：
Seung, HS
中科院分区：
文献类型：
--
作者：
Hahnloser, RHR;Sarpeshkar, R;Seung, HS
数字电路如触发器使用反馈来实现多稳态和非线性，以将信号恢复到逻辑电平，例如0和1。反馈电路通常被设计成线性工作，因此信号在一定范围内，并且响应是唯一的。相比之下，皮层回路对感觉刺激的反应既可以是多稳态的，也可以是分级的（1-4）。我们建议，新皮层结合数字选择的一组活跃的神经元与模拟反应，通过动态变化的正反馈固有的经常性连接。强正反馈导致微分不稳定性，该微分不稳定性在嵌入突触权重中的约束下驱动一组活跃神经元的选择。一旦被选中，活跃的神经元就会产生较弱的、稳定的反馈，从而对输入进行模拟放大。在这里，我们提出了我们的模型的皮层处理作为一个电子电路，模拟这种混合操作，因此能够执行类似的刺激选择，增益调制和时空模式生成在新皮层的计算。
Digital circuits such as the flip-flop use feedback to achieve multistability and nonlinearity to restore signals to logical levels, for example 0 and 1. Analogue feedback circuits are generally designed to operate linearly, so that signals are over a range, and the response is unique. By contrast, the response of cortical circuits to sensory stimulation can be both multistable and graded(1-4). We propose that the neocortex combines digital selection of an active set of neurons with analogue response by dynamically varying the positive feedback inherent in its recurrent connections. Strong positive feedback causes differential instabilities that drive the selection of a set of active neurons under the constraints embedded in the synaptic weights. Once selected, the active neurons generate weaker, stable feedback that provides analogue amplification of the input. Here we present our model of cortical processing as an electronic circuit that emulates this hybrid operation, and so is able to perform computations that are similar to stimulus selection, gain modulation and spatiotemporal pattern generation in the neocortex.