A superposable silicon synapse with programmable reversal potential.
A superposable silicon synapse with programmable reversal potential.
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具有可编程反转电位的可叠加硅突触。
DOI：
10.1109/embc.2012.6346045
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发表时间：
2012
期刊：
影响因子：
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通讯作者：
Boahen,Kwabena
中科院分区：
文献类型：
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作者：
Benjamin,BenV;Arthur,JohnV;Gao,Peiran;Merolla,Paul;Boahen,Kwabena
我们提出了一种新的对数域硅突触设计的亚阈值模拟操作，模拟生物学中常见的突触相互作用。我们的电路通过以可叠加的方式模拟神经递质释放-再摄取和受体结合-解结合的过程来模拟离子通道电导的动态门控：只需要一个电路来模拟生物神经元接收的整个突触群体（给定类型）。与严格兴奋或抑制的先前设计不同，我们的硅突触首次在对数域中实现可编程反转电位（即，驱动力）。为了证明设计的可扩展性，我们在180 nm CMOS上制作了64 K个硅神经元的阵列，每个神经元具有四个独立的可叠加突触电路，每个突触电路占用11.0×21.5 μ m2。在验证了这些突触对神经元的尖峰频率具有预测的影响之后，我们探索了一个递归网络，其中突触的反转电位设置在神经元的阈值附近，充当分流器。这些分流突触同步神经元的尖峰比nonshunting突触更强大，证实了逆转电位可以有重要的网络水平的影响。
We present a novel log-domain silicon synapse designed for subthreshold analog operation that emulates common synaptic interactions found in biology. Our circuit models the dynamic gating of ion-channel conductances by emulating the processes of neurotransmitter release-reuptake and receptor binding-unbinding in a superposable fashion: Only a single circuit is required to model the entire population of synapses (of a given type) that a biological neuron receives. Unlike previous designs, which are strictly excitatory or inhibitory, our silicon synapse implements - for the first time in the log-domain - a programmable reversal potential (i.e., driving force). To demonstrate our design's scalability, we fabricated in 180nm CMOS an array of 64K silicon neurons, each with four independent superposable synapse circuits occupying 11.0×21.5 μm2apiece. After verifying that these synapses have the predicted effect on the neurons' spike rate, we explored a recurrent network where the synapses' reversal potentials are set near the neurons' threshold, acting as shunts. These shunting synapses synchronized neuronal spiking more robustly than nonshunting synapses, confirming that reversal potentials can have important network-level implications.