Silicon Synchrony

In interneuron networks in silicon, we have found:

  • Synchrony by inhibition requires synaptic delay or rise-time
  • Rise-time (or delay) not the inhibitory decay constant, determines the network frequency
  • Shunting inhibition (conductance-based) enhances synchrony
Running a simulation on a neuromorphic chip You observe all 256 silicon neurons' spike rates (yellow dots) and spike trains (white ticks) in real-time; some neurons are silent (gaps). You select a neuron (white square and red ticks) to see its membrane potential (orange trace) and hear it spike ('pop' sound). You can change the neurons' connectivity and observe the resulting behavior: Here, they inhibit their neighbors and synchrony results—a 40Hz rhythm is evident in the population histogram (beneath spike trains; the other histogram shows individual spike rates). [John Arthur 2006]

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