Silicon neurons that burst when primed

The authors present a silicon neuron that responds with a high-frequency burst of spikes (> 250Hz) when appropriately primed; otherwise it responds with lower frequency single spikes (< 100Hz). Our model is based upon neurons that relay sensory inputs to the cortex. The bursts (2-6 spikes) are caused by an excitatory calcium channel, designed using circuits that capture the channel´s nonlinear dynamics. With sufficient priming, the channel opens quickly and closes slowly when the neuron´s voltage increases. Priming the channel requires lowering the neuron´s voltage for a sufficient period; thus, inhibitory inputs that can control the cell´s response mode. We fabricated 7200 relay neurons on a 11.5mm² chip in 0.25mum CMOS. We plan to use feedback from a cortex chip to prime the relay neurons and thereby realize attention.