A neuromorphic real-time VLSI design of Ca2+ dynamic in an astrocyte

Neurophysiological experiments have illustrated that astrocytes, the most abundant subtype of the glial cells, have the potential to dynamically regulate and control synaptic transmissions in neural networks. As these cells are able to provide energy substrates for neurons, they play an important role in human brain processing. This paper proposes an analogue implementation of an astrocyte model that can describe the contribution from activation pathways, by modeling the calcium dynamics of astrocyte with different bias currents. The proposed VLSI circuit has been designed using 0.35 μm CMOS standard technology in HSpice software. Simulation results demonstrated that the proposed astrocyte circuit has the advantages of low power consumption and compactness. Furthermore, it is a real-time VLSI design that uses a number of transistors operating in the subthreshold region; therefore, it is believed that the proposed design can be used for implementations of dense arrays of neural networks in several applications.