Analog implementation of neuron-astrocyte interaction in tripartite synapse

Neural synchronization is considered as an important mechanism for information processing. In addition, recent neurophysiological findings approve that astrocytes adjust the synaptic transmission of neural networks. Motivated by these observations, we develop an analog neuromorphic circuit to implement the tripartite synapse. To model the dynamics of the intracellular calcium waves produced by the astrocytes, we utilize a simplified model which considers the key physiological pathways of neuron-astrocyte communication. Next, using an astrocyte analog circuit, a tripartite synapse circuit is constructed by connecting two modified differential pair integrator neurons and one astrocyte circuits. It is designed and simulated using HSPICE simulator in 0.35 mu m standard CMOS technology. The simulation results of the tripartite synapse circuit, demonstrate that astrocyte circuit plays a crucial role in neuronal firing synchronicity from hardware point of view. In this way, astrocyte-neuron collaboration leads to the emergence of synchronous/asynchronous patterns in neural responses. Therefore, it makes possible to have a new circuit in which astrocyte actively contributes in neural information processing.