A computational model to investigate astrocyte glutamate modulation effect on tripartite synapse and neuronal network state

摘要

Astrocytes, most numerous glial cells in brain, respond to neural activities by provoking calcium waves and releasing transmitters to adjacent synapses and consequently, modulate neural activities. Here, we used leaky integrate and fire (LIF) neuron and a minimal functional astrocyte models with detailed synaptic mechanism to investigate astrocyte modulation impact on firing of tripartite synapse and network firing states. We assumed astrocyte facilitates and depress synapses by D-serine acting on N-methyl-d-aspartic acid (NMDA) receptors in post-synaptic neuron, and glutamate acting on metabotropic glutamate receptors (mGluRs) in pre-synaptic terminal. The model predicted that in the presence of astrocyte, a tripartite synapse exhibited bi-stable activity in the terms of pre-and post-synaptic neural firing rate; and neural population with bi-stable characteristic exhibited more stability on high firing rates, and impaired astrocyte function lead to less stable network activity.