Table 2.

Microglia regulation of neuronal activity and synaptic plasticity

Signaling (or physical contact)	Effect on activity or plasticity	Reference
Neuronal ATP and A1R, and microglial P2RY12	Inhibit excessive activity	Badimon et al., 2020
Direct microglia and synapse contact	Enhance activity, calcium and synchronization	Akiyoshi et al., 2018
Microglial PI3K and BDNF	Enhance plasticity	Chen et al., 2017; Burk et al., 2018; Saw et al., 2020
Neuronal CD200 and microglial CD200R	Enhance plasticity	Feng et al., 2019; Sun et al., 2020
Microglial TNFα and IL-1β	Inhibit plasticity	Pettigrew, 2016; Hoshino et al., 2017; Lin, 2019
Neuronal CX3CL1 and microglial CX3CR1	Enhance plasticity	Basilico et al., 2019; Kim et al., 2020

A1R: A1 receptor; ATP: adenosine triphosphate; BDNF: brain-derived neurotrophic factor; CD200: cluster of differentiation 200; CD200R: cluster of differentiation 200 receptor; CX3CL1: C-X3-C motif chemokine ligand 1; CX3CR1: C-X3-C motif chemokine receptor 1; IL-1β: interleukin 1 beta; PI3K: phosphoinositide 3-kinase; TNF-α: tumor necrosis factor alpha.