Microglia are the principal immune response cells in the central nervous system. Resting microglia constantly survey the microenvironment in the normal brain. Upon brain dysfunction, microglia are activated and exert detrimental or beneficial effects on the surrounding neurons. The long-term goal of my lab is to understand microglia-neuron communication in normal and diseased brain. We are interested in fundamental questions on: (1) How microglia sense neuronal activities? (2) How microglia regulate neuronal and synaptic function? (3) What are the molecular mechanisms and functional consequences of microglia activation in brain diseases? To address these questions, we use the combination of two photon deep-brain imaging, electrophysiology, mouse genetics to dissect the role of microglia in neuronal circuits and in brain disorders, with particular focus on epilepsy and chronic pain. Our studies provide a novel insight on microglial function in brain hemostasis and suggest microglia as a potential therapeutic target for the treatment of epilepsy and chronic pain.