Microglia in experimental brain injury: Implications on neuronal injury and circuit remodeling

Neurons in the brain are supported by glial cells, including astrocytes and microglia. Together, these cells establish and maintain functional circuits. Often overlooked, microglia function as the immune cells of the central nervous system, monitoring the microenvironment for changes in signaling, pathogens and injury. This chapter discusses the various roles of microglia in the healthy and in diseased brain with a focus on traumatic brain injury. Within the healthy brain, ramified microglia constantly survey the microenvironment playing roles in neurotransmission and maintenance of synaptic integrity. In injury, microglia may interact with neurons to mediate the transition between injury-induced circuit dismantling and subsequent reorganization. Increased understanding of microglial roles could identify therapeutic targets to mitigate the consequences of neurological diseases.