[Microglia in Brain Development].

Microglia, traditionally known as resident immune cells in the brain, have been recently identified as one of the important cell types engaging in the formation and maintenance of neural circuitry, especially during the development. In this review, I describe the diversity of microglial functions revealed in different phases of development, ranging from neurogenesis to circuit formation. In particular, microglia possess dual functions in supporting the survival of neuronal structures or neural cells themselves, and removing excess neural components. Understanding these processes and underlying molecular mechanisms will provide important insights into the regulation of neural circuitry development. It further implicates the involvement of microglial dysfunction in neurodevelopmental disorders.