Microglia: first responders in the central nervous system.

Microglia has emerged not only as an essential inflammatory cell but also as a major player in the development of the adult brain. Microglia phagocytize extra-numerical synapses during postnatal development, maintain and strengthen the remaining subset of synapses, remodel synaptic circuits and clearing apoptotic newborn neurons. Thereby, microglia plays a crucial role for the establishment, plasticity and function of adult neural circuits. In addition to the key role in normal brain function, any imbalance in microglia activity has been associated with neurodegenerative diseases. Microglial cells respond rapidly to smallest pathological changes, this being a vital aspect in many tissue scaring and the local confinement of focal lesions. It is assumed that the high motility of microglial cells represents an important requirement to fulfill the numerous functions. In this review will highlight the role of microglial motility in the healthy and the injured brain, and discuss how impairment of microglia motility can affect normal brain function.