Microglia cells have very important and critical functions in the brain related to the nervous system and signal transmission systems in nerve cells. These are mainly: neurogenesis; production of nerve cells; synaptogenesis; production of myelin; proliferation of synapses in nerve cells; neural and synaptic plasticity; opening of nerve cells to functions such as orientation, stimulation, and education with defined behavioral residences; synaptic pruning; ensuring the balance (E/I balance) of synaptic excitation and inhibition; ensuring the connections in nerve cells and signal transmissions (neural connectivity). In summary, microglia cells play a key role for healthy nerve cells, synapses, and signal transmission systems.