Astrocytes Astrocytes form a parallel universe in the microcosm of the brain, where the number of neurons is quite comparable to the number of stars in the galaxy. Just 25 years ago they were considered to be just an auxiliary structure supporting the whole cellular structure, but today scientists attribute a quite important, special significance to them. Star-shaped cells do hold up the complex architecture of the brain, but not only. They maintain homeostasis, store and redistribute energy, protect the brain from attacks by foreign molecules, provide recycling of neurotransmitters, ensure normal functioning of synapses and control the entire system of signal transmission; and the list goes on.