Glial cells outnumber neurons in the human brain 10:1. Nevertheless, for too many years glial cells were the underdogs of the central nervous system and not many neuroscientists deemed them a worthy cause to study. That the term gliais derived from the Greek word for glue did not help the cause. Fortunately, this has changed and in the last 2 decades glial cells have caught up to their axon-bearing cousins. It now has become clear that glial cells (ie, astrocytes, oligodendrocytes, and microglia) are equal partners with neurons in assuring healthy function of the most complex organ we know. They control development, functional activity, and death of neuronal circuits and glial dysfunction plays a crucial role in neurodegenerative disease. Most intriguingly, it has become clear only in the last few years that glial cells are part of the stem cell complement of the central nervous system.
Glial Neurobiology: A Textbook. Arch Neurol. 2008;65(9):1254. doi:10.1001/archneur.65.9.1254-a