Glia are the class of nerve cells that provide structural support for neurons. Also referred to as neuroglia, the cells are continuously capable of division and are more than ten times as abundant as neurons in the human brain. Featured below is a digital image of the glia and nuclei of a rat cerebellum mid-saggital section captured with a BioRad Radiance confocal. The glia are labeled orange and the nuclei are green.

Glia and Nuclei in Rat Cerebellum Specimen: Fluorescently labeled thin section Technique: Confocal Microscopy

The term neuroglia literally means “nerve glue” and refers to what was formerly believed to be the only function of the cells. Increasing evidence, however, suggests that neuroglia play a more active role in the operations of the brain. The cells provide neurons with nutrients and remove toxic materials to preserve homeostasis, as well as act as electrical insulation. Specific varieties of glia have additional functions. For instance, astrocytes divide after brain injury to fill spaces formerly occupied by neurons and oligodendroglial cells produce the protein myelin.

Historically, scientists have argued that neuroglia, which lack synapses and axons, are not electrically excitable. Yet, recent experiments have demonstrated that in vitro the cells are responsive to voltage in a manner reminiscent of excitable neurons. Nevertheless, there is no current research available that indicates the occurrence of similar neuroglial electrical activity in the body. If such evidence were to arise, however, the implications for understanding the brain and its activity would be extraordinary.