Table 1.

Classification of astrocytes.

Types of astrocytes	Anatomical locations	Cellular morphologies	Functions	Reference
Protoplasmic astrocytes	Grey matter	Short branched;	• Maintenance of the blood–brain barrier;	Peters et al., 1991; Bushong et al., 2002; Nishiyama et al., 2002; Ogata and Kosaka, 2002; Oberheim et al., 2006; Sofroniew and Vinters, 2010
		Thick processes	• Regulation of blood flow;
			• In synapse formation;
			• Neuronal metabolism
Fibrous astrocytes	White matter	Thin and straight processes	• Maintenance of the blood–brain barrier;	Sofroniew and Vinters, 2010
			• Regulation of blood flow;
			• In synapse formation;
			• Neuronal metabolism
Interlaminar astrocytes	Pial surface (humans and monkey)	Spherical cell bodies	• Regulation of calcium wave;	Oberheim et al., 2009
			• Thick network of GFAP fibers
Varicose projection astrocytes	Fifth and sixth layer of the cerebral cortex	Long processes. (up to 1 mm in length)	Unknown	Oberheim et al., 2009, 2012
Epithelial glial cells (Bergmann glia)	Purkinje-cell layer of cerebellum	Long processes	• Synaptic transmission.	Fuller and Burger, 1992; Olude et al., 2015
Fañanas cells	Cerebellar cortex	Feather-like arrangement	Unknown	Fuller and Burger, 1992
Müller cells	Retina of juvenile	A type of radial glial	• Retinal homeostasis;	Fuller and Burger, 1992; Vecino et al., 2015
			• Phagocytosis of neural debris;
			• Metabolic activity;
			• Glycogen within their cytoplasm
Pituicytes	Neurohypophysis	Irregular shaped cytoplasm	Unknown	Burger and Scheithauer, 1993
Interstitial epiphyseal cells	Epiphysis	Cytoplasmic processes	Unknown	Fuller and Burger, 1992

Astrocytic domain organization varies with pathology and anatomical locations.