The original neuronal star cells conceived by Ramon Ya Kagal were in 1913 using a golden dye. This bulb targeting intermediate filaments, which we now know, is composed mainly of adipose fibroblastic protein, a protein that is used today as an astral sign.

Cajal describes the morphological diversity of these cells with some cells surrounding neurons, while others are closely related to blood vessels. We begin by discussing the heterogeneity of stellar cells using contemporary tools and by questioning the assumption by classical neuroscience that neurons and glia are derived from distinct groups of ancestral cells.

Stellar cells have long been neglected as active participants in intracellular communication and processing information in the central nervous system, in part due to the absence of electrical excitation. The follow-up chapters review "nuts and bolts" in physiology.

Stellar cells have a variety of ion channels, the neurotransmitter receptors, and transport mechanisms that enable astrocytes to respond to many of the same signals that act on neurons. Because astrocytes can detect chemical transmitters that are released from neurons and can trigger their own extracellular signals, there is a growing awareness that they play physiological roles in regulating neural activity and interlocking transmission.

In addition to these physiological roles, it is increasingly recognized that astrocytes play crucial roles during neurological disease. These states include gliomas, Alexander's disease, and epilepsy to name a few..