Science and technology | Out of ’cyte, out of mind

Neurons are not the only brain cells that think

Astrocytes, for instance, may play a role in depression and anxiety

Hippocampus tissue. Light micrograph of a sagittal (side view) section through the hippocampus of the brain showing the nerve cells within it. The hippocampus is a structure of the limbic system of the brain. There is a hippocampus in each cerebral hemisphere, and they are thought to be responsible for spatial awareness and the formation of memories. Different structures have been stained different colours: the nuclei of cells are red, neurofilaments are blue and glial cells are green. Neurofilaments are proteins found in the axons (output processes) of nerve cells. Glial cells (neuroglia) are cells that support and nourish nerve cells. Magnification: x160 when printed 10cm wide. — Image: Science Photo Library

Jan 23rd 2023

Most people, if they think about the matter at all, probably think of thinking as something done by the huge network of specialised, electrically conductive cells called neurons that occupies the upper half of their skulls. And, as far as it goes, that is true. The 86bn neurons in a human brain do indeed do much of the cognitive heavy lifting. But not all of it.

Supporting them is a cast of three other varieties of brain cell—microglia, oligodendrocytes and astrocytes—collectively called glial cells (short for “neuroglia”, from the Greek for “nerve glue”). Until recently, these were neglected by neurology. That has changed. Glial cells (their filaments stained green in the section of rat hippocampus pictured, with neuron filaments stained blue and the nuclei of both stained red) are now fashionable topics of study. The results have blown away the idea that they are mere glue.

This article appeared in the Science & technology section of the print edition under the headline "The other brain cells"