Our Brain’s Underrated Little Helpers

The importance of our supporting brain cells

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When we think of the brain and brain cells we automatically think of neurons. They are after all where information is transmitted. They give us those wonderful electric sparks that are called action potentials, the magnificent brain waves, and supposedly what is highlighted when magnificent fMRI pictures show colourful blobs on maps of the brain. Some of this is true, but our neurons cannot work without another set of cells, namely what are collectively called glial cells and their role is critical in all aspects of the brain.

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Neurons get all the glory in the brain. They send sparks of electricity along their lengths and can come in different forms and shapes. They release transmitters and grow and connect to other neurons or deteriorate in various neuro degenerative diseases.

But there is another group of cells that are essential to brain function – indeed the brain could not function without them. These are collectively called glial cells and include three types:

1. Astrocytes

2. Oligodendrocytes

3. Microglia

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Let’s quickly cover the last two, as important as they are, for this article we will remain brief. Oligodendrocytes, what a name, are often called Schwan cells, that’s easier, and are generally responsible for building the myelin sheath on axons. This is the fatty white mass, that contribute so the whiteness of brain white matter, we spoke about this briefly last issue. This myelin sheath increases the transmission speed, and efficiency of transmission, between neurons and across regions. They therefore function as accelerators improving efficiency of the brain. Their importance is noticeable in neurodegenerative disorders, notably multiple sclerosis (MS). MS is an autoimmune disorder with the brain (microglia outlined below) identifying Schwann cells as imposters, attacking them and breaking down the myelin sheath which leads to increasing disruptions and coordination problems and potentially to early death.

The next group of glial cells are microglia, a fascinating bunch of cells, it seems a shame to spend so little time on them. They are as the name suggests, micro, and mobile. They operate as macrophages. Macrophages are immune cells that engulf our cellular invaders to protect the integrity of our cells, and system. Therefore, we can consider microglia as the cleaners of the brain. They clean up debris and potential invaders. But they are also involved in more spectacular cleaning up processes such as what is known as apostasies, when neurons kill themselves, and also clearing out and cleaning up damaged neurons and synapses. After traumatic brain damage the damaged regions will be flooded with microglia who go about cleaning up cells. In fact, a lot of the brain damage incurred from traumatic injuries occurs after the injury from the brain’s own cleaning up processes!

But the real star, proverbially and visually, of the glial community is the astrocyte.