The glia club: Supporting the grey matter of the brain
Neurons are viewed as the main heroes of the brain, encoding information communicating with each other, which can lead to memories, brilliant thoughts and consciousness. But there are other cells within the brain and they are the secret helpers of the brain and mind: glia cells. So what can be as, or even more important, than the signal transduction of neurons?
Oligodendrocytes are the one of three subtypes of glia cells and when they fail and die, a well-known disease ensues: Multiple Sclerosis (MS). Neurons transmit information in the form of electrical signals down their axon, an elongated part of their cell which can stretch all the way from the foot to the spinal cord, and in the majority of neurons the axon is “insulated” by oligodendrocytes. This means, that electricity can speed down faster the axon and so information transmission is quicker. Oligodendrocytes wrap around the neurons in the form of myelin sheets and when these sheets degenerate in MS, signal transduction is slowed down and impairments ensure.
The star-like shaped cells, astrocytes, are another form of glia cells. They do a lot of different things within the brain such as being closely associated with the blood brain barrier, which prevents harmful molecules from entering the brain, and transport nutrients to neurons. Astrocytes also help neurons stay healthy through informing them of nearby inflammation and prevent toxic overstimulation of neurons by removing neurotransmitters from the environment. Intriguingly, astrocytes also seem to communicate with each other, through calcium waves, indicating changes within the astrocytes themselves, which spread throughout astrocytes, similar to neuronal activity spreading through the brain, but less understood. Astrocytes seem to be the dark horse of the brain. They are involved in so many processes and perform so many functions, that dysfunctional astrocytes are detrimental to the brain. Studying these dysfunctions on the other hand though is difficult, as understanding why this leads symptoms is a challenge exactly because astrocytes are involved in so many functions.
Finally, there are microglia cells. In the rest of the body, we have immune cells which can detect any foreign intruders and can then alert the body to start killing these cells. Microglia have this function in the brain. They can detect anything, which isn’t supposed to be there and can alert neurons and astrocytes to the pending attack. In the recent years, microglia have been implicated in a range of diseases such as Alzheimer’s disease.
Glia cells perform so many life-sustaining functions within the brain but have the tendency to be overlooked and personally, I believe this is partially because they are difficult to understand and many secrets they hold are yet to be understood. But simply because it is a challenge, we shouldn’t give up, otherwise the field of neuroscience would have never developed the way it has.
