- Elena Quintana Menéndez and Eduardo García Laredo
- The Conversation*
Today much of the research on bipolarity and schizophrenia no longer focuses on neurons, but on the glia. What’s that?
The “glia”, “glial cells” or simply “glia” are cells that are found in our nervous tissue. Not only in our brain: they are also in the peripheral nerves that run through our body.
Throughout history all the cells of our brain that were not classifiable as neurons (that is, they lack the ability to send electrical impulses, which they are not electrically excitable) were classified as glia.
There are not a few cells that fall within that label. If we consider that there are about a hundred trillion neurons in our brain, there are ten times as many glial cells. Almost nothing.
In general we know that its percentage, the amount of glia per neuron, increases exponentially according to the complexity of the organism. This indicates that it is a very important element.
Classifying all these cells as glia, just like that, turned this word into a generic and vague term.
It encompassed too many types of very different groups of cells, and of very diverse origins. This was not due to the laziness of researchers when looking for words, but to the historical complexity involved. discover and study the glia.
Over time new classifications became necessary. Some were based on their size: the macroglia – such as astrocytes and oligodendrocytes – and the microglia. Also in its location: central nervous system or peripheral nervous system.
The “aristocracy” need help
We have already seen what glias are and that they are not few.
But,why has it become important your investigation? Are not neurons the privileged cells of the brain, the smartest of the class, the most important and beautiful, the “butterflies of the soul” as defined by the great Ramón y Cajal?
Well yes, we cannot deny that neurons will always be the electric aristocracy brain cells, but neither do they need more help in their day-to-day life than previously thought.
Formerly it was assumed that the main role of the glia was the simple attachment of the neuron, that of uniting and creating the internal structure of the brain.
If the brain was a Christmas tree, the glias would be the tree and the branches, and the neurons would be the decorations. Not surprisingly, the word glía comes from the Greek λοία, which translates as “union or glue”. Neuroglia would come to mean the “glue of neurons”.
Today it is becoming increasingly clear that the function of microglia is not only to support neurons and to be the brain glue. They are “helper” cells that can significantly influence the normal maturation and functioning of neurons.
In this sense, we can simplify their relationship in an example in which we see the precious neuron as a little princess and the glía as her cohort of servants who always accompany her and who are in charge of taking care of her, feeding her and protecting her.
They have to do great work for the well-being and facilitate the schedule of obligations of his lady (and little recognized until now).
Today we know that each of these maidservants have very specialized functions.
We can see the microglia both as “guardians” who ensure the safety of their wives, as “cleaners” of remains (since they are specialized macrophages of the brain that, among other tasks, will detect infections and take immune measures).
We can see astrocytes with various functions, such as “cooks” who are responsible for feeding neurons. They are also “secretaries” that help the neuron to send its signals.
Whose “fault” is it when the system fails?
The question that arises is somewhat obvious: when there is not quite adequate functioning in neural function, is it really the neuron that fails or is it that its helpers do not do their job correctly? Or do both fail?
The vast majority of research tends to point out that the glia plays its role in the activity of neurons in bipolarity and in schizophrenia.
The exact answer is more difficult than it sounds. We have already talked about the large number of glia, their subtypes, their location, and their different functions. Not only that, we also have to see other related aspects, such as the age and development of the subject.
All this makes it very complex to obtain resounding answers with so many conditioning factors. Several studies have found decreases in the number and quantity of glial cells in people who have suffered affective episodes severe (mainly in the prefrontal cortex).
Nor can it be ruled out that the activation of glial cells greatly influences the synthesis of neurotransmitters as important as serotonin and neuronal plasticity itself (which would be the brain’s ability to modify its structure and function).
Unfortunately still there is a long way to go until you can reach firm conclusions.
Even so, it seems more than evident that knowledge of the glia will help enormously to discover and establish new relationships between brain and behavior, and that it may open the doors to new research and forms of treatment of psychotic and affective conditions.
* Elena Quintana Menéndez He is a lab manager at the Autonomous University of MadridY Eduardo Garcia Laredo He is director of final works of the Master of Cognitive Neuroscience and Education at the Camilo José Cela University.
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Eddie is an Australian news reporter with over 9 years in the industry and has published on Forbes and tech crunch.