Brains on Brains Week 1: Neurons and Glia

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The blog “A Plastic Journey: Introspection of Brains Learning About Brains” delves into the qualia, feelings and thoughts brought forth in the authors’ brains upon learning about the human brain and its functions. The blog will follow loosely the structure of the course “NBE-E4210 – Structure and operation of the human brain.” The blog is written in the form of a fact-filled, loopy and introspective story. [Logo: Oxford University Press (2018).]

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The levels at which a brain can be explained at can be numerous. Possible levels introduced in the course material (NBE-E4210, 2018) include the following, ranging from the very small to the very large, as seen in graph 1 below.

Graph 1: Different levels of systems (Source: NBE-E4210)

Of these levels, Bear et al. (2015) start off by explaining the functioning of neural cells – cells specialized for neural activity. Simplifying the matter to a degree, there are two types of neural cells: neurons and glia. These are broad categories, and there are multiple subcategories within them. Neurons are the information-transmitting and communicating cells that most often spring to mind when thinking about neural cells.

Bear et al. (2015) give a rather tasty analogy: in a chocolate chip cookie, neurons resemble the chocolate chips whereas glia resemble cookie dough that the neurons are attached to. Although von Bartheld et al. (2016) propose a neuron-glia ratio of 1:1 or less (when previously thought to be closer to 10:1), the analogy still bears some relevance to the matter. Neurons form the information transmitting network that is insulated by the glial cells. On the cellular level, these cell types form the landscape of the human brain.

Gaining knowledge about the brain on this level springs to mind a plethora of questions. The human brain constitutes of these two cell types, but what relevance do they bear for the brain, the self, the I itself? What have I gained from learning about these cells? What does it mean to be a neuron? Am I a system, or its parts? Am I an I, am I a brain, am I brain matter? Am I neurons insulated by glial cells? It is undeniable that these cells are what constitute the brain, but the relevance of the cells to the self is unclear. It can be argued that the self is a construct of a higher systemic degree that emerges from a complex system, in this context from the cells. The relation is perhaps best brought to light in situations where the cells are somehow damaged or malignant. This relation is unfortunately clear for people who are born with Pelizaeus-Merzbacher disease, a severe disease which originates from genetic malformations in the myelinating glial cells (Rasband, 2016). People with PMD can suffer from a plethora of motor problems and might never in their whole life learn to walk or speak.

On the cellular level, it is rather clear that the brain consists of neurons and glial cells. It is, however, far from clear what the self consists of on the level of a self. Hedons have been proposed as an unit to quantify the subjective pleasure experienced by an individual. Would it be possible to similarly attempt to quantify buildings blocks of the self of humans or other beings as well? Purely theoretical constructs of this kind might help to discuss and quantify questions around selves and the various degrees of “selfness” that exist in the world.  If measures of this kind were ever to take a foothold in the neurosciences, however, let us just hope that they are called something else than selfies.

 

SOURCES

von Bartheld, C. S., Bahney, J., Herculano‐Houzel, S. 2016. The search for true numbers of neurons and glial cells in the human brain: A review of 150 years of cell counting. Journal of Comparative Neurology. 524:3865–3895.

Bear, M.F., Connors, B., Paradiso, M. 2015. Neuroscience: Exploring the Brain. 4th Edition. Lippincott, Williams & Wilkins.

Rasband, M. N. 2016. Glial Contributions to Neural Function and Disease. Molecular and Cellular Proteomics. 15(2), 355–361.

Posted by Free Willy

About Free Willy

The blog "A Plastic Journey: Introspection of Brains Learning About Brains" delves into the qualia, feelings and thoughts brought forth in the authors' brains upon learning about the human brain and its functions. The blog will follow loosely the structure of the course "NBE-E4210 - Structure and operation of the human brain." The blog is written in the form of a fact-filled, loopy and introspective story.
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