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Right or wrong: The neuromyths !

Updated: Jun 26, 2023

Today, I will answer to 5 well-known questions about neuroscience. The purpose of this article is to break misconceptions (or neuromyths) about brain by explaining each false belief. Please feel free to navigate around this Right or Wrong article. Let's go!




Do we use 10% of our brain ?

We use 10% of our brain.

WRONG

This idea does not only come from fiction (like Lucy by Luc Besson) but is widely spread on the internet. We don't really know where this myth comes from. Some people explain that this 10% comes from the following belief: "we have 10% of neurons and 90% of glial cells" (central cells that are present in our nervous system to optimize our neurons). Our craze for neurons to the detriment of glial cells has possibly reduced the definition of the brain capacity to our number of neurons. Thus, we switched from “The neural man” to “The glial man” (books in bibliography). However, the neuron / glial cells ratio is not as well defined. We estimate that there are 1 to 3 glial cell(s) per neuron. The creation of this neuromyth could also come from other theories dating from the end of the XIX century. However, the links are still obscure to verify the origin of this false belief.

However, we use all of our brain mass (1.2 kg on average). Each region is responsible for an activity, and the existence of neural networks (i.e. the communication between several brain regions) demonstrates that brain activity is totally distributed. In addition, our brain is economical: we activate more intensely the neural connections we need depending on the moment. For example, a mouse that walks through a labyrinth will solicit neural connections relating to space (e.g. activation of place cells) and smell to locate. The place cells will then be reactivated during sleep to memorize the traveled distance. This step consolidates the spatial memory.

Thanks to this example, we can understand that a specific task leads to a located neuron activation. Thus, we do not use 10% of our brain but we use specific brain regions depending on the goal.





Left and Right Brains

The left hemisphere is dedicated to logic while the right hemisphere is dedicated to creativity.

WRONG

This sentence is widely used online. By taping the word “brain” on Google, we can easily find pictures that associate our two hemispheres to different kinds of activities (logic and creativity, see the picture below). Worst, this sentence is assumed by many professionals that lead creativity workshops.

Each brain has a prefered task

Creativity is a distributed process in the brain (see my article “Creativity through cognitive sciences”). Different neural networks are involved such as the lateral temporal fronto-parietal networks and the default mode network (a network which is activated when we do not perform any particular tasks). However, brain lateralization exists. Karolis and his colleagues recently published an article about dominant activities of the left and the right hemispheres (see image). For example, emotions are more present in the right hemisphere, and symbolic communication (language, gestures, etc.) is more represented in the left hemisphere. This last result remains intuitive for symbolic communication because the regions of language (Broca and Wernicke region) are located in the left hemisphere.

NB: To learn more about creativity and to explore a set of techniques, take part in my creativity workshops! (Go to the "Creativity Workshop" french tab for more information or contact me).






Neuron

We no longer produce neurons from adulthood.

RIGHT and WRONG


Hippocampus

This question is difficult to resolve. Indeed, several studies have demonstrated a positive and a negative answer (example in the bibliography: “positive” article (1); “negative” article (2)). This difference is probably due to the different methods used for each experiment. However, the majority of the scientific community tends to say that there is always a production of neurons in a specific brain region: the hippocampus. This region is particularly known for being responsible for memory and more specifically, for encoding new memories. Therefore, the production of neurons, a process called "neurogenesis", seems to be present in adulthood in the hippocampus. But, the intensity of this process decreases severely with age. Don't be worried! Remember that the production of new neurons and the loss of the number of neurons is not a proof of intelligence. For example, at birth, we have many more neurons than in adulthood However, it is essential to clean up our brain and remove unnecessary neural connections to improve our precision and our dexterity. Thus, although we know that the number of neural connections (therefore the number of neurons) facilitates information processing and that the decrease of neurons is sometimes associated with neurodegenerative diseases, there are many other factors involved in the optimization of the treatment of information.






Video games

Video games are bad for our health.

RIGHT and WRONG

It depends on how you play! Of course, playing without thinking and by reflexes is not good for our brain except if you want to cause a zombification of your thoughts. But video games can be very stimulating! Playing moderately and challenging yourself on a video game trains our cognitive abilities! Whether it is a war game (FPS, ex: Ghost Recon), a strategy game (ex: Warcraft), an MMORPG (ex: Guild Wars) or a car game, the brain works! You have to find yourself in the environment, put yourself in the shoes of other players (Theory of mind), train your reflexes or memorize an action. In a study published in 2003 in the journal Nature, C. Shawn Green and Daphne Bavelier showed that video games modify a set of attentional visual skills. For instance, the results show that the visual attention of players is more persistent than non-players when they have to find a target. On the other hand, the spatial distribution of their attentional resources is more efficient (in central and peripheral vision). Thus, video games seem to train our selective visual attention. However, the risks of epilepsy and addiction (screen or games addictions) still exist. Therefore, you can be more enthusiastic about video games but you have to practice responsibly.






Man's brain versus Woman's brain

On average, the woman’s brain is smaller than the man’s brain.

RIGHT

Ladies and Gentlemen, don't get carried away before reading my next lines. It’s true that a woman’s brain weighs approximately 1,144 g compared to 1,325 g for the man’s brain. However, no link has been rigorously demonstrated between intelligence and brain weight for the human race. Indeed, "intelligence" can be measured by solving mathematical problems or by performing social tasks. Thus, it is very difficult to associate brain weight with the different types of existing intelligence. Last but not least, let me share with you one of the most cited anecdotes to prove this misconception: Albert Einstein's brain weighed less (1,230 g) than the average weight of a man’s brain. Also, it is logical that a man, because of his cranial cavity morphology, has the capacity to host a larger organ than a woman. So, there is no room for macho comments.


I hope this article gave you some answers or some precisions about these 5 questions!


Lydia Bessaï.




BIBLIOGRAPHY


Right or Wrong: We use 10% of our brain.

1. Lavilléon, Gaetan de, Marie Masako Lacroix, Laure Rondi-Reig, and Karim Benchenane. “Explicit Memory Creation during Sleep Demonstrates a Causal Role of Place Cells in Navigation.” Nature Neuroscience 18, no. 4 (April 2015): 493–95. https://doi.org/10.1038/nn.3970.

Book 1: L'homme neuronal - Jean-Pierre Changeux (French)

Book 2: L'homme glial - Yves Agid & Pierre Magistretti (French)


Right or Wrong: The left hesmisphere is dedicated to logic while the right hemisphere is dedicated to creativity.

1. Bendetowicz D, Urbanski M, Garcin B, Foulon C, Levy R, Bréchemier ML, Rosso C, Thiebaut de Schotten M, Volle E. Brain. "Two critical brain networks for generation and combination of remote associations". 2017 Nov 22.

2. “The Architecture of Functional Lateralisation and Its Relationship to Callosal Connectivity in the Human Brain | Nature Communications.” Accessed November 5, 2019. https://www.nature.com/articles/s41467-019-09344-1.


Right or Wrong: We no longer produce neurons from adulthood.

1. Tobin, Matthew K., Kianna Musaraca, Ahmed Disouky, Aashutosh Shetti, Abdullah Bheri, William G. Honer, Namhee Kim, et al. “Human Hippocampal Neurogenesis Persists in Aged Adults and Alzheimer’s Disease Patients.” Cell Stem Cell 24, no. 6 (June 6, 2019): 974-982.e3. https://doi.org/10.1016/j.stem.2019.05.003.

2. Sorrells, Shawn F., Mercedes F. Paredes, Arantxa Cebrian-Silla, Kadellyn Sandoval, Dashi Qi, Kevin W. Kelley, David James, et al. “Human Hippocampal Neurogenesis Drops Sharply in Children to Undetectable Levels in Adults.” Nature 555, no. 7696 (March 2018): 377–81. https://doi.org/10.1038/nature25975.


Right or Wrong: Video games are bad for our health.

1. C.S. Green et D. Bavelier, « Action video game modifies visual selective attention », Nature, n° 423, 29 mai 2003.


Right or Wrong: On average, the woman’s brain is smaller than the man’s brain.

To know more (french article): https://www.passeportsante.net/fr/Actualites/Dossiers/DossierComplexe.aspx?doc=differences-cerveaux-feminins-et-masculins

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