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Unravelling the Neurogenetic Links: Brain Architecture, Left-Handedness, and Cognitive Abilities

In this article, we will focus on the fascinating relationship between brain architecture, left-handedness, and cognitive abilities. Our study delves into the specific functions of the cerebellum, brainstem, and cerebrum, shedding light on their roles in voluntary muscle movement, information transmission, and intellectual activities.


Figure 1: The Brain. Image adapted from: https://media.istockphoto.com/id/627013932/photo/brain-powerconcept.jpgs=612x612&w=0&k=20&c=pvKa43S62Nj6y9to13Uhmo9uSDhIdxYycQFnxUxjsBs=


The human brain is an intricately complex organ responsible for intelligence, sensory interpretation, and the initiation of bodily functions and behaviors. Situated within the skull, it is securely housed within the cranium, offering protection against potential injuries. The cranium acts as a shield, safeguarding the brain by encasing it within the skull structure.

The brain consists of various structures, each with distinct responsibilities and functions. These structures collaborate to facilitate seamless brain functioning. The brain can be classified into three fundamental units: the forebrain, the midbrain, and the hindbrain. The cerebral cortex, a thin layer of grey matter, forms a significant part of the brain and contains a high concentration of neurons. It plays a crucial role in higher-level cognitive functions such as perception, thought, language, attention, and memory. Research conducted by Oxford's Experimental Psychology Department has focused on the prefrontal cortex, revealing its critical role in future planning and individuals' advanced sense of task performance. Different regions of the cerebral cortex have specific functions that are still not fully understood. Recent studies have associated specific cells in the somatosensory cortex, known as "quiet" cells, with the sense of touch. The cerebellum aids in voluntary muscle movement, posture, and balance. The brainstem relays information between the body and the brain and controls involuntary bodily functions.



Figure 2: The Brain Structure. Image adapted from: https://www.news-medical.net/health/Human-Brain-Structure.aspx

The cerebellum is responsible for facilitating voluntary muscle movement, including posture and balance. In contrast, the brain stem serves as a conduit for relaying information between the body and the brain, controlling both involuntary bodily functions. The cerebrum, located at the forefront of the brain, is divided into two hemispheres of equal structure. Each hemisphere governs different functions and is associated with intellectual activities. Research indicates a relationship between left-handedness and brain architecture. Left-handed individuals exhibit enhanced communication between the right and left hemispheres of the brain.

A recent study conducted at the University of Oxford involved the analysis of approximately 400,000 genomes. The findings suggested that certain genetic variants are associated with left-handedness. Among the analyzed individuals, 38,332 were identified as left-handed. Four distinct genetic regions were identified, with three of them playing a role in brain development and structure. These genetic regions involve proteins associated with microtubules, which guide cellular functions within the body's cytoskeleton. The study's participants made fascinating discoveries. Left-handed individuals demonstrated an advantage in verbal tasks due to highly coordinated communication between brain hemispheres. However, it's important to note that not all left-handed individuals possess identical characteristics.

Further research indicated that left-handed individuals have a slightly lower likelihood of developing Parkinson's disease, but a slightly higher likelihood of schizophrenia. It is important to acknowledge that these correlations are subtle and do not establish causation. Understanding these genetic links is of utmost importance in order to improve prevention strategies for these serious medical conditions.


Figure 3: MRI of the brain whilst clenching, shows the parts of the brain used. This image shows statistical maps projected onto a standard brain template. The maps compare brain activity during different tasks: (A) Fist clenching compared to baseline (rest). (B) Teeth clenching compared to baseline. (C) Teeth clenching compared to fist clenching. The areas labelled are DLPFC (dorsolateral prefrontal cortex), PPC (posterior parietal cortex), SMA (supplementary motor area), and SMC (sensorimotor cortex). The statistical threshold used is P < 0.005, meaning only significant results are shown without correction for multiple comparisons. Image adapted from: https://www.tandlaegebladet.dk/sites/default/files/articles-pdf/TB-2011-03-200.pdf


The brain has long been a subject of extensive study and research conducted by numerous scientists and researchers. Among the various theories surrounding the brain, one prominent notion suggests that humans only utilize 10% of their brain capacity. The idea that such a small percentage of the brain is actively functioning is intriguing. However, this theory has been debunked through the use of functional magnetic resonance imaging (fMRI) scanners, which enable researchers to observe brain activity in real-time. When individuals clench or unclench, it is evident that more than a mere tenth of the brain is engaged. Even if the 10% claim referred to brain cell activity, it would still be inaccurate, as brain cells consume a substantial amount of energy, accounting for approximately 20% of the oxygen we breathe. Given the brain's involvement in a wide range of activities, it is implausible that we only utilize 10% of its capacity.

Within the brain, there are glial cells that provide physical and nutritional support to the remaining 90% of the brain. However, these glial cells do not possess the ability to transform into neurons or provide additional brain power. It is important to note that when individuals learn new things, the brain undergoes changes by establishing new connections between nerve cells or eliminating outdated connections that are no longer necessary.

In conclusion, the brain is a captivating topic of study. It comprises various components, each with distinct functions. As the brain is intricately connected to the body, there appears to be a correlation between brain activity and left-handedness. Nevertheless, numerous theories and myths surrounding the brain have emerged over the years due to its enigmatic nature. One such myth is the belief that we only utilize 10% of our brains, which has been dispelled by modern technology and research.

References

  1. Hammond, C. (2022) 'Do we only use 10% of our brains?', BBC Future. Available at: https://www.bbc.com/future/article/20121112-do-we-only-use-10-of-our-brains "Make-up of the Brain" (no date). Available at: https://oxford.shorthandstories.com/the-make-up-of-the-brain/index.html

  2. "Researchers Identify Genetic Regions Associated with Left-Handedness and Link Them with Brain Architecture in Language Regions" (2019). Nuffield Department of Orthopaedics, Rheumatology and Musculoskeletal Sciences. Available at: https://www.ndorms.ox.ac.uk/news/researchers-identify-genetic-regions-associated-with-left-handedness-and-link-them-with-brain-architecture-in-language-regions

  3. "Brain Basics: Know Your Brain" (no date). National Institute of Neurological Disorders and Stroke. Available at: https://www.ninds.nih.gov/health-information/public-education/brain-basics/brain-basics-know-your-brain#:~:text=The%20brain%20is%20the%20most,qualities%20that%20define%20our%20humanity.

  4. Hammond, C. (2022a) 'Do we only use 10% of our brains?', BBC Future. Available at: https://www.bbc.com/future/article/20121112-do-we-only-use-10-of-our-brains




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