Myths are falsehoods that are based on some element of the truth, or on misinterpretations of the truth. Some myths are widely believed and have over time become “common knowledge”. The human brain is an extremely complicated organ and it is only with the advent of new imaging technology that scientists have a better understanding of the intricate processes that takes place in the brain.
Some of the most widely used brain myths:
You only use 10% of your brain – and just imagine what we would achieve if we could use 100% of the brain! This myth is often repeated, but the truth is that we use virtually all of the brain every day. The different areas in the brain are involved in separate functions, for example the pituitary gland and hypothalamus regulate hormones and temperature, while the frontal lobes in the cerebral cortex are involved in thinking and reasoning. The occipital lobes allow you to see and comprehend, while the temporal lobes help you to process what you hear. The brainstem and cerebellum are involved with breathing, the circulation of blood and digesting your food. The hippocampus is involved with memory, which will help with remembering that it is a myth that we only use 10% of the brain.
Drinking alcohol kills brain cells – the truth is that the amount of alcohol required to kill brain cells would also kill the person. The moderate use of alcohol does not appear to damage brain cells. Alcoholics can show signs of brain damage – but not due to the killing of brain cells, but as a result of damage to the dendrites found at the end of neurons that affects communication in the brain.
Doing crossword puzzles can keep your brain young – while crosswords may improve the ability to find words in your memory, it do not mean that doing crosswords (flexing one part of the brain) also improves the overall cognition or memory. There is no scientific evidence for the claim that doing crosswords will ward off cognitive decline or dementia.
Personality shows a right-brain or left-brain dominance – and those with a dominant left brain are more technical and logical, while the ‘right-brained” people are more creative. The truth is that the two hemispheres of the brain, while different, are co-dependent. Brain imaging technologies (such as MRI scans) have revealed that on average we use both sides of the brain equally, as we all are “brain-ambidextrous”. There are aspects of right-brain or left-brain dominance that are valid, as the left side of the brain controls the right side of the body and vice versa. This becomes evident when a brain injury in one side of the brain affects the body on the other side.
The way you think is not decided by which side of the brain you use, as both sides work together on every mental task. People are often labeled as being “right-brain” or “left-brain” dominant, when in effect the way they function and present themselves are based on personality and natural aptitude (which refers to inherent abilities and natural skill or talent).
Brain damage is permanent – and once brain cells are damaged, they are gone for good. Scientists now know that the brain has flexibility (called plasticity), meaning the ability to change continuously during one’s lifetime, for example, a given function can be transferred to a different location, the proportion of grey matter can change, and synapses may strengthen or weaken over time. The brain can adapt to trauma or disease, and even generate new brain cells in the hippocampus (seat of memory) under the right circumstances.
Some scientific facts about the brain:
• The brain accounts for 2% of body mass, yet uses 20% of the oxygen that we breathe in. A loss of oxygen, even for only 3 minutes, can result in neural damage and brain cells beginning to die
• The heart pumps about 20% of the blood in the body to the brain. The constant high rate of blood flow is required by the heavy metabolic demands of the glial cells and neurons in the brain.
• About 90% of the cells in the brain are glial cells, of which there are far more than the number of nerve cells called neurons. Glial cells can be regarded as serving the neurons, as they make myelin to protect neurons and speed transmission. They also support neurons in many other ways, such as repairing damaged or injured neurons, and disposing of dead neurons.
• During a baby’s first month the number of synapses (connections) in the brain increases from 50 trillion to 1 quadrillion. If the baby’s body grew accordingly, its weight would have increased from 4 kg to 77 kg!
• Brain activities during a baby’s first 6 – 12 months have been measured and revealed that synapses are formed in the prefrontal cortex (the seat of forethought and logic) at such a high rate that it consumes twice the amount of energy used by an adult brain. This fast pace continues for the child’s first decade.
• The brain has no sense of pain, which allows neurosurgeons to probe areas of the brain while the patient is awake and able to provide feedback.
• Some parts of the brain are quite primitive, such as the cerebellum and brain stem, which help us coordinate movements and control basic functions like breathing.
• The cerebrum is the biggest and most evolved part of the brain, which controls conscious experiences and voluntary movements, also enabling us to feel, think, and create, as well as to receive, store and retrieve memories.
• The human brain is spongy to the touch and looks very similar to a head of cauliflower.
• The brain represents about 2% of body weight, but around 25% of the cholesterol in the body is found in the brain, where it plays an important role in cell membrane function and acts as an antioxidant.
• The colour of the brain is often pictured as a dull grey mass, but in reality it has grey matter and white matter, while the blood vessels are red. An area in the middle is black. Due to the chemicals that are used to preserve them, brains in laboratories turns grey.
• The brain remains active while you are sleeping. It runs functions like breathing and consolidates the day’s information by sorting through the information and locking the things you have learned into your memory.
• Your intelligence is not only determined by your genes (around 50%), but other major contributors are your home life, education, nutrition and resources.
More scientific facts – the brain is a remarkably powerful computer:
• The brain has an estimated one hundred billion neurons. In comparison the same amount of A4 pages would form a stack that is 8 000 km high!
• Neurons are nerve cells with special properties. Each neuron has dendrites that gather information transmitted from other cells, and an axon that transmits information to other cells. Each neuron communicates with between 1000 and 10,000 other cells.
• Neurons secrete chemical molecules called neurotransmitters that ferry nerve impulses across the tiny gaps, or synapses, to other neurons, which means neurons don’t actually touch other neurons.
• The amount of neurotransmitters that are secreted play an important role. When many are secreted, the messages travel strongly, but if few are secreted the messages are weak.
• The brain can be compared to an extremely powerful computer, as the estimated 100 billion neurons, each with an average of 10 000 connections, result in an estimated one quadrillion number of connections in the brain. (That is 1,000,000,000,000,000 total connections.)
• In the words of Dr Bredesen: “Every feeling, every thought, every memory, every decision, every creation, every scam ever prepared, every tender act, every act of terrorism, every sin and every act of human kindness – all originated in these connections.”
• “Every thought ever thought by a human being – is the result of signals travelling down one neuron, crossing the synapse to the next neuron in a particular circuit, travelling down this neuron, on and on until you speak or move or otherwise give real-world expression to the activity inside your brain.”
Sources:
Brain Mythology. Published online. BrainHQ. (www.brainhq.com)
How your brain works: myths and facts. Published 29 September 2017. WebMD. (www.webmd.com) No, you are not left-brained of right-brained. Published online 15 February 2018. Psychology Today. (www.psychologytoday.com)
The end of Alzheimer’s. Dr Dale Bredesen. Book published 2017. Penguin Random House UK. 307p.
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