On my way over to Sydney I watched a film on the plane called Limitless, a sci-fi thriller about a washed-up writer who discovers a drug which greatly enhances his brain's abilities. Although the film provided me with some mediocre entertainment for a couple of hours, I did pick up on the following short quote and his drug dealer:
Drug dealer: You know how they say we can only access 10% of our brain?
[Vernon points at the pill on the table]
Drug dealer: This lets you access all of it.
This got me wondering (1) where and how this myth originated, and; (2) if there were any other common misconceptions regarding the most intriguing of all organs, the brain.
I think there are several possible origins of the myth, the most likely of which is misinterpretation of a scientific finding by the popular media. For example, early studies on the cellular composition of the brain found that there are approximately 10 times the number of glial cells as there are neurons. At that time glial cells were considered to be no more than the 'glue' that held all the neurons in place, possibly leading the untrained observer to conclude that only 10% of our brain is 'used'. Of course, no neuroscientist these days would say that glia are just glue, they are emerging as highly dynamic multi-functional cells that play a crucial role in homeostasis, disease, and repair... but that is a story for another time. Other statements that could have been misinterpreted include the proportions of neurons firing at any one time, or the proportion of the brain that had a known function.
Another common misconception is that we are born with all the neurons we will ever have, and that once they are gone they are gone. We now know that this is not the case, and have identified 2 areas in the adult brain where new neurons are produced in a process called neurogenesis. This discovery has created a lot of interest in the neuroscience community, and brings with it renewed hope for treating brain injuries and neurodegenerative conditions such as Alzheimer's. Since this area is so exciting at the moment it will certainly become the topic of a future blog post.
Other myths relating to the brain include:
"Humans have the biggest brains of all animals"
While we regard ourselves as the most intelligent, we do not have the biggest brains. The human brain weights about 1.5kg, while the brain of an elephant weighs 5kg, and a sperm whale brain weighs about 8kg! Of course a whale is much bigger than a person, so calculating a brain-to-body mass index is often done to estimate an animal's relative intelligence. Using this measure, called encephalization quotient (EQ) humans top the chart with an EQ of ~7.5. In comparison, an elephant has an EQ in the range 1-2, and the sperm whale's EQ is only 0.3!
"Vaccines cause autism"
A lot of controversy arose in 1998 around a paper published in the Lancet by Andrew Wakefield suggesting that there was a link between the MMR vaccine and autism. Subsequent publications by Wakefield declared that the vaccine was not safe, and were immediately picked up by the popular media (that did not mention the overwhelming evidence that MMR was safe). It was later found that Wakefield had significant conflicts of interest, and had altered results, resulting in his papers being retracted. There is now no evidence for a link between vaccines and autism.
