Friday, November 13, 2015

Do We Humans Only Have Access (normally) to a Percentage of Our Brain?

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Do We Humans Only Have Access (normally) to a Percentage of Our Brain?
Multiple Responses:
1.
The human brain is complex. Along with performing millions of mundane acts, it composes concertos, issues manifestos and comes up with elegant solutions to equations. It's the wellspring of all human feelings, behaviors, experiences as well as the repository of memory and self-awareness. So it's no surprise that the brain remains a mystery unto itself.

Adding to that mystery is the contention that humans "only" employ 10 percent of their brain. If only regular folk could tap that other 90 percent, they too could become savants who remember π to the twenty-thousandth decimal place or perhaps even have telekinetic powers.

Though an alluring idea, the "10 percent myth" is so wrong it is almost laughable, says neurologist Barry Gordon at Johns Hopkins School of Medicine in Baltimore. Although there's no definitive culprit to pin the blame on for starting this legend, the notion has been linked to the American psychologist and author William James, who argued in The Energies of Men that "We are making use of only a small part of our possible mental and physical resources." It's also been associated with Albert Einstein, who supposedly used it to explain his cosmic towering intellect.

The myth's durability, Gordon says, stems from people's conceptions about their own brains: they see their own shortcomings as evidence of the existence of untapped gray matter. This is a false assumption. What is correct, however, is that at certain moments in anyone's life, such as when we are simply at rest and thinking, we may be using only 10 percent of our brains.

"It turns out though, that we use virtually every part of the brain, and that [most of] the brain is active almost all the time," Gordon adds. "Let's put it this way: the brain represents three percent of the body's weight and uses 20 percent of the body's energy."

The average human brain weighs about three pounds and comprises the hefty cerebrum, which is the largest portion and performs all higher cognitive functions; the cerebellum, responsible for motor functions, such as the coordination of movement and balance; and the brain stem, dedicated to involuntary functions like breathing. The majority of the energy consumed by the brain powers the rapid firing of millions of neurons communicating with each other. Scientists think it is such neuronal firing and connecting that gives rise to all of the brain's higher functions. The rest of its energy is used for controlling other activities—both unconscious activities, such as heart rate, and conscious ones, such as driving a car.

Although it's true that at any given moment all of the brain's regions are not concurrently firing, brain researchers using imaging technology have shown that, like the body's muscles, most are continually active over a 24-hour period. "Evidence would show over a day you use 100 percent of the brain," says John Henley, a neurologist at the Mayo Clinic in Rochester, Minn. Even in sleep, areas such as the frontal cortex, which controls things like higher level thinking and self-awareness, or the somatosensory areas, which help people sense their surroundings, are active, Henley explains.

Take the simple act of pouring coffee in the morning: In walking toward the coffeepot, reaching for it, pouring the brew into the mug, even leaving extra room for cream, the occipital and parietal lobes, motor sensory and sensory motor cortices, basal ganglia, cerebellum and frontal lobes all activate. A lightning storm of neuronal activity occurs almost across the entire brain in the time span of a few seconds.

"This isn't to say that if the brain were damaged that you wouldn't be able to perform daily duties," Henley continues. "There are people who have injured their brains or had parts of it removed who still live fairly normal lives, but that is because the brain has a way of compensating and making sure that what's left takes over the activity."

Being able to map the brain's various regions and functions is part and parcel of understanding the possible side effects should a given region begin to fail. Experts know that neurons that perform similar functions tend to cluster together. For example, neurons that control the thumb's movement are arranged next to those that control the forefinger. Thus, when undertaking brain surgery, neurosurgeons carefully avoid neural clusters related to vision, hearing and movement, enabling the brain to retain as many of its functions as possible.

What's not understood is how clusters of neurons from the diverse regions of the brain collaborate to form consciousness. So far, there's no evidence that there is one site for consciousness, which leads experts to believe that it is truly a collective neural effort. Another mystery hidden within our crinkled cortices is that out of all the brain's cells, only 10 percent are neurons; the other 90 percent are glial cells, which encapsulate and support neurons, but whose function remains largely unknown. Ultimately, it's not that we use 10 percent of our brains, merely that we only understand about 10 percent of how it functions.

2.
"They say we can only access 20 percent of our brains... well, this [drug] lets you access all of it!"

That's the promise and premise behind the new thriller "Limitless," about a writer who takes an experimental drug that allows him to use 100 percent of his brain, providing him with superhuman memory, concentration, and other fantastic abilities.

Many people believe we only use a small fraction of our brains. Some people even claim that they are able to use more of their brains than others, providing them with psychic powers. After all, as the plot of "Limitless" asks — Who knows what we could do by tapping into the other 80 or 90 percent we're not using?

Accessing all of your brain may seem like an amazing pipe dream — except that you're already doing it. There's no higher gear, no untapped potential that you don't already have access to. It's a myth. The fact is that people use all of their brains. Brain-imaging research clearly shows that the entire brain is engaged. There are no "unused" or "inaccessible" parts. It's true that some chemicals and drugs can boost the brain's ability to remember, process information, or be alert—as any coffee or energy drinker knows.

"The last century has witnessed the advent of increasingly sophisticated technologies for snooping in the brain’s traffic," according to Dr. Scott Lilienfeld in his book "50 Great Myths of Popular Psychology: Shattering Widespread Misconceptions about Human Behavior," (Wiley-Blackwell, 2010). "Despite this detailed mapping, no quiet areas awaiting new assignments have emerged. In fact, even simple tasks generally require contributions of processing areas spread throughout virtually the whole brain.”

If the myth were true it would suggest that most of the brain is unnecessary or irrelevant. When Rep. Gabrielle Giffords was shot in the head in January, she suffered severe traumatic brain damage, and she will never fully recover. If it were true that people only used a small portion of their brains, we might expect to hear her surgeon report, "Luckily, the bullet only damaged the 80 percent of her brain that she didn't use, so she will be fine."

The screenwriter for "Limitless" shouldn't feel bad; Christopher Nolan made the same mistake in his mind-bendy thriller "Inception," which included a character saying, "We all use only a fraction of our brain's potential."

3.
Spoiler alert: Don't believe everything Morgan Freeman's characters tell you.

Just as his god-like Vitruvius fed sweet, naive Emmet a bogus prophecy in The Lego Movie, The Washington Postpoints out Freeman's latest character is once again doling out Hollywood falsehoods with authority in the summer thriller Lucy.

This time, the movie myth that needs busting is that human beings use only 10 percent of their brains—a "fact" Freeman cites while playing Professor Norman in the TV ads for Lucy, whose title character (played by Scarlett Johansson) "is able to kick butt and take names … because some drug made her a super-powered brainiac."

But it's pure science fiction that it takes a chemical cocktail to make humans use their entire brains. It turns out that we are all already giving it everything we've got, according to Dr. Barry Gordon, a professor of neurology at the School of Medicine and professor of cognitive science at the Krieger School of Arts and Sciences.

The Post refers to an interview with Dr. Gordon, published by Scientific American in 2008.

Gordon, a behavioral neurologist and cognitive neuroscientist, told Scientific American that "we use virtually every part of the brain, and that [most of] the brain is active almost all the time," he said. "Let's put it this way: the brain represents three percent of the body's weight and uses 20 percent of the body's energy."

So that settles it, once and for all—with all due respect to Mr. Freeman, who shouldn't take this debunking personally. As the institution once falsely credited with declaring that bones are the coolest part of the body, we can relate.

4.
The 10 percent of the brain myth is the widely perpetuated urban legend that most or all humans only make use of 10 percent (or some other small percentage) of their brains. It has been misattributed to many people, including Albert Einstein. By extrapolation, it is suggested that a person may harness this unused potential and increase intelligence.

Changes in grey and white matter following new experiences and learning have been shown, but it has not yet been proven what the changes are. The popular notion that large parts of the brain remain unused, and could subsequently be "activated", rests in popular folklore and not science. Though mysteries regarding brain function remain—e.g. memory, consciousness—the physiology of brain mapping suggests that all areas of the brain have a function.

5.
When I saw the trailer for Lucy, a new thriller starring a superhuman Scarlett Johansson, my first thought was: Yes! Hollywood finally cast a black actor as a neuroscientist! And my second thought was bummer, because that neuroscientist, played by Morgan Freeman, immediately discredits himself: “It is estimated most human beings only use 10 percent of the brain’s capacity,” he says. “Imagine if we could access 100 percent.”

Luckily, we don’t have to imagine. Unless you have a traumatic brain injury or other neurological disorder, you already have access to 100 percent of your brain! Your brain is available all the time, even when you’re sleeping. Even the most basic functions of your brain use more than 10 percent—your hindbrain and cerebellum, which control automatic bodily functions like breathing and balance, make up 12 percent of your brain, and you definitely need those just to stay alive.

Basic biology also tells us that it’s unlikely we’re leaving 90 percent of the brain unused. Unused cells tend to atrophy; for instance, muscle atrophy occurs in people who have a broken arm in a sling for several weeks. Parts of the brain we aren’t using would also atrophy—and this is actually what happens when our brains are deprived of blood flow or oxygen, as happens during a stroke or heart attack. Remember Terri Schiavo? She was in a vegetative state for 15 years after she went into cardiac arrest, which damaged 50 percent of her brain. Even damage to small, specific portions of the brain can drastically affect day-to-day functioning, leaving people unable to talk, read, or understand language. Losing 90 percent of your brain would be catastrophic and almost certainly fatal.

Well, maybe Dr. Freeman meant something else? There is a way to measure what parts of the brain are actively working. Neuroscientists often measure brain activity by identifying the places in which brain cells, called neurons, are sending chemical and electrical signals to other neurons. Perhaps what Freeman’s neuroscientist character meant was that only 10 percent of our neurons are firing at any given time. But this interpretation doesn’t fare much better: By any measure of brain activity, more than 10 percent is being used, and in any case, you don’t want 100 percent of your neurons firing at once, because that would constitute a killer seizure.

Another major premise of Lucy is that if we were able to use more than 10 percent of the brain, we could unlock “secrets of the universe.” Judging from the trailer, this apparently includes stopping time, making people around you fall down, and spontaneously changing your own hair and eye color. This probably doesn’t bear explaining, but just in case you were wondering: Sadly, your individual brain cannot control space-time, others’ actions, or the expression of your genes. We’ll have to wait for some other type of fictional drug to turn us into crime-fighting mutants.

6.
THE NEW LUC BESSON movie Lucy, starring Scarlett Johansson, opens tomorrow in theaters countrywide. It’s based on the immortal myth that we use only 10 percent of our brains. Johansson’s character is implanted with drugs that allow her to access 100 percent of her brain capacity. She subsequently gains the ability to learn Chinese in an instant, beat up bad guys, and throw cars with her mind (among other new talents). Morgan Freeman plays neuroscientist Professor Norman, who’s built his career around the 10 percent claim. “It is estimated most human beings use only 10 percent of the brain’s capacity,” he says, “Imagine if we could access 100 percent.”

As it happens, I’ve written a book all about brain myths (Great Myths of the Brain; due out this November). I thought I’d use what I learned to give you a 60-second explainer on the 10 percent myth.

Where does the myth originate?
No-one knows for sure. A popular theory has it that the journalist Lowell Thomas helped spread the myth in his preface to Dale Carnegie’s block-buster self-help book How to Win Friends and Influence People. Thomas misquoted the brilliant American psychologist William James as saying that the average person specifically “develops only 10 percent of his latent mental ability.” In fact James had referred more vaguely to our “latent mental energy.” Others have claimed that Einstein attributed his intellectual giftedness to being able to use more than 10 percent of his brain, but this is itself a myth. Another possible source of the 10 percent myth is neurosurgeon Wilder Penfield’s discovery in the 1930s of “silent cortex” – brain areas that appeared to have no function when he stimulated them with electricity. We know today that these areas are functional.

Is Lucy the first movie to use the 10 percent myth as a premise?
No, the 2011 movie Limitless, starring Bradley Cooper was based on the same idea, except the precise figure was placed at 20 percent. Cooper’s character takes a pill that lets him access the full 100 percent. Both the 1991 film Defending Your Life (thanks to A Voice in The Wilderness for flagging this up in the comments) and Flight of the Navigator (1986) include claims that most of us use a fraction of our brains. The myth is also invoked in the TV series Heroes, to explain why some people have special powers.

Does anyone really believe this myth anymore?
Apparently so. For example, in 2012, a survey of school teachers in Britain and The Netherlands found that 48 per cent and 46 per cent, respectively, endorsed the myth. Last year, a US survey by the Michael J Fox Foundation for Parkinson’s Research found that 65 percent of people believed in the myth.

Is there any truth to the myth?
Certainly there is no truth to the idea that we only use 10 percent of our neural matter. Modern brain scans show activity coursing through the entire organ, even when we’re resting. Minor brain damage can have devastating effects – not what you’d expect if we had 90 percent spare capacity. Also, consider the situation when neural tissue representing a limb is rendered redundant by the loss of that limb. Very quickly, neighbouring areas recruit that tissue into new functions, for example to represent other body regions. This shows how readily the brain utilises all available neural tissue.

So why does the myth persist?
For many people, the 10 percent myth sounds both feasible and appealing because they see it in terms of human potential. Many of us believe that we could achieve so much more – learning languages, musical instruments, sporting skills – if only we applied ourselves. It’s easy to see how this morphs into the shorthand idea that we use just 10 percent of our brain’s capacity or potential.

Does it matter that films like Lucy spread the 10 percent myth?
It certainly bothers a lot of neuroscientists. There are so many widely held misunderstandings about the brain that scientists find it extremely unhelpful to have more nonsense spread to millions of movie goers. Other people I’ve spoken to are more optimistic and think that audiences will realize that the claims are not meant to be taken seriously. I have to admit, I enjoyed Limitless despite the daft premise.

I haven’t yet seen Lucy. I’d love to hear your thoughts on whether it’s a good movie in spite of the bad science, and if so, does that justify further propagation of the 10 percent myth?

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