How much of our brain do we use?
You no more use 90% of your brain potential than you use 90% of your muscle potential all of the time. To say that we use all of our brain, would be like saying Arnold Schwarzenegger or Lou Firigno had as 90 pound teenagers reached the pinnacle of their muscular development. You no more use all of your brain all of the time than you use 100% of your lung capacity sitting at your computer keyboard. You no more use all of your brain all of the time than you use all of your car all of the time; that you always drive at the full potential of your Honda; that you always drive at the top speed of your car; that your trunk and seats are always filled to capacity; that you have even figured out and daily employ every single way in which you could use your car. To say that we use all of our brain ignores the fact that you keep losing your car keys all the time. To say that we use all of our brain ignores the fact that you couldn't remember where you left your car in the parking garage- even though this is well within your brain potential.
Do you really use only 10% of your brain?
In other words, the statement, "We use only 10% of our brains" is false; it's a myth. We use all of our brain. Let's look at the possible origins of this myth and the evidence that we use all of our brain. Where Did the 10% Myth Begin? The 10% statement may have been started with a misquote of Albert Einstein or the misinterpretation of the work of Pierre Flourens in the 1800s. It may have been William James who wrote in 1908: "We are making use of only a small part of our possible mental and physical resources" (from The Energies of Men, p. 12). Perhaps it was the work of Karl Lashley in the 1920s and 1930s that started it. Lashley removed large areas of the cerebral cortex in rats and found that these animals could still relearn specific tasks. We now know that destruction of even small areas of the human brain can have devastating effects on behavior. That is one reason why neurosurgeons must carefully map the brain before removing brain tissue during operations for epilepsy or brain tumors: they want to make sure that essential areas of the brain are not damaged.
Can someone be alive with half of a brain?
Yes, hundreds of people have survived in the past with only half of their brain.In a process known as Hemispherectomy, one hemisphere (half) of the brain is surgically removed. This radical step has to be taken in some extreme cases of seizures and neurological disorders in order to save the life of the patient.Neurosurgeons have performed the operation on children as young as three months old. Astonishingly, memory and personality develop normally.Of course, the operation has its downside: You can walk, run—some dance or skip—but you lose use of the hand opposite of the hemisphere that was removed. You have little function in that arm and vision on that side is lost.In short, yes, people can survive with half a brain. But the younger the person when he undergoes the procedure, the better off he will be. This is due to the plasticity of the young brain.
Is it possible to survive with half a brain?
I agree with Taylor. It's possible for a young child to have half of their brain removed without significant long-term effects, since at a young age, the brain is still developing (still getting its "wiring" straightened out), and the remaining hemisphere can compensate for the loss (assisted by various forms of therapy). An adult brain, on the other hand, has already formed most of the connections required for normal functioning. Since there is no longer much development, it is much more difficult for the brain to "re-wire" itself and compensate for the injury. In an adult, there would be severe damage to their coordination and cognitive abilities. Normally, removing part of the brain is only done in extreme circumstances, when the patient's life is in danger due to severe injury, a brain tumor, or severe seizures that originate throughout part of the brain. It is usually only performed as a last resort, and due to the consequences (and the extreme danger of the procedure itself), doctors are understandably even more reluctant to perform the procedure on adults than young children.
If we don't use 100% of our brain, then what part(s) of our brain can we legitimately live without?
From Medical News Today…”According to a survey from 2013, around 65 percent of Americans believe that we only use 10 percent of our brain.But this is just a myth, according to an interview with neurologist Barry Gordon in Scientific American. He explained that the majority of the brain is almost always active.The 10 percent myth was also debunked in a study published in Frontiers in Human Neuroscience.One common brain imaging technique, called functional magnetic resonance imaging (fMRI), can measure activity in the brain while a person is performing different tasks.Using this and similar methods, researchers show that most of our brain is in use most of the time, even when a person is performing a very simple action.A lot of the brain is even active when a person is resting or sleeping.The percentage of the brain in use at any given time varies from person to person. It also depends on what a person is doing or thinking about.”
Approximately what percentage of the brain do we use, and why?
Exactly 100%Brain is plastic and modifies itself as needed. So even if you only have half of it(from when you are very little) you can get all the necessary functions an adult has in the whole brain just in your one half. However that doesn’t mean other people are using only 50% of their brain its just that their brain is organized differently.If you didn’t use a part of your brain it would atrophy (die off). If some tissue isn’t being used it shuts itself down and dies off so that it doesn’t use up precious resources that are much more needed by tissues that are actually doing something productive. It’s a survival mechanism that optimizes fuel consumption and enables organisms to adapt.A bed ridden young cyclist will be astonished when witnessing wasting of his previously impressively toned quadriceps muscle in just a few weeks.
Is it true that humans only use 10% of their brains?
I just want to expand a little on what Joel Lewenstein wrote.What would it even mean to "use" 10% of your brain? Only 10% of your neurons are necessary for your normal functioning? Are you willing to sacrifice 90% of your brain to see if that's true?One of the methods neuroscientists use to study brain function is to look at patients with brain lesions and show how those affect cognition and behavior. It's precisely what I do:http://www.berkeley.edu/news/med...http://blog.ketyov.com/2010/10/v...http://blog.ketyov.com/2010/11/v...We know very well that a lesion to most any given brain region has a behavioral effect.While that's a practical example, from even a theoretical standpoint, not doing something is still an active state in the central nervous system. For example, the photoreceptors of your eye are always firing action potentials and releasing neurostransmitter in the absence of light (this is called the "dark current"). When light stimulates those cells, they stop firing action potentials and releasing transmitter. Thus, the act of not doing something is the actual signal. (From a signal standpoint, this is really quite amazing and makes a lot of sense: a signal is more clean if you shut a noisy system off and use that to communicate digitally than it is to try and boost a signal above background noise).So in the brain, even regions that appear to be not doing anything may actually be doing some communication/information transfer/processing/whatever.EDIT: Also, neurons follow a "fire together, wire together" and "use it or lose it" type of pattern. Neurons that communicate with one another a lot (that is, fire together) are less likely to undergo programmed cell death (apoptosis) through a complicated biochemical reinforcement. In contrast, if a lonely neuron isn't really doing much, then it is "pruned", that is, it isn't receiving a biochemical signal telling it to not commit cellular suicide, so it breaks down.So even if we were only using 10% of our brains in some hypothetical world, the other, useless 90% would start to go away!
Which animals sleep half their brain at a time?
All cetaceans (in other words - whales, dolphins, and porpoises) (because they need to continually surface)SealsManateesDucks (which can even choose which side of their brain sleeps - see http://www.sciencenews.org/sn_ar...)Swainson's thrushes (which can also choose which side of their brain sleeps http://faculty.washington.edu/ch...)Numerous other birds (I'll try to find more sources)Rats (partially) - see http://www.sciencenews.org/view/...You can find more at http://scholar.google.com/schola...Surprisingly enough, birds might even be able to sleep in the middle of flight! (although part of their brain remains awake)See http://www.ncbi.nlm.nih.gov/pubm...The daily need to sleep in most animals has led to the common belief that birds, such as the common swift (Apus apus), which spend the night on the wing, sleep in flight. The electroencephalogram (EEG) recordings required to detect sleep in flight have not been performed, however, rendering the evidence for sleep in flight circumstantial. The neurophysiology of sleep and flight suggests that some types of sleep might be compatible with flight. As in mammals, birds exhibit two types of sleep, slow-wave sleep (SWS) and rapid eye-movement (REM) sleep. Whereas, SWS can occur in one or both brain hemispheres at a time, REM sleep only occurs bihemispherically. During unihemispheric SWS, the eye connected to the awake hemisphere remains open, a state that may allow birds to visually navigate during sleep in flight. Bihemispheric SWS may also be possible during flight when constant visual monitoring of the environment is unnecessary. Nevertheless, the reduction in muscle tone that usually accompanies REM sleep makes it unlikely that birds enter this state in flight. Upon landing, birds may need to recover the components of sleep that are incompatible with flight. Periods of undisturbed postflight recovery sleep may be essential for maintaining adaptive brain function during wakefulness. The recent miniaturization of EEG recording devices now makes it possible to measure brain activity in flight. Determining if and how birds sleep in flight will contribute to our understanding of a largely unexplored aspect of avian behavior and may also provide insight into the function of sleep.