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On September 17th, 1998 the Ithaca Journal ran its first "Ask A Scientist!" article in which Professor Neil Ashcroft , who was then the director of CCMR, answered the question "What is Jupiter made of?" Since then, we have received over 1,000 questions from students and adults from all over the world. Select questions are answered weekly and published in the Ithaca Journal and on our web site. "Ask A Scientist!" reaches more than 21,000 Central New York residents through the Ithaca Journal and countless others around the world throught the "Ask a Scientist!" web site.

Across disciplines and across the state, from Nobel Prize winning scientist David Lee to notable science education advocate Bill Nye, researchers and scientists have been called on to respond to these questions. For more than seven years, kids - and a few adults - have been submitting their queries to find out the answer to life's everyday questions.

Previous Week's Question Published: 29 August, 2007 Next Week's Question
Humans use 100 percent of their brains--despite the popular myth
If humans only use 10% of their brains, what is the other 90% doing?

The myth that humans only use 10% of their brains has been around for a long time, but it is not true. We use 100% of our brains.

Our brains are divided into many different regions that serve different functions. For example, your eyes are directly connected to several specific parts of your brain. These areas connect to several other brain regions called "visual cortices," all of which connect to other regions in turn. Each of these brain regions receives visual information from your eyes, but does different things with that information. For example, some areas in the visual cortices are devoted to detecting the direction in which objects are pointing, or are specifically tuned to detect movement. Other parts of your brain then weave all this information back together to create "what you see."

Similarly, there are brain regions devoted to each of your other senses, regions to control body movements, regions to manipulate memory, regions for language. These regions can be further subdivided; one region of your brain that detects touch, for example, is organized sort of like a map of your body (called a homunculus), except that proportionately more brain area is devoted to touch in especially sensitive regions like fingers and lips. (In fact, this is partly why your fingers and lips are more sensitive to touch than, say, your leg. Try reading Braille with your leg!).

Recently, medical imaging technologies that measure activity in people's brains without surgery have enabled scientists to answer questions like "what parts of the brain are especially active when performing a complex memory task?", "what parts are most active during different types of sleep?", or even "what parts are active during recognition of a particular brand of car?" These techniques can help scientists better understand how the different regions of the brain work together to create the complex web of sensation, experience, and knowledge that we all enjoy. They also demonstrate clearly that every region of the brain lights up for something.

Where did the "10% myth" first come from? It isn't clear. It might be because less than 10% of the cells in our brains are actually neurons (nerve cells) - the rest are called glial cells. Glial cells perform all kinds of different tasks, from insulating the brain's "wires" to maintaining the brain's chemistry to helping regulate the many connections among neurons (called synapses) in which memory can be stored. Glial cells aren't neurons, but they are certainly being used! The myth could also have arisen because much of the brain is fairly adaptable, allowing people (especially young people) to recover most of their capabilities even after losing parts of their brains to injury, cancer, or surgery. This isn't always true, however; it is harder for older adults to recover function after brain injury, and we know that even small amounts of brain damage (such as strokes) in just the wrong places can be devastating.

So take care of your brain! You'll need all of it.