

August 15, 2013
The orange shaded areas show parts of the brain in the left and right hemisphere responsible for moving this patient's hand. Motor function is organized such that the left side of the brain controls muscles in the right side of the body and vice versa.


Chances are, you've heard the label of being a "right-brained" or "left-brained" . Logical, detail-oriented and analytical? That's left-brained behavior. Creative, thoughtful and subjective? Your 's right side functions stronger —or so long-held assumptions suggest.


For years in , the terms left-brained and right-brained have come to refer to , with an assumption that some people use the right side of their brain more, while some use the left side more.

Following a two-year study, University of Utah researchers have debunked that through identifying specific networks in the left and right brain that process lateralized functions.

Lateralization of means that there are certain that are mainly specialized to one of the brain's left or right hemispheres. During the course of the study, researchers analyzed resting brain scans of 1,011 people between the ages of seven and 29. In each person, they studied functional lateralization of the brain measured for thousands of —finding no relationship that individuals preferentially use their left -brain network or right- brain network more often.

"It's absolutely true that some brain functions occur in one or the other side of the brain. Language tends to be on the left, attention more on the right. But people don't tend to have a stronger left- or right-sided brain network. It seems to be determined more connection by connection, " said Jeff Anderson, M.D., Ph.D., lead author of the study, which is formally titled "An Evaluation of the Left-Brain vs. Right-Brain Hypothesis with Resting State Functional Connectivity Magnetic Resonance Imaging." It is published in the journal PLOS ONE this month.

Researchers obtained brain scans for the population they studied from a database called INDI, the International Neuroimaging Data-Sharing Initiative. The participants' scans were taken during a functional connectivity MRI analysis, meaning a participant laid in a scanner for 5 to 10 minutes while their resting brain activity was analyzed.

By viewing brain activity, scientists can correlate in one region of the brain compared to another. In the study, researchers broke up the brain into 7,000 regions and examined which regions of the brain were more lateralized. They looked for connections—or all of the possible combinations of brain regions—and added up the number of connections for each brain region that was left- lateralized or right-lateralized. They discovered patterns in brain imaging for why a brain connection might be strongly left- or right-lateralized, said Jared Nielsen, a graduate student in neuroscience who carried out the study as part of his coursework.

"If you have a connection that is strongly left- lateralized, it relates to other strongly lateralized connection only if both sets of connections have a brain region in common," said Nielsen.

Results of the study are groundbreaking, as they may change the way people think about the old right-brain versus left-brain theory, he said.

"Everyone should understand the personality types associated with the terminology 'left-brained' and 'right-brained' and how they relate to him or her personally; however, we just don't see patterns where the whole left-brain network is more connected or the whole right- is more connected in some people. It may be that personality types have nothing to do with one hemisphere being more active, stronger, or more connected," said Nielsen.

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1 / 5 (1) Aug 15, 2013
Too bad the 1011 subjects were not pianists playing the same scores cross handed.
not rated yet Aug 16, 2013
There is evidence to the contrary.
Perhaps what this shows is that the technology is leading us astray.
Further, the L/R brain division idea might be being misrepresented.
Basic evolutionary theory says that we have two brains for a reason. What is that reason?

I interpret the images to mean that there are thought processes going on that the individual is unaware of. So if the researcher asks the subject to count to ten and be aware of counting, that does not preclude other thoughts from taking place that the subject is unaware of.
Surgical seperation of the two brains show that this is indeed the case.
1 / 5 (1) Aug 17, 2013
"Basic evolutionary theory says that we have two brains for a reason." - E
For the same reason the sign " = " evolved from human thought.

Symmetry is a successful working model interpretation of nature.
There is a difference between function and purpose.

The purpose of science is to control as many aspects of nature as possible.
A token gesture for the insecure.
not rated yet Aug 19, 2013
It seems an internet test I once did turns out to be right. Its result was that both my hemispheres were equally strong (or weak, no preference for any hemisphere anyway) .


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