3D “Semantic Atlas” Of The Brain Reveals How We All Give Meaning To Words

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A team of neuroscientists at the University of California (UC), Berkeley have made a major advancement in our understanding of the spoken word by actually mapping out how the brain organizes how we apply meaning to language. Publishing their results in the journal Nature, they reveal that it’s not just one part of the brain that lights up when language processing is required – it’s all of it.

Remarkably, people’s “semantic maps” – neurological atlases indicating which regions of the brain ascribe meaning – appear to be incredibly similar. This hints at the possibility that all our brains are more or less organized in the same way to deal with languages.

“We’re trying to build an atlas just like a world atlas,” study coordinator Jack Gallant, a UC Berkeley neuroscientist, told the Los Angeles Times. “If I give you a globe, you can do anything with it – you could look at how big the ocean is or what the highest mountain is or what the distance from New York to California is.”

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It has been previously thought that information relating to the definite or abstract meaning of words was represented in a collection of brain structures called the “semantic system,” although pinpointing exactly where it is has proven quite difficult. Producing language using the brain is complex enough, but ascribing multiple meanings to words is what makes our species unique, and tracking this process in the brain is no easy task.

For this ambitious study, the researchers aimed to definitively locate this elusive semantic system. Seven subjects were hooked up to magnetic resonance imaging (MRI) machinery, which looks at where blood and oxygen flows in the brain with spectacular precision. In this case, the flow to and from 50,000 individual brain regions were tracked.

They were then asked to listen to more than 2 hours of English language tales from The Moth Radio Hour, a storytelling initiative in which sad, poignant, or funny autobiographical yarns are spun. As they listened, computer programs listened in for common words and grouped them when found to have similar or identical meanings.

The researchers then matched up the appearance of these words with the blood flow in the subjects’ brains. They found that although words can be matched to multiple, different parts of the brain, there were also about 100 distinct areas all over the brain associated with groups of linguistic meanings.

For example, the word “top” lights up a part of the brain linked with buildings and structures, but also another segment that deals with clothing and appearance. Each of these regions clearly has a specific focus, and several categories were identified, including “social,” “visual,” “violence,” “number” and “time.”

“Although the maps are broadly consistent across individuals, there are also substantial individual differences,” Gallant said in a statement. “We will need to conduct further studies across a larger, more diverse sample of people before we will be able to map these individual differences in detail.”

The development of language made everything we see today possible, from the greatest works of literature and art to our risky ventures to distant worlds; it allows our thoughts to become both tangible and immortal. It is undoubtedly one of the greatest human endeavors, and this remarkable semantic atlas brings us a step closer to unveiling its truly ancient secrets.

[IFLScience]

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