Define "global language network" in the brain

Japanese, Italian, Swahili, Tagalog and dozens of other spoken languages ​​cause the same “global language network” to project itself into the brains of native speakers.

This axis of language processing has been extensively studied in English speakers, but now neuroscientists have confirmed that the exact same network is activated in speakers of 45 different languages, representing 12 different language families.

The big belly of Evelina Fedorenko, an assistant professor of neuroscience at MIT and a member of the McGovern Institute for Brain Research at MIT, said in a statement. statement: “This is a very simple study that extends some of the findings from English to a wide range of languages. We hope that now that we see that basic properties seem to be common across languages, we can ask about potential differences between languages ​​in how they are implemented in the brain.”

For example, speakers of “tonal” languages ​​such as Mandarin convey the meanings of different words through shifts in their dialect or key; English is not a tonal language, so the brain may process it a little differently.

The study, published Monday (July 18) in the journal Nature Neuroscience, involved two native speakers of each language who underwent brain scans while performing various cognitive tasks. Specifically, the team scanned the participants’ brains using a technology called functional magnetic resonance imaging (fMRI), which tracks the flow of oxygenated blood through the brain.

Active brain cells require more energy and oxygen, so fMRI provides an indirect measurement of brain cell activity.

During an fMRI scan, participants listened to excerpts from Lewis Carroll’s Alice’s Adventures in Wonderland in their native languages. The researchers hypothesized that all listeners should use the same language network to process stories read in their native language.

Participants also listened to several recordings that theoretically do not activate this language network. For example, they listened to recordings in which the words of a native speaker were distorted beyond recognition, and passages were read by a native speaker in an unfamiliar language. In addition to completing these language tests, participants were asked to solve math problems and complete memory tasks; In theory, like rambling notes, memory or math tests shouldn’t activate the language network.

Language areas of the brain are selective, says first author Saima Malik Moralida, a PhD student in the Biosciences, Audio, and Technology program at Harvard University. And it shouldn’t be responsive during other tasks, such as the spatial working memory task we found in speakers of the 45 languages ​​we tested.

In English speakers, the areas of the brain that are active during speech processing appear primarily in the left hemisphere, primarily in the frontal lobe, located behind the forehead, and in the temporal lobe, located behind the ear. By creating “maps” of the brain activity of all subjects, the researchers found that the same areas of the brain are activated no matter what language is heard.

The team observed small differences in brain activity between people speaking different languages. However, the same small degree of variation was observed among English speakers.

These results are not necessarily surprising, but they lay an important foundation for future research, the team writes in their report.

“While we expect this to be the case, this presentation is an important basis for future systematic, deep and nuanced language comparisons,” they wrote.

Source: Living Science