New research from MIT suggests the brain’s language system extends well beyond the traditional regions associated with speech and comprehension.
By analyzing brain scans from 772 people, researchers identified 17 additional areas that respond selectively to language. The findings, published in The Journal of Neuroscience, could provide a more complete picture of how the brain processes words, sentences, and meaning.
Researchers Identify 17 Additional Language Regions
For decades, scientists have focused on regions such as Broca’s area and areas of the left frontal and temporal lobes as the brain’s primary language-processing centers.
The new study found that language-responsive regions are also located in other parts of the brain, including the cerebellum, hippocampus, amygdala, medial frontal cortex, and temporal lobe.
“Even though there are all these distant components, it’s pretty restricted in terms of volume,” said Evelina Fedorenko, an MIT associate professor of brain and cognitive sciences and senior author of the study, per MIT News. “You don’t need that much of the brain to do language.”
The 17 newly identified regions collectively represent only about 5% of the adult brain’s total volume, which Fedorenko compared to roughly the size of a large strawberry.
How the Researchers Tracked Language Activity
The researchers analyzed functional magnetic resonance imaging, or fMRI, data collected from 772 participants who completed a language-localizer task.
Participants either read or listened to meaningful sentences or encountered sequences of nonwords. Researchers compared the brain’s response to the two conditions to identify regions that responded more strongly to meaningful language.
“It’s a very simple paradigm that lets you identify this core language system in individual brains,” said Agata Wolna, an MIT postdoctoral researcher and lead author, according to MIT News.
The researchers broadened their search beyond the areas typically identified by standard statistical methods. They used a less restrictive threshold and specifically examined regions where MRI signals can be weaker.
Unexpected Role for the Cerebellum
Five of the 17 newly identified language-responsive regions are located in the cerebellum, a brain structure traditionally associated with coordinating movement.
Researchers also found that some of these cerebellar areas responded during nonlinguistic cognitive tasks. That raises the possibility that certain regions help integrate information from multiple brain systems rather than serving exclusively as language centers.
“Those areas that respond to both language and some other tasks could be really interesting and important because they may be doing something like integrating information from different cortical systems,” Fedorenko said.
Language-responsive areas were also identified in the hippocampus, which is involved in memory, and the amygdala, which plays an important role in emotional processing.
Separating Language From General Thinking
The researchers wanted to determine whether the newly identified regions were responding specifically to language or simply becoming active because the tasks required concentration.
For approximately 490 participants, they also had brain-scan data from a spatial working-memory task. Participants had to remember the locations of flashing squares on a grid, activating a brain network associated with general cognitive demands.
Comparing the two tasks helped researchers distinguish language-selective activity from activity associated with general problem-solving and mental effort.
Some of the newly identified areas responded preferentially to language, while others responded to both language and nonlinguistic tasks.
Why the Regions May Have Been Overlooked
The researchers believe some of these language-responsive areas may have escaped attention in previous studies because they are relatively small or produce weaker MRI signals.
Earlier research often relied on strict statistical thresholds or averaged brain activity across participants, potentially obscuring subtle differences between individuals.
By examining individual brain patterns and searching more broadly, the MIT team was able to identify areas that might otherwise have been dismissed as unrelated to language.
A Broader Understanding of Language
The findings do not mean that language is processed uniformly throughout the brain. Instead, they suggest that a relatively compact core language system works alongside other specialized regions.
The hippocampus, amygdala and cerebellum, for example, could potentially connect language with memory, emotion or other cognitive processes, although the precise functions of the newly identified regions remain unknown.
Researchers plan to study these areas further using different language tasks and nonlinguistic activities.
The work could eventually contribute to a better understanding of language disorders and brain injuries, as well as how language interacts with memory, emotion and other cognitive functions.
For now, the study offers a more complete map of the brain’s language network — and shows that the machinery behind human communication is more distributed than scientists once believed.
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