Scientists have discovered how two distinct brain networks interact with each other to help us make meaning out of words and derive complex, higher-level meaning from sentences like the one you’re reading right now.
“This study helps us better understand how distributed nodes in the brain’s language network work together and interact to enable us to understand complex sentences,” says neuroscientist Oscar Woolnough from the University of Texas Health Science Center at Houston.
Although a lot of research has been done which brain regions light up when people readuntil now, we not understood completely how neural circuits worked in these brain regions to help us understand words.
The researchers gained unprecedented insight into the human brain by examining the brain activity of 36 people who had intracranial electrodes implanted as part of the treatment for epilepsy.
The team recorded participants’ neural activity in real time as they read three things: meaningful sentences; a list of words or pseudo-words; and sentences that used correct grammar and syntax but were filled with made-up words, which the researchers called “Jabberwocky” sentences.
It became clear that there were two adjacent brain networks that worked both separately and together to make sense of what was read.
In the first network, the frontal lobe of the brain sends signals to the temporal lobe. This network is activated when a person begins to figure out meaning as they move along a sentence.
The second network uses a different part of the brain’s temporal lobe and sends signals back to the frontal lobe and was activated by words on a list rather than reading a whole sentence, suggesting that it improves understanding of individual words.
Together, these networks seem to allow us to understand both worlds and give meaning to whole sentences.
“Our brains are remarkably interconnected, and understanding language requires a precise sequence of rapid, dynamic processes occurring at multiple locations in our brain.” says Woolnough.
The research is important, not only because it’s cool to understand how our brains perform such a basic task, but also because there are many people who have trouble reading or suffer from disorders like dyslexia who are affected roughly 15 percent by people in the US.
“Our work makes it clear that most processes – say comprehension or language production – do not take place in a single region, but are best understood as very transient states reaching many separate areas of the brain through very brief but crucial interactions”, says lead study author, neurosurgeon Nitin Tandon, also of the University of Texas Health Science Center.
The research was published in PNAS.
