Reading a sentence entails integrating the meanings of individual words to infer more complex, higher-order meanings. To identify the specific roles and interactions of the brain areas involved in reading, a new study monitored the neural activity of patients implanted with intracranial electrodes as they read regular sentences and sentences deficient in meaning or structure.
The study- led by Oscar Woolnough, Ph.D., postdoctoral research fellow in the Vivian L. Smith Department of Neurosurgery with McGovern Medical School at UTHealth Houston, and Nitin Tandon, MD, professor and chair ad interim of the department in the medical school- found that: Two distinct brain regions are activated while reading. These brain regions work together to integrate the meanings of the individual words to obtain more complex, higher-order meanings.
According to scientists, this study improves their comprehension of how distributed hubs in the brain’s language network work together and interact to allow us to understand complex sentences.
Woolnough, first author of the study and member of the Texas Institute for Restorative Neurotechnologies (TIRN) at UTHealth Houston, said, “Our brains are remarkably interconnected, and for us to understand language requires a precise sequence of rapid, dynamic processes to occur in multiple sites all across our brain.”
Scientists recorded the brain activity of patients while reading three forms of sentences: regular sentences, “Jabberwocky” sentences (based on Lewis Carroll’s “Jabberwocky” poem), which use correct grammar and syntax but contain nonsense words, making them meaningless; and lists of words or nonsense words.
Two brain networks that are crucial to the reading process were discovered from these recordings. One network involves a portion of the frontal lobe of the brain that communicates with the temporal lobe, which gradually activates as a sentence’s complexity increases.
The second network incorporates a different part of the temporal lobe of the brain that communicates with a part of the frontal lobe in order to understand the context of a phrase and make it easier to comprehend and digest each new word that is read.
Tandon, the study’s senior author, said, “Implanted electrodes in the brain provide us an unparalleled insight into the inner workings of the human mind, especially for rapid processes, such as reading. Our work is making it clear that most processes – say comprehension or language generation – don’t occur in a single region but are best understood as very transient states that many separate areas of the brain achieve by very brief, yet critical, interactions.”
Scientists hope their study could pave the way towards new treatment options for the reading disorder, which affects approximately 15% of people in the U.S.’
Journal Reference:
- Oscar Woolnough, Cristian Donos, Elliot Murphy, et al. Spatiotemporally distributed frontotemporal networks for sentence reading. PNAS. DOI: 10.1073/pnas.2300252120