How does the brain process the meaning of words at a cellular level? Research sheds light on the mechanism

The human brain has the ability to understand words, store them, label them in specific regions according to their meaning, trigger emotional responses when capturing them, and anticipate instantaneous responses when interacting with an interlocutor. The brain’s abilities in relation to language are undoubtedly impressive. However, how it achieves this remains an enigma for neuroscience.

There are schemes that provide a simplified view of how the brain processes language. In the left frontal lobe there are neurons specialized in the formal characteristics of speech and grammatical structures. The left temporal lobe, another region, is responsible for understanding. Sensory channels such as the eyes, ears and even touch carry information to these areas of the brain to trigger reactions to words.

All languages ​​have thousands of words. The brain can understand them and use them in combination to create complex communication. Many of these words can refer to a single concept but with different emotional charges. They can also be written and sound the same, but differ depending on the context. For example, “puppy” and “can” refer to the same animal, but one arouses sympathy while the other does not. Likewise, “bank” can be both a financial institution and a place to sit.

The encoder in the brain

Some scientists believe that this instantaneous differentiation of words and contexts is the work of an “encoder” in the brain that separates and distributes meaning in real time. Recently, Massachusetts General Hospital, affiliated with Harvard University, has investigated this phenomenon. In an article published in Natureclaim that the brain has a kind of tool that lists words related by meaning (thesaurus) to help neurons daily.

To explore the process, the researchers built a detailed map of how neurons in the human brain represent the meanings of words. They used a novel technique that allowed the activity of up to 300 neurons to be recorded in real time while 10 people listened to sentences and short stories.

The neuronal resolution allowed us to observe that each word activated a pair of neurons in the prefrontal cortex, and only words grouped in a category could activate them. For example, some cells were activated only when hearing words related to certain actions or members of a group. They also lit up with synonyms and related lists like “farm: cow, pig, chicken.”

The study concludes that the brain carries out semantic coding while listening to language to temporarily store it according to its meaning. Prefrontal neurons respond to the categories of words and thus send them directly to the most studied specific brain areas. “Taken together, these findings reveal finely detailed cortical organization of semantic representations at the neural scale in humans and begin to illuminate meaning processing at the cellular level during language comprehension,” the paper states.

Harvard University compares this encoder to a thesaurus. The latter is a literary tool that brings together a series of words or terms to represent a concept. They are useful for exercising memory and enriching vocabulary.