Imagine learning a new language, word by word, and then creating sentences using the words you’ve learned. Now imagine doing this with functional magnetic resonance imaging.
Scientists at the University of Rochester have introduced an approach that focuses on the signature of single words within a sentence. Andrew Anderson, a research fellow, says:
“Using fMRI data, we wanted to know if given a whole sentence, can we filter out what the brain’s representation of a word is — that is to say, can we break the sentence apart into its word components, then take the components and predict what they would look like in a new sentence,”
Study participants read dozens of sentences to themselves while researchers monitored their brain activity. By analyzing the activity for each sentence, specific word signatures were identified. These signatures were then used to predict the brain activity of new sentences. The original 240 sentences were broad, with many words shared between them, for example:
- “The green car crossed the bridge,”
- “The magazine was in the car,” and
- “The accident damaged the yellow car”
Using the neural activity pattern associated with all three sentences, scientists were able to estimate the representation of the common word, “car.” They also had participants rate each word, on a scale of 1-6, for over 50 attributes that would predict the strength of association. These attributes ranked the sensory, emotional, and social context of the words, for example–“color,” “pleasant,” “loud,” and “time.” Senior author and professor of brain and cognitive sciences at Rochester, Rajeev Raizada, said in a press release:
“Coffee has a color, smell, you can drink it—coffee makes you feel good—it has sensory, emotional, and social aspects…The strength of association of each word and its attributes allowed us to estimate how its meanings would be represented across the brain using fMRI.”
The research, which is published in the Journal Cerebral Cortex, are a small part of a growing body of literature examining the ways language and meaning are represented in the brain. Anderson hopes that in the future, this kind of research could help individuals who have problems producing language. This includes individuals who suffer from strokes or traumatic brain injuries.