June 3, 2008
UNIT 9: Human BiologyResearchers Learn How Brain Represents Meaning
In the past, scientists who study brain function have used functional magnetic resonance imaging (fMRI) to determine which areas of the brain are activated when an individual is instructed to think about a certain word. Now, researchers at Carnegie Mellon University in Pittsburgh, Pennsylvania have developed a computer model that can predict the unique brain activation connected with concrete nouns—words for things that you sense through sight, sound, touch, taste, or odor. This computer model is helping brain scientists understand how the brain codes the meanings of certain words.
The computer model was developed by a team of researchers led by Tom M. Mitchell, a computer scientist, and Marcel Just, a cognitive neuroscientist. The results of their research were recently published in the journal Science.
“We believe we have identified a number of basic building blocks that the brain uses to represent meaning,” said Mitchell. “Coupled with computational methods that capture the meaning of a word by how it is used in text files, those building blocks can be assembled to predict neural activation patterns for any concrete noun. And we have found that these predictions are quite accurate for words where fMRI data is available to test them.”
Through their research, the team of scientists found that the brain represents the meaning of a concrete noun in places in the brain connected with how it is sensed or used.
“The meaning of an apple, for instance, is represented in brain areas responsible for tasting, for smelling, for chewing,” said Just. “An apple is what you do with it.”
The researchers also discovered that some words are connected to areas of the brain associated with planning and long-term memory. For example, thinking about an apple may trigger a person’s memory of going to an orchard to pick apples.
The scientists are excited to continue their research. In the future, they plan to study the brain activation patterns for adjective-noun combinations, prepositional phrases, and simple nouns and concepts. The research team also plans to further their study of noun-connections by researching how the brain represents abstract nouns and concepts.