uit: Carnegie Mellon University (2010, January 13). Identifying thoughtsthrough brain codes leads to deciphering the brain's dictionary. ScienceDaily.
"In effect, we discovered how the brain's dictionary is organized," said Just, the D.O. Hebb Professor of Psychology and director of the Center for Cognitive Brain Imaging. "It isn't alphabetical or ordered by the sizes of objects or their colors. It's through the three basic features that the brain uses to define common nouns like apartment, hammer and carrot."
As the researchers report January 12 in the journal PLoS One, the three codes or factors concern basic human fundamentals:
1. how you physically interact with the object (how you hold it, kick it, twist it, etc.);
2. how it is related to eating (biting, sipping, tasting, swallowing); and
3. how it is related to shelter or enclosure.
The three factors, each coded in three to five different locations in the brain, were found by a computer algorithm that searched for commonalities among brain areas in how participants responded to 60 different nouns describing physical objects. For example, the word apartment evoked high activation in the five areas that code shelter-related words.
The research also showed that the noun meanings were coded similarly in all of the participants' brains. "This result demonstrates that when two people think about the word 'hammer' or 'house,' their brain activation patterns are very similar. But beyond that, our results show that these three discovered brain codes capture key building blocks also shared across people,
Additionally, the team was able to predict where the activation would be for a previously unseen noun. A computer program assigned a score to each word for each of the three dimensions, and that score predicted how much brain activation there would be in each of 12 specified brain locations.
To test the theory, the team used the word scores to identify which word a participant was thinking about, just by analyzing the person's brain activation patterns for that word. The program was able to tell which of the 60 words a participant was thinking about, with a rank accuracy as high as 84 percent for two of the participants, and an average rank accuracy of 72 percent across all 10 participants (where pure guessing would be accurate 50 percent of the time).
"With psychiatric and neurological illnesses, the meanings of certain concepts are sometimes distorted," Just said. "These new techniques make it possible to measure those distortions and point toward a way to 'undistort' them. For example, a person with agoraphobia, the fear of open spaces, might have an exaggerated coding of the shelter dimension. A person with autism might have a weaker coding of social contact."
"We teach to the mind but we are shaping the brain, and now we can give the brain a test of how well it has learned a concept," says Just...
de volledige tekst van de studie: Just et al. A Neurosemantic Theory of Concrete Noun Representation Based on the Underlying Brain Codes. PLoS ONE, 2010; 5 (1)