Featured Research

from universities, journals, and other organizations

Identifying thoughts through brain codes leads to deciphering the brain's dictionary

Date:
January 13, 2010
Source:
Carnegie Mellon University
Summary:
Two hundred years ago, archaeologists used the Rosetta Stone to understand the ancient Egyptian scrolls. Now, a team of scientists has discovered the beginnings of a neural Rosetta Stone. By combining brain imaging and machine learning techniques, neuroscientists and computer scientists determined how the brain arranges noun representations. Understanding how the brain codes nouns is important for treating psychiatric and neurological illnesses.

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. The theory generated a prediction of the activation for apartment based only on the patterns derived from the other 59 words. As one slice of the observed brain image from a human participant (left) and the theory (right) shows, the theory makes precise predictions, particularly about the two shelter-related coding areas in this slice (circled), where brighter red indicates more activation.
Credit: Carnegie Mellon University

Two hundred years ago, archaeologists used the Rosetta Stone to understand the ancient Egyptian scrolls. Now, a team of Carnegie Mellon University scientists has discovered the beginnings of a neural Rosetta Stone. By combining brain imaging and machine learning techniques, neuroscientists Marcel Just and Vladimir Cherkassky and computer scientists Tom Mitchell and Sandesh Aryal determined how the brain arranges noun representations. Understanding how the brain codes nouns is important for treating psychiatric and neurological illnesses.

"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.

In the case of hammer, the motor cortex was the brain area activated to code the physical interaction. "To the brain, a key part of the meaning of hammer is how you hold it, and it is the sensory-motor cortex that represents 'hammer holding,'" said Cherkassky, who has a background in both computer science and neuroscience.

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," said Mitchell, head of the Machine Learning Department in the School of Computer Science.

This study marked the first time that the thoughts stimulated by words alone were accurately identified using brain imaging, in contrast to earlier studies that used picture stimuli or pictures together with words. The programs were able to identify the thought without benefit of a picture representation in the visual area of the brain, focusing instead on the semantic or conceptual representation of the objects.

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. The theory generated a prediction of the activation for apartment based only on the patterns derived from the other 59 words. As one slice of the observed brain image from a human participant (left) and the theory (right) shows, the theory makes precise predictions, particularly about the two shelter-related coding areas in this slice (circled), where brighter red indicates more activation.

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).

One absent code in the study that is essential for the human species concerns sex or love or reproduction. "Our vocabulary of 60 test nouns lacked any words related to the missing dimension, such as 'spouse' or 'boyfriend' or even 'person,'" Just said. "We certainly expect some human dimension to be part of the brain's coding of nouns, in addition to the three dimensions we found."

"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."

Another implication is in developing and testing domain expertise at the neural level. "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. "If an instructor knows how an advanced concept is represented in the brains of experts in that area, she will be able to teach to the brain test. We can do it for hammers and carrots right now. In the near future isotope and telomere may soon be on some brain researcher's agenda."

The research was funded by grants from the W.M. Keck Foundation and the National Science Foundation.


Story Source:

The above story is based on materials provided by Carnegie Mellon University. Note: Materials may be edited for content and length.


Journal Reference:

  1. Just et al. A Neurosemantic Theory of Concrete Noun Representation Based on the Underlying Brain Codes. PLoS ONE, 2010; 5 (1): e8622 DOI: 10.1371/journal.pone.0008622

Cite This Page:

Carnegie Mellon University. "Identifying thoughts through brain codes leads to deciphering the brain's dictionary." ScienceDaily. ScienceDaily, 13 January 2010. <www.sciencedaily.com/releases/2010/01/100112201347.htm>.
Carnegie Mellon University. (2010, January 13). Identifying thoughts through brain codes leads to deciphering the brain's dictionary. ScienceDaily. Retrieved July 31, 2014 from www.sciencedaily.com/releases/2010/01/100112201347.htm
Carnegie Mellon University. "Identifying thoughts through brain codes leads to deciphering the brain's dictionary." ScienceDaily. www.sciencedaily.com/releases/2010/01/100112201347.htm (accessed July 31, 2014).

Share This




More Mind & Brain News

Thursday, July 31, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Dieting At A Young Age Might Lead To Harmful Health Habits

Dieting At A Young Age Might Lead To Harmful Health Habits

Newsy (July 30, 2014) Researchers say women who diet at a young age are at greater risk of developing harmful health habits, including eating disorders and alcohol abuse. Video provided by Newsy
Powered by NewsLook.com
It's Not Just Facebook: OKCupid Experiments With Users Too

It's Not Just Facebook: OKCupid Experiments With Users Too

Newsy (July 29, 2014) If you've been looking for love online, there's a chance somebody has been looking at how you're looking. Video provided by Newsy
Powered by NewsLook.com
How Your Face Can Leave A Good Or Bad First Impression

How Your Face Can Leave A Good Or Bad First Impression

Newsy (July 29, 2014) Researchers have found certain facial features can make us seem more attractive or trustworthy. Video provided by Newsy
Powered by NewsLook.com
Losing Sleep Leaves You Vulnerable To 'False Memories'

Losing Sleep Leaves You Vulnerable To 'False Memories'

Newsy (July 27, 2014) A new study shows sleep deprivation can make it harder for people to remember specific details of an event. Video provided by Newsy
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

Health News

    Environment News

    Technology News



      Save/Print:
      Share:

      Free Subscriptions


      Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

      Get Social & Mobile


      Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

      Have Feedback?


      Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
      Mobile: iPhone Android Web
      Follow: Facebook Twitter Google+
      Subscribe: RSS Feeds Email Newsletters
      Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins