Psychologist identifies area of brain key to choosing words

Dec 24, 2008

New research by a Rice University psychologist clearly identifies the parts of the brain involved in the process of choosing appropriate words during speech.

The study, published in the current issue of the Proceedings of the National Academy of Sciences, could help researchers better understand the speech problems that stroke patients experience.

When speaking, a person must select one word from a competing set of words. For example, if the speaker wants to mention a specific animal, he has to single out "dog" from "cat," "horse" and other possibilities. If he wants to describe someone's temperament, he has to choose whether "happy," "sad," "ecstatic" or some other adjective is more appropriate.

Tatiana Schnur, assistant professor of psychology at Rice, wanted to determine whether one particular part of the brain, the left inferior frontal gyrus (LIFG), is necessary for resolving the competition for choosing the correct word.

She and her colleagues compared brain images from 16 healthy volunteers and 12 volunteers who suffer from aphasia, an acquired language disorder as a result of stroke. People who have aphasia frequently experience difficulty with speech.

The researchers found that while two parts of the brain, the LIFG and the left temporal cortex, respond to increased conflict among words competing for selection during speech, only the LIFG is necessary to resolve the competition for successful word production. The LIFG includes Broca's area, named after the 19th-century French scientist Paul Pierre Broca. It is responsible for aspects of speech production, language processing and language comprehension.

The study covered two experiments where people name a series of images and conflict between words increases as more images are named. In the first experiment, healthy speakers' brain activations were measured using functional magnetic resonance imaging. The second experiment mapped performance deficits to lesion locations in participants with aphasia.

By looking at direct parallels between the healthy and aphasic volunteers, Schnur and colleagues coupled location in the brain with specific speech processes. The research found that the ability of aphasic speakers "to resolve competition that arises in the course of language processing appears to depend on the integrity of the LIFG." This result could open an exciting line of research, as damage to this mechanism may explain the hesitant, nonfluent speech exhibited by those described as Broca's aphasics.

The study, "Localizing Interference During Naming: Convergent Neuroimaging and Neuropsychological Evidence for the Function of Broca's Area," was funded by the National Institutes of Health.

Source: Rice University

Explore further: Protein may improve liver regeneration

Related Stories

Applause triggers award for Meccanoid robot in Vegas

Jan 12, 2015

The open source robotic building platform, Meccanoid G15 KS from Spin Master, won top prize in a "Last Gadget Standing" showdown at CES on Thursday. Damon Poeter of PCMag described The Meccanoid G15 KS as ...

Method to reconstruct overt and covert speech

Oct 31, 2014

Can scientists read the mind, picking up inner thoughts? Interesting research has emerged in that direction. According to a report from New Scientist, researchers discuss their findings in converting brain ...

Recommended for you

Protein may improve liver regeneration

9 hours ago

Researchers at UC Davis have illuminated an important distinction between mice and humans: how human livers heal. The difference centers on a protein called PPARα, which activates liver regeneration. Normally, mouse PPARα ...

Female embryos less likely to survive to birth

17 hours ago

New research has challenged the prevailing belief that the higher proportion of male babies born in the general population results from a higher proportion of males being conceived. 

User comments : 0

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.