WASHINGTON, Dec. 24 (Xinhua) -- New research by scientists from Rice University clearly identify 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 describe someone's temperament, he has to choose whether "happy," "sad," "ecstatic" or some other adjective is more appropriate.

    The Rice research team 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.

    They 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.

    This result could open an exciting line of research, as damage to this mechanism may explain the hesitant, nonfluent speech exhibited by aphasics, said the authors.