Researchers at Washington University's School of Medicine in St. Louis have found that children activate different and more regions of their brains than adults when they perform word tasks. This may reflect the more efficient use of our brains as we mature. It may also shed insight on the brain function seen in children with Tourette's syndrome or cerebral palsy, among other conditions.
WHAT IS fMRI: Magnetic resonance imaging (MRI) uses radio waves and a strong magnetic field rather than X-rays to take clear and detailed pictures of internal organs and tissues. fMRI uses this technology to identify regions of the brain where blood vessels are expanding, chemical changes are taking place, or extra oxygen is being delivered. These are indications that a particular part of the brain is processing information and giving commands to the body. As a patient performs a particular task, the metabolism will increase in the brain area responsible for that task, changing the signal in the MRI image. So by performing specific tasks that correspond to different functions, scientists can locate the part of the brain that governs that function.
WHAT'S NEW: The fMRI scanner takes images for long periods of time, like leaving the shutter open on a camera. While it is easy to detect brain activity, however, it's difficult to tell how the brain reacts to specific stimuli. The Washington University researchers used an improved method known as "event-related" fMRI, in which the scanner takes a series of quick snapshots three seconds apart. This enabled them to tell which parts of the brain were activated as it was stimulated by the word-generation tasks.
HOW THE BRAIN RECOGNIZES WORDS: Even before a baby says his first word, his brain is sorting out the sounds and shapes of the words and sentences he sees around him. By the age of two, children already know quite a bit about sentence structure and basic grammar. Our ability to learn languages resides in a specific portion of the brain. The brain is hard-wired with connections, made by billions of neurons that send electrical signals to the brain when they are stimulated.
The American Association of Physicists in Medicine contributed to the information contained in the TV portion of this report.