Brain Shuts Visual Areas While Performing Hearing Tasks

US researchers have discovered that the brain can reduce people’s ability to see for enabling them to hear complex sounds.

US researchers have discovered that the brain can reduce people’s ability to see for enabling them to hear complex sounds. Collaborators from Wake Forest University Baptist Medical Center and the University of North Carolina conducted a study involving 20 professional musicians and 20 non-musicians, and found that both groups diverted brain activity away from visual areas while performing hearing tasks.

While making a presentation at a conference organised by the Society for Neuroscience in San Diego, California, the researchers revealed that they used functional Magnetic Resonance Imaging to measure real-time changes in the subjects’ brain activities based on the blood flow to different areas of their brains.

As the participants lied in the scanner, they were made to hear two different musical tones that were clearly different but began at almost the same time, only a few thousands of a second between them. The participants had to identify which of the tones was played first.

The task was made harder for the professional musicians by moving the tones much closer together for them, considering the differences between their background and that of non-musicians. Both groups showed reduction in activity in the brains’ visual part, as the activity in the auditory part rose.

As the task grew harder, the non-musicians diverted more and more activity away from the visual parts of the brain to the auditory side, indicating that they were struggling to concentrate. The professional musicians, however, did not suppress activity in the visual parts of their brains after a certain point.

According to the researchers, the years of training might have provided the musicians with a distinct advantage in the way their brains were organised. "This is like closing your eyes to listen to music. Imagine the difference between listening to someone talk in a quiet room and that same discussion in a noisy room - you don't see as much of what's going on in the noisy room," the BBC quoted lead researchers Dr. Jonathan Burdette as saying.

Another researcher, Dr David Hairston, said that the study gave a clear indication that the brain’s ability to filters information from different senses was very flexible and adaptive, and changed with the demands of the task at hand. "How this operates can change with highly specialised training and experience," he said.