Researchers track auditory perception across brain regions

Sounds you consciously perceive affect your brain differently than sounds you don’t, a recent Yale study found.

For the study, researchers played participants a series of tones—ranging in intensity from undetectable to fully audible—over a white noise background. Since the participants were also patients undergoing seizure monitoring, and therefore had electrodes implanted on the surface of the brain, this allowed the researchers to record detailed brain activity while the participants listened to the tones.

“We found that when sounds were consciously perceived, there was a wave of activity that flowed through widespread areas of the brain,” said Hal Blumenfeld, the Mark Loughridge and Michele Williams Professor of Neurology at Yale School of Medicine and senior author of the study, which was published in NeuroImage.

“But when the same sounds were not consciously perceived, brain activity was limited to a small region around the auditory cortex.”

The activity was similar to what has been observed with visual perception, suggesting there are shared neural mechanisms between the two systems. The findings advance researchers’ understanding of what happens in the brain during sensory perception and shed light on the neurological underpinnings of human consciousness.