In aIn a study published Oct. 10 in The Journal of Neuroscience, scientists report an interaction between the region of the brain that processes sound, the auditory cortex, and the amygdala, active in the processing of negative emotions.
When we hear an unpleasant noise, the researchers said, the amygdala modulates the auditory cortex response, heightening its activity and provoking a negative reaction.
“It appears there is something very primitive kicking in,” said Sukhbinder Kumar, a co-author of the report, from Newcastle University in the U.K. “It’s a possible distress signal from the amygdala to the auditory cortex.”
The researchers used a scanning method known as functional magnetic resonance imaging to examine how 13 volunteers responded to a range of sounds. Listening to the noises while inside a brain scanner, they rated the sounds from most unpleasant—the sound of knife scraping against a bottle—to pleasing: bubbling water.
Researchers then studied the brain response to each type of sound.