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.