By mapping the brain activity of a group of subjects while they listened to music, a researcher at the University of California (UC), Davis believes the region of the brain where memories of our past are supported and retrieved, also serves as a hub that links familiar music, memories and emotion.
The discovery may help to explain why music can elicit strong responses from people with Alzheimer's disease, said the study's author, Petr Janata, associate professor of psychology at UC Davis' Center for Mind and Brain. The hub is located in the medial prefrontal cortex region-right behind the forehead-and one of the last areas of the brain to atrophy over the course of the disease, according to the study published online in Cerebral Cortex.
"What seems to happen is that a piece of familiar music serves as a soundtrack for a mental movie that starts playing in our head. It calls back memories of a particular person or place, and you might all of a sudden see that person's face in your mind's eye," Janata said. "Now we can see the association between those two things - the music and the memories."
Janata and colleagues enrolled 13 UC Davis students into the study. While his subjects listened to excerpts of 30 different tunes through headphones, they recorded their brain activity using functional MRI (fMRI). To assure the best chance that students would associate at least some of the tunes with memories from their past, he chose songs randomly from "top 100" charts from years when each subject would have been eight to 18 years old.
Immediately following the MRI session, students completed a survey about the content and vividness of the memories that each familiar tune had elicited. The surveys revealed that, on average, a student recognized about 17 of the 30 excerpts, and of these, about 13 were moderately or strongly associated with an autobiographical memory. Moreover, songs that were linked to the strongest, most salient memories were the ones that evoked the most vivid and emotion-laden responses.
When examining fMRI images and comparing them to the self-reported reactions, the researchers discovered that the degree of salience of the memory corresponded to the amount of activity in the upper part of the medial pre-frontal cortex.
"What's cool about this is that one of the main parts of the brain that's tracking the music is the same part of the brain that's responding overall to how autobiographically salient the music is," Janata said.
Because memory for autobiographically important music seems to be spared in people with Alzheimer's disease, Janata said, one of his long-term goals is to use this research to help develop music-based therapy for people with the disease.
"Providing patients with MP3 players and customized playlists," he speculated, "could prove to be a quality-of-life improvement strategy that would be both effective and economical."