Got a song stuck in your head?

By Lee Bowman
March 15, 2005

If you've ever gotten a song stuck in your head, you know
how annoying it can be. Researchers at Dartmouth University
can't stop the aggravation, but they do have a good idea
what parts of the brain keep replaying the music.

Using brain imaging techniques and a good CD collection,
they found that the auditory cortex, the same part of the
brain that passes information from the ears to the brain,
also holds onto musical memories.

If people are listening to familiar music, the researchers
say, they automatically call on those auditory memories to
fill in gaps when the music stops.

Using functional magnetic resonance imaging, researchers
watched as subjects tried to mentally fill in the blanks to
songs both familiar and unfamiliar that were missing short
snippets.

All participants reported hearing a continuation of the
familiar, but not the unfamiliar, tunes during the gaps.
And the imaging tests showed that gaps in the familiar
songs induced more activity in the brain's auditory
association area.

"We played music in the scanner (FMRI), and then we hit a
virtual 'mute' button," explained David Kraemer, a graduate
student in Dartmouth's Psychological and Brain Sciences
Department and author of the study, published in the
journal Nature.

With familiar songs, "we found that people couldn't help
continuing the song in their heads, and when they did this,
the auditory cortex remained active even though the music
had stopped," Kraemer added.

The researchers said the findings extend previous work on
auditory imagery and parallel work on visual memory, which
both show that sensory-specific memories are stored in the
brain regions that first experienced those events.

"It's fascinating that although the ear isn't actually
hearing the song, the brain is perceptually hearing it,"
said co-author William Kelley, assistant professor of
psychological and brain sciences.

The playback also differed somewhat depending on whether a
song had words. If the music gapped during an instrumental
song, say the theme from the "Pink Panther," the subjects
activated different parts of the auditory cortex,
apparently going further back in the memory-processing
stream to fill in the blanks. But when remembering songs
with words, people relied only on the more advanced
structures for auditory processing.