Alzheimer’s is progressive. As more brain cells die, more of the past vanishes. Of all the attempts to hold on to memories in the face of this loss — through drugs, diet and exercise — music has proved to be among the most successful. Again, fMRI offers a possible explanation for why.
Listening to music, fMRI reveals, is (like memory itself) a full-brain workout; a wide distribution of brain structures light up, including the:
- Brain stem. Rousing classical music makes the pulse and blood pressure rise; soothing lullabies make them drop.
- Motor centers. These are the source of the irrepressible urge to tap the toe or bob the head in time with music.
- Language centers. They light up to a song with lyrics we remember.
- Auditory cortex. This is where music’s pitches and tones are processed.
- Emotion centers. Here feelings of yearning, joy, exultation, sadness, fear or loss are touched off by changes in the music’s tempo, pitch, volume; in the executive centers, thoughts and memories connected to the music are activated.
- Visual systems. Think of how a dark and stormy passage of Beethoven’s Ninth Symphony can call up images in your mind of black and turbulent skies. Disney did it for us with “Night on Bald Mountain” in Fantasia.
This full-brain workout hints at why melodies and lyrics — particularly those from songs that have personal significance to us — have such a peculiar sticking power in our memories. fMRI scans reveal that such “auto-biographically salient” music is written into many parts of the brain — the movement center, for instance—not touched by Alzheimer’s until the very last stages of the disease. Music, by stimulating these preserved parts of the memory network, seems to reach into those areas of the neocortex, the brain’s wrinkled outer layer, to find those neurons that have not yet died off, thus triggering memories thought to be lost forever.
