Music and its effect on the brain is being studied more and more closely to help people suffering brain diseases and disorders.

Like a friendly Pied Piper, the violinist keeps up a toe-tapping beat as dancers weave through busy hospital hallways and into the chemotherapy unit, patients looking up in surprised delight. Upstairs, a cellist strums an Irish folk tune for a patient in intensive care.

Music increasingly is becoming a part of patient care - although it's still pretty unusual to see roving performers captivating entire wards, like at MedStar Georgetown University Hospital one autumn morning.

Moving beyond programs like Georgetown's, the National Institutes of Health is bringing together musicians, music therapists and neuroscientists to tap into the brain's circuitry and figure out how.

"The brain is able to compensate for other deficits sometimes by using music to communicate," said NIH Director Dr. Francis Collins, a geneticist who also plays guitar.

To turn that ability into a successful therapy, "it would be a really good thing to know which parts of the brain are still intact to be called into action. To know the circuits well enough to know the backup plan," Collins added.

Learning to play an instrument, for example, sharpens how the brain processes sound and can improve children's reading and other school skills. Stroke survivors who can't speak sometimes can sing, and music therapy can help them retrain brain pathways to communicate. Similarly, Parkinson's patients sometimes walk better to the right beat.

What's missing is rigorous science to better understand how music might improve health in a range of other ways.

Soprano Renee Fleming worked with Collins to start the Sound Health initiative.

She spent two hours in an MRI scanner to help researchers tease out what brain activity is key for singing. Fleming spoke, sang and imagined singing during the scans.

NIH researcher David Jangraw found several brain regions were more active when Fleming imagined singing than when she actually sang, including the brain's emotion centre and areas involved with motion and vision.

One theory: it took more mental effort to keep track of where she was in the song, and to maintain its emotion, without auditory feedback.

Cells that regularly connect - for example, when a musician practices - strengthen bonds into circuitry that forms an efficient network for, in Fleming's case, singing.