Robert Gupta, violinist with the LA Philharmonic, talks about a violin lesson he once gave to a brilliant, schizophrenic musician -- and what he learned. Called back onstage later, Gupta plays his own transcription of the prelude from Bach's Cello Suite No. 1.

When Robert Gupta was caught between a career as a doctor and as a violinist, he realized his place was in the middle, with a bow in his hand and a sense of social justice in his heart. He tells a moving story of society's marginalized and the power of music therapy, which can succeed where conventional medicine fails.

It's a master class in collaboration as violinist Robert Gupta and cellist Joshua Roman perform Halvorsen's "Passacaglia" for violin and viola. Roman takes the viola part on his Stradivarius cello. It's powerful to watch the two musicians connect moment to moment (and recover from a mid-performance hiccup). The two are both TED Fellows, and thei...