RadioLab is talking about putting this guy named Bob into an MRI and having him start tune 1 in his head (they then started the cd), then start tune 2 (cd), then tune 3, then tune 4. Each piece of music was started at a different time; when they asked him where the tune was in his head, it was the exact note where the CD was. He had 4 different pieces of music going in his head and he was able to keep them separate. And they matched note for note in his head to the CDs even though he was not listening to the CDs; he was just running the entire orchestral piece in his head. He could even watch each of the musicians play their instrument, see their faces, watch their instruments - he is unable to actually listen to CDs because they are not up to the quality of the music he hears in his head.
He says that he sees each of the orchestras in his head separately in space.
I am depressed.