To prove it, she and colleagues at the Max Planck Institute in Berlin stuck electrodes all over the heads of two guitarists while they played themselves silly. The result, shown in blue and orange waveforms, was a dance of synchronicity not unlike two tango dancers cutting up a dance floor.
The point of this particular experiment, a follow up to one that found musicians thinking similar thoughts while playing the same piece of music, was to see if playing different parts (of the same piece) the would elicit the same cognitive sympathy (neural symphony?). And so it did. This will surprise some, but feel like the right answer for aficionados of jazz improvisation, for instance, which requires musicians to listen very deeply to one another as they play, though the result may seem like everyone's going their own way.
Though the study's source material, Scheidler's "Sonata in G Major," is much tamer than Ornette Coleman, I think the extrapolation is warranted. Perhaps a follow up study? Sänger herself isn't afraid to generalize from her discovery: "We think that different people's brain waves also synchronise when people mutually coordinate their actions in other ways, such as during sport, or when they communicate with one another," she claims.