Science Shows How Piano Players' Brains Are Actually Different From Everybody Elses'

 

Pianists' brains develop differently because of the many simultaneous skills needed to play: 

• Note reading - letters for each of the keys, played by different hands

• Rhythm and counting - how many beats each note is held for. Difficult for complex rhythms in higher grades. 

• Fingering (which finger to put on what key) and finger placement (where on the key will this finger be comfortable - different positions and combinations of multiple fingers)

• Dynamics - changes in the softs and louds which make up the character of the piece / tell a narrative / convey an emotion 

• Gradation of touch - how much arm weight do I need to let rest on to the keys? (Cue Debussy, Ravel, Faure)

• Improvisation - making things up as we go along which (hopefully) sound good!

• Emotional connection and highlighting the melody whilst also playing accompaniment

• and I'm sure there are a few I haven't thought of...

Wow that list was longer than I thought! And to quote a part of the link above:
 

"Playing the piano is "the ultimate instrument in terms of skill and demand: Two hands have to play together simultaneously while navigating 88 keys. They can play up to 10 notes at a time. To manage all those options, pianists have to develop a totally unique brain capacity — one that has been revealed by science." 

Studies since the 1980s have been showing similar results (albeit now dated) of how much  brain plasticity and activity is involved in playing.