It might be a 'whole is greater than the sum of its parts' kind of thing. It could be an aura around the entirety with no particular organ of its own. Replacng some parts wouldn't necessarily change the totality any more than changing violin strings or rehairing the bow would cause notes to be dropped from the music.
I agree in principal with that. One neuron in isolation is like one hand attempting to clap.
But I don't think you have to get all Buddhist about this. Our knowledge of neurons is conceptually at the same point as our knowledge of DNA was in 1950.