My guess is that you could predict consonance/dissonance without recording neuronal activity. It's already in the physics: consonant sounds share more harmonics, bottom up. You could measure that without neurons, just a device that can detect differences in the harmonic spectrum. (And it would be trivial to make neural devices mirror the same property.)
Besides, consonant/dissonant does not correspond to aesthetically "pleasant/unpleasant" (and the right aesthetic adjective is not quite the word "pleasant" anyway): Some of the most excruciatingly beautiful harmonic moments are dissonant ones. (It has more to do with the drawing out or manipulation of expectation in the passage from dissonant to consonant -- but that too is a trivialization...)
(As happens so often: take an absolutely trivial empirical correlation, and make one of its correlates our own precious brain activity, and people are almost superstitiously ready to marvel, the same way they do at their own horoscopes, when they seem to fit...)
And, of course, having detected the physical difference, you're left with the usual (hard) problem, which is not why one feels pleasant and the other not, but why any of it feels like anything at all...