In his book, McCloud presents "the Big Triangle" theory. Basically, it's a pyramid that represents the degree of abstraction that takes place in sequential art via the marriage of images and words. McCloud starts with a demonstration of abstraction:
For a more in-depth presentation of this, he has a convenient slideshow on his website. Based on that, I'd place physical motion (emotion) on the lower left-hand corner of the pyramid, words or lyrics on the right, and the combination of notes, the equivalent of the "abstraction," at the top.
So what's the point of all this? Rand suggested that there was a lack of a "conceptual vocabulary of music":
The formulation of a common vocabulary of music . . . would require: a translation of the musical experience, the inner experience, into conceptual terms; an explanation of why certain sounds strike us a certain way; a definition of the axioms of musical perception, from which the appropriate esthetic principles could be derived, which would serve as a base for the objective validation of esthetic judgments . . . .
I think that this "big triangle" could be a tool in that "musical vocabulary." Using McCloud's pyramid, we can translate this phenomenon in musical terms by replacing images with physical motion, and words with the cognitive aspects of melody (the integration of tones into melody, the interplay of melodic counterpoint, the perception of form in large scale compositions, etc.) This can also be compared to intensional versus extensional music. Basically, in my theory of how music induces emotion, I take Rand's "cognitive view" and pair it with the association of musical movement with physical movement, particularly movements that are associated with emotional states (as well as emotional projection via tone.) McCloud's pyramid could be used in this capacity to reveal the degree to which a composition utilizes one method in relation to the other.
The other point is that the pyramid presents another way of looking at the "reason/emotion" dichotomy of Apollo and Dionysus, the dichotomy championed by Nietzsche and challenged by Ayn Rand. But the pyramid makes visible why such a dichotomy is even considered possible: the somatic, kinetic elements of music can compel one to movement, such as an urge to dance, (or even in a reluctant foot tapping against one's will!), and the mental process of integration in complex musical pieces (which requires memory and repeated listening of tonal relations.) One's philosophy and "sense of life" determine how one feels about the "co-mingling" of these two aspects (acceptance or rejection of the dichotomy.) The pyramid makes visible this tension of opposites, this "tug of war."