Lots of good thoughts here. I'll have to study up a bit before I can summarize or analyze the conversation thus far. In the meantime...try a Google search using PET, brain, music...(a PET scan is the brain scan which demonstrates brain activity).

I found a link (http://cogweb.ucla.edu/EP/Music_Leutwyler_01.html) with some facinating information.

How does the brain process music? Are there special neural circuits dedicated to creating or interpreting it? If so, are they, like language, unique to human beings? Or do other animals possess true musical ability? Why is an appreciation for music practically universal? Has it conveyed some evolutionary advantage through time? The field of biomusicology is still fairly young, but during the past few years, it has started to answer some of these questions.

From these studies they concluded that musicality resided primarily on one side of the brain—the right hemisphere.
The scientists found that people with damage to the left temporal lobe had difficulty recognizing changes only in key, whereas those with damage to the right side struggled to recognize changes in both key and contour.

...used positron emission tomography (PET) to monitor the effects of changes in pitch. What they found—much to their surprise—was that Brodmann's areas 18 and 19 in the visual cortex lit up. These areas are better known as the "mind's eye" because they are, in essence, our imagination's canvas.

But music goes much deeper than that—below the outer layers of the auditory and visual cortex to the limbic system, which controls our emotions. The emotions generated there produce a number of well-known physiological responses. Sadness, for instance, automatically causes pulse to slow, blood pressure to rise, a drop in the skin's conductivity and a rise in temperature. Fear increases heart rate; happiness makes you breathe faster. By monitoring such physical reactions, Carol Krumhansl of Cornell University demonstrated that music directly elicits a range of emotions. Music with a quick tempo in a major key, she found, brought about all the physical changes associated with happiness in listeners. In contrast, a slow tempo and minor key led to sadness.

I better quit copying and pasting before I get in trouble. Following the paragraph above, there is a paragraph about consonant and dissonant patterns of notes causing the limbic area to light up -- you guessed it -- As expected, dissonance made areas of the limbic system linked to unpleasant emotions light up in the PET scans, whereas the consonant melodies stimulated limbic structures associated with pleasure.

******hehe*******

I have no idea how they defined consonant and dissonant, but I may trace the references cited (when I have more time.)

...the canyon wren's trill cascades down the musical scale lie the opening of Chopin's 'Revolutionary' Etude." That same bird sings in the chromatic scale, which divides the octave into 12 semitones, and the hermit thrush sings in the so-called pentatonic scale.

There is much more in this one link.