I follow whatever interests me... curiosity, imagination, whimsy, pleasure, satisfaction. I guess if you have to use the head/heart metaphor, it's the heart. The ancient Egyptians would have thought so, since they were convinced the brain is just an organ that produces snot and the heart is where consciousness resides.
(But I'm pretty sure my central nervous system is leading the way, because have you heard my music? It's full of anxiety, but I prefer a balanced stereo field with no hard panning.
)I improvise. Stay in the moment, go fast and loose, paint with broad strokes, damn the torpedoes, etc. And I commit -- I record just the full mix of live sessions with the effects baked in, no stems. If I have to multitrack (adding more parts after the initial session) I usually do it separately and then put the two recordings together in Sound Forge. All my editing is "destructive" and final -- EQ, dynamics, fixing clicks/pops/glitches, reducing noise, etc.
This keeps the flow going, stops me from needlessly monkeying with minor details to "improve" something when it's really just different instead of better, helped me develop my skill at recording in the fist place as well as that style of editing. It works for me.
I suck at "writing" music, but I think I'm pretty okay at creating music.
