Just another note on the belly brain/ "main" brain interaction.
Last november I passed my diploma examinations at the university. I had stuffed my "head brain" for months with knowledge but my gut was really, really nervous. I had just about three hours of shallow sleep before my first exam...
Last saturday I had my shodan test in aiki toho iai (Shoji Nishio Sensei's iaido). I wasn't nervous at all, just a little bit excited. I think my body / belly brain just knew for sure that I had trained mind AND body hard for this and that it couldn't go wrong... I found this quite interesting and assuring. I was even able to sleep for half an hour right before the test which is a really good sign in my case. And so everything went fine, I even enjoyed doing the test!