"For example, scientists were shocked to learn that about 90 percent of the fibers in the primary visceral nerve, the vagus, carry information from the gut to the brain and not the other way around."
I think that Science will be surprised (again) when they finally find out (confirm) that the microflora are initiating a lot of this *information* being transmitted between the gut and the brain... whether that microflora is composed primarily of the good guys or not.