Seems like that could be true if a single signal in the brain was an entire thought. If it takes a million signals in the brain to make you decide to go to the bathroom before you wet yourself, then the signal to thought ratio may not support true understanding of very much at all. The differences in complexity don't save us if the process of thinking is sufficiently inefficient in utilizing that complexity.
I don't think you appreciate the utter complexity of such a process--taking a piss--and the cluster of signals, organs, action potentials and secretions, working in concert, that make this happen. It's not unlike the amount of forces, working in harmony--though mostly dependent on "luck" (where they happen to be in an expanding universe-- that keep the planets in orbit where they are, or how stars form and die.
bear in mind, too, that once that process is finished--the trip to the toilet--that allocated activity can be used for other purposes. One isn't constantly taking a piss, or let's hope not, anyway.
Make no mistake--the human brain is, by far, the most complex structure in the known universe, and likely our least-understood frontier.
Check out some of
Oliver Sack's stuff.