[ordu]

I attended a course of neurophysiology, and the most stunning thing I've found was that all (or maybe almost all, I don't remember clearly) the neurotransmitters used by a human's neurons exist in a single cellular organisms, even in prokaryotes. Serotonin, glutamat, dopamin and others could be found in bacteria, so bacteria had all the chemistry needed for a central neural system hundreds of millions years ago, and nevertheless it took hunderds of millions years ago to build Einstein's brains.