**2.1. Brain's wiring diagram**

The basic building block of brains is the neuron, which by itself has a very especial nature in terms of energy consumption, higher than any other kind of cell in living creatures [14]. From human to rotifers and very simple worms, neurons group themselves into elaborated networks called brains, where the common factor seems to be carefully knitted structuring complexity, with high job specializations [15, 16].
