Does consciousness go down to individual neurons?

Antonio Damasio, one of the leaders in the investigation of what makes humans conscious, certainly thinks that's what will prove out.

And, because of the number of connections each individual neuron has, that could mean that consciousness for a computer or robot may be quite some ways off, still.

Back to futurist dreamland for Ray Kurzweil, Michio Kaku and others, in that case.

Even if Damasio isn't totally on the right trail, I think he's headed in the right direction. Now, what led to the precursor of consciousness to "emerge" at some level of animal life? How much brain complexity was needed? Is neuronal number per body weight, or neuronal connections per body weight, a power law situation?