I have just begun re-reading Origin of Consciousness after about a 25 year hiatus.
I was curious whether recent neurological discoveries had validated any of Jaynes' ideas. I was already aware of the recent discovery of "mirror" neurons that supposedly account for our ability to empathize with others. These would seem to be an esential building block of consciousness. I know that they have identified mirror neurons in other great apes, but not in other species.
Then I ran across a discussion of what is referred to as "theory of mind". It is a discrete area of the brain which appears to be responsible for our ability to form what Jaynes called an "analog I". This discovery seems to further provide a neurological basis for consciousness in accord with Jaynes. Here's the Wikipedia reference for "theory of mind"http://en.wikipedia.org/wiki/Theory_of_mind