[patfla]

The article says ARHGAP11B promotes the growth of upper-layer neurons.

Jeff Hawkins has this intriguing idea that the transition is all about the runaway growth of, in particular, grid cells which is slightly confusing in that the major place grid cells have been found is in the entorhinal cortex. If they're responsible for a vast amplification of the neocortex I'd expect them to be all over the neocortex.

Whatever the case, I wonder if the two relate and, in particular, just what upper-layer neurons do that lends them to such a vast array of applications?

Clearly though there was runaway brain growth at a particular point in time and I wonder how that worked in terms of Darwinian development? It's a striking change for what one assumes is a relatively brief period of time. Punctuated equilibrium, right?