I see. Well, I can't really dispute that then. OK.
I should mention though that it appears that there is a homologous aspect to the neocortex in birds. It's just shaped totally differently, but it seems to have the same type of function and contain the same type of cells.
>"All mammals have a neocortex, and it's virtually identical across all of them," said Jennifer Dugas-Ford, PhD[...]researcher at the University of Chicago[...]"But when you go to the next closest group, the birds and reptiles, they don't have anything that looks remotely similar to neocortex."
>But in the 1960s, neuroscientist Harvey Karten studied the neural inputs and outputs of the DVR, finding that they were[...]similar to the pathways traveling to and from the neocortex[...]As a result, he proposed that the DVR performs a similar function to the neocortex despite its dramatically different anatomy.
>Dugas-Ford, Ragsdale and co-author Joanna Rowell decided to test Karten's hypothesis by using recently discovered sets of molecular markers that can identify specific layers of mammalian cortex: the layer 4 "input" neurons or layer 5 "output" neurons. The researchers then looked for whether these marker genes were expressed in the DVR nuclei.
>In two different bird species[...]the level 4 and 5 markers were expressed by distinct nuclei of the DVR, supporting Karten's hypothesis that the structure contains cells homologous to those of mammalian neocortex.
>"Here was a completely different line of evidence," Ragsdale said. "There were molecular markers that picked out specific layers of cortex; whereas the original Karten theory was based just on connections, and some people dismissed that. But in two very distant birds, all of the gene expression fits together very nicely with the connections."
>Dugas-Ford called the evidence "really incredible."
>"All of our markers were exactly where they thought they would be in the DVR when you're comparing them to the neocortex," she said.