I expect there may indeed be differences in the brain between conservative and liberal characters. They'd likely correspond or reduce to authoritarian/hypermasculine/cryto-sociopathic personalities versus empathetic/feminine/hyperrational ones.
The conservative mindset would be a platform for regressing to an animalistic dominance hierarchy (theocracy, monarchy, plutocracy, etc), whereas the liberal's would amount to the human potential for escaping jungle life and for setting up a novel, if perhaps doomed (self-destructive) civilization, based on reason, cooperation, and creativity.
So I'd expect the brain differences to be consistent with my political writings. Thanks for the link, though. I'll look into it.