I'm a graduate student in neuroscience. After reading your post, I performed several searches on PubMed, which is a search engine for all peer-reviewed medical and biomedical research journals. I found that nothing has been published on activation of the amygdala in Democrats vs. Republicans, conservatives vs. liberals, or any number of other searches. The New York Times article you referred to also did not quote any published papers or show any data. Before you start arguing about the significance of fundamental brain differences between liberals and conservatives, you should consider that there is no scientifically vaildated data on this. The New York Times certainly isn't a bastion of scientific criticism or a valid scientific source for that matter. Maybe UCLA researchers have gotten some prelimiary data that people are excited about, but unless the research has been peer-reviewed, published and hopefully confirmed by multiple groups, it's just an unverified claim. 9 times out of 10 these unpublished (but sometimes highly publicized) data turn out to be bogus.