That’s gross! Study uncovers physiological nature of disgust in politics http://www.sciencedaily.com/releases/2011/10/111025122617.htm

In a new study, political scientists closely measured people’s physiological reactions as they looked at a series of pleasant and unpleasant images. Participants who identified themselves as conservative — and, in particular, those who said they were against gay marriage –had strong physiological reactions when shown the gross pictures. The study, the latest to examine the connection between political differences and humans’ built-in physiological traits, was co-authored by University of Nebraska-Lincoln political science professors Kevin Smith and John Hibbing and appears this month in the online journal PLoS ONE, published by the Public Library of Science

This correlates with previous studies that illustrate a bond between a hyperactive amygdala and certain political leanings.

EDIT: Amygdala not hypothalamus.