Disgust and the insula: fMRI responses to pictures of mutilation and contamination.

Although previous functional brain imaging studies have found that the insula responds selectively to facial expressions of disgust, it remains unclear whether the insula responds selectively to disgust-inducing pictures. In this fMRI study, healthy volunteers viewed pictures of contamination, human mutilation, attacks and neutral scenes during scanning, and then rated pictures for the 'basic' emotions. The anterior insula responded to contamination and mutilation but not attacks, while the ventral visual areas responded to attacks and mutilations more strongly than contamination. The above activations were predicted by disgust and arousal ratings respectively. Additionally, mutilations uniquely activated the right superior parietal cortex. These results support selective disgust processing at the insula, and suggest distinct neural responses to contamination and mutilation.