Abstract
Perceiving one's own bodily state had been proposed as the origin of feeling emotions. Insular cortex is considered to play a critical role in integrating interoception (perception of the internal bodily state) and perception of on-going environmental information regarding emotions. This brain region is also known as the neural substrate of recognition and experience of disgust. In the present study, we compared emotional processing abilities for a male patient A, who had right anterior insular damage due to viral encephalitis. The photographs depicting facial expressions were presented to this patient and age-matched controls, and they were requested to make judgments for the categories and intensities of the facial emotion on each picture. During the judgments, skin conductance responses (SCR) were recorded to examine how the insular damage affects regulation and perception of internal bodily states. Although patient A showed correct judgments on happy and neutral faces, he had difficulties to discriminate negative facial expressions such as angry and disgust. Furthermore, patient A underestimated the intensity of the angry faces compared with controls. However, we observed no significant differences on SCR to facial expressions between Patient A and controls. These results indicate that the right insular cortex is not unique to recognize disgust, but have an important role to discriminate the negative emotions in general. Our findings also support the notion that this area is the critical for receiving internal bodily states and interpreting the sensation to make subjective feeling.
