Study Of Brain Mechanism For Contagious Itch And Empathy For Itch

One often feels itchy when watching someone scratching in the absence of peripheral itch stimuli. This contagious itch may be a form of empathy. In this study, we used the psychology paradigm of empathy combined with functional magnetic resonance imaging (fMRI) in an attempt to understand the neuronal mechanism of itch empathy, which might underlie various psychogenic itch disorders.This study was a2x2within subjects design. The participants watched two sets of videos (scratching video and neutral video), and then were asked to rate both the itch intensity that they felt themselves and the itch intensity that the person in the video felt, respectively. The results showed that there was a significant difference between the scores from the two perspectives, suggesting that the participants could distinguish their feelings from others. However, this ability had no correlation with empathy ability which was measured by Interpersonal Relation Inventory (IRI). Further fMRI experiments revealed a significant difference in the brain activations between subjects rating how they felt and how the person in the video felt. The brain areas activated when rating itch intensity that the subject felt is similar to the core network of empathy for pain, including anterior insula and anterior cingulate cortex. Hence, we believed that contagious itch was also a form of empathy, and this kind of empathy may be processed through emotional contagion.