3D-printed pacifier-shaped mouthpiece for fMRI-compatible gustometers

Gustometers have made it possible to deliver liquids in functional magnetic resonance imaging (fMRI) settings for decades, and mouthpieces are a critical part of these taste delivery systems. Here, we propose an innova- tive 3D-printed fMRI mouthpiece inspired by children's pacifiers, allowing human participants to swallow while lying down in an MRI scanner. We used a large sample to validate the effectiveness of our method. The results suggest that the mouthpiece can be used to deliver taste stimuli by showing significant clusters of activation in the insular and piriform cortex, which are regions that have been consistently identified in taste processing. This mouthpiece fulfills several criteria guaranteeing a gustatory stimulus of quality, making the delivery pre- cise and reliable. Moreover, this new pacifier-shaped design is simple and cheap to manufacture, hygienic, comfortable to keep in the mouth, and flexible to use in diverse cases. We hope that this new method will pro- mote and facilitate the study of taste and flavor perception in the context of reward processing in affective neuroscience, and thus, help provide an integrative approach to the study of the emotional nature of rewards