Prolonged insula activation during perception of aftertaste.

Although a critical component of taste perception, the neural basis of aftertaste perception has yet to be elucidated with neuroimaging. This functional neuroimaging study assessed the temporal dynamics of neural responses to sucrose and aspartame in eight healthy volunteers. Aspartame has a sweetness flavor profile similar to sucrose but a longer temporal profile. Participants underwent functional magnetic resonance imaging while tasting sucrose and aspartame solutions administered through a magnetic resonance imaging compatible delivery device. The insula showed significantly longer activation to aspartame than sucrose, whereas other regions activated by the task (somatosensory cortex, thalamus, amygdala, and basal ganglia) did not show a prolonged response to either tastant. These findings implicate the insula in aftertaste perception.