Category-specific integration of homeostatic signals in caudal, but not rostral, human insula

Prevailing theories hold that the insula is functionally organized along its caudal-to-rostral axis, with posterior regions coding lower-level sensory information, and anterior regions coding higher-level stimulus significance relative to the body’s homeostatic needs. Contrary to predictions of this model, the response of the taste-sensitive region of the caudal, but not rostral, insula to food images was directly related to the body’s homeostatic state as indexed by levels of peripheral glucose.