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

Abstract

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.

Trial registration: ClinicalTrials.gov NCT00846040.

Figure 1. fMRI Task Descriptions

Panel A: Food/non-food picture repetition detection task. Panel B: Single trial in the gustatory mapping task. See online methods for detailed task descriptions.

Figure 2. Insula gustatory cortex responses to food and non-food pictures as a function of circulating glucose level

The anterior insula gustatory cortex exhibited overall greater responses to food than non-food images. In the dorsal mid-insula, however, the response to food, but not non-food, images was modulated by peripheral glucose.