Figure 4. Gustatory and Interoceptive Co-Activation.

Prior to the GIA task, subjects performed a Gustatory Mapping (GM) task, which involved the presentation of sweet and neutral tastants during scanning (Avery et al. 2015; see Methods section for details). Using imaging data acquired during the GM task, we next examined whether those interoceptive-specific regions of the brain identified using the GIA task (see Figure 3, Table 3) were also co-activated by gustatory stimulation. Within each of those cortical surface regions, we compared the hemodynamic response to sweet vs. neutral tastants (t(14), two-tailed paired t-test). Neither region of the anterior cingulate cortex exhibited a significant response to the tastants, nor did their activity discriminate between them (p > 0.24; see Table 3). Only the ventral and mid-insula regions exhibited co-activation for gustatory and interoceptive processing.