Figure 4.

Coronal and axial sections showing neural response to food and floral odors vs. odorless air in bilateral piriform and OFC. The bar graphs show the percent signal change for the three odor conditions: food odors (fo od, red), floral (fl od, yellow), and odorless air (od less, blue) (±s.e.m.), averaged over subjects). The response was taken from the voxel that responded maximally, as identified in the SPM analysis. Thus, these estimates are non-independent, and are provided to illustrate the relative difference in neural response. For illustrative purposes we also plotted the percent signal change for the strong sweet taste (st swt tst, dark green) and the weak sweet taste (wk swt tst, light green), which do not show a differential response in piriform and OFC.