Fig. 20

Responses of 5 S fibers were plotted at 4 concentrations for 7 different stimuli. The plot shows that the S fibers increased their responses to sweeteners but not to the other 5 stimuli; NaCl, citric and ascorbic acids, QHCl and denatonium This shows two important features. The S fibers respond exclusively to increase of sweetener concentrations and the increase of the non-sweeteners had no effect on the S fibers. Only sucrose and SC 45647 increased the frequency of action potentials in these 5 S fibers. The result does not support the across-fiber pattern theory but instead strongly supports the conclusion that labelled-line includes all taste fiber types, N, Q, H, S. GH unpublished