Fig. 6.

Effects of peripheral stimulation of the SLN, X, and PEN toward the esophagus on esophageal motility. SLN stimulation had no effect on esophageal motility in 3 of 3 animals (see Table 2), X stimulation activated the esophagus at 10 cm from the CP in 6 of 6 animals (see Table 2), and PEN stimulation activated the esophagus at 1, 4, and 7 cm from the CP in 1 of 3 animals, but at 1 and 4 cm in 3 of 3 animals (see Table 2). Also, electrical stimulation caused large noise artifacts on the EMG electrodes; therefore, no conclusions were drawn from these responses. In summary, motor innervation of the esophagus is provided by the X and PEN, and not the SLN; therefore, when we transected the RLNp and found that initiation of the esophageal phase of swallowing was blocked (see Fig. 4), this change was due to elimination of sensory feedback, and not motor innervation.