Figure 7. Representative record demonstrating the influence of sealing the mouth on pharyngeal airflow mechanics during medial XIIth nerve stimulation.

V̇_I,max and P_crit were initially determined during 60 Hz stimulation of the medial branches of both XIIth nerves with the mouth open (left panel). The mouth was then sealed, and V̇_I,max and P_crit were again determined during 60 Hz medial XIIth nerve stimulation (right panel). Note that when the mouth was open, medial XIIth stimulation caused a large increase in V̇_I,max, with no change in P_crit (indicating the majority of the increase in airflow is oral). In contrast, once the mouth had been sealed (eliminating the oral flow pathway), medial XIIth nerve stimulation caused a significantly more negative P_crit, and a much smaller increase in V̇_I,max.