Figure 4 - Intensity-dependent response of a vagal afferent fiber to graded esophageal distention (ED, 5–80 mmHg, 30 seconds).

The fiber had ongoing spontaneous firing (15 impulses/s) with a balloon placed in the distal esophagus. In each panel, the top trace illustrates the nerve activity represented as frequency histogram (1-second bin-width), the middle trace is nerve action potentials, and the bottom trace illustrates distending pressures. The fiber exhibited increasing firing to pressure up to 40 mmHg. However, the firing frequency did not increment at greater distending pressures (60 and 80 mmHg). The fiber exhibited a pause in firing after the end of distention (10–80 mmHg).