Fig. 1.

Diagram showing the mucosa–submucosa preparation used to study the effects of mucosal stimulation on the activity of submucosal neurons. The myenteric plexus is removed to permit submucosal responses to be analyzed in the absence of confounding effects from myenteric neurons. A central segment of mucosa was left intact (facing up) for stimulation but was elsewhere stripped away to permit the submucosal plexus to be visualized. The submucosal ganglia that were selected for recording were those that were adjacent to the mucosal edge and positioned on a connective that appeared to run toward the site of stimulation.