The nerve-muscle preparation of the stomatogastric system used in this study. A, Schematic of the STNS and muscle indicating intracellular and extracellular recording sites. B, Schematic of the lobster stomach showing the location of the PY-innervated muscles p2, p8, and p10 in the pylorus. C, Photomicrograph ofthe surgically isolated muscles with intact innervation.