The purpose of this study was to investigate the neural pathway from t
he vestibular labyrinth to the medullary vomiting center in the cat, u
sing electrophysiological techniques. During electrical stimulation of
the canal nerve, we found conflicting results: the pressure in the st
omach sometimes increased, and sometimes decreased. There might be sev
eral neural structures between the semicircular canal nerve and the vo
miting center in the dorsolateral portion of the reticular formation o
f medulla oblongata. Retching or vomiting-like behavior during both re
spiration and movement of the stomach was recorded during stimulation
at several sites in the lateral medullary reticular formation. However
, the evoked unit activities were not always induced by stimulation of
the canal nerve.