Role of the vestibular commissure in gaze-holding in the cat: a pharmacological evaluation.

Recent theoretical studies have proposed that the vestibular commissure is a major component of the horizontal gaze-holding system. In order to test this hypothesis, we injected either bicuculline, a GABA receptor antagonist, or strychnine, a glycine receptor antagonist, into the medial vestibular nucleus of alert cats. The intervestibular connection is indeed inhibitory and mediated by GABA and glycine. As neither bicuculline nor strychnine caused serious deficit of the gaze-holding system, we conclude that the vestibular commissure is not essential for gaze-holding.