• Stimulation of the Vestibular Apparatus in the Guinea Pig by Static Pressure Changes: Head and Eye Movements

Head and eye movements elicited by static pressure increases of up to 1‐min duration in the external auditory meatus were recorded using guinea pigs as subjects. The minimum stimulus intensity required to produce a response was 1.5–2.0 cm Hg. Observations were made of response latencies, durations, and amplitudes as a function of stimulus intensities, durations, and onset rates. Head and eye movements elicited by the pressure stimulation were found to be significantly correlated. The results of this investigation are interpreted as supporting the hypothesis that stapes footplate displacement, and consequently perilymph/endolymph displacement, produce direct mechanical stimulation of the semicircular‐canal receptors. Moreover, these results suggest that the same mechanism might be responsible for stimulation of the vestibular system by low‐frequency inaudible sound and for the vestibular effects observed in response to audio‐frequency high‐intensity sound. In the latter case, vestibular stimulation is hypothesized to occur as a result of a shift in the average position of the stapes footplate owing to overdriving the ossicular chain.