Effect of cupula shrinkage on the semicircular canal activity.

CONCLUSION

With half-sized cupula, the semicircular canal nerve potentials decreased under slow stimulus, thus potentially leading to reduced caloric response. This also suggests that shrunken cupula may cause dizziness because of its hypermobility.

OBJECTIVES

To examine the physiological effect of half-sized cupula on the semicircular canal nerve potential.

METHODS

The isolated cupula of the bullfrog was sectioned in half with fine scissors and was replaced on the crista. Mechanical endolymphatic flow and slow and fast stimuli were delivered and the evoked action potentials were recorded.

RESULTS

The cupula was successfully sectioned in half and was replaced on the crista. With the half-sized cupula, the action potentials became smaller under slow stimulus than under fast stimulus.