Canal-plugging in the Rhesus Monkey A Tool to Study the Contribution of Individual Canals to Nystagmus Generation

Abstract

Plugging of the semicircular canals was first described by Ewald in 1892 (3). With a drill one makes a small opening in the bony canal and fills it with bone chips. The idea is to block any fluid movement or pressure build-up across the capula during angular acceleration without interfering with normal afferent activity in the hair cells of the capula. The following operations were successfully done in animals subjected to a battery of vestibular tests:

1. all 3 canals on both sides plugged;

2. both lateral canals plugged;

3. all vertical canals plugged;

4. paired anterior and controlateral posterior canals plugged.