Action potentials in the nerve from the posterior semicircular canal of the cat

A method is described to implant electrodes for recording the electrical activity in the branch of the vestibular nerve from the posterior semicircular canal of the cat. A tungsten electrode eroded to a point is inserted into the nerve through the internal auditory meatus and held in position with dental cement. Satisfactory observations have been obtained for more than 4 weeks from such a preparation. There is a continuous discharge observed in the nerve, when the head is stationary. With the posterior semicircular canal in the plane of rotation the resting discharge increases when the head is given an angular acceleration in the ampulla-leading direction, and decreases if the acceleration is in the ampulla-trailing direction. Blocking the canal does not alter the resting discharge but abolishes the responses to acceleration.