[Eye movements induced by the parallel-swing method in rabbits].

Abstract

Eye movements induced by sinusoidal linear accelerations generated by the parallel-sled, have been recorded by means of monocular electronystagmographic recordings in the horizontal and vertical plane. Qualitatively the recorded eye movements are vertical sinusoidal eye movements. When the sled moves to the right, the right eye moves upward, and the left eye downward. When the sled moves to the left, the inverse takes place. This seems to suggerate that the vestibulo-ocular reflex tested here, tries to compensate an imaginary rotation of the laboratory animal in the direction of the resultant acceleration stimulus. The false difference between the two eyes is 180 degrees, independant of the frequency of the sled. The false-difference between the sled and the eye movements increases with the frequency. The natural frequency is 0,6 Hz. The maximal amplitude is reached at the same frequency of 0,6 Hz (resonance frequency). Artefacts are present from the frequency of 0,8 Hz on. These are caused by movements of the needle electrodes on their own, due to the big accelerations on these frequencies. They are clearly distinguishable from the real eye movements. The gain "G" is incomplete, higher for the lower frequencies (0,5 for 0,3 Hz), and lower for the higher frequencies (0,1 for 0,8 Hz).