Experimental Studies On Optokinetic Nystagmus: I. Normal Cats

Abstract

Opto-kinetic nystagmus in normal cats was studied under a variety of conditions. The relationships between the various parameters of nystagmus and the opto-kinetic stimulus were consistently stable throughout the repeated testing for periods up to seven months. The frequency of the opto-kinetic nystagmus was primarily dependent on the velocity of the opto-kinetic stimulus and independent of the number of stripes placed on the wall of the opto-kinetic drum. The frequency, amplitude and the velocity of the slow component of nystagmus increased with increase in the velocity of the opto-kinetic drum, until a maximum was reached at stimulus velocities of 40 to 50 degrees/sec. The velocity of the eye during the slow component of nystagmus is not constant. It has an exponential course, the velocity becoming progressively smaller during each nystagmic beat. The duration of both the fast and slow components diminished with increase in the frequency of nystagmus. The physiological significance of these measurements is emphasied.