OPTOKINETIC NYSTAGMUS (OKN)EYE-MOVEMENT OF RABBIT IN CLOSE LOOP AND OPEN LOOP CONDITIONS
家兔的开环及闭环视动震颤（OKN）研究

The optokinetic nystagmus of rabbit were investigated. In close loop condition, the eye-movement velocity was directly proportional to the velocity of stimulus, and the gain of the OKN was approximately equal to one. In open loop condition, the eye movement velocity was considerably larger than the velocity of stimulus and the maximum gain of the open loop OKN reached about 100; it indicates that the OKN system is controlled by a negative feedback mechanism of hacking movement. The OKN response decreased while the stimulus field was reduced; it means that there is a spatial summation mechanism of moving information in rabbit OKN system. A narrow horizontal zone in the central part of the visual field was high sensitive to stimulus, the OKN response can be evoked by a single moving spot when located within that central part of the visual streak. So it is possible that the retinal function and the movement perecption of the visual system could be diagnosed by the local OKN Which is elicited by the local small stimulus in open loop conditionn.