Nystagmic responses of hippocampal origin in normal rabbits

Nystagmic responses in intact, healthy rabbits given hippocampal stimulation were studied and the following results were obtained. Two types of mystagmic responses were derived from the hippocampus. 1) One was a horizontal nystagmic response with a middle amplitude and was directed to the right and the left. This type of nystagmic response was first induced in the 'pre- and post-stimulus' phase after repeated electric stimulation of the hippocampus and was found in almost every rabbit examined. Furthermore, there was a positive correlation between the development of nystagmic response and repetition of the stimulation. 2) The other was a horizontal nystagmic response with a small amplitude directed toward the side of the stimulation. This type of nystagmic response was induced in the 'during-stimulus' phase and was found in two rabbits. There was no positive correlation between development of nystagmic response of this type and repetition of the stimulation.