Abstract

Objectives
: We aimed to study the role of vestibular input on spatial memory performance in mice that had undergone bilateral surgical labyrinthectomy, SCC occlusion and 4G hypergravity exposure.
Methods
: ICR mice(n=30) were used for the experiment. The experimental group divided into 3 groups. One group had undergone bilateral chemical labyrinthectomy, and the other group had performed SCC occlusion surgery and the last group was exposed to 4G hypergravity for two weeks. The movement of mice were recorded using camera in Y maze which had 3 radial arms. We counted the number of visiting arms and analyzed the information of arm selection using program we developed before and after procedure.
Results
: The bilateral labyrinthectomy group which semicircular canal & otolithic function was impaired showed low behavioral performance and spacial memory. The semicircular canal occlusion with CO2 laser group which only semicircular canal function was impaired showed no difference in performance activity and spatial memory. However the hypergravity exposure group in which only otolithic function impaired showed spatial memory function was affected but the behavioral performance was spared. The impairment of spatial memory recovered after a few days after exposure in hypergravity group.
Conclusion
: This spatial memory function was affected by bilateral vestibular loss. Space-related information processing seems to be determined by otolithic organ information rather than semicircular canals. Due to otolithic function impairment, spatial learning was impaired after exposure to gravity changes in animals and this impaired performance was compensated after normal gravity exposure.

• Keywords: Hypergravity; Spatial learning; Mouse; Vestibular lesion; Behavior;