Effect of Noisy Galvanic Vestibular Stimulation on Spatial Learning and Memory of Rats

Background and Aim: Previous studies have shown promising findings on effectiveness of noisy Galvanic Vestibular Stimulation (nGVS) in various cognitive disorders. The connections of the vestibular system with the hippocampus has been proven. Here we investigated the effect of vestibular galvanic stimulation on the improvement of spatial learning and memory of rats. Methods: Twelve Wistar rats were randomly divided into control and nGVS groups. The nGVS group underwent 30-minute sessions of stimulation at sub-threshold levels for a duration of fourteen days. Following the intervention, both groups underwent assessments of cognitive indices through the Morris water maze task, hippocampal neuronal spike rate by Single-Unit Recording (SUR) and the concentrations of c-fos protein in the hippocampus were measured using ELISA device. Results: The nGVS group exhibited a significant difference compared to the control group in both the time taken to reach the target platform and the percentage of time spent in     the goal quarter during the Morris water maze test. The nGVS treatment significantly enhanced spike rate of hippocampal dentate gyrus (p<0.01) compared to the control group. Additionally, c-fos protein concentrations were increased in the nGVS (5.833) than the control group (4.126), (p<0.001). Conclusion: According to the obtained results, nGVS plays a role in improving spatial memory, and a longer duration of intervention is suggested to achieve more obvious improvement results.   Keywords: Galvanic vestibular stimulation; spatial cognition; single-unit recording; hippocampus; rat