Effects of bilateral vestibular deafferentation on anxiety-related behaviours in Wistar rats

Abstract

Despite frequent reports that patients with vestibular dysfunction exhibit an unusually high incidence of anxiety disorders, few studies have investigated the emotional effects of vestibular damage in animals. In this study we investigated the effects of a permanent surgical bilateral vestibular deafferentation (BVD) on the performance of rats in a series of anxiety tests at 3 weeks (3-W), 3 months (3-M) and 5 months (5-M) following the lesion. We used the elevated plus maze (EPM), elevated T maze (ETM), hyponeophagia and social interaction tests. Contrary to expectation, we found that, at 3 and 5 M post-op, BVD rats spent more rather than less time on the open arms of the EPM compared to sham controls, and they displayed a lack of learned inhibitory avoidance in the ETM. Compared to sham controls, BVD rats showed no significant difference over the 3 time points in their latencies to eat in a novel situation; however, they did engage in social interaction to a significantly lesser extent. Finally, blood corticosterone levels were not significantly different between BVD and sham rats at 6 months post-op. These results suggest that BVD causes changes in the performance of rats in the EPM and ETM that might reflect emotional changes, or could be due to the cognitive impairment and hyperactivity caused by BVD.