Vestibular function in Belgian Waterslager canaries (Serinus canarius)

The purpose of this study was to measure vestibular function in Belgian Waterslager canaries using short latency vestibular evoked potentials (VsEPs) elicited by linear acceleration stimuli. Responses were recorded with vertex to mastoid leads using traditional signal averaging. Response thresholds, latencies, and amplitudes were quantified and compared to non-Waterslager controls. Cochlear and vestibular organs were also processed for scanning electron microscopy. Results indicated that vestibular response thresholds were slightly, but significantly, higher for Belgian Waterslager canaries and response amplitudes at 0 dBre:1.0 g/ms were significantly reduced compared to non-Waterslagers. Response peak latencies were not significantly different. The most striking morphological finding was that the stereociliary bundles of Waterslager saccular hair cells showed no common orientation. Previous reports have also found significantly less hair cells in Waterslager saccules (Weisleder and Park, Hear. Res. 80 (1994) 6470); however, the present study did not confirm this finding. The utricle and ampullae appeared normal. The present results indicate that vestibular neural function, as measured with VsEPs, is affected in Belgian Waterslager canaries. The results also suggest that one structural correlate of the functional loss is the disordered stereociliary bundles in the sacculus.