Anatomy and surgical approach of rat's vestibular sensors and nerves

- The specific role of each vestibular sensor is still unknown for complex functions such as cognition.
- Reaching each vestibular sensor and its nerve in rats requires precise landmarks.
- Histology and microtomography demonstrate precise landmarks in 2 and 3 dimensions.
- These landmarks allow a selective approach to each vestibular sensor and nerve in rat.

BackgroundThe rat is one of the most used species in the neurosciences, but how to selectively reach each of its 5 vestibular sensors has never been described. Besides, new functions of the vestibular system have been recently discovered in the rat involving vegetative, circadian and cognitive functions. But the central pathways sustaining these functions and the role of each of the vestibular sensors are not clear.New methodsHere we want to describe the anatomy and look for a direct surgical approach to the 5 vestibular sensors in rats, as an indispensable technique to further study the central vestibular pathways.To do so we studied 10 rats either by microtomography with osmium tetroxide staining, histology with hematoxilyn-eosine staining or microsurgical dissection.ResultsThe microtomography allows a 3D representation of the 5 vestibular sensors and their nerves, with precise landmarks confirmed by the histological analysis. Each of the landmarks are illustrated and a selective surgical approach to each sensor and their nerves, is described step by step.Comparison with existing methodSelective approaches to the vestibular sensors have been used in other species such as cats, monkeys and recently humans but the current study is the first allowing this technique in rats.ConclusionEach vestibular sensor of the rat can be reached by a selective surgical approach. This allows further techniques such as electrophysiology or neurotracing of the central vestibular pathways. This also indicates the rat as a potential model for vestibular prostheses.

316