Virtual labyrinth model of vestibular afferent excitation via implanted electrodes: Validation and application to design of a multichannel vestibular prosthesis

摘要: To facilitate design of a multichannel vestibular prosthesis that can restore sensation to individuals with bilateral loss hair cell function, we created virtual labyrinth model. Model geometry was generated through 3-dimensional (3D) reconstruction microMRI and microCT scans normal chinchillas (Chinchilla lanigera) acquired 30–48 μm 12 voxels, respectively. Virtual electrodes were positioned based on anatomic landmarks, the extracellular potential field during current pulse computed using finite element methods. Potential fields then served as inputs stochastic, nonlinear dynamic models for each 2,415 afferent axons spiking dynamics modified Smith Goldberg model incorporating parameters varied fiber location in neuroepithelium. Action propagation implemented by well validated myelinated fibers. We tested comparing predicted actual 3D angular vestibulo-ocular reflex (aVOR) axes eye rotation elicited prosthetic stimuli. Actual responses measured video-oculography. The individualized animal placing localization real electrodes. from relative proportion excited within three ampullary nerves. Multiple features observed empirically emergent properties model, including effects active return electrode position, stimulus amplitude waveform shape target recruitment stimulation selectivity. modeling procedure is partially automated be readily adapted other species, humans.