Electrophysiological evidence for signal processing in the vestibular neuroepithelium

Signal processing in the vestibular neuroepithelium can be inferred from modulation of extracellularly recorded action potentials on primary afferents and from intracellularly graded potentials in hair cells. Electrophysiological evidence which is currently available suggests that different afferents or classes of afferents may carry different types of information to different effectors such as the extra-ocular muscles or the muscles of the neck, limbs and torso. While different classes of vestibular afferents have different time-domain and frequency-domain responses and thus provide evidence for temporal signal processing in the neuroepithelium, there is currently little evidence that spatial signal processing occurs in the vestibular neuroepithelium as in the retina, for example. It may be that microspatial signal processing occurs in the vestibular neuroepithelium since there is anatomical evidence for synaptic contact between adjacent hair cells and small (50-100 mu m) regional innervation of clusters of hair cells.<>