Function and Morphology of the Otolith Organ

- Review of the Literature -

Abstract

The function and morphology of the otolith organs was examined with respect to the information transduction of head tilting and linear acceleration.
It has generally been accepted that hair cells of the otolith organs are activated when hairs are reflected to the direction of the kinocillium (morphological polarization vector). Head tilting and acceleration stimulate hair cells with the same morphological polarization vector to increase their firing rates. To prove this theory, the correspondence between morphological and functional polarization vectors of otolith hair cells must be demonstrated.
The functional polarization vectors of the otolith organs were predicted after physiological investigation of the vestibular ganglion (Scarpa's ganglion) cells. A similarity between the functional polarization vector of the superior vestibular ganglion cells and the morphological polarization vector of the utricular macula was suspected. Likewise a relation between the inferior vestibular ganglion cells and the saccular macula was also suspected. By this method, however, the peripheral innervation pattern of the vestibular ganglion cells could not be identified and the functional role of the differentiation of hair cells (types 1 and 2) as well as the significance of existence of striola remain unknown.