Figure 6: Schematic representation of the cochlea and the afferent innervation of the hair cells. (a) The axis of the cochlea (modiolus) harbors the spiral ganglion cells. The cell bodies are located in Rosenthal’s canal. (b) The afferent innervation of the hair cells takes place via the nerve fibres of the spiral ganglion cell neurons (SGN). Type I spiral ganglion neurons are myelinated and lead to the inner hair cells (IHC).Type II spiral ganglion neurons are not myelinated and lead to the outer hair cells (OHC). Each type II cell forms synaptic contacts with numerous outer hair cells. Type I cells, however, typically show contact with only one inner hair cell (Figure modified after Rusznák & Szücs [119], by kind permission of Springer Science + Business Media).