Unbiased number of vestibular ganglion neurons in the mouse.

Vestibular sensory information from the labyrinth and otolith organs is conducted to the central nervous system exclusively via primary vestibular afferents (PVA) originating from neurons located in the vestibular ganglion (VG). In the present study, the total number of VG neurons was determined in two different wild-type mouse strains using the principles of unbiased stereological counting methods by means of the physical disector. 3316 (+/-225 SD) neurons were present in the VG of the B6CBA-strain and 3551 (+/-239 SD) in C57BL/6J-mice. Since no statistical difference was detected between the two strains, the pooled mean number was 3433 (+/-232 SD) neurons. This is the first unbiased estimate of VG neurons aimed at providing a numerical basis for comparative studies and for the impact of experimental, pharmacological and pathological conditions as well as ageing on the survival and maintenance of VG neurons.