Unbiased quantification of the microdissected human Scarpa's ganglion neurons.

Abstract

The objective of the present study was to obtain unbiased estimates of the total number of Scarpa's vestibular ganglion neurons in individuals with normal vestibular function. Application of unbiased stereology using microdissected human temporal bone specimens. Postmortem temporal bones were obtained from five young subjects with no history of audiovestibular disease (age range 42-49 years). The vestibular nerve containing the Scarpa's ganglion was microdissected, embedded in paraffin, and cut into 40 microm serial sections. Unbiased estimates of the total number of neurons were obtained using the optical fractionator technique of stereology. An average of 23,599 (coefficient of variation [CV] = 0.11) vestibular ganglion neurons was obtained. There was no significant difference between the results obtained from the microdissected specimens and results that had been obtained from an age-matched group derived from a previously published report from our laboratory using archival human temporal bone specimens. This study represents the first report to demonstrate the combination of the microdissection technique and the unbiased stereologic technique in the human temporal bone. This study demonstrates the reliability of the microdissection technique as an alternative method of human temporal bone processing for unbiased stereology. The utility of the microdissection technique is that specimens can be used for quantification, immunohistochemistry, and other powerful applications.