AFFERENT-PROJECTIONS OF THE SUPERIOR AND RECURRENT LARYNGEAL NERVES

The central afferent projections of the superior and recurrent laryngeal nerves were investigated in the rat, utilizing the transganglionic transport of WGA-HRP. Labelled superior laryngeal nerve terminal fields were found bilaterally in the interstitial and medial subnuclei of the nucleus tractus solitarii with the ipsilateral being more dense. The distribution of the recurrent laryngeal nerve terminals were similar to that of the SLN with two major differences: the projections were ipsilateral, and there was a marked decrease in the terminal field density. The terminal field density differences were confirmed by quantitatively identifying the labelled ganglion cells of the vagus nerve. These findings accurately delineate the first integrative components in the mediation of the complex laryngeal reflexes.