[Neurophysiological research on the bulbar projections of different groups of afferents of the superior laryngeal nerve].

Bulbar projections of superior laryngeal afferent fibres were investigated using the method of ortho- and antidromic testing in 17 adult cats anaesthetized with nembutal (40 mg/kg, i.p.). Terminals of the most excitable afferents (group A beta) were distributed predominantly ipsilaterally within nucleus tractus solitarius (NTS), adjacent part of lateral tegmental field (FTL), and rostral part of retrofacial nucleus (RFN). The high threshold afferent projections of the superior laryngeal nerve (groups A gamma and A delta) were also found within this nuclei but were more extensive as compared with low threshold afferents within NTS and FTL. Projection pattern within RFN was found to be reverse. Superior laryngeal afferent terminals with the high threshold only (group A delta) were found within caudal nucleus of the spinal trigeminal tract and probably within dorsal motor nucleus of the vagus nerve just rostral to obex.