RECORDING FROM AFFERENTS IN THE INTACT RECURRENT LARYNGEAL NERVE DURING RESPIRATION AND VOCALIZATION

The goal of this study was to determine whether sensory fibers in an i ntact recurrent laryngeal nerve (RLN) are influenced by respiration or vocalization. Patterns of RLN afferent activity were examined during respiration and evoked vocalization by means of midbrain electrical st imulation in cats anesthetized with alpha-chloralose. Nerve bundles we re dissected from an intact RLN, with motor function preserved. The bu ndles were cut and the laryngeal end was placed on floating bipolar el ectrodes. Fifteen right RLNs were examined. A total of 9 single and mu ltiunit afferent fibers from 4 cats were isolated and examined during respiration. Four units, analyzed from 3 fibers, showed respiratory ph ase modulation. Eight units, analyzed from 4 fibers in I cat, were obs erved during vocalization and showed no vocalization phase modulation. The RLN afferents could contribute to reflex modulation of the respir atory cycle, but more extensive sampling would be necessary to preclud e effects from vocalization.