To determine whether the auditory or vestibular system causes the sound-induced laryngeal reflex, which has been considered to participate in the auditory feedback control of vocalization, click-induced laryngeal responses were compared before and after sectioning of the cochlear and/or vestibular nerves in cats. The sound-induced reflex modulation of respiratory muscle activity was also investigated, because respiratory movement is important for vocal control. Sectioning of the cochlear nerves had little influence on these responses. In contrast, sectioning of the vestibular nerves abolished these responses. It was concluded that the sound-induced laryngeal and respiratory reflexes are attributed to the vestibular system.
1Departments of Otolaryngology, School of Medicine, Chiba University, 1-8-1 Inohana, Chiba 260–0856, Japan
2Departments of Physiology, School of Medicine, Chiba University, 1-8-1 Inohana, Chiba 260–0856, Japan
3Corresponding Author: Keisuke Shiba and Ken Nakazawa
Acknowledgements: This work was supported in part by Grant-in-Aid 09771330 for Encouragement of Young Scientists from the Japanese Ministry of Education, Science and Culture. We thank Dr Yasuko Sekita for participating in some experiments.
Received 6 October 1999; accepted 3 November 1999