Temperature-dependent regulation of vocal pattern generator.
Vocalizations of Xenopus laevis are generated by central pattern generators (CPGs). The advertisement call of male X. laevis is a complex biphasic motor rhythm consisting of fast and slow trills (a train of clicks). We found that the trill rate of these advertisement calls is sensitive to temperature and that this rate modification of the vocal rhythms originates in the central pattern generators. In vivo the rates of fast and slow trills increased linearly with an increase in temperature. In vitro a similar linear relation between temperature and compound action potential frequency in the laryngeal nerve was found when fictive advertisement calls were evoked in the isolated brain. Temperature did not limit the contractile properties of laryngeal muscles within the frequency range of vocalizations. We next took advantage of the temperature sensitivity of the vocal CPG in vitro to localize the source of the vocal rhythms. We focused on the dorsal tegmental area of the medulla (DTAM), a brain stem nucleus that is essential for vocal production. We found that bilateral cooling of DTAM reduced both fast and slow trill rates. Thus we conclude that DTAM is a source of biphasic vocal rhythms.
Yamaguchi
Ayako
A
Boston University, Biology Department, Boston, MA 02215, USA. ay@bu.edu
Gooler
David
D
Herrold
Amy
A
Patel
Shailja
S
Pong
Winnie W
WW
D000200:Action Potentials / Q000187:drug effects / Q000502:physiology; D000704:Analysis of Variance; D000818:Animals; D001703:Biophysics; D001833:Body Temperature Regulation / Q000502:physiology*; D004558:Electric Stimulation; D066298:In Vitro Techniques; D007821:Laryngeal Muscles / Q000187:drug effects / Q000502:physiology; D008297:Male; D009474:Neurons / Q000502:physiology; D012701:Serotonin / Q000494:pharmacology; D013018:Sound Spectrography / Q000379:methods; D013696:Temperature; D017557:Ventral Tegmental Area / Q000187:drug effects / Q000502:physiology; D014828:Vocalization, Animal / Q000187:drug effects / Q000502:physiology*; D014982:Xenopus laevis
D012701:Serotonin