Seasonality of Two Midbrain Auditory Responses in the Treefrog, Hyla chrysoscelis

Multi-unit responses and averaged evoked potentials (AEPs) were recorded over 14 months from the torus semicircularis, a midbrain auditory nucleus, in Hyla chrysoscelis. Audiograms collected during the breeding period (late March through Aug.) showed lower thresholds for mid- and high-frequency tones and an increase in the amplitude of the midbrain AEP. Audiograms collected during the non-breeding season had thresholds elevated by as much as 18 dB and were less trimodal in overall shape. These differences may result from a reduction in the number of responsive neurons in the auditory midbrain caused by changes in the reproductive state of the animal and seasonal fluctuations in hormone levels. THE breeding behavior of North American

[1]  J. Wingfield,et al.  Correlation between blood level of androgens and sexual behavior in male leopard frogs, Rana pipiens. , 1976, General and comparative endocrinology.

[2]  S. Chung,et al.  Hearing in the frog: a neurophysiological study of the auditory response in the midbrain , 1981, Proceedings of the Royal Society of London. Series B. Biological Sciences.

[3]  R. Schmidt.  Hormonal Mechanisms of Frog Mating Calling , 1966 .

[4]  R. R. Capranica,et al.  A comparative study of auditory sensitivity in the genus Bufo (amphibia) , 1981, Behavioural Processes.

[5]  J. Loftus-Hills.  Comparative aspects of auditory function in Australian anurans , 1973 .

[6]  R. R. Capranica,et al.  Sexual differences in the auditory system of the tree frog Eleutherodactylus coqui. , 1976, Science.

[7]  C. M. Bogert.  The influence of sound on the behavior of amphibians and reptiles. , 1962 .

[8]  D. B. Ralin.  EVOLUTIONARY ASPECTS OF MATING CALL VARIATION IN A DIPLOID‐TETRAPLOID SPECIES COMPLEX OF TREEFROGS (ANURA) , 1977, Evolution; international journal of organic evolution.

[9]  D. Kelley.  Auditory and vocal nuclei in the frog brain concentrate sex hormones. , 1980, Science.

[10]  G. Fellers.  Aggression, territoriality, and mating behaviour in North American treefrogs , 1979, Animal Behaviour.

[11]  R. Fay,et al.  Forward masking and suppression in the midbrain of the southern grey treefrog (Hyla chrysoscelis) , 1982, Journal of comparative physiology.

[12]  B. Johnstone,et al.  Auditory function, communication, and the brain-evoked response in anuran amphibians. , 1970, The Journal of the Acoustical Society of America.

[13]  R. Northcutt.  Central Auditory Pathways in Anamniotic Vertebrates , 1980 .

[14]  D. Pfaff,et al.  Hormone effects on male sex behavior in adult South African clawed frogs, Xenopus laevis , 1976, Hormones and Behavior.

[15]  K. Wells.  The social behaviour of anuran amphibians , 1977, Animal Behaviour.

[16]  H. D. Potter,et al.  Patterns of acoustically evoked discharges of neurons in the mesencephalon of the bullfrog. , 1965, Journal of neurophysiology.

[17]  R. Fay,et al.  Underwater Hearing in the Frog, Rana Catesbeiana , 1981 .