Jason A. Miranda and Walter Wilczynski (2009): Female reproductive state influences the auditory midbrain response. J. Comp. Physiol. A 195 (4), 341-349.
Abstract: Female behavioral responses to sensory stimuli can be highly variable across the reproductive cycle. Female green treefrogs (Hyla cinerea) use the male vocal signal to locate and choose a mate. Gravid females approach a vocalizing male to mate but do not approach if they have recently mated. Such differences in behavioral response may be due in part to shifts in the neural representation of auditory information in the brain. In this study, we investigated the influence of female reproductive state on neural responses in the auditory midbrain to both communication signals (advertisement calls) and non-communication sounds (band limited noise bursts). Recently mated females exhibited significantly reduced response strengths compared to females not recently mated. Reduced response strengths in post-mated females were in response to both noise bursts and male advertisement calls but were limited to the lower frequency range corresponding to the amphibian papilla of the peripheral auditory system. Our results therefore show that the ability of social signals to stimulate the auditory system differs in females depending on their reproductive state, and that the differential effect on low versus high spectral sensitivities may influence the way the two spectral peaks of male advertisement calls are represented. URL: http://www.springerlink.com/content/9j37775870361347/ For reprints please contact Jason A. Miranda (Email: [email protected]) T. Aran Mooney, Paul E. Nachtigall, Kristen A. Taylor, Marianne H. Rasmussen and Lee A. Miller (2009): Auditory temporal resolution of a wild white-beaked dolphin (Lagenorhynchus albirostris). J. Comp. Physiol. A 195 (4), 375-384. Abstract: Adequate temporal resolution is required across taxa to properly utilize amplitude modulated acoustic signals. Among mammals, odontocete marine mammals are considered to have relatively high temporal resolution, which is a selective advantage when processing fast traveling underwater sound. However, multiple methods used to estimate auditory temporal resolution have left comparisons among odontocetes and other mammals somewhat vague. Here we present the estimated auditory temporal resolution of an adult male white-beaked dolphin, (Lagenorhynchus albirostris), using auditory evoked potentials and click stimuli. Ours is the first of such studies performed on a wild dolphin in a capture-and-release scenario. The white-beaked dolphin followed rhythmic clicks up to a rate of approximately 1,1251,250 Hz, after which the modulation rate transfer function (MRTF) cut-off steeply. However, 10% of the maximum response was still found at 1,450 Hz indicating high temporal resolution. The MRTF was similar in shape and bandwidth to that of other odontocetes. The estimated maximal temporal resolution of white-beaked dolphins and other odontocetes was approximately twice that of pinnipeds and manatees, and more than ten-times faster than humans and gerbils. The exceptionally high temporal resolution abilities of odontocetes are likely due primarily to echolocation capabilities that require rapid processing of acoustic cues. URL: http://www.springerlink.com/content/u6v8498417101773/ For reprints please contact T. Aran Mooney (Email: [email protected]) Kind regards Sonja ************************** Dr. Sonja Amoser Steinrieglstraße 286 3400 Weidlingbach [email protected]
