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:
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
1,125?1,250 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:
Kind regards
Sonja
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Dr. Sonja Amoser
Steinrieglstraße 286
3400 Weidlingbach
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