Andrea Megela Simmons (2013): ?To Ear is Human, to Frogive is Divine?: Bob
Capranica?s legacy to auditory neuroethology. J. Comp. Physiol. A 199 (3),
169-182.
Abstract: Bob Capranica was a towering figure in the field of auditory
neuroethology. Among his many contributions are the exploitation of the
anuran auditory system as a general vertebrate model for studying
communication, the introduction of a signal processing approach for
quantifying sender?receiver dynamics, and the concept of the matched filter
for efficient neural processing of complex vocal signals. In this paper,
meant to honor Bob on his election to Fellow of the International Society
for Neuroethology, I provide a description and analysis of some of his most
important research, and I highlight how the concepts and data he contributed
still inspire neuroethology today.
URL: http://link.springer.com/article/10.1007/s00359-012-0786-2
For reprints please contact Andrea M. Simmons (email:
James V. Lee, Edward L. Maclin, Kathy A. Low, Gabriele Gratton, Monica
Fabiani & David F. Clayton (2013): Noninvasive diffusive optical imaging of
the auditory response to birdsong in the zebra finch. J. Comp. Physiol. A
199 (3), 227-238.
Abstract: Songbirds communicate by learned vocalizations with concomitant
changes in neurophysiological and genomic activities in discrete parts of
the brain. Here, we tested a novel implementation of diffusive optical
imaging (also known as diffuse optical imaging, DOI) for monitoring brain
physiology associated with vocal signal perception. DOI noninvasively
measures brain activity using red and near-infrared light delivered through
optic fibers (optodes) resting on the scalp. DOI does not harm subjects, so
it raises the possibility of repeatedly measuring brain activity and the
effects of accumulated experience in the same subject over an entire life
span, all while leaving tissue intact for further study. We developed a
custom-made apparatus for interfacing optodes to the zebra finch
(Taeniopygia guttata) head using 3D modeling software and rapid prototyping
technology, and applied it to record responses to presentations of birdsong
in isoflurane-anesthetized zebra finches. We discovered a subtle but
significant difference between the hemoglobin spectra of zebra finches and
mammals which has a major impact in how hemodynamic responses are
interpreted in the zebra finch. Our measured responses to birdsong playback
were robust, highly repeatable, and readily observed in single trials.
Responses were complex in shape and closely paralleled responses described
in mammals. They were localized to the caudal medial portion of the brain,
consistent with response localization from prior gene expression,
electrophysiological, and functional magnetic resonance imaging studies.
These results define an approach for collecting neurophysiological data from
songbirds that should be applicable to diverse species and adaptable for
studies in awake behaving animals.
URL: http://link.springer.com/article/10.1007/s00359-012-0788-0
For reprints please contact David F. Clayton (email:
Nina U. Pohl, Hans Slabbekoorn, Heinrich Neubauer, Peter Heil, Georg M.
Klump & Ulrike Langemann (2013): Why longer song elements are easier to
detect: threshold level-duration functions in the Great Tit and comparison
with human data. J. Comp. Physiol. A 199 (3), 239-252.
Abstract: Our study estimates detection thresholds for tones of different
durations and frequencies in Great Tits (Parus major) with operant
procedures. We employ signals covering the duration and frequency range of
communication signals of this species (40?1,010 ms; 2, 4, 6.3 kHz), and we
measure threshold level-duration (TLD) function (relating threshold level to
signal duration) in silence as well as under behaviorally relevant
environmental noise conditions (urban noise, woodland noise). Detection
thresholds decreased with increasing signal duration. Thresholds at any
given duration were a function of signal frequency and were elevated in
background noise, but the shape of Great Tit TLD functions was independent
of signal frequency and background condition. To enable comparisons of our
Great Tit data to those from other species, TLD functions were first fitted
with a traditional leaky-integrator model. We then applied a probabilistic
model to interpret the trade-off between signal amplitude and duration at
threshold. Great Tit TLD functions exhibit features that are similar across
species. The current results, however, cannot explain why Great Tits in
noisy urban environments produce shorter song elements or faster songs than
those in quieter woodland environments, as detection thresholds are lower
for longer elements also under noisy conditions.
URL: http://link.springer.com/article/10.1007/s00359-012-0789-z
For reprints please contact Ulrike Langemann (email:
Kind regards
Sonja
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Dr. Sonja Amoser
Steinrieglstraße 286
3400 Weidlingbach
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