Perceptual interaction between carrier periodicity and amplitude-modulation in the gerbil (<Emphasis Type="Italic">Meriones unguiculatus</Emphasis>) |
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Authors: | Lutz Wiegrebe Veronika Sonnleitner |
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Institution: | 1.Biocentre,Universit?t München,Planegg-Martinsried,Germany;2.Biocentre,Universit?t München,Martinsried,Germany |
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Abstract: | Due to its extended low-frequency hearing, the Mongolian gerbil (Meriones unguiculatus) has become a well-established animal model for human auditory processing. Here, two experiments are presented which quantify
the gerbil’s sensitivity to amplitude modulation (AM) and carrier periodicity (CP) in broad-band stimuli. Two additional experiments
investigate a possible interaction of the two types of periodicity. The results show that overall sensitivity to AM and CP
is considerably less than in humans (by at least 10 dB). The gerbil’s amplitude-modulation sensitivity is almost independent
of modulation frequency up to a modulation frequency of 1 kHz. Above, amplitude-modulation sensitivity deteriorates dramatically.
On the basis of individual animals, carrier-periodicity detection may improve with increasing fundamental frequency up to
about 500 Hz or may be independent of fundamental frequency. Amplitude-modulation thresholds are consistent with the hypothesis
that intensity difference limens in the gerbil may be considerably worse than in humans, leading to the relative insensitivity
for low modulation frequencies. Unlike in humans, inner-ear filtering appears not to limit amplitude-modulation sensitivity
in the gerbil. Carrier-periodicity sensitivity changes with fundamental frequency similar to humans. Unlike in humans, there
is no systematic interaction between AM and CP in the gerbil. This points to a relatively independent processing of the perceptual
cues associated with AM and CP. |
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Keywords: | Gerbil Modulation Pitch Periodicity Psychoacoustics |
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