Daniel Šuta, Jirí Popelár, Eugen Kvasnák and Josef Syka (2007):
Representation of species-specific vocalizations in the medial
geniculate body of the guinea pig. Exp. Brain Res. 183 (3), 377-388.
Abstract: Individual nuclei of the auditory pathway contribute in a
specific way to the processing of complex acoustical signals. We
investigated the responses of single neurons to typical guinea pig
vocalizations (purr, chutter, chirp and whistle) in the ventral part of
the medial geniculate body (MGB) of anesthetized guinea pigs. The
neuronal and population peristimulus time histograms (PSTHs) reflected
the repetition frequency of individual phrases in the calls. The
patterns of PSTHs correlated well with the sound temporal envelope in
calls with short phrases (purr, chirp). The dominant onset character of
the neuronal responses resulted in a lower correlation between the sound
envelope and the PSTH pattern in the case of longer calls (chutter and
whistle). A time-reversed version of whistle elicited on average a 13%
weaker response than did the natural whistle. The rate-characteristic
frequency (CF) profile provided only a coarse representation of the
sound frequency spectrum without detailed information about the
individual spectral peaks and their relative magnitudes. In comparison
with the inferior colliculus (Šuta et al. in J Neurophysiol
90:3794-3808, 2003), the processing of species-specific vocalizations in
the MGB differs in: (1) a less precise representation of the temporal
envelope in the case of longer calls, but not in the case of calls
consisting of one or more short phrases; (2) a less precise rate-CF
representation of the spectral envelope in the case of low-frequency
calls, but not in the case of broad-band calls; (3) a smaller difference
between the responses to natural and time-reversed whistle.
URL: http://www.springerlink.com/content/c1l5t26h722l6623/
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Sonja
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