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Titolo:
Temporal representation of iterated rippled noise as a function of delay and sound level in the ventral cochlear nucleus
Autore:
Wiegrebe, L; Winter, IM;
Indirizzi:
Ctr Neural Basis Hearing, Dept Physiol, Cambridge CB2 3EG, England Ctr Neural Basis Hearing Cambridge England CB2 3EG idge CB2 3EG, England
Titolo Testata:
JOURNAL OF NEUROPHYSIOLOGY
fascicolo: 3, volume: 85, anno: 2001,
pagine: 1206 - 1219
SICI:
0022-3077(200103)85:3<1206:TROIRN>2.0.ZU;2-K
Fonte:
ISI
Lingua:
ENG
Soggetto:
AUDITORY-NERVE FIBERS; STEADY-STATE VOWELS; AMPLITUDE-MODULATION; DISCHARGE PATTERNS; INFERIOR COLLICULUS; COMPLEX TONES; SINGLE UNITS; PITCH; CAT; RESPONSES;
Tipo documento:
Article
Natura:
Periodico
Settore Disciplinare:
Life Sciences
Citazioni:
50
Recensione:
Indirizzi per estratti:
Indirizzo: Wiegrebe, L Univ Munich, Inst Zool, Luisenstr 14, D-80333 Munich, Germany Univ Munich Luisenstr 14 Munich Germany D-80333 nich, Germany
Citazione:
L. Wiegrebe e I.M. Winter, "Temporal representation of iterated rippled noise as a function of delay and sound level in the ventral cochlear nucleus", J NEUROPHYS, 85(3), 2001, pp. 1206-1219

Abstract

The discharge patterns of single units in the ventral cochlear nucleus (VCN) of anesthetized guinea pigs were examined in response to iterated rippled noise (IRN) as a function of the IRN delay (which determines the IRN pitch) and the IRN sound level. Delays were varied over five octaves in half-octave steps, and sound levels were varied over a 30- or 50-dB range in stepsof 5 dB. Neural responses were analyzed in terms of first-order and all-order inter-spike intervals (ISIs). The IRN quasi-periodicity was preserved in the all-order ISIs for most units independent of unit type or best frequency (BF). A deterioration of the temporal all-order code was found, however, when the neural response was influenced by inhibition. The IRN quasi-periodicity was also preserved in first-order ISIs for a limited range of IRN delays and levels. Sustained Chopper units (CS) in the VCN responded with very regular ISIs when the IRN delay corresponded to the unit's chopping period; i.e., the unit showed an increased proportion of intervals corresponding to the IRN delay (interval enhancement) relative to an equal-level, white-noise stimulation. This interval enhancement has a band-pass characteristic with a peak corresponding to the chopping period. Moreover, for CS units in rate saturation, the chopping period, and thus the interval enhancement to the IRN, did not vary with level. Units classified as onset-chopper alsoshow a band-pass interval enhancement to the IRN stimuli; however, they show more level-dependent changes than CS units. Primary-like (PL) units alsoshow level-dependent changes in their ability to code the IRN pitch in first-order intervals. The range of delays where PL units showed interval enhancement was broader and extended to shorter delays. Based on these findings, it is suggested that CS units may play an important role in pitch processing in that they transform a higher-order interval code into a first-order interval place code. Their limited dynamic range together with the preservation of the temporal stimulus features in saturation may serve as a physiological basis for the perceived level independence of pitch.

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Documento generato il 05/12/20 alle ore 19:04:37