PMID- 11247990
OWN - NLM
STAT- MEDLINE
DCOM- 20010419
LR  - 20171213
IS  - 0022-3077 (Print)
IS  - 0022-3077 (Linking)
VI  - 85
IP  - 3
DP  - 2001 Mar
TI  - Temporal representation of iterated rippled noise as a function of delay and 
      sound level in the ventral cochlear nucleus.
PG  - 1206-19
AB  - 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 steps of 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 also show a band-pass 
      interval enhancement to the IRN stimuli; however, they show more level-dependent 
      changes than CS units. Primary-like (PL) units also show 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.
FAU - Wiegrebe, L
AU  - Wiegrebe L
AD  - Department of Physiology, Centre for the Neural Basis of Hearing, Cambridge CB2 
      3EG, United Kingdom. wiegrebe@zi.biologie.uni-muenchen.de
FAU - Winter, I M
AU  - Winter IM
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
PL  - United States
TA  - J Neurophysiol
JT  - Journal of neurophysiology
JID - 0375404
SB  - IM
MH  - Action Potentials/physiology
MH  - Animals
MH  - Auditory Threshold/physiology
MH  - Cochlear Nucleus/cytology/*physiology
MH  - Guinea Pigs
MH  - Neurons/classification/physiology
MH  - *Noise
MH  - Pitch Perception/physiology
MH  - Reaction Time/physiology
MH  - *Sound
MH  - Time Factors
EDAT- 2001/03/15 10:00
MHDA- 2001/04/21 10:01
CRDT- 2001/03/15 10:00
PHST- 2001/03/15 10:00 [pubmed]
PHST- 2001/04/21 10:01 [medline]
PHST- 2001/03/15 10:00 [entrez]
AID - 10.1152/jn.2001.85.3.1206 [doi]
PST - ppublish
SO  - J Neurophysiol. 2001 Mar;85(3):1206-19. doi: 10.1152/jn.2001.85.3.1206.