PMID- 19357334
OWN - NLM
STAT- MEDLINE
DCOM- 20090803
LR  - 20090527
IS  - 0022-3077 (Print)
IS  - 0022-3077 (Linking)
VI  - 101
IP  - 6
DP  - 2009 Jun
TI  - Spontaneous activity of auditory nerve fibers in the barn owl (Tyto alba): 
      analyses of interspike interval distributions.
PG  - 3169-91
LID - 10.1152/jn.90779.2008 [doi]
AB  - In vertebrate auditory systems, the conversion from graded receptor potentials 
      across the hair-cell membrane into stochastic spike trains of the auditory nerve 
      (AN) fibers is performed by ribbon synapses. The statistics underlying this 
      process constrain auditory coding but are not precisely known. Here, we examine 
      the distributions of interspike intervals (ISIs) from spontaneous activity of AN 
      fibers of the barn owl (Tyto alba), a nocturnal avian predator whose auditory 
      system is specialized for precise temporal coding. The spontaneous activity of AN 
      fibers, with the exception of those showing preferred intervals, is commonly 
      thought to result from excitatory events generated by a homogeneous Poisson point 
      process, which lead to spikes unless the fiber is refractory. We show that the 
      ISI distributions in the owl are better explained as resulting from the action of 
      a brief refractory period ( approximately 0.5 ms) on excitatory events generated 
      by a homogeneous stochastic process where the distribution of interevent 
      intervals is a mixture of an exponential and a gamma distribution with shape 
      factor 2, both with the same scaling parameter. The same model was previously 
      shown to apply to AN fibers in the cat. However, the mean proportions of 
      exponentially versus gamma-distributed intervals in the mixture were different 
      for cat and owl. Furthermore, those proportions were constant across fibers in 
      the cat, whereas they covaried with mean spontaneous rate and with characteristic 
      frequency in the owl. We hypothesize that in birds, unlike in mammals, more than 
      one ribbon may provide excitation to most fibers, accounting for the different 
      proportions, and that variation in the number of ribbons may underlie the 
      variation in the proportions.
FAU - Neubauer, Heinrich
AU  - Neubauer H
AD  - Leibniz Institute for Neurobiology, 39118 Magdeburg, Germany.
FAU - Koppl, Christine
AU  - Koppl C
FAU - Heil, Peter
AU  - Heil P
LA  - eng
PT  - Journal Article
PT  - Research Support, Non-U.S. Gov't
DEP - 20090408
PL  - United States
TA  - J Neurophysiol
JT  - Journal of neurophysiology
JID - 0375404
SB  - IM
MH  - Acoustic Stimulation/methods
MH  - Action Potentials/*physiology
MH  - Animals
MH  - Auditory Pathways/physiology
MH  - Cochlear Nerve/*physiology
MH  - Computer Simulation
MH  - Models, Neurological
MH  - Nerve Fibers/*physiology
MH  - Probability
MH  - Strigiformes/*physiology
MH  - Time Factors
EDAT- 2009/04/10 09:00
MHDA- 2009/08/04 09:00
CRDT- 2009/04/10 09:00
PHST- 2009/04/10 09:00 [entrez]
PHST- 2009/04/10 09:00 [pubmed]
PHST- 2009/08/04 09:00 [medline]
AID - 90779.2008 [pii]
AID - 10.1152/jn.90779.2008 [doi]
PST - ppublish
SO  - J Neurophysiol. 2009 Jun;101(6):3169-91. doi: 10.1152/jn.90779.2008. Epub 2009 
      Apr 8.