Central projections of auditory nerve fibers in the barn owl

1991 ◽  
Vol 314 (2) ◽  
pp. 306-318 ◽  
Author(s):  
C. E. Carr ◽  
R. E. Boudreau
Keyword(s):  
Auditory Nerve ◽  
Barn Owl ◽  
Nerve Fibers ◽  
Central Projections ◽  
Auditory Nerve Fibers

Frequency Tuning and Spontaneous Activity in the Auditory Nerve and Cochlear Nucleus Magnocellularis of the Barn Owl Tyto alba

1997 ◽  
Vol 77 (1) ◽  
pp. 364-377 ◽  
Author(s):  
Christine Köppl
Keyword(s):  
Response Latency ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Frequency Tuning ◽  
Barn Owl ◽  
Nerve Fibers ◽  
Spontaneous Discharge ◽  
Tyto Alba ◽  
Nucleus Magnocellularis ◽  
Auditory Nerve Fibers

Köppl, Christine. Frequency tuning and spontaneous activity in the auditory nerve and cochlear nucleus magnocellularis of the barn owl Tyto alba. J. Neurophysiol. 77: 364–377, 1997. Single-unit recordings were obtained from the brain stem of the barn owl at the level of entrance of the auditory nerve. Auditory nerve and nucleus magnocellularis units were distinguished by physiological criteria, with the use of the response latency to clicks, the spontaneous discharge rate, and the pattern of characteristic frequencies encountered along an electrode track. The response latency to click stimulation decreased in a logarithmic fashion with increasing characteristic frequency for both auditory nerve and nucleus magnocellularis units. The average difference between these populations was 0.4–0.55 ms. The most sensitive thresholds were ∼0 dB SPL and varied little between 0.5 and 9 kHz. Frequency-threshold curves showed the simple V shape that is typical for birds, with no indication of a low-frequency tail. Frequency selectivity increased in a gradual, power-law fashion with increasing characteristic frequency. There was no reflection of the unusual and greatly expanded mapping of higher frequencies on the basilar papilla of the owl. This observation is contrary to the equal-distance hypothesis that relates frequency selectivity to the spatial respresentation in the cochlea. On the basis of spontaneous rates and/or sensitivity there was no evidence for distinct subpopulations of auditory nerve fibers, such as the well-known type I afferent response classes in mammals. On the whole, barn owl auditory nerve physiology conformed entirely to the typical patterns seen in other bird species. The only exception was a remarkably small spread of thresholds at any one frequency, this being only 10–15 dB in individual owls. Average spontaneous rate was 72.2 spikes/s in the auditory nerve and 219.4 spikes/s for nucleus magnocellularis. This large difference, together with the known properties of endbulb-of-Held synapses, suggests a convergence of ∼2–4 auditory nerve fibers onto one nucleus magnocellularis neuron. Some auditory nerve fibers as well as nucleus magnocellularis units showed a quasiperiodic spontaneous discharge with preferred intervals in the time-interval histogram. This phenomenon was observed at frequencies as high as 4.7 kHz.

The central projections of intracellularly labeled auditory nerve fibers in cats

1984 ◽  
Vol 229 (3) ◽  
pp. 432-450 ◽  
Author(s):  
D. M. Fekete ◽  
E. M. Rouiller ◽  
M. C. Liberman ◽  
D. K. Ryugo
Keyword(s):  
Auditory Nerve ◽  
Nerve Fibers ◽  
Central Projections ◽  
Auditory Nerve Fibers

Responses of auditory‐nerve fibers to multiple‐tone complexes

1987 ◽  
Vol 82 (6) ◽  
pp. 1989-2000 ◽  
Author(s):  
Li Deng ◽  
C. Daniel Geisler ◽  
Steven Greenberg
Keyword(s):  
Auditory Nerve ◽  
Nerve Fibers ◽  
Auditory Nerve Fibers
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