Preservation of amplitude modulation coding in the presence of background noise by chinchilla auditory‐nerve fibers

1996 ◽  
Vol 99 (1) ◽  
pp. 475-490 ◽  
Author(s):  
Robert D. Frisina ◽  
Kenneth J. Karcich ◽  
Todd C. Tracy ◽  
Daniel M. Sullivan ◽  
Joseph P. Walton ◽  
...  
Keyword(s):  
Amplitude Modulation ◽  
Auditory Nerve ◽  
Background Noise ◽  
Nerve Fibers ◽  
Modulation Coding ◽  
Auditory Nerve Fibers

Effects of continuous noise backgrounds on rate response of auditory nerve fibers in cat

1984 ◽  
Vol 51 (6) ◽  
pp. 1326-1344 ◽  
Author(s):  
J. A. Costalupes ◽  
E. D. Young ◽  
D. J. Gibson
Keyword(s):  
Auditory Nerve ◽  
Noise Level ◽  
Background Noise ◽  
Dynamic Range ◽  
Discharge Rate ◽  
Nerve Fibers ◽  
Noise Levels ◽  
High Noise ◽  
Continuous Noise ◽  
Auditory Nerve Fibers

This study describes the effects of broadband background noise on the average discharge rate to best-frequency (BF) tones of auditory nerve fibers in the cat. The effects of exposure to long-term continuous noise are compared to the effects of noise gated on and off simultaneously with test tones. Addition of background noise causes a shift of the dynamic portion of tone-evoked rate versus level functions to higher tone intensities. The shift occurs at a mean rate of 0.61 dB of shift for each 1-dB increment in noise level. The rate of shift is independent of best frequency and spontaneous discharge rate. The noise level at which the shift begins is frequency dependent and is consistent with the frequency-dependent bandwidths of auditory nerve fiber tuning curves. The adjustment of the dynamic range shows many similarities to two-tone suppression. Therefore, it is most likely that it is caused by suppression of the response to the BF test tone by energy present in the noise at surrounding frequencies. At high noise levels, the ability of auditory nerve fibers to respond to test tones is limited by the rate response to the noise. As noise level increases, the discharge rate it evokes approaches a fiber's saturation rate and ultimately eliminates the fiber's ability to respond to test tones. Low spontaneous rate fibers, which have been shown to have higher thresholds and wider dynamic range (17,29), are significantly more resistant to saturation by high noise levels. Exposure to broadband noise prior to onset of test tones produces an overall decrement in response rate. This phenomenon is similar to the effects of short-term adaptation (32) and seems to develop independently of the shift of dynamic range. At high noise levels, previous exposure to the noise produces a small dynamic range shift. This effect is similar to that produced by suppression but is smaller. The effect is occluded in continuous noise backgrounds by the adjustment of sensitivity produced by suppression.

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

Responses of Single Auditory‐Nerve Fibers in Cochleas Damaged by Ototoxic Drugs

1969 ◽  
Vol 46 (1A) ◽  
pp. 106-107
Author(s):  
R. A. Levine ◽  
E. C. Moxon ◽  
N. Y. S. Kiang
Keyword(s):  
Auditory Nerve ◽  
Nerve Fibers ◽  
Ototoxic Drugs ◽  
Auditory Nerve Fibers

Encoding timing and intensity in the ventral cochlear nucleus of the cat

1986 ◽  
Vol 56 (2) ◽  
pp. 261-286 ◽  
Author(s):  
W. S. Rhode ◽  
P. H. Smith
Keyword(s):  
Firing Rate ◽  
Cochlear Nucleus ◽  
Auditory Nerve ◽  
Cell Types ◽  
Nerve Fibers ◽  
Frequency Selectivity ◽  
Firing Rates ◽  
Ventral Cochlear Nucleus ◽  
Auditory Nerve Fibers ◽  
Different Cell Types

Physiological response properties of neurons in the ventral cochlear nucleus have a variety of features that are substantially different from the stereotypical auditory nerve responses that serve as the principal source of activation for these neurons. These emergent features are the result of the varying distribution of auditory nerve inputs on the soma and dendrites of the various cell types within the nucleus; the intrinsic membrane characteristics of the various cell types causing different responses to the same input in different cell types; and secondary excitatory and inhibitory inputs to different cell types. Well-isolated units were recorded with high-impedance glass microelectrodes, both intracellularly and extracellularly. Units were characterized by their temporal response to short tones, rate vs. intensity relation, and response areas. The principal response patterns were onset, chopper, and primary-like. Onset units are characterized by a well-timed first spike in response to tones at the characteristic frequency. For frequencies less than 1 kHz, onset units can entrain to the stimulus frequency with greater precision than their auditory nerve inputs. This implies that onset units receive converging inputs from a number of auditory nerve fibers. Onset units are divided into three subcategories, OC, OL, and OI. OC units have extraordinarily wide dynamic ranges and low-frequency selectivity. Some are capable of sustaining firing rates of 800 spikes/s at high intensities. They have the smallest standard deviation and coefficient of variation of the first spike latency of any cells in the cochlear nuclei. OC units are candidates for encoding intensity. OI and OL units differ from OC units in that they have dynamic ranges and frequency selectivity ranges much like those of auditory nerve fibers. They differ from one another in their steady-state firing rates; OI units fire mainly at the onset of a tone. OI units also differ from OL units in that they prefer frequency sweeps in the low to high direction. Primary-like-with-notch (PLN) units also respond to tones with a well-timed first spike. They differ from onset cells in that the onset peak is not always as precise as the spontaneous rate is higher. A comparison of spontaneous firing rate and saturation firing rate of PLN units with auditory nerve fibers suggest that PLN units receive one to four auditory nerve fiber inputs. Chopper units fire in a sustained regular manner when they are excited by sound.(ABSTRACT TRUNCATED AT 400 WORDS)

Sign in / Sign up

Export Citation Format

Share Document