Forward “masking” of responses from single fibers of the cat auditory nerve

1977 ◽  
Vol 61 (S1) ◽  
pp. S28-S28
Author(s):  
J. W. Bauer
Keyword(s):  
Auditory Nerve ◽  
Forward Masking ◽  
Single Fibers

Responses of auditory nerve fibers of the unanesthetized decerebrate cat to click pairs as simulated echoes

1996 ◽  
Vol 76 (1) ◽  
pp. 17-29 ◽  
Author(s):  
K. Parham ◽  
H. B. Zhao ◽  
D. O. Kim
Keyword(s):  
Auditory System ◽  
Auditory Nerve ◽  
Nerve Fibers ◽  
Forward Masking ◽  
Auditory Nerve Fiber ◽  
Decerebrate Cat ◽  
Compound Action Potentials ◽  
Fiber Characteristic ◽  
Auditory Nerve Fibers ◽  
Central Auditory Neurons

1. To elucidate the peripheral contribution to "echo" processing in the auditory system, we examined the characteristics of auditory nerve responses to click-pair stimuli in unanesthetized, decerebrate cats. We used equilevel click pairs at peak levels of 45, 65, and 85 dB SPL re 20 microPa. The interclick intervals ranged from 1 to 32 ms. This study reports results from 78 auditory nerve fibers in 7 cats. The fibers were divided into 2 groups: 33 low- and 45 high-spontaneous rate (SR), with SRs less than and > or = 20 spikes/s, respectively. A method was introduced to quantify the second-click response, and its recovery was examined as a function of the interclick interval. 2. In general, auditory nerve fibers showed a gradual recovery of the second-click response as interclick interval was increased. Noticeable differences in the second-click response recovery functions emerged among fiber populations that were related to the SR. Low-SR fibers showed little change in the recovery functions of the second-click response as the click level was increased from 45 to 85 dB SPL. In contrast, high-SR fibers showed slower recoveries with increasing click level from 45 to 85 dB SPL. At 45 and 65 dB SPL, the recovery functions of the two SR groups were similar. At 85 dB SPL, high-SR fibers exhibited slower recovery than low-SR fibers, regardless of fiber characteristic frequency. The interclick intervals at 50% second-click response ranged from 1 to 6 ms (mean, 1.4 ms) among low-SR fibers. The interclick intervals at 50% second-click response for high-SR fibers, whereas similar to those for the low-SR fibers at 45 and 65 dB SPL, ranged from 2 to 16 ms (mean, 3 ms) for high-SR fibers, at 85 dB SPL. 3. We also examined auditory nerve compound action potentials (CAPs) evoked by click-pair stimuli for various interclick intervals and click levels. With increasing interclick interval, the amplitude of the second-click CAP increased, and with increasing level, the second-click CAP showed slower recovery. At 45 dB SPL, the recovery functions of the second-click CAP were similar to those of the high- and low-SR fibers. At higher levels, the CAP exhibited lower second-click response values than both high- and low-SR fiber populations for interclick intervals < 4-8 ms. At 85 dB SPL, as interclick interval increased, between 8 and 16 ms, the CAP second-click response converged with that of the high-SR fibers, and by 32 ms, the second-click response values were similar for the CAP, high- and low-SR fibers. 4. The present results are consistent with those of forward masking studies at the level of the auditory nerve in that both demonstrate a short-term reduction of the neural responses. However, the two results differ in that we observed that high-SR fibers exhibited slower recovery than low-SR fibers in response to click-pair stimuli, opposite of the trend observed in the forward masking studies of responses to pure-tone bursts. 5. The present results on auditory nerve fiber responses to click-pair stimuli provide a reference for comparison with responses of central auditory neurons to similar stimuli. This information should serve to elucidate the peripheral contribution to the processing of echoes in the auditory system.

scholarly journals Auditory Temporal Acuity Probed With Cochlear Implant Stimulation and Cortical Recording

2010 ◽  
Vol 103 (1) ◽  
pp. 531-542 ◽  
Author(s):  
Alana E. Kirby ◽  
John C. Middlebrooks
Keyword(s):  
Auditory Cortex ◽  
Pulse Rate ◽  
Auditory Nerve ◽  
Acoustic Noise ◽  
Forward Masking ◽  
Neural Mechanisms ◽  
Gap Detection ◽  
Temporal Acuity ◽  
Pulse Trains ◽  
Modulation Detection

Cochlear implants stimulate the auditory nerve with amplitude-modulated (AM) electric pulse trains. Pulse rates >2,000 pulses per second (pps) have been hypothesized to enhance transmission of temporal information. Recent studies, however, have shown that higher pulse rates impair phase locking to sinusoidal AM in the auditory cortex and impair perceptual modulation detection. Here, we investigated the effects of high pulse rates on the temporal acuity of transmission of pulse trains to the auditory cortex. In anesthetized guinea pigs, signal-detection analysis was used to measure the thresholds for detection of gaps in pulse trains at rates of 254, 1,017, and 4,069 pps and in acoustic noise. Gap-detection thresholds decreased by an order of magnitude with increases in pulse rate from 254 to 4,069 pps. Such a pulse-rate dependence would likely influence speech reception through clinical speech processors. To elucidate the neural mechanisms of gap detection, we measured recovery from forward masking after a 196.6-ms pulse train. Recovery from masking was faster at higher carrier pulse rates and masking increased linearly with current level. We fit the data with a dual-exponential recovery function, consistent with a peripheral and a more central process. High-rate pulse trains evoked less central masking, possibly due to adaptation of the response in the auditory nerve. Neither gap detection nor forward masking varied with cortical depth, indicating that these processes are likely subcortical. These results indicate that gap detection and modulation detection are mediated by two separate neural mechanisms.

Discharge patterns of single fibers in the pigeon auditory nerve

1974 ◽  
Vol 70 (3) ◽  
pp. 431-447 ◽  
Author(s):  
Murray B. Sachs ◽  
Eric D. Young ◽  
Richard H. Lewis
Keyword(s):  
Auditory Nerve ◽  
Single Fibers ◽  
Discharge Patterns

scholarly journals Physiological correlates of forward masking in single nerve‐fiber and compound neural responses recorded from the auditory nerve

1989 ◽  
Vol 85 (S1) ◽  
pp. S13-S13
Author(s):  
Evan M. Relkin ◽  
John R. Doucet ◽  
Robert L. Smith ◽  
Christopher W. Turner
Keyword(s):  
Nerve Fiber ◽  
Auditory Nerve ◽  
Forward Masking ◽  
Neural Responses ◽  
Single Nerve

Microstimulation of auditory nerve for estimating cochlear place of single fibers in a deaf ear

1997 ◽  
Vol 113 (1-2) ◽  
pp. 140-154 ◽  
Author(s):  
C van den Honert ◽  
C.C Finley ◽  
S Xue
Keyword(s):  
Auditory Nerve ◽  
Single Fibers
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