scholarly journals Specific loss of neural sensitivity to interaural time difference of unmodulated noise stimuli following noise-induced hearing loss

2020 ◽  
Vol 124 (4) ◽  
pp. 1165-1182
Author(s):  
Hariprakash Haragopal ◽  
Ryan Dorkoski ◽  
Austin R. Pollard ◽  
Gareth A. Whaley ◽  
Timothy R. Wohl ◽  
...  
Keyword(s):  
Hearing Loss ◽  
Interaural Time Difference ◽  
Acoustic Trauma ◽  
Sound Level ◽  
Broadband Noise ◽  
Neural Responses ◽  
Auditory Midbrain ◽  
Midbrain Neurons ◽  
Perceptual Abilities ◽  
Encode Time

Sensorineural hearing loss compromises perceptual abilities that arise from hearing with two ears, yet its effects on binaural aspects of neural responses are largely unknown. We found that, following severe hearing loss because of acoustic trauma, auditory midbrain neurons specifically lost the ability to encode time differences between the arrival of a broadband noise stimulus to the two ears, whereas the encoding of sound level differences between the two ears remained uncompromised.

scholarly journals Improved pure tone sensitivity after simulated hearing loss

2020 ◽  
Author(s):  
Patrick Krauss
Keyword(s):  
Hearing Loss ◽  
Stochastic Resonance ◽  
Acoustic Trauma ◽  
Broadband Noise ◽  
Mongolian Gerbils ◽  
New Paradigm ◽  
Resonance Model ◽  
Sound Perception ◽  
Increased Sensitivity ◽  
Zwicker Tone

AbstractRecently, it was proposed that a processing principle called adaptive stochastic resonance plays a major role in the auditory system, and serves to maintain optimal sensitivity even to highly variable sound pressure levels. As a side effect, in case of reduced auditory input, such as permanent hearing loss, this mechanism may eventually lead to the perception of phantom sounds like tinnitus or the Zwicker tone illusion. Using computational modeling, the biological plausibility of this processing principle was already demonstrated. Here, we provide empirical results that further support the stochastic resonance model of auditory perception. In particular, Mongolian gerbils were exposed to long-term notched noise, which mimics hearing loss for frequencies within the notch. Remarkably, the animals developed increased sensitivity, i.e. improved hearing thresholds, for the frequency centered within the notch, but nut for frequencies outside the notch. In addition, most animals treated with the new paradigm showed identical behavioral signs of phantom sound perception as animals with acoustic trauma induced tinnitus. In contrast, animals treated with broadband noise as a control condition did not show any significant threshold change, nor behavioral signs of phantom sound perception.

scholarly journals Discrimination of Communication Vocalizations by Single Neurons and Groups of Neurons in the Auditory Midbrain

2010 ◽  
Vol 103 (6) ◽  
pp. 3248-3265 ◽  
Author(s):  
David M. Schneider ◽  
Sarah M. N. Woolley
Keyword(s):  
Individual Recognition ◽  
Spike Trains ◽  
Single Neurons ◽  
Neural Responses ◽  
Auditory Midbrain ◽  
Bird Songs ◽  
Complex Sounds ◽  
Temporal Precision ◽  
Midbrain Neurons ◽  
Wide Range

Many social animals including songbirds use communication vocalizations for individual recognition. The perception of vocalizations depends on the encoding of complex sounds by neurons in the ascending auditory system, each of which is tuned to a particular subset of acoustic features. Here, we examined how well the responses of single auditory neurons could be used to discriminate among bird songs and we compared discriminability to spectrotemporal tuning. We then used biologically realistic models of pooled neural responses to test whether the responses of groups of neurons discriminated among songs better than the responses of single neurons and whether discrimination by groups of neurons was related to spectrotemporal tuning and trial-to-trial response variability. The responses of single auditory midbrain neurons could be used to discriminate among vocalizations with a wide range of abilities, ranging from chance to 100%. The ability to discriminate among songs using single neuron responses was not correlated with spectrotemporal tuning. Pooling the responses of pairs of neurons generally led to better discrimination than the average of the two inputs and the most discriminating input. Pooling the responses of three to five single neurons continued to improve neural discrimination. The increase in discriminability was largest for groups of neurons with similar spectrotemporal tuning. Further, we found that groups of neurons with correlated spike trains achieved the largest gains in discriminability. We simulated neurons with varying levels of temporal precision and measured the discriminability of responses from single simulated neurons and groups of simulated neurons. Simulated neurons with biologically observed levels of temporal precision benefited more from pooling correlated inputs than did neurons with highly precise or imprecise spike trains. These findings suggest that pooling correlated neural responses with the levels of precision observed in the auditory midbrain increases neural discrimination of complex vocalizations.

scholarly journals Response Growth With Sound Level in Auditory-Nerve Fibers After Noise-Induced Hearing Loss

2004 ◽  
Vol 91 (2) ◽  
pp. 784-795 ◽  
Author(s):  
Michael G. Heinz ◽  
Eric D. Young
Keyword(s):  
Hearing Loss ◽  
Hair Cell ◽  
Auditory Nerve ◽  
Outer Hair Cell ◽  
Dynamic Range ◽  
Nerve Fibers ◽  
Sound Level ◽  
Broadband Noise ◽  
Noise Induced Hearing Loss ◽  
Rate Level

People with sensorineural hearing loss are often constrained by a reduced acoustic dynamic range associated with loudness recruitment; however, the neural correlates of loudness and recruitment are still not well understood. The growth of auditory-nerve (AN) activity with sound level was compared in normal-hearing cats and in cats with a noise-induced hearing loss to test the hypothesis that AN-fiber rate-level functions are steeper in impaired ears. Stimuli included best-frequency and fixed-frequency tones, broadband noise, and a brief speech token. Three types of impaired responses were observed. 1) Fibers with rate-level functions that were similar across all stimuli typically had broad tuning, consistent with outer-hair-cell (OHC) damage. 2) Fibers with a wide dynamic range and shallow slope above threshold often retained sharp tuning, consistent with primarily inner-hair-cell (IHC) damage. 3) Fibers with very steep rate-level functions for all stimuli had thresholds above approximately 80 dB SPL and very broad tuning, consistent with severe IHC and OHC damage. Impaired rate-level slopes were on average shallower than normal for tones, and were steeper in only limited conditions. There was less variation in rate-level slopes across stimuli in impaired fibers, presumably attributable to the lack of suppression-induced reductions in slopes for complex stimuli relative to BF-tone slopes. Sloping saturation was observed less often in impaired fibers. These results illustrate that AN fibers do not provide a simple representation of the basilar-membrane I/O function and suggest that both OHC and IHC damage can affect AN response growth.

scholarly journals Long-Term Impairment of Sound Processing in the Auditory Midbrain by Daily Short-Term Exposure to Moderate Noise

2017 ◽  
Vol 2017 ◽  
pp. 1-10 ◽  
Author(s):  
Liang Cheng ◽  
Shao-Hui Wang ◽  
Kang Peng ◽  
Xiao-Mei Liao
Keyword(s):  
Noise Exposure ◽  
Sound Level ◽  
Frequency Range ◽  
Short Term ◽  
Auditory Midbrain ◽  
Sound Processing ◽  
Midbrain Neurons ◽  
Short Term Exposure ◽  
Processing Properties

Most citizen people are exposed daily to environmental noise at moderate levels with a short duration. The aim of the present study was to determine the effects of daily short-term exposure to moderate noise on sound level processing in the auditory midbrain. Sound processing properties of auditory midbrain neurons were recorded in anesthetized mice exposed to moderate noise (80 dB SPL, 2 h/d for 6 weeks) and were compared with those from age-matched controls. Neurons in exposed mice had a higher minimum threshold and maximum response intensity, a longer first spike latency, and a higher slope and narrower dynamic range for rate level function. However, these observed changes were greater in neurons with the best frequency within the noise exposure frequency range compared with those outside the frequency range. These sound processing properties also remained abnormal after a 12-week period of recovery in a quiet laboratory environment after completion of noise exposure. In conclusion, even daily short-term exposure to moderate noise can cause long-term impairment of sound level processing in a frequency-specific manner in auditory midbrain neurons.

scholarly journals Stimulus-frequency-dependent dominance of sound localization cues across the cochleotopic map of the inferior colliculus

2020 ◽  
Vol 123 (5) ◽  
pp. 1791-1807 ◽  
Author(s):  
Ryan Dorkoski ◽  
Kenneth E. Hancock ◽  
Gareth A. Whaley ◽  
Timothy R. Wohl ◽  
Noelle C. Stroud ◽  
...  
Keyword(s):  
Inferior Colliculus ◽  
Division Of Labor ◽  
Sound Localization ◽  
High Frequency ◽  
Stimulus Frequency ◽  
Neural Responses ◽  
Auditory Midbrain ◽  
Sound Sources ◽  
High Frequencies ◽  
Midbrain Neurons

A “division of labor” has previously been assumed in which the directions of low- and high-frequency sound sources are thought to be encoded by neurons preferentially sensitive to low and high frequencies, respectively. Contrary to this, we found that auditory midbrain neurons encode the directions of both low- and high-frequency sounds regardless of their preferred frequencies. Neural responses were shaped by different sound localization cues depending on the stimulus spectrum—even within the same neuron.

scholarly journals Simulated transient hearing loss improves auditory sensitivity

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Patrick Krauss ◽  
Konstantin Tziridis
Keyword(s):  
Hearing Loss ◽  
Stochastic Resonance ◽  
Acoustic Trauma ◽  
Broadband Noise ◽  
Moderate Intensity ◽  
Mongolian Gerbils ◽  
New Paradigm ◽  
Resonance Model ◽  
Sound Perception ◽  
Zwicker Tone

AbstractRecently, it was proposed that a processing principle called adaptive stochastic resonance plays a major role in the auditory system, and serves to maintain optimal sensitivity even to highly variable sound pressure levels. As a side effect, in case of reduced auditory input, such as permanent hearing loss or frequency specific deprivation, this mechanism may eventually lead to the perception of phantom sounds like tinnitus or the Zwicker tone illusion. Using computational modeling, the biological plausibility of this processing principle was already demonstrated. Here, we provide experimental results that further support the stochastic resonance model of auditory perception. In particular, Mongolian gerbils were exposed to moderate intensity, non-damaging long-term notched noise, which mimics hearing loss for frequencies within the notch. Remarkably, the animals developed significantly increased sensitivity, i.e. improved hearing thresholds, for the frequency centered within the notch, but not for frequencies outside the notch. In addition, most animals treated with the new paradigm showed identical behavioral signs of phantom sound perception (tinnitus) as animals with acoustic trauma induced tinnitus. In contrast, animals treated with broadband noise as a control condition did not show any significant threshold change, nor behavioral signs of phantom sound perception.

scholarly journals Temporary Unilateral Hearing Loss Impairs Spatial Auditory Information Processing in Neurons in the Central Auditory System

2021 ◽  
Vol 15 ◽  
Author(s):  
Jennifer L. Thornton ◽  
Kelsey L. Anbuhl ◽  
Daniel J. Tollin
Keyword(s):  
Hearing Loss ◽  
Interaural Level Difference ◽  
Inhibitory Input ◽  
Auditory Information ◽  
Hearing Impairments ◽  
Auditory Midbrain ◽  
Auditory Periphery ◽  
Midbrain Neurons ◽  
Auditory Information Processing ◽  
Conductive Hearing

Temporary conductive hearing loss (CHL) can lead to hearing impairments that persist beyond resolution of the CHL. In particular, unilateral CHL leads to deficits in auditory skills that rely on binaural input (e.g., spatial hearing). Here, we asked whether single neurons in the auditory midbrain, which integrate acoustic inputs from the two ears, are altered by a temporary CHL. We introduced 6 weeks of unilateral CHL to young adult chinchillas via foam earplug. Following CHL removal and restoration of peripheral input, single-unit recordings from inferior colliculus (ICC) neurons revealed the CHL decreased the efficacy of inhibitory input to the ICC contralateral to the earplug and increased inhibitory input ipsilateral to the earplug, effectively creating a higher proportion of monaural responsive neurons than binaural. Moreover, this resulted in a ∼10 dB shift in the coding of a binaural sound location cue (interaural-level difference, ILD) in ICC neurons relative to controls. The direction of the shift was consistent with a compensation of the altered ILDs due to the CHL. ICC neuron responses carried ∼37% less information about ILDs after CHL than control neurons. Cochlear peripheral-evoked responses confirmed that the CHL did not induce damage to the auditory periphery. We find that a temporary CHL altered auditory midbrain neurons by shifting binaural responses to ILD acoustic cues, suggesting a compensatory form of plasticity occurring by at least the level of the auditory midbrain, the ICC.

Promoting Hearing Loss Prevention in Audiology Practice

2012 ◽  
Vol 13 (1) ◽  
pp. 3-19 ◽  
Author(s):  
David C. Byrne ◽  
Christa L. Themann ◽  
Deanna K. Meinke ◽  
Thais C. Morata ◽  
Mark R. Stephenson
Keyword(s):  
Hearing Loss ◽  
Sound Level ◽  
Health Campaigns ◽  
Loss Prevention ◽  
Hearing Conservation ◽  
Prevention Services ◽  
Occupational Programs ◽  
Strategic Position ◽  
Public Health Campaigns ◽  
Self Protection

An audiologist should be the principal provider and advocate for all hearing loss prevention activities. Many audiologists equate hearing loss prevention with industrial audiology and occupational hearing conservation programs. However, an audiologist’s involvement in hearing loss prevention should not be confined to that one particular practice setting. In addition to supervising occupational programs, audiologists are uniquely qualified to raise awareness of hearing risks, organize public health campaigns, promote healthy hearing, implement intervention programs, and monitor outcomes. For example, clinical audiologists can show clients how to use inexpensive sound level meters, noise dosimeters, or phone apps to measure noise levels, and recommend appropriate hearing protection. Audiologists should identify community events that may involve hazardous exposures and propose strategies to minimize risks to hearing. Audiologists can help shape the knowledge, beliefs, motivations, attitudes, and behaviors of individuals toward self-protection. An audiologist has the education, tools, opportunity, and strategic position to facilitate or promote hearing loss surveillance and prevention services and activities. This article highlights real-world examples of the various roles and substantial contributions audiologists can make toward hearing loss prevention goals.

Developmental Patterns of Duration Discrimination

1993 ◽  
Vol 36 (4) ◽  
pp. 842-849 ◽  
Author(s):  
Jill L. Elfenbein ◽  
Arnold M. Small ◽  
Julia M. Davis
Keyword(s):  
Standard Stimulus ◽  
Discrimination Performance ◽  
Noise Burst ◽  
Duration Discrimination ◽  
Broadband Noise ◽  
Developmental Patterns ◽  
Age Related ◽  
Perceptual Abilities

The purpose of this study was to determine whether the auditory perceptual abilities of children are characterized by an age-related improvement in duration discrimination. Forty children, ages 4 to 10 years, and 10 adults served as subjects. Difference limens were obtained using a 350-msec broadband noise burst as the standard stimulus in a three-interval forcedchoice paradigm. Data were characterized by significant differences between the performances of the 4-, 6-, and 8-year-olds and those of the adults. Acquisition of adult-like discrimination performance was demonstrated between the ages of 8 and 10 years.

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