scholarly journals Perceptual gating of a brainstem reflex facilitates speech understanding in humans

2020 ◽  
Author(s):  
Heivet Hernandez-Perez ◽  
Jason Mikiel-Hunter ◽  
David McAlpine ◽  
Sumitrajit Dhar ◽  
Sriram Boothalingam ◽  
...  
Keyword(s):  
Background Noise ◽  
Auditory Pathway ◽  
Background Information ◽  
Auditory Periphery ◽  
Brainstem Reflex ◽  
Specific Effects ◽  
Auditory Scene ◽  
Subcortical Nuclei ◽  
Speech Features ◽  
Medial Olivocochlear

AbstractNavigating “cocktail party” situations by enhancing foreground sounds over irrelevant background information is typically considered from a cortico-centric perspective. However, subcortical circuits, such as the medial olivocochlear reflex (MOCR) that modulates inner ear activity itself, have ample opportunity to extract salient features from the auditory scene prior to any cortical processing. To understand the contribution of auditory subcortical nuclei and the cochleae, physiological recordings were made along the auditory pathway while listeners differentiated non(sense)-words and words. Both naturally-spoken and intrinsically-noisy, vocoded speech — filtering that mimics processing by a cochlear implant—significantly activated the MOCR, whereas listening to speechin-background noise revealed instead engagement of midbrain and cortical resources. An auditory periphery model reproduced these speech degradation-specific effects, providing a rationale for goal-directed MOCR gating to enhance representation of speech features in the auditory nerve. These results highlight two strategies co-existing in the auditory system to accommodate categorically different speech degradations.

scholarly journals Simple transformations capture auditory input to cortex

2020 ◽  
Vol 117 (45) ◽  
pp. 28442-28451
Author(s):  
Monzilur Rahman ◽  
Ben D. B. Willmore ◽  
Andrew J. King ◽  
Nicol S. Harper
Keyword(s):  
Auditory Nerve ◽  
Time Course ◽  
Primary Auditory Cortex ◽  
Auditory Pathway ◽  
Auditory Nerve Fiber ◽  
Neural Responses ◽  
Auditory Periphery ◽  
Cortical Responses ◽  
Combined Models ◽  
Simple Models

Sounds are processed by the ear and central auditory pathway. These processing steps are biologically complex, and many aspects of the transformation from sound waveforms to cortical response remain unclear. To understand this transformation, we combined models of the auditory periphery with various encoding models to predict auditory cortical responses to natural sounds. The cochlear models ranged from detailed biophysical simulations of the cochlea and auditory nerve to simple spectrogram-like approximations of the information processing in these structures. For three different stimulus sets, we tested the capacity of these models to predict the time course of single-unit neural responses recorded in ferret primary auditory cortex. We found that simple models based on a log-spaced spectrogram with approximately logarithmic compression perform similarly to the best-performing biophysically detailed models of the auditory periphery, and more consistently well over diverse natural and synthetic sounds. Furthermore, we demonstrated that including approximations of the three categories of auditory nerve fiber in these simple models can substantially improve prediction, particularly when combined with a network encoding model. Our findings imply that the properties of the auditory periphery and central pathway may together result in a simpler than expected functional transformation from ear to cortex. Thus, much of the detailed biological complexity seen in the auditory periphery does not appear to be important for understanding the cortical representation of sound.

Differences in Responses from the Cochleae and Central Nervous Systems of Females with Low versus High Acceptable Noise Levels

2006 ◽  
Vol 17 (09) ◽  
pp. 667-676 ◽  
Author(s):  
Ashley W. Harkrider ◽  
Joanna W. Tampas
Keyword(s):  
Auditory System ◽  
Background Noise ◽  
Otoacoustic Emissions ◽  
Auditory Brainstem ◽  
Auditory Brainstem Responses ◽  
Intersubject Variability ◽  
Hearing Sensitivity ◽  
Central Regions ◽  
Central Nervous Systems ◽  
Medial Olivocochlear

Studies of acceptable noise level (ANL) consistently report large intersubject variability in acceptance of background noise while listening to speech. This variability is not related to age, gender, hearing sensitivity, type of background noise, speech perception in noise performance, or efferent activity of the medial olivocochlear pathway. An exploratory study was conducted to determine if differences in aggregate responses from the peripheral and central auditory system can account for intersubject variability in ANL. Click-evoked otoacoustic emissions (CEOAEs), binaural auditory brainstem responses (ABRs), and middle latency responses (MLRs) were measured in females with normal hearing with low (n = 6) versus high (n = 7) ANLs. Results of this preliminary study indicate no differences between the groups for CEOAEs or waves I or III of the ABR. Differences between the two groups emerge for the amplitudes of wave V of the ABR and for the Na-Pa component of the MLR, suggesting that physiological variations arising from more central regions of the auditory system may mediate background noise acceptance.

Acoustic communication

2018 ◽  
Author(s):  
Heiner Römer
Keyword(s):  
Acoustic Communication ◽  
Background Noise ◽  
Near Field ◽  
Background Information ◽  
Natural Environments ◽  
Far Field ◽  
Sensory Receptors ◽  
Substrate Vibration ◽  
Field Sound ◽  
Mechanical Disturbances

This chapter, takes a broad look at insect acoustic communication, by including near-field and far-field sound, as well as substrate vibration, as signals. These mechanical disturbances differ greatly in their physical properties—they propagate in their natural environments over distances that can span from a few millimetres up to several hundred metres. Therefore, background information is provided to understand how the insect sound-emitting systems for the different signals work and in which behavioral contexts they are used. Evidence is also provided to describe the substantial changes signals undergo on their way to receivers, the effects of background noise on communication and how unintended receivers may represent costs in this system. Finally, a short overview of the structure and evolution of the tremendous diversity of sensory receptors is presented.

scholarly journals Contributions of distinct auditory cortical inhibitory neuron types to the detection of sounds in background noise

2021 ◽  
Author(s):  
Anna Andreevna Lakunina ◽  
Nadav Menashe ◽  
Santiago Jaramillo
Keyword(s):  
Background Noise ◽  
Inhibitory Neuron ◽  
Cell Types ◽  
Auditory Pathway ◽  
Acoustic Signals ◽  
Auditory Signal ◽  
Auditory Stimuli ◽  
Natural Environments ◽  
Neural Responses ◽  
Noisy Environments

The ability to separate background noise from relevant acoustic signals is essential for appropriate sound-driven behavior in natural environments. Examples of this separation are apparent in the auditory system, where neural responses to behaviorally relevant stimuli become increasingly noise-invariant along the ascending auditory pathway. However, the mechanisms that underlie this reduction in responses to background noise are not well understood. To address this gap in knowledge, we first evaluated the effects of auditory cortical inactivation on mice of both sexes trained to perform a simple auditory signal-in-noise detection task, and found that outputs from the auditory cortex are important for the detection of auditory stimuli in noisy environments. Next, we evaluated the contributions of the two most common cortical inhibitory cell types, parvalbumin-expressing (PV+) and somatostatin-expressing (SOM+) interneurons, to the perception of masked auditory stimuli. We found that inactivation of either PV+ or SOM+ cells resulted in a reduction in the ability of mice to determine the presence of auditory stimuli masked by noise. These results indicate that a disruption of auditory cortical network dynamics by either of these two types of inhibitory cells is sufficient to impair the ability to separate acoustic signals from noise.

scholarly journals Hyperactivity in the medial olivocochlear efferent system is a common feature of tinnitus and hyperacusis in humans

2015 ◽  
Vol 114 (5) ◽  
pp. 2551-2554 ◽  
Author(s):  
Joshua J. Sturm ◽  
Catherine J. C. Weisz
Keyword(s):  
Therapeutic Target ◽  
Auditory Pathway ◽  
High Rate ◽  
Potential Therapeutic Target ◽  
Efferent System ◽  
Olivocochlear System ◽  
Medial Olivocochlear System ◽  
Medial Olivocochlear ◽  
Efferent Suppression ◽  
Medial Olivocochlear Efferent System

Tinnitus and hyperacusis are common, burdensome sources of morbidity with a high rate of co-occurrence. Knudson et al. ( J Neurophysiol 112: 3197–3208, 2014) demonstrated that efferent suppression of cochlear activity by the medial olivocochlear system is enhanced in individuals with tinnitus and/or hyperacusis. Their findings stress that atypical activity in the efferent auditory pathway may represent a shared substrate, as well as a potential therapeutic target, in tinnitus and hyperacusis.

Electrically Evoked Responses in Onset Chopper Neurons in Guinea Pig Cochlear Nucleus

2007 ◽  
Vol 97 (5) ◽  
pp. 3288-3297 ◽  
Author(s):  
Wilhelmina H.A.M. Mulders ◽  
Alan R. Harvey ◽  
Donald Robertson
Keyword(s):  
Synaptic Input ◽  
Cochlear Nucleus ◽  
Auditory Periphery ◽  
Olivocochlear System ◽  
High Shock ◽  
Excitatory Synaptic Input ◽  
Medial Olivocochlear System ◽  
Electrical Shocks ◽  
Medial Olivocochlear ◽  
Ivth Ventricle

Extracellular recordings were obtained from single cochlear nucleus neurons in guinea pigs anesthetized with Nembutal and Hypnorm. Neurons were classified by their spontaneous firing rates and responses to acoustic stimuli. In addition, electrical shocks were applied to the midline at the level of the IVth ventricle and spike responses were recorded. Spikes were evoked by shocks only in neurons that were classified as onset choppers (Oc). The shock-evoked spikes could be extinguished by acoustically evoked action potentials in the same neurons. In roughly 30% of the sample of Oc neurons, quantitative aspects of the timing of this extinction were not compatible with the shock-evoked spike being antidromically conducted from Oc output axons. Together with the presence of temporal jitter at high shock rates, the data suggest the possibility that at least some of the shock-evoked spikes may be generated by excitatory synaptic input to the Oc neurons, most likely from the collaterals of the medial olivocochlear system (MOCS), whose axons pass close to the floor of the IVth ventricle. This excitatory synaptic input may operate to modulate the activity of Oc neurons in addition to MOCS actions in the auditory periphery.

scholarly journals An ensemble technique for speech recognition in noisy environments

2020 ◽  
Vol 18 (2) ◽  
pp. 835
Author(s):  
Imad Qasim Habeeb ◽  
Tamara Z. Fadhil ◽  
Yaseen Naser Jurn ◽  
Zeyad Qasim Habeeb ◽  
Hanan Najm Abdulkhudhur
Keyword(s):  
Speech Recognition ◽  
Noise Reduction ◽  
Speech Signal ◽  
Background Noise ◽  
Test Results ◽  
Noisy Environments ◽  
Ensemble Technique ◽  
Reduction Techniques ◽  
Speech Features ◽  
Main Factor

<span>Automatic speech recognition (ASR) is a technology that allows a computer and mobile device to recognize and translate spoken language into text. ASR systems often produce poor accuracy for the noisy speech signal. Therefore, this research proposed an ensemble technique that does not rely on a single filter for perfect noise reduction but incorporates information from multiple noise reduction filters to improve the final ASR accuracy. The main factor of this technique is the generation of K-copies of the speech signal using three noise reduction filters. The speech features of these copies differ slightly in order to extract different texts from them when processed by the ASR system. Thus, the best among these texts can be elected as final ASR output. The ensemble technique was compared with three related current noise reduction techniques in terms of CER and WER. The test results were encouraging and showed a relatively decreased by 16.61% and 11.54% on CER and WER compared with the best current technique. ASR field will benefit from the contribution of this research to increase the recognition accuracy of a human speech in the presence of background noise.</span>

scholarly journals Olivocochlear Changes Associated With Aging Predominantly Affect the Medial Olivocochlear System

2021 ◽  
Vol 15 ◽  
Author(s):  
Sergio Vicencio-Jimenez ◽  
Madison M. Weinberg ◽  
Giuliana Bucci-Mansilla ◽  
Amanda M. Lauer
Keyword(s):  
Background Noise ◽  
Cholinergic Neurons ◽  
Public Health Problem ◽  
Auditory Brainstem ◽  
Olivocochlear System ◽  
Age Related ◽  
Inhibitory Proteins ◽  
Medial Olivocochlear System ◽  
Brainstem Response ◽  
Medial Olivocochlear

Age-related hearing loss (ARHL) is a public health problem that has been associated with negative health outcomes ranging from increased frailty to an elevated risk of developing dementia. Significant gaps remain in our knowledge of the underlying central neural mechanisms, especially those related to the efferent auditory pathways. Thus, the aim of this study was to quantify and compare age-related alterations in the cholinergic olivocochlear efferent auditory neurons. We assessed, in young-adult and aged CBA mice, the number of cholinergic olivocochlear neurons, auditory brainstem response (ABR) thresholds in silence and in presence of background noise, and the expression of excitatory and inhibitory proteins in the ventral nucleus of the trapezoid body (VNTB) and in the lateral superior olive (LSO). In association with aging, we found a significant decrease in the number of medial olivocochlear (MOC) cholinergic neurons together with changes in the ratio of excitatory and inhibitory proteins in the VNTB. Furthermore, in old mice we identified a correlation between the number of MOC neurons and ABR thresholds in the presence of background noise. In contrast, the alterations observed in the lateral olivocochlear (LOC) system were less significant. The decrease in the number of LOC cells associated with aging was 2.7-fold lower than in MOC and in the absence of changes in the expression of excitatory and inhibitory proteins in the LSO. These differences suggest that aging alters the medial and lateral olivocochlear efferent pathways in a differential manner and that the changes observed may account for some of the symptoms seen in ARHL.

scholarly journals Binaural processing by the gecko auditory periphery

2011 ◽  
Vol 105 (5) ◽  
pp. 1992-2004 ◽  
Author(s):  
Jakob Christensen-Dalsgaard ◽  
Yezhong Tang ◽  
Catherine E. Carr
Keyword(s):  
Auditory Nerve ◽  
Auditory Pathway ◽  
Peak Frequency ◽  
Auditory Periphery ◽  
Transmission Delays ◽  
Binaural Processing ◽  
Mouth Cavity ◽  
Tokay Gecko ◽  
Interaural Level Differences ◽  
Nerve Recordings

Lizards have highly directional ears, owing to strong acoustical coupling of the eardrums and almost perfect sound transmission from the contralateral ear. To investigate the neural processing of this remarkable tympanic directionality, we combined biophysical measurements of eardrum motion in the Tokay gecko with neurophysiological recordings from the auditory nerve. Laser vibrometry shows that their ear is a two-input system with approximately unity interaural transmission gain at the peak frequency (∼1.6 kHz). Median interaural delays are 260 μs, almost three times larger than predicted from gecko head size, suggesting interaural transmission may be boosted by resonances in the large, open mouth cavity ( Vossen et al. 2010 ). Auditory nerve recordings are sensitive to both interaural time differences (ITD) and interaural level differences (ILD), reflecting the acoustical interactions of direct and indirect sound components at the eardrum. Best ITD and click delays match interaural transmission delays, with a range of 200–500 μs. Inserting a mold in the mouth cavity blocks ITD and ILD sensitivity. Thus the neural response accurately reflects tympanic directionality, and most neurons in the auditory pathway should be directional.

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