Processing Of Sound Information Research Articles

What’s in a sample? Epistemic uncertainty and metacognitive awareness in risk taking

In a fundamentally uncertain world, sound information processing is a prerequisite for effective behavior. Given that information processing is subject to inevitable cognitive imprecision, decision makers should adapt to this imprecision and to the resulting epistemic uncertainty when taking risks. We tested this metacognitive ability in two experiments in which participants estimated the expected value of different number distributions from sequential samples and then bet on their own estimation accuracy. Results show that estimates were imprecise, and this imprecision increased with higher distributional standard deviations. Importantly, participants adapted their risk-taking behavior to this imprecision and hence deviated from the predictions of Bayesian models of uncertainty that assume perfect integration of information. To explain these results, we developed a computational model that combines Bayesian updating with a metacognitive awareness of cognitive imprecision in the integration of information. Modeling results were robust to the inclusion of an empirical measure of participants’ perceived variability. In sum, we show that cognitive imprecision is crucial to understanding risk taking in decisions from experience. The results further demonstrate the importance of metacognitive awareness as a cognitive building block for adaptive behavior under (partial) uncertainty.

Audio signal transmission method in network-based audio analytics system

The subject matter of the article is аudio signal transmission method in network-based audio analytics system. The creation of a network-based audio analytics system leads to the emergence of new classes of load sources that transmit packetized sound data. Therefore, without constructing adequate mathematical models, it is impossible to build a well-functioning network-based audio analytics system. A fundamental question in traffic theory is the question of load source models. The development of an method for transmitting audio signals in a network-based audio analytics system becomes necessary. Based on this, the goal of the work is to create methods an method for transmitting audio signals in a network-based audio analytics system to ensure efficiency and accuracy in audio analytics. The following tasks were solved in the article: the formation of a model for the system's load sources, investigation of connection and traffic management, implementation of control and traffic monitoring functions in the network, research of methods to ensure the quality of audio signal transmission and the development of a method of transmitting an audio signal by virtual routes switching. To achieve these goals, the following methods are used: mathematical signal processing, data compression algorithms, optimization of network protocols, and the use of high-speed network connections. The obtained results include modeling of the system's load sources, examination of connection and traffic management, investigation of methods to ensure the quality of audio signal transmission and a method of transmitting an audio signal by virtual routes switching was proposed. In conclusion, the possibilities of using simulation modeling of nodes in the network-based audio analytics system are highly limited. This is explained by the fact that the acceptable level of information loss in data centers is very low. The use of the developed method enables effective control and processing of sound information in real-time. This method can find broad applications in various fields, including security, healthcare, management systems, and other industries where the analysis of audio signals is a crucial element.

Localized manipulation of spoof surface acoustic skyrmions with deep-subwavelength gradient structures

Skyrmions with stable vector field configurations have produced various derivatives with various topological textures, such as the Néel type, Bloch type, anti-type, and higher-order Néel type. Here, we theoretically and experimentally demonstrate that the vector field configuration of Néel-type skyrmionic modes can be locally manipulated using gradient grooves in a deep-subwavelength three-dimensional multilayer cylindrical structure. We experimentally observe that the skyrmionic modes can be contracted or expanded to manipulate the distribution of the velocity vectors by tuning the groove depth gradient along the structural radius, which is robust against structural deformations and defects. This type of controllable acoustic skyrmion provides new dimensions for advanced sound information processing, transportation, and data storage in compact structures.

Observation of localized acoustic skyrmions

Recently, acoustic skyrmions have been explored by tailoring velocity vectorial near-field distributions based on the interference of multiple spoof surface acoustic waves, providing new dimensions for advanced sound information processing, transport, and data storage. Here, we theoretically investigate and experimentally demonstrate that a deep-subwavelength spiral metastructure can also generate the acoustic skyrmion configuration. Analyzing the resonant response of the metastructure and observing the spatial profile of the velocity field, we find that the localized skyrmionic modes correspond to eigenmodes of the spiral structure. Thus, the skyrmionic modes do not require carefully tailored external excitation condition and they have multiple resonating frequencies unlike the single skyrmionic mode realized by the interference of multiple waves. We also demonstrate that the topological protected skyrmions supported by the subwavelength metastructure is robust against structure deformations and existence of structure defects. The real-space acoustic skyrmion topology may open new avenues for designing ultra-compact and robust acoustic devices, such as acoustic sensors, acoustic tweezers, and acoustic antennas.

Обґрунтування компонентів методичної системи навчання комп’ютерних технологій опрацювання звукової інформації учнів старшої школи на уроках інформатики

The article substantiates the relevance of the development and use of the components of the methodical system for teaching sound processing technologies to high school students in computer science classes. This is due to the need to develop the ability to work with sound and develop the skills of creating, processing, and editing sound effects and soundtracks, and their publication. The research presents an analysis of the scientific and methodological literature of scientists who dealt with issues of computer science teaching methods and researched the use of computer technologies in music. Foreign experience in implementing practical examples is highlighted related to sound information processing in primary, secondary school and higher education lessons. The goals, content, methods, means, and forms of the methodical system of teaching high school students of computer technologies for sound information processing are substantiated. The goals of training the students are to create the theoretical foundations of sound, to develop skills and abilities to work with software and audio services for creating and processing sound data, etc. The research contains the analysis of the training course proposed by the Ministry of Education and Science for the program-variable module “Computer technologies for sound information processing”. The authors of this article suggest supplementing it with an additional content line, “Sound information and sound design”. According to the results of the proposed content line students will have the skills and abilities to create sound information in the field of entertaining content, educational activities, advertising, etc. The peculiarities of the choice of teaching methods and tools are described according to the content component. As a result of the study, it is found that the proposed methodical system of teaching computer technologies for sound information processing can help create an attractive and effective educational process, which will contribute to the practical application of acquired knowledge and skills by students.

Elements of the methodology for teaching the theme "Creating and processing of sound information" using the free sound editor Audacity

The article presents the framework of the methodology for teaching the theme "Creating and processing of sound information" of the informatics course at the level of basic general education using the free cross-platform offline sound editor Audacity. The concept of "teaching methodology" refers to the process of transferring from the teacher to the student a certain necessary and sufficient set of algorithms for creating certain information objects that correspond to the information technology being studied. As a result of the analysis of possible software options to support the teaching of the theme under consideration in the informatics course, it is concluded that offline free cross-platform sound editors with low minimum system requirements is the best option. One of the most successful software options is the Audacity audio editor, which has a number of advantages over its counterparts. The article questions the principle of invariance of the method of teaching information technology, in particular technology for creating and processing sound information, with respect to the software and hardware used in the educational process, and substantiates the conclusion about the partial failure of this principle. A possible variant of the framework of the methodology for teaching the theme of the informatics course under consideration is given, which includes the division of the learning content into seven stages. Each of the stages includes a description of the presentation of the relevant educational material, including the technology for performing practical work aimed at mastering the basic elements of the functionality of the Audacity sound editor by students. The description of the author’s teaching methodology also contains the lesson planning corresponding to it on the theme " Creating and processing of sound information" of the informatics course for the basic school. The advantages of the proposed teaching methodology include the possibility of its use for both full-time and distance learning, as well as the low cost of its use in the educational process of a general education school. In addition, the methodology under consideration ensures a high resistance of the educational process to the destructive impact on the information structure of Russian educational organizations, which includes, among other things, an unmotivated refusal of licenses to use foreign-made proprietary software.

Temporal-specific roles of fragile X mental retardation protein in the development of the hindbrain auditory circuit.

Fragile X mental retardation protein (FMRP) is an RNA-binding protein abundant in the nervous system. Functional loss of FMRP leads to sensory dysfunction and severe intellectual disabilities. In the auditory system, FMRP deficiency alters neuronal function and synaptic connectivity and results in perturbed processing of sound information. Nevertheless, roles of FMRP in embryonic development of the auditory hindbrain have not been identified. Here, we developed high-specificity approaches to genetically track and manipulate throughout development of the Atoh1+ neuronal cell type, which is highly conserved in vertebrates, in the cochlear nucleus of chicken embryos. We identified distinct FMRP-containing granules in the growing axons of Atoh1+ neurons and post-migrating NM cells. FMRP downregulation induced by CRISPR/Cas9 and shRNA techniques resulted in perturbed axonal pathfinding, delay in midline crossing, excess branching of neurites, and axonal targeting errors during the period of circuit development. Together, these results provide the first in vivo identification of FMRP localization and actions in developing axons of auditory neurons, and demonstrate the importance of investigating early embryonic alterations toward understanding the pathogenesis of neurodevelopmental disorders.

Psychoacoustic methods in diagnosis of central auditory processing disorders in prematurely born children

The presence of numerous perinatal risk factors and comorbid pathology in prematurely born children, even in the absence of peripheral auditory deficit, can lead to disruptions in the processes of higher nervous sound information processing with the formation of central auditory disorders. Audiological assessment of the functional state of auditory system central parts in prematurely born children. The study involved 54 deeply premature born infants, which were divided into 3 groups depending on age (6-7, 8-9, and 10-11 years), 18 subjects in each group, and 70 healthy, term-born children of the corresponding age. In addition to the traditional audiological examination, all children underwent an assessment of functional state of the central parts of auditory system through a pause detection test (Random Gap Detection Test, RGDT); the perception of fast rhythmic sequences of stimuli, monaural low excess speech testing, binaural interaction test in alternating binaural speech format (ABS ), dichotic presentation of pairs of single digits, single digits and monosyllables, two-digit numerals, Russian matrix phrasal test in noise (RUMatrix) were studied. Prematurely born infants of all age groups were significantly worse compared to control group (p<0.01) while having RGDT, a test for assessing the perception of fast rhythmic sequences of stimuli and dichotic binaural integration tests. Monaural intelligibility of monosyllabic words in silence in children of all three groups did not differ from normal values, but it suffered from contralateral use of noise interference in children aged 6-7. According to the RUMatrix test, legibility of phrases in noise was impaired in 65% of subjects. Test results in the ABS format revealed a significant violation of speech intelligibility (p<0.01) only in children of the younger age group. In prematurely born children, there is a dysfunction of the central parts of the auditory system, which is multilevel in nature, partially leveling as children grow older. Moreover, the processes of temporary processing of acoustic information suffer to the greatest extent, not being compensated up to adolescence.

Topologically correct central projections of tetrapod inner ear afferents require Fzd3

Inner ear sensory afferent connections establish sensory maps between the inner ear hair cells and the vestibular and auditory nuclei to allow vestibular and sound information processing. While molecular guidance of sensory afferents to the periphery has been well studied, molecular guidance of central projections from the ear is only beginning to emerge. Disorganized central projections of spiral ganglion neurons in a Wnt/PCP pathway mutant, Prickle1, suggest the Wnt/PCP pathway plays a role in guiding cochlear afferents to the cochlear nuclei in the hindbrain, consistent with known expression of the Wnt receptor, Frizzled3 (Fzd3) in inner ear neurons. We therefore investigated the role of Wnt signaling in central pathfinding in Fzd3 mutant mice and Fzd3 morpholino treated frogs and found aberrant central projections of vestibular afferents in both cases. Ear transplantations from knockdown to control Xenopus showed that it is the Fzd3 expressed within the ear that mediates this guidance. Also, cochlear afferents of Fzd3 mutant mice lack the orderly topological organization observed in controls. Quantification of Fzd3 expression in spiral ganglion neurons show a gradient of expression with Fzd3 being higher in the apex than in the base. Together, these results suggest that a gradient of Fzd3 in inner ear afferents directs projections to the correct dorsoventral column within the hindbrain.

Early postnatal noise exposure degrades the stimulus-specific adaptation of neurons in the rat auditory cortex in adulthood

Many auditory cortical neurons exhibit stimulus-specific adaptation (SSA), i.e., they respond weakly to frequently occurring stimuli but strongly to the same stimuli when presented rarely. SSA has been proposed to be a potential mechanism to engage deviance detection or novelty detection. Previous studies on SSA were investigated in animals reared in normal environment. It has been shown that early postnatal noise exposure impairs the development of cortical processing of sound information. However, it is not understood whether postnatal middle-level noise exposure affects the SSA in the primary auditory cortex (AI), and if yes, whether the impacts of noise exposure on SSA varied with noise exposure periods. Here we used a frequency oddball paradigm to determine the SSA of AI neurons in three groups of rats: the control rats were reared in normal environment without noise exposure, the young noise-exposed rats received a 70 dB SPL white noise exposure from P10 to P56, and the adult noise-exposed rats received the same noise exposure from P57 to P103. We found that early postnatal noise exposure reduced the proportion of SSA neurons in AI and decreased the strength of SSA of AI neurons in the young noise-exposed rats in adulthood. In contrast, the same noise exposure to adult rats had no significant impacts on the SSA of AI neurons in adult noise-exposed rats. The results suggest that environmental noise might be a risk factor for abnormal postnatal development of cortical processing of frequency deviance in a sound sequence.

Dual-band acoustic topological insulator based on honeycomb lattice sonic crystal

Based on honeycomb-lattice sonic crystals with gear-like scatterers, we study and design a pseudospin-dependent dual-band acoustic topological insulator. Compared with cylindrical scatterers with only a single tunable structure parameter (radius), there exist four tunable parameters for the gear scatterer, which enables the sonic crystal to realize four-fold accidental degeneracy at two different frequencies simultaneously. By changing structure parameters of the gear-like scatterers, we can obtain topological phase transitions between two sonic crystals. Based on this, we design acoustic topological waveguides based on two honeycomb-lattice sonic crystals with different topological phases, and introduce two kinds of defects (a lattice disorder and a bend) into the topological waveguide near the domain wall. Numerical simulations show that pseudospin edge states almost immune to two types of defects and can pass through the topological waveguides with negligible backscatterings. Compared with the results for the topological waveguide without defects, the measured transmission spectra are almost unchanged with the two types of defects, which further experimentally verify the robustness of pseudospin-dependent edge states. Additionally, by keeping the structure of the sonic crystals unchanged, we can also obtain another four-fold accidental degenerate Dirac point and the corresponding topological sound phase transitions in the high-frequency region. The simulations show that there also exists a pair of edge states in the overlapped bulk bandgap of the two sonic crystals in the high-frequency region. It is worth noting that the tiny gap between two edge states is larger than that in the low-frequency region, which may arise from the greater difference between the distributions of pressure eigenfunction of two sonic crystals. The proposed dual-band acoustic topology insulator has potential applications in multi-band sound communication and sound information processing.

INFORMATION TRAINING OF STUDENTS UNDER CONDITIONS OF PEDAGOGICAL COLLEGE (ON EXAMPLE OF MUSIC TEACHER)

The article deals with the theoretical issues of forming competence in the use of information and communication technologies (ICT) of music teachers in the pedagogical college, taking into account the main areas of their professional activities and ICT opportunities. The structure and content of information training in the conditions of a pedagogical college is developed on the example of the future teacher of music. The main directions of the professional activity of the music teacher in the conditions of the informatization of education are revealed: automation of information and methodical support of musical and pedagogical activity; diagnosis of the processes and results of training in general and musical disciplines; individualized learning; encoding and processing of sound information; computer reproduction of pedagogical repertoire of vocal and instrumental genres; accompanying using specialized hardware that is interfaced with a computer; computer arrangement of the works of the pedagogical repertoire, taking into account the performing abilities of the students. It is shown that in accordance with the main directions of the music teacher's activity, the information preparation of the student of the pedagogical college in the field of application of information and communication technologies should include three components: training on general issues of computerization of education; methodical training; substantive training.

Acoustic temporal modulation detection in normal-hearing and cochlear implanted listeners: effects of hearing mechanism and development.

Temporal modulation detection ability matures over many years after birth and may be particularly sensitive to experience during this period. Profound hearing loss during early childhood might result in greater perceptual deficits than a similar loss beginning in adulthood. We tested this idea by measuring performance in temporal modulation detection in profoundly deaf children and adults fitted with cochlear implants (CIs). At least two independent variables could constrain temporal modulation detection performance in children with CIs: altered encoding of modulation information due to the CI-auditory nerve interface, and atypical development of central processing of sound information provided by CIs. The effect of altered encoding was investigated by testing subjects with one of two different hearing mechanisms (normal hearing vs. CI) and the effect of atypical development was studied by testing two different age groups. All subjects were tested for their ability to detect acoustic temporal modulations of sound amplitude. A comparison of the slope, or cutoff frequency, of the temporal modulation transfer functions (TMTFs) among the four subject groups revealed that temporal resolution was mainly constrained by hearing mechanism: normal-hearing listeners could detect smaller amplitude modulations at high modulation frequencies than CI users. In contrast, a comparison of the height of the TMTFs revealed a significant interaction between hearing mechanism and age group on overall sensitivity to temporal modulation: sensitivity was significantly poorer in children with CIs, relative to the other three groups. Results suggest that there is an age-specific vulnerability of intensity discrimination or non-sensory factors, which subsequently affects sensitivity to temporal modulation in prelingually deaf children who use CIs.

The emerging framework of mammalian auditory hindbrain development

A defining feature of the mammalian auditory system is the extensive processing of sound information in numerous ultrafast and temporally precise circuits in the hindbrain. By exploiting the experimental advantages of mouse genetics, recent years have witnessed an impressive advance in our understanding of developmental mechanisms involved in the formation and refinement of these circuits. Here, we will summarize the progress made in four major fields: the dissection of the rhombomeric origins of auditory hindbrain nuclei; the molecular repertoire involved in circuit formation such as Hox transcription factors and the Eph-ephrin signaling system; the timeline of functional circuit assembly; and the critical role of spontaneous activity for circuit refinement. In total, this information provides a solid framework for further exploration of the factors shaping auditory hindbrain circuits and their specializations. A comprehensive understanding of the developmental pathways and instructive factors will also offer important clues to the causes and consequences of hearing-loss related disorders, which represent the most common sensory impairment in humans.

Frequency-specific corticofugal modulation of the dorsal cochlear nucleus in mice.

The primary auditory cortex (AI) modulates the sound information processing in the lemniscal subcortical nuclei, including the anteroventral cochlear nucleus (AVCN), in a frequency-specific manner. The dorsal cochlear nucleus (DCN) is a non-lemniscal subcortical nucleus but it is tonotopically organized like the AVCN. However, it remains unclear how the AI modulates the sound information processing in the DCN. This study examined the impact of focal electrical stimulation of AI on the auditory responses of the DCN neurons in mice. We found that the electrical stimulation induced significant changes in the best frequency (BF) of DCN neurons. The changes in the BFs were highly specific to the BF differences between the stimulated AI neurons and the recorded DCN neurons. The DCN BFs shifted higher when the AI BFs were higher than the DCN BFs and the DCN BFs shifted lower when the AI BFs were lower than the DCN BFs. The DCN BFs showed no change when the AI and DCN BFs were similar. Moreover, the BF shifts were linearly correlated to the BF differences. Thus, our data suggest that corticofugal modulation of the DCN is also highly specific to frequency information, similar to the corticofugal modulation of the AVCN. The frequency-specificity of corticofugal modulation does not appear limited to the lemniscal ascending pathway.

Dilation of the inferior colliculus and hypersensitivity to sound in Wnt1-cre and Wnt1-GAL4 double-transgenic mice

The processing of sound information is mediated by the cochlea and the central auditory system. Among the central auditory system, the inferior colliculus (IC) has leading roles in the acoustic processing. In a previous study, we demonstrated psychiatric disorder-related behavioral abnormalities in a genetically modified animal of Wnt1-cre and Wnt1-GAL4 double-transgenic (dTg) mouse. Here we report an abnormal morphology of the IC and dysacusis in the dTg mice. The IC in the brain of the dTg mice is dilated in appearance and histologic analysis revealed a high cell-density in the IC. Also, the dTg mice showed high scores in a startle response test using a click box that emits a 20-kHz sound. Auditory brainstem response (ABR) test revealed lower ABR thresholds of the dTg mice at a test-stimulus frequency of 32kHz, but not at 4–16kHz. These findings suggest that the dTg mice could be a useful animal model for studying the physiologic function of the IC and the pathophysiology of psychiatric disorder-related dysacusis.

Losing the sound of concepts: Damage to auditory association cortex impairs the processing of sound-related concepts

Conceptual knowledge is classically supposed to be abstract and represented in an amodal unitary system, distinct from the sensory and motor brain systems. A more recent embodiment view of conceptual knowledge, however, proposes that concepts are grounded in distributed modality-specific brain areas which typically process sensory or action-related object information. Recent neuroimaging evidence suggested the significance of left auditory association cortex encompassing posterior superior and middle temporal gyrus in coding conceptual sound features of everyday objects. However, a causal role of this region in processing conceptual sound information has yet to be established. Here we had the unique chance to investigate a patient, JR, with a focal lesion in left posterior superior and middle temporal gyrus. To test the necessity of this region in conceptual and perceptual processing of sound information we administered four different experimental tasks to JR: Visual word recognition, category fluency, sound recognition and voice classification. Compared with a matched control group, patient JR was consistently impaired in conceptual processing of sound-related everyday objects (e.g., “bell”), while performance for non-sound-related everyday objects (e.g., “armchair”), animals, whether they typically produce sounds (e.g., “frog”) or not (e.g., “tortoise”), and musical instruments (e.g., “guitar”) was intact. An analogous deficit pattern in JR was also obtained for perceptual recognition of the corresponding sounds. Hence, damage to left auditory association cortex specifically impairs perceptual and conceptual processing of sounds from everyday objects. In support of modality-specific theories, these findings strongly evidence the necessity of auditory association cortex in coding sound-related conceptual information.

Corticofugal Modulation of Initial Neural Processing of Sound Information from the Ipsilateral Ear in the Mouse

BackgroundCortical neurons implement a high frequency-specific modulation of subcortical nuclei that includes the cochlear nucleus. Anatomical studies show that corticofugal fibers terminating in the auditory thalamus and midbrain are mostly ipsilateral. Differently, corticofugal fibers terminating in the cochlear nucleus are bilateral, which fits to the needs of binaural hearing that improves hearing quality. This leads to our hypothesis that corticofugal modulation of initial neural processing of sound information from the contralateral and ipsilateral ears could be equivalent or coordinated at the first sound processing level.Methodology/Principal FindingsWith the focal electrical stimulation of the auditory cortex and single unit recording, this study examined corticofugal modulation of the ipsilateral cochlear nucleus. The same methods and procedures as described in our previous study of corticofugal modulation of contralateral cochlear nucleus were employed simply for comparison. We found that focal electrical stimulation of cortical neurons induced substantial changes in the response magnitude, response latency and receptive field of ipsilateral cochlear nucleus neurons. Cortical stimulation facilitated auditory response and shortened the response latency of physiologically matched neurons whereas it inhibited auditory response and lengthened the response latency of unmatched neurons. Finally, cortical stimulation shifted the best frequencies of cochlear neurons towards those of stimulated cortical neurons.ConclusionOur data suggest that cortical neurons enable a high frequency-specific remodelling of sound information processing in the ipsilateral cochlear nucleus in the same manner as that in the contralateral cochlear nucleus.

In Vivo Dynamic Clamp Study of Ih in the Mouse Inferior Colliculus

Approximately half of the cells in the mouse inferior colliculus have the hyperpolarization-activated mixed cation current I(h), yet little is known about its functional relevance in vivo. We therefore studied its contribution to the processing of sound information in single cells by making in vivo whole cell recordings from the inferior colliculus (IC) of young-adult anesthetized C57Bl/6 mice. Following pharmacological block of the endogenous channels, a dynamic clamp approach allowed us to study the responses to current injections or auditory stimuli in the presence and absence of I(h) within the same neuron, thus avoiding network or developmental effects. The presence of I(h) changed basic cellular properties, including depolarizing the resting membrane potential and decreasing resting membrane resistance. Sound-evoked excitatory postsynaptic potentials were smaller but at the same time reached a more positive membrane potential when I(h) was present. With I(h), a subset of cells showed rebound spiking following hyperpolarizing current injection. Its presence also changed more complex cellular properties. It decreased temporal summation in response to both hyperpolarizing and depolarizing repetitive current stimuli, and resulted in small changes in the cycle-averaged membrane potential during sinusoidal amplitude modulated (SAM) tones. Furthermore, I(h) minimally decreased the response to a tone following a depolarization, an effect that may make a small contribution to forward masking. Our results thus suggest that previously observed differences in IC cells are a mixture of direct effects of I(h) and indirect effects due to the change in membrane potential or effects due to the co-expression with other channels.

A Low-Affinity Antagonist Reveals Saturation and Desensitization in Mature Synapses in the Auditory Brain Stem

Postsynaptic receptor desensitization has been observed to contribute to depression in immature synapses. However, it is not clear whether desensitization persists and causes depression in mature synapses. We investigate this issue at the endbulb of Held, the synapse made by auditory nerve (AN) fibers onto bushy cells (BCs) of the anteroventral cochlear nucleus, where depression could influence the processing of sound information. Experiments using cyclothiazide (CTZ) have implicated desensitization in endbulbs from postnatal day 16 (P16) to P21 mice, but application of γ-D-glutamylglycine (DGG) did not reveal desensitization in endbulbs >P22. To reconcile these findings, we have studied the effects of both CTZ and DGG on endbulbs from P5 to P40 CBA/CaJ mice. In paired-pulse protocols, both CTZ and DGG reduced depression in all ages at intervals <10 ms, consistent with their effects preventing desensitization. However, DGG increased depression at intervals >20 ms, consistent with DGG's use to prevent saturation. DGG application revealed receptor saturation even under conditions of very low release probability. Preventing desensitization by CTZ occluded the effects of DGG on desensitization and revealed the effects of saturation at short intervals. We developed an approach to separate DGG's effect on saturation from its effect on desensitization, which showed that desensitization has an impact during bursts of auditory nerve activity. Dynamic-clamp experiments indicated that desensitization can reduce BC spike probability and increase latency and jitter. Thus desensitization may affect sound processing in the mature auditory system.