Auditory System - Auditory Pathway II

Purpose The effects of neurological diseases on the auditory system have been a notable issue for investigators because the auditory pathway is closely associated with neural systems. The purposes of this study are to evaluate the efferent auditory system function and hearing quality in Parkinson's disease (PD) and to compare the findings with age-matched individuals without PD to present a perspective on aging. Method The study included 35 individuals with PD (mean age of 48.50 ± 8.00 years) and 35 normal-hearing peers (mean age of 49 ± 10 years). The following tests were administered for all participants: the first section of the Speech, Spatial and Qualities of Hearing Scale; pure-tone audiometry, speech audiometry, tympanometry, and acoustic reflexes; and distortion product otoacoustic emissions (DPOAEs) and contralateral suppression of DPOAEs. SPSS Version 25 was used for statistical analyses, and values of p < .05 were considered statistically significant. Results There were no statistically significant differences in the pure-tone audiometry thresholds and DPOAE responses between the individuals with PD and their normal-hearing peers ( p = .732). However, statistically significant differences were found between the groups in suppression levels of DPOAEs and hearing quality ( p < .05). In addition, a statistically significant and positive correlation was found between the amount of suppression at some frequencies and the Speech, Spatial and Qualities of Hearing Scale scores. Conclusions This study indicates that medial olivocochlear efferent system function and the hearing quality of individuals with PD were affected adversely due to the results of PD pathophysiology on the hearing system. For optimal intervention and follow-up, tasks related to hearing quality in daily life can also be added to therapies for PD.

Download Full-text

Neural Transformation of Dissonant Intervals in the Auditory Brainstem

Music Perception An Interdisciplinary Journal ◽

10.1525/mp.2015.32.5.445 ◽

2015 ◽

Vol 32 (5) ◽

pp. 445-459 ◽

Cited By ~ 4

Author(s):

Kyung Myun Lee ◽

Erika Skoe ◽

Nina Kraus ◽

Richard Ashley

Keyword(s):

Auditory System ◽

Auditory Processing ◽

Response Spectrum ◽

Phase Locking ◽

Auditory Pathway ◽

Auditory Brainstem ◽

Neural Representation ◽

Auditory Brainstem Responses ◽

Distortion Products ◽

Stimulus Waveform

Acoustic periodicity is an important factor for discriminating consonant and dissonant intervals. While previous studies have found that the periodicity of musical intervals is temporally encoded by neural phase locking throughout the auditory system, how the nonlinearities of the auditory pathway influence the encoding of periodicity and how this effect is related to sensory consonance has been underexplored. By measuring human auditory brainstem responses (ABRs) to four diotically presented musical intervals with increasing degrees of dissonance, this study seeks to explicate how the subcortical auditory system transforms the neural representation of acoustic periodicity for consonant versus dissonant intervals. ABRs faithfully reflect neural activity in the brainstem synchronized to the stimulus while also capturing nonlinear aspects of auditory processing. Results show that for the most dissonant interval, which has a less periodic stimulus waveform than the most consonant interval, the aperiodicity of the stimulus is intensified in the subcortical response. The decreased periodicity of dissonant intervals is related to a larger number of nonlinearities (i.e., distortion products) in the response spectrum. Our findings suggest that the auditory system transforms the periodicity of dissonant intervals resulting in consonant and dissonant intervals becoming more distinct in the neural code than if they were to be processed by a linear auditory system.

Download Full-text

Effect of Adult-Onset Deafness on the Human Central Auditory System

Annals of Otology Rhinology & Laryngology ◽

10.1177/000348949710600505 ◽

1997 ◽

Vol 106 (5) ◽

pp. 385-390 ◽

Cited By ~ 28

Author(s):

Jean K. Moore ◽

John K. Niparko ◽

Michele R. Miller ◽

Lucy M. Perazzo ◽

Fred H. Linthicum

Keyword(s):

Cell Size ◽

Auditory System ◽

Cochlear Nucleus ◽

Ganglion Cells ◽

Normal Population ◽

Degenerative Change ◽

Auditory Pathway ◽

Consistent Difference ◽

Adult Onset ◽

Central Auditory System

Degenerative change in the central auditory system was assessed in seven subjects with profound bilateral adult-onset deafness. The degree of transneuronal atrophy was determined by measuring cell size at three levels of the brain stem auditory pathway (anteroventral cochlear nucleus, medial superior olivary nucleus, and inferior colliculus). Within subjects, the relative degree of cell shrinkage was similar across all levels of the central pathway. Across subjects, the best neuronal preservation was seen in a case of viral labyrinthitis with 1 year of bilateral deafness and a near-normal population of cochlear ganglion cells. Reduction in cell size was greatest in cases of bacterial labyrinthitis or Scheibe degeneration with reduced populations of ganglion cells and longer periods of deafness. At the level of the cochlear nucleus, there was no consistent difference in cell size between the side stimulated by a functioning prosthetic device and the nonstimulated side.

Download Full-text

Temporal integration at consecutive processing stages in the auditory pathway of the grasshopper

Journal of Neurophysiology ◽

10.1152/jn.00390.2014 ◽

2015 ◽

Vol 113 (7) ◽

pp. 2280-2288 ◽

Cited By ~ 2

Author(s):

Sarah Wirtssohn ◽

Bernhard Ronacher

Keyword(s):

Auditory System ◽

Time Windows ◽

Temporal Integration ◽

Auditory Pathway ◽

Network Activity ◽

High Temporal Resolution ◽

Energy Integration ◽

Metathoracic Ganglion ◽

Feed Forward Network ◽

Receptor Neurons

Temporal integration in the auditory system of locusts was quantified by presenting single clicks and click pairs while performing intracellular recordings. Auditory neurons were studied at three processing stages, which form a feed-forward network in the metathoracic ganglion. Receptor neurons and most first-order interneurons (“local neurons”) encode the signal envelope, while second-order interneurons (“ascending neurons”) tend to extract more complex, behaviorally relevant sound features. In different neuron types of the auditory pathway we found three response types: no significant temporal integration (some ascending neurons), leaky energy integration (receptor neurons and some local neurons), and facilitatory processes (some local and ascending neurons). The receptor neurons integrated input over very short time windows (<2 ms). Temporal integration on longer time scales was found at subsequent processing stages, indicative of within-neuron computations and network activity. These different strategies, realized at separate processing stages and in parallel neuronal pathways within one processing stage, could enable the grasshopper's auditory system to evaluate longer time windows and thus to implement temporal filters, while at the same time maintaining a high temporal resolution.

Download Full-text

Plasticity in the auditory system of crickets: phonotaxis with one ear and neuronal reorganization within the auditory pathway

Journal of Comparative Physiology A ◽

10.1007/bf00603663 ◽

1987 ◽

Vol 161 (4) ◽

pp. 583-604 ◽

Cited By ~ 30

Author(s):

Franz Huber

Keyword(s):

Auditory System ◽

Auditory Pathway ◽

Neuronal Reorganization

Download Full-text

Mapping the human subcortical auditory system using histology, post mortem MRI and in vivo MRI at 7T

10.1101/568139 ◽

2019 ◽

Cited By ~ 2

Author(s):

Kevin Richard Sitek ◽

Omer Faruk Gulban ◽

Evan Calabrese ◽

G. Allan Johnson ◽

Agustin Lage-Castellanos ◽

...

Keyword(s):

Auditory System ◽

Structural Connectivity ◽

Three Dimensional ◽

Auditory Pathway ◽

7 Tesla ◽

Post Mortem ◽

Subcortical Structures ◽

Isotropic Resolution ◽

Histological Data

AbstractStudying the human subcortical auditory system non-invasively is challenging due to its small, densely packed structures deep within the brain. Additionally, the elaborate three-dimensional (3-D) structure of the system can be difficult to understand based on currently available 2-D schematics and animal models. We addressed these issues using a combination of histological data, post mortem magnetic resonance imaging (MRI), and in vivo MRI at 7 Tesla. We created anatomical atlases based on state-of-the-art human histology (BigBrain) and post mortem MRI (50 μm). We measured functional MRI (fMRI) responses to natural sounds and demonstrate that the functional localization of subcortical structures is reliable within individual participants who were scanned in two different experiments. Further, a group functional atlas derived from the functional data locates these structures with a median distance below 2mm. Using diffusion MRI tractography, we revealed structural connectivity maps of the human subcortical auditory pathway both in vivo (1050 μm isotropic resolution) and post mortem (200 μm isotropic resolution). This work captures current MRI capabilities for investigating the human subcortical auditory system, describes challenges that remain, and contributes novel, openly available data, atlases, and tools for researching the human auditory system.

Download Full-text

Elimination of peripheral auditory pathway activation does not affect motor responses from ultrasound neuromodulation

10.1101/428342 ◽

2018 ◽

Author(s):

Morteza Mohammadjavadi ◽

Patrick Peiyong Ye ◽

Anping Xia ◽

Julian Brown ◽

Gerald Popelka ◽

...

Keyword(s):

Auditory System ◽

Focused Ultrasound ◽

Response Duration ◽

Brain Structures ◽

Auditory Pathway ◽

Auditory Brainstem ◽

Normal Hearing ◽

Auditory Brainstem Responses ◽

Motor Responses ◽

Peripheral Auditory System

AbstractRecent studies in a variety of animal models including rodents, monkeys, and humans suggest that transcranial focused ultrasound (tFUS) has considerable promise for non-invasively modulating neural activity with the ability to target deep brain structures. However, concerns have been raised that motor responses evoked by tFUS may be due to indirect activation of the auditory pathway rather than direct activation of motor circuits. In this study, tFUS-induced electromyography (EMG) signals were recorded and analyzed in wild-type (WT) normal hearing mice and two strains of genetically deaf mice to examine the involvement of the peripheral auditory system in tFUS-stimulated motor responses. In addition, auditory brainstem responses (ABRs) were measured to elucidate the effect of the tFUS stimulus envelope on auditory and motor responses. We also varied the tFUS stimulation duration to measure its effect on motor response duration. We show, first, that the sharp edges in a tFUS rectangular envelope stimulus activate the peripheral afferent auditory pathway and, second, that smoothing these edges eliminates the auditory responses without affecting the motor responses in normal hearing WT mice. We further show that by eliminating peripheral auditory activity using two different strains of deaf knockout mice, motor responses are the same as in normal hearing WT mice. Finally, we demonstrate a high correlation between tFUS pulse duration and EMG response duration. These results support the concept that tFUS-evoked motor responses are not a result of stimulation of the peripheral auditory system.

Download Full-text

Expression Patterns of the Neuropeptide Urocortin 3 and Its Receptor CRFR2 in the Mouse Central Auditory System

Frontiers in Neural Circuits ◽

10.3389/fncir.2021.747472 ◽

2021 ◽

Vol 15 ◽

Author(s):

Sara Pagella ◽

Jan M. Deussing ◽

Conny Kopp-Scheinpflug

Keyword(s):

Auditory System ◽

Expression Patterns ◽

Cell Types ◽

Auditory Pathway ◽

Sensory Systems ◽

Synaptic Activity ◽

Superior Olivary Complex ◽

Autocrine Signaling ◽

Urocortin 3 ◽

Context Dependent

Sensory systems have to be malleable to context-dependent modulations occurring over different time scales, in order to serve their evolutionary function of informing about the external world while also eliciting survival-promoting behaviors. Stress is a major context-dependent signal that can have fast and delayed effects on sensory systems, especially on the auditory system. Urocortin 3 (UCN3) is a member of the corticotropin-releasing factor family. As a neuropeptide, UCN3 regulates synaptic activity much faster than the classic steroid hormones of the hypothalamic-pituitary-adrenal axis. Moreover, due to the lack of synaptic re-uptake mechanisms, UCN3 can have more long-lasting and far-reaching effects. To date, a modest number of studies have reported the presence of UCN3 or its receptor CRFR2 in the auditory system, particularly in the cochlea and the superior olivary complex, and have highlighted the importance of this stress neuropeptide for protecting auditory function. However, a comprehensive map of all neurons synthesizing UCN3 or CRFR2 within the auditory pathway is lacking. Here, we utilize two reporter mouse lines to elucidate the expression patterns of UCN3 and CRFR2 in the auditory system. Additional immunolabelling enables further characterization of the neurons that synthesize UCN3 or CRFR2. Surprisingly, our results indicate that within the auditory system, UCN3 is expressed predominantly in principal cells, whereas CRFR2 expression is strongest in non-principal, presumably multisensory, cell types. Based on the presence or absence of overlap between UCN3 and CRFR2 labeling, our data suggest unusual modes of neuromodulation by UCN3, involving volume transmission and autocrine signaling.

Download Full-text