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Pérez-Valenzuela C, Vicencio-Jiménez S, Caballero M, Delano PH, Elgueda D. Wireless electrocochleography in awake chinchillas: A model to study crossmodal modulations at the peripheral level. Hear Res 2024; 451:109093. [PMID: 39094370 DOI: 10.1016/j.heares.2024.109093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/01/2023] [Revised: 07/07/2024] [Accepted: 07/25/2024] [Indexed: 08/04/2024]
Abstract
The discovery and development of electrocochleography (ECochG) in animal models has been fundamental for its implementation in clinical audiology and neurotology. In our laboratory, the use of round-window ECochG recordings in chinchillas has allowed a better understanding of auditory efferent functioning. In previous works, we gave evidence of the corticofugal modulation of auditory-nerve and cochlear responses during visual attention and working memory. However, whether these cognitive top-down mechanisms to the most peripheral structures of the auditory pathway are also active during audiovisual crossmodal stimulation is unknown. Here, we introduce a new technique, wireless ECochG to record compound-action potentials of the auditory nerve (CAP), cochlear microphonics (CM), and round-window noise (RWN) in awake chinchillas during a paradigm of crossmodal (visual and auditory) stimulation. We compared ECochG data obtained from four awake chinchillas recorded with a wireless ECochG system with wired ECochG recordings from six anesthetized animals. Although ECochG experiments with the wireless system had a lower signal-to-noise ratio than wired recordings, their quality was sufficient to compare ECochG potentials in awake crossmodal conditions. We found non-significant differences in CAP and CM amplitudes in response to audiovisual stimulation compared to auditory stimulation alone (clicks and tones). On the other hand, spontaneous auditory-nerve activity (RWN) was modulated by visual crossmodal stimulation, suggesting that visual crossmodal simulation can modulate spontaneous but not evoked auditory-nerve activity. However, given the limited sample of 10 animals (4 wireless and 6 wired), these results should be interpreted cautiously. Future experiments are required to substantiate these conclusions. In addition, we introduce the use of wireless ECochG in animal models as a useful tool for translational research.
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Affiliation(s)
| | - Sergio Vicencio-Jiménez
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile; Johns Hopkins School of Medicine, Otolaryngology-Head and Neck Surgery Department, Baltimore, MD 21231, USA; Biomedical Neuroscience Institute, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Mia Caballero
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Paul H Delano
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile; Servicio Otorrinolaringología, Hospital Clínico de la Universidad de Chile, Santiago, Chile; Centro Avanzado de Ingeniería Eléctrica y Electrónica, AC3E, Universidad Técnica Federico Santa María, Valparaíso, Chile; Biomedical Neuroscience Institute, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Diego Elgueda
- Departamento de Patología Animal, Facultad de Ciencias Veterinarias y Pecuarias, Universidad de Chile 8820808, Santiago, Chile.
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2
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Fernández Del Campo IS, Carmona-Barrón VG, Diaz I, Plaza I, Alvarado JC, Merchán MA. Multisession anodal epidural direct current stimulation of the auditory cortex delays the progression of presbycusis in the Wistar rat. Hear Res 2024; 444:108969. [PMID: 38350175 DOI: 10.1016/j.heares.2024.108969] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/18/2023] [Revised: 01/23/2024] [Accepted: 02/02/2024] [Indexed: 02/15/2024]
Abstract
Presbycusis or age-related hearing loss (ARHL) is one of the most prevalent chronic health problems facing aging populations. Along the auditory pathway, the stations involved in transmission and processing, function as a system of interconnected feedback loops. Regulating hierarchically auditory processing, auditory cortex (AC) neuromodulation can, accordingly, activate both peripheral and central plasticity after hearing loss. However, previous ARHL-prevention interventions have mainly focused on preserving the structural and functional integrity of the inner ear, overlooking the central auditory system. In this study, using an animal model of spontaneous ARHL, we aim at assessing the effects of multisession epidural direct current stimulation of the AC through stereotaxic implantation of a 1-mm silver ball anode in Wistar rats. Consisting of 7 sessions (0.1 mA/10 min), on alternate days, in awake animals, our stimulation protocol was applied at the onset of hearing loss (threshold shift detection at 16 months). Click- and pure-tone auditory brainstem responses (ABRs) were analyzed in two animal groups, namely electrically stimulated (ES) and non-stimulated (NES) sham controls, comparing recordings at 18 months of age. At 18 months, NES animals showed significantly increased threshold shifts, decreased wave amplitudes, and increased wave latencies after click and tonal ABRs, reflecting a significant, spontaneous ARHL evolution. Conversely, in ES animals, no significant differences were detected in any of these parameters when comparing 16 and 18 months ABRs, indicating a delay in ARHL progression. Electrode placement in the auditory cortex was accurate, and the stimulation did not cause significant damage, as shown by the limited presence of superficial reactive microglial cells after IBA1 immunostaining. In conclusion, multisession DC stimulation of the AC has a protective effect on auditory function, delaying the progression of presbycusis.
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Affiliation(s)
- Inés S Fernández Del Campo
- Lab.4 Auditory Neuroplasticity, Institute for Neuroscience of Castilla y León. University of Salamanca. Salamanca, Spain
| | - Venezia G Carmona-Barrón
- Lab.4 Auditory Neuroplasticity, Institute for Neuroscience of Castilla y León. University of Salamanca. Salamanca, Spain
| | - I Diaz
- Lab.4 Auditory Neuroplasticity, Institute for Neuroscience of Castilla y León. University of Salamanca. Salamanca, Spain
| | - I Plaza
- Lab.4 Auditory Neuroplasticity, Institute for Neuroscience of Castilla y León. University of Salamanca. Salamanca, Spain
| | - J C Alvarado
- Facultad de Medicina, IDINE, Universidad de Castilla la Mancha, Albacete, Spain
| | - M A Merchán
- Lab.4 Auditory Neuroplasticity, Institute for Neuroscience of Castilla y León. University of Salamanca. Salamanca, Spain.
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Cheng FY, Xu C, Gold L, Smith S. Rapid Enhancement of Subcortical Neural Responses to Sine-Wave Speech. Front Neurosci 2022; 15:747303. [PMID: 34987356 PMCID: PMC8721138 DOI: 10.3389/fnins.2021.747303] [Citation(s) in RCA: 9] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 12/02/2021] [Indexed: 01/15/2023] Open
Abstract
The efferent auditory nervous system may be a potent force in shaping how the brain responds to behaviorally significant sounds. Previous human experiments using the frequency following response (FFR) have shown efferent-induced modulation of subcortical auditory function online and over short- and long-term time scales; however, a contemporary understanding of FFR generation presents new questions about whether previous effects were constrained solely to the auditory subcortex. The present experiment used sine-wave speech (SWS), an acoustically-sparse stimulus in which dynamic pure tones represent speech formant contours, to evoke FFRSWS. Due to the higher stimulus frequencies used in SWS, this approach biased neural responses toward brainstem generators and allowed for three stimuli (/bɔ/, /bu/, and /bo/) to be used to evoke FFRSWSbefore and after listeners in a training group were made aware that they were hearing a degraded speech stimulus. All SWS stimuli were rapidly perceived as speech when presented with a SWS carrier phrase, and average token identification reached ceiling performance during a perceptual training phase. Compared to a control group which remained naïve throughout the experiment, training group FFRSWS amplitudes were enhanced post-training for each stimulus. Further, linear support vector machine classification of training group FFRSWS significantly improved post-training compared to the control group, indicating that training-induced neural enhancements were sufficient to bolster machine learning classification accuracy. These results suggest that the efferent auditory system may rapidly modulate auditory brainstem representation of sounds depending on their context and perception as non-speech or speech.
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Affiliation(s)
- Fan-Yin Cheng
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, Austin, TX, United States
| | - Can Xu
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, Austin, TX, United States
| | - Lisa Gold
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, Austin, TX, United States
| | - Spencer Smith
- Department of Speech, Language, and Hearing Sciences, University of Texas at Austin, Austin, TX, United States
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Jeschke M, Ohl FW, Wang X. Effects of Cortical Cooling on Sound Processing in Auditory Cortex and Thalamus of Awake Marmosets. Front Neural Circuits 2022; 15:786740. [PMID: 35069125 PMCID: PMC8766342 DOI: 10.3389/fncir.2021.786740] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2021] [Accepted: 12/10/2021] [Indexed: 12/15/2022] Open
Abstract
The auditory thalamus is the central nexus of bottom-up connections from the inferior colliculus and top-down connections from auditory cortical areas. While considerable efforts have been made to investigate feedforward processing of sounds in the auditory thalamus (medial geniculate body, MGB) of non-human primates, little is known about the role of corticofugal feedback in the MGB of awake non-human primates. Therefore, we developed a small, repositionable cooling probe to manipulate corticofugal feedback and studied neural responses in both auditory cortex and thalamus to sounds under conditions of normal and reduced cortical temperature. Cooling-induced increases in the width of extracellularly recorded spikes in auditory cortex were observed over the distance of several hundred micrometers away from the cooling probe. Cortical neurons displayed reduction in both spontaneous and stimulus driven firing rates with decreased cortical temperatures. In thalamus, cortical cooling led to increased spontaneous firing and either increased or decreased stimulus driven activity. Furthermore, response tuning to modulation frequencies of temporally modulated sounds and spatial tuning to sound source location could be altered (increased or decreased) by cortical cooling. Specifically, best modulation frequencies of individual MGB neurons could shift either toward higher or lower frequencies based on the vector strength or the firing rate. The tuning of MGB neurons for spatial location could both sharpen or widen. Elevation preference could shift toward higher or lower elevations and azimuth tuning could move toward ipsilateral or contralateral locations. Such bidirectional changes were observed in many parameters which suggests that the auditory thalamus acts as a filter that could be adjusted according to behaviorally driven signals from auditory cortex. Future work will have to delineate the circuit elements responsible for the observed effects.
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Affiliation(s)
- Marcus Jeschke
- Laboratory of Auditory Neurophysiology, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States,Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany,Auditory Neuroscience and Optogenetics Group, Cognitive Hearing in Primates Laboratory, German Primate Center-Leibniz Institute for Primate Research, Göttingen, Germany,*Correspondence: Marcus Jeschke
| | - Frank W. Ohl
- Department Systems Physiology of Learning, Leibniz Institute for Neurobiology, Magdeburg, Germany,Institute of Biology, Otto-von-Guericke-University Magdeburg, Magdeburg, Germany,Center for Behavioral Brain Sciences (CBBS), Magdeburg, Germany
| | - Xiaoqin Wang
- Laboratory of Auditory Neurophysiology, Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, MD, United States,Xiaoqin Wang
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Vaithiyalingam Chandra Sekaran N, Deshpande MS, Ibrahim BA, Xiao G, Shinagawa Y, Llano DA. Patterns of Unilateral and Bilateral Projections From Layers 5 and 6 of the Auditory Cortex to the Inferior Colliculus in Mouse. Front Syst Neurosci 2021; 15:674098. [PMID: 34744644 PMCID: PMC8566350 DOI: 10.3389/fnsys.2021.674098] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2021] [Accepted: 08/19/2021] [Indexed: 12/04/2022] Open
Abstract
The auditory cortex sends massive projections to the inferior colliculus, but the organization of this pathway is not yet well understood. Previous work has shown that the corticocollicular projection emanates from both layers 5 and 6 of the auditory cortex and that neurons in these layers have different morphological and physiological properties. It is not yet known in the mouse if both layer 5 and layer 6 project bilaterally, nor is it known if the projection patterns differ based on projection location. Using targeted injections of Fluorogold into either the lateral cortex or dorsal cortex of the inferior colliculus, we quantified retrogradely labeled neurons in both the left and right lemniscal regions of the auditory cortex, as delineated using parvalbumin immunostaining. After dorsal cortex injections, we observed that approximately 18-20% of labeled cells were in layer 6 and that this proportion was similar bilaterally. After lateral cortex injections, only ipsilateral cells were observed in the auditory cortex, and they were found in both layer 5 and layer 6. The ratio of layer 5:layer 6 cells after lateral cortex injection was similar to that seen after dorsal cortex injection. Finally, injections of different tracers were made into the two inferior colliculi, and an average of 15-17% of cells in the auditory cortex were double-labeled, and these proportions were similar in layers 5 and 6. These data suggest that (1) only the dorsal cortex of the inferior colliculus receives bilateral projections from the auditory cortex, (2) both the dorsal and lateral cortex of the inferior colliculus receive similar layer 5 and layer 6 auditory cortical input, and (3) a subpopulation of individual neurons in both layers 5 and 6 branch to innervate both dorsal cortices of the inferior colliculus.
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Affiliation(s)
- Nathiya Vaithiyalingam Chandra Sekaran
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Meena S. Deshpande
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Baher A. Ibrahim
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Gang Xiao
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Yoshitaka Shinagawa
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Daniel A. Llano
- Department of Molecular and Integrative Physiology, University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
- Carle Illinois College of Medicine, Urbana, IL, United States
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Díaz I, Colmenárez-Raga AC, Pérez-González D, Carmona VG, Plaza Lopez I, Merchán MA. Effects of Multisession Anodal Electrical Stimulation of the Auditory Cortex on Temporary Noise-Induced Hearing Loss in the Rat. Front Neurosci 2021; 15:642047. [PMID: 34393701 PMCID: PMC8358804 DOI: 10.3389/fnins.2021.642047] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2020] [Accepted: 04/30/2021] [Indexed: 11/13/2022] Open
Abstract
The protective effect of the efferent system against acoustic trauma (AT) has been shown by several experimental approaches, including damage to one ear, sectioning of the olivocochlear bundle (OCB) in the floor of the IV ventricle, and knock-in mice overexpressing outer hair cell (OHC) cholinergic receptors, among others. Such effects have been related to changes in the regulation of the cholinergic efferent system and in cochlear amplification, which ultimately reverse upon protective hearing suppression. In addition to well-known circuits of the brainstem, the descending corticofugal pathway also regulates efferent neurons of the olivary complex. In this study, we applied our recently developed experimental paradigm of multiple sessions of electrical stimulation (ES) to activate the efferent system in combination with noise overstimulation. ABR thresholds increased 1 and 2 days after AT (8-16 kHz bandpass noise at 107 dB for 90 min) recovering at AT + 14 days. However, after multiple sessions of epidural anodal stimulation, no changes in thresholds were observed following AT. Although an inflammatory response was also observed 1 day after AT in both groups, the counts of reactive macrophages in both experimental conditions suggest decreased inflammation in the epidural stimulation group. Quantitative immunocytochemistry for choline acetyltransferase (ChAT) showed a significant decrease in the size and optical density of the efferent terminals 1 day after AT and a rebound at 14 days, suggesting depletion of the terminals followed by a long-term compensatory response. Such a synthesis recovery was significantly higher upon cortical stimulation. No significant correlation was found between ChAT optical density and size of the buttons in sham controls (SC) and ES/AT + 1day animals; however, significant negative correlations were shown in all other experimental conditions. Therefore, our comparative analysis suggests that cochleotopic cholinergic neurotransmission is also better preserved after multisession epidural stimulation.
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Affiliation(s)
| | | | | | | | | | - Miguel A. Merchán
- Instituto de Neurociencias de Castilla y León (INCYL), Universidad de Salamanca, Salamanca, Spain
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Köhler MHA, Demarchi G, Weisz N. Cochlear activity in silent cue-target intervals shows a theta-rhythmic pattern and is correlated to attentional alpha and theta modulations. BMC Biol 2021; 19:48. [PMID: 33726746 PMCID: PMC7968255 DOI: 10.1186/s12915-021-00992-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2020] [Accepted: 02/24/2021] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND A long-standing debate concerns where in the processing hierarchy of the central nervous system (CNS) selective attention takes effect. In the auditory system, cochlear processes can be influenced via direct and mediated (by the inferior colliculus) projections from the auditory cortex to the superior olivary complex (SOC). Studies illustrating attentional modulations of cochlear responses have so far been limited to sound-evoked responses. The aim of the present study is to investigate intermodal (audiovisual) selective attention in humans simultaneously at the cortical and cochlear level during a stimulus-free cue-target interval. RESULTS We found that cochlear activity in the silent cue-target intervals was modulated by a theta-rhythmic pattern (~ 6 Hz). While this pattern was present independently of attentional focus, cochlear theta activity was clearly enhanced when attending to the upcoming auditory input. On a cortical level, classical posterior alpha and beta power enhancements were found during auditory selective attention. Interestingly, participants with a stronger release of inhibition in auditory brain regions show a stronger attentional modulation of cochlear theta activity. CONCLUSIONS These results hint at a putative theta-rhythmic sampling of auditory input at the cochlear level. Furthermore, our results point to an interindividual variable engagement of efferent pathways in an attentional context that are linked to processes within and beyond processes in auditory cortical regions.
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Affiliation(s)
- Moritz Herbert Albrecht Köhler
- Centre for Cognitive Neuroscience, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria.
- Department of Psychology, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria.
| | - Gianpaolo Demarchi
- Centre for Cognitive Neuroscience, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
- Department of Psychology, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
| | - Nathan Weisz
- Centre for Cognitive Neuroscience, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
- Department of Psychology, University of Salzburg, Hellbrunner Straße 34, 5020, Salzburg, Austria
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Asilador A, Llano DA. Top-Down Inference in the Auditory System: Potential Roles for Corticofugal Projections. Front Neural Circuits 2021; 14:615259. [PMID: 33551756 PMCID: PMC7862336 DOI: 10.3389/fncir.2020.615259] [Citation(s) in RCA: 26] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2020] [Accepted: 12/17/2020] [Indexed: 01/28/2023] Open
Abstract
It has become widely accepted that humans use contextual information to infer the meaning of ambiguous acoustic signals. In speech, for example, high-level semantic, syntactic, or lexical information shape our understanding of a phoneme buried in noise. Most current theories to explain this phenomenon rely on hierarchical predictive coding models involving a set of Bayesian priors emanating from high-level brain regions (e.g., prefrontal cortex) that are used to influence processing at lower-levels of the cortical sensory hierarchy (e.g., auditory cortex). As such, virtually all proposed models to explain top-down facilitation are focused on intracortical connections, and consequently, subcortical nuclei have scarcely been discussed in this context. However, subcortical auditory nuclei receive massive, heterogeneous, and cascading descending projections at every level of the sensory hierarchy, and activation of these systems has been shown to improve speech recognition. It is not yet clear whether or how top-down modulation to resolve ambiguous sounds calls upon these corticofugal projections. Here, we review the literature on top-down modulation in the auditory system, primarily focused on humans and cortical imaging/recording methods, and attempt to relate these findings to a growing animal literature, which has primarily been focused on corticofugal projections. We argue that corticofugal pathways contain the requisite circuitry to implement predictive coding mechanisms to facilitate perception of complex sounds and that top-down modulation at early (i.e., subcortical) stages of processing complement modulation at later (i.e., cortical) stages of processing. Finally, we suggest experimental approaches for future studies on this topic.
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Affiliation(s)
- Alexander Asilador
- Neuroscience Program, The University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
| | - Daniel A. Llano
- Neuroscience Program, The University of Illinois at Urbana-Champaign, Champaign, IL, United States
- Beckman Institute for Advanced Science and Technology, Urbana, IL, United States
- Molecular and Integrative Physiology, The University of Illinois at Urbana-Champaign, Champaign, IL, United States
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9
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Auditory attentional filter in the absence of masking noise. Atten Percept Psychophys 2021; 83:1737-1751. [PMID: 33389676 DOI: 10.3758/s13414-020-02210-z] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 11/13/2020] [Indexed: 12/16/2022]
Abstract
Signals containing attended frequencies are facilitated while those with unexpected frequencies are suppressed by an auditory filtering process. The neurocognitive mechanism underlying the auditory attentional filter is, however, poorly understood. The olivocochlear bundle (OCB), a brainstem neural circuit that is part of the efferent system, has been suggested to be partly responsible for the filtering via its noise-dependent antimasking effect. The current study examined the role of the OCB in attentional filtering, particularly the validity of the antimasking hypothesis, by comparing attentional filters measured in quiet and in the presence of background noise in a group of normal-hearing listeners. Filters obtained in both conditions were comparable, suggesting that the presence of background noise is not crucial for attentional filter generation. In addition, comparison of frequency-specific changes of the cue-evoked enhancement component of filters in quiet and noise also did not reveal any major contribution of background noise to the cue effect. These findings argue against the involvement of an antimasking effect in the attentional process. Instead of the antimasking effect mediated via medial olivocochlear fibers, results from current and earlier studies can be explained by frequency-specific modulation of afferent spontaneous activity by lateral olivocochlear fibers. It is proposed that the activity of these lateral fibers could be driven by top-down cortical control via a noise-independent mechanism. SIGNIFICANCE: The neural basis for auditory attentional filter remains a fundamental but poorly understood area in auditory neuroscience. The efferent olivocochlear pathway that projects from the brainstem back to the cochlea has been suggested to mediate the attentional effect via its noise-dependent antimasking effect. The current study demonstrates that the filter generation is mostly independent of the background noise, and therefore is unlikely to be mediated by the olivocochlear brainstem reflex. It is proposed that the entire cortico-olivocochlear system might instead be used to alter the hearing sensitivity during focus attention via frequency-specific modulation of afferent spontaneous activity.
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11
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Bowen M, Terreros G, Moreno-Gómez FN, Ipinza M, Vicencio S, Robles L, Delano PH. The olivocochlear reflex strength in awake chinchillas is relevant for behavioural performance during visual selective attention with auditory distractors. Sci Rep 2020; 10:14894. [PMID: 32913207 PMCID: PMC7483726 DOI: 10.1038/s41598-020-71399-8] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 08/03/2020] [Indexed: 11/06/2022] Open
Abstract
The auditory efferent system comprises descending projections from the cerebral cortex to subcortical nuclei, reaching the cochlear receptor through olivocochlear fibres. One of the functions attributed to this corticofugal system is to suppress irrelevant sounds during selective attention to visual stimuli. Medial olivocochlear neurons can also be activated by sounds through a brainstem reflex circuit. Whether the individual variability of this reflex is related to the cognitive capacity to suppress auditory stimuli is still controversial. Here we propose that the individual strength per animal of the olivocochlear reflex is correlated with the ability to suppress auditory distractors during visual attention in awake chinchillas. The olivocochlear reflex was elicited with a contralateral broad-band noise at ~ 60 dB and ipsilateral distortion product otoacoustic emissions were obtained at different frequencies (1-8 kHz). Fourteen chinchillas were evaluated in a behavioural protocol of visual attention with broad-band noise and chinchilla vocalizations as auditory distractors. Results show that the behavioural performance was affected by both distractors and that the magnitudes of the olivocochlear reflex evaluated at multiple frequencies were relevant for behavioural performance during visual discrimination with auditory distractors. These results stress the ecological relevance of the olivocochlear system for suppressing natural distractors.
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Affiliation(s)
- Macarena Bowen
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Departamento de Fonoaudiología, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Gonzalo Terreros
- Instituto de Ciencias de la Salud, Universidad de O'Higgins, Rancagua, Chile
| | - Felipe N Moreno-Gómez
- Laboratorio de Bioacústica y Ecología del Comportamiento Animal, Departamento de Biología y Química, Facultad de Ciencias Básicas, Universidad Católica del Maule, Talca, Chile
| | - Macarena Ipinza
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Sergio Vicencio
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Luis Robles
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Paul H Delano
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile.
- Departamento de Otorrinolaringología, Hospital Clínico de la Universidad de Chile, Santiago, Chile.
- Biomedical Neuroscience Institute, BNI. Facultad de Medicina, Universidad de Chile, Santiago, Chile.
- Centro Avanzado de Ingeniería Eléctrica y Electrónica, AC3E, Universidad Técnica Federico Santa María, Valparaíso, Chile.
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12
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Boothalingam S, Allan C, Allen P, Purcell DW. The Medial Olivocochlear Reflex Is Unlikely to Play a Role in Listening Difficulties in Children. Trends Hear 2020; 23:2331216519870942. [PMID: 31558110 PMCID: PMC6767729 DOI: 10.1177/2331216519870942] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The medial olivocochlear reflex (MOCR) has been implicated in several auditory processes. The putative role of the MOCR in improving speech perception in noise is particularly relevant for children who complain of listening difficulties (LiD). The hypothesis that the MOCR may be impaired in individuals with LiD or auditory processing disorder has led to several investigations but without consensus. In two related studies, we compared the MOCR functioning of children with LiD and typically developing (TD) children in the same age range (7-17 years). In Study 1, we investigated ipsilateral, contralateral, and bilateral MOCR using forward-masked click-evoked otoacoustic emissions (CEOAEs; n = 17 TD, 17 LiD). In Study 2, we employed three OAE types: CEOAEs (n = 16 TD, 21 LiD), stimulus frequency OAEs (n = 21 TD, 30 LiD), and distortion product OAEs (n = 17 TD, 22 LiD) in a contralateral noise paradigm. Results from both studies suggest that the MOCR functioning is not significantly different between the two groups. Some likely reasons for differences in findings among published studies could stem from the lack of strict data quality measures (e.g., high signal-to-noise ratio, control for the middle ear muscle reflex) that were enforced in the present study. The inherent variability of the MOCR, the subpar reliability of current MOCR methods, and the heterogeneity in auditory processing deficits that underlie auditory processing disorder make detecting clinically relevant differences in MOCR function impractical using current methods.
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Affiliation(s)
- Sriram Boothalingam
- Department of Communication Sciences and Disorders, University of Wisconsin, Madison, WI, USA.,Waisman Center, University of Wisconsin, Madison, WI, USA
| | - Chris Allan
- School of Communication Sciences and Disorders, Western University, London, ON, Canada.,National Centre for Audiology, Western University, London, ON, Canada
| | - Prudence Allen
- School of Communication Sciences and Disorders, Western University, London, ON, Canada.,National Centre for Audiology, Western University, London, ON, Canada
| | - David W Purcell
- School of Communication Sciences and Disorders, Western University, London, ON, Canada.,National Centre for Audiology, Western University, London, ON, Canada
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13
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Weaver AJ, DiGiovanni JJ, Ries DT. Pspan: A New Tool for Assessing Pitch Temporal Processing and Patterning Capacity. Am J Audiol 2019; 28:322-332. [PMID: 31084578 DOI: 10.1044/2019_aja-18-0117] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022] Open
Abstract
Purpose The purpose of this study was to evaluate whether merging the clinical pitch pattern test procedure with psychoacoustic adaptive methods would create a new tool feasible to capture individual differences in pitch temporal processing and patterning capacity of children and adults. Method Sixty-six individuals, young children (ages 10-12 years, n = 22), older children (ages 13-15 years, n = 23), and adults (ages 18-33 years, n = 21), were recruited and assigned to subgroups based on reported duration (years) of instrumental music instruction. Additional background information was collected in order to assess if the pitch temporal processing and patterning span developed, the Pspan, was sensitive to individual differences across participants. Results The evaluation of the Pspan task as a scale indicated good parallel reliability across runs assessed by Cronbach's alpha, and scores were normally distributed. Between-subjects analysis of variance indicated main effects for both age groups and music groups recruited for the study. A multiple regression analysis with the Pspan scores as the dependent variable found that 3 measures of music instruction, age in years, and paternal education were predictive of enhanced temporal processing and patterning capacity for pitch input. Conclusions The outcomes suggest that the Pspan task is a time-efficient data collection tool that is sensitive to the duration of instrumental music instruction, maturation, and paternal education. In addition, results indicate that the task is sensitive to age-related auditory temporal processing and patterning performance changes during adolescence when children are 10-15 years old.
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Affiliation(s)
- Aurora J. Weaver
- Auditory Psychophysics and Signal Processing Lab, Division of Communication Sciences and Disorders, Ohio University, Athens
- Auditory and Music Perception Lab, Department of Communication Disorders, Auburn University, AL
| | - Jeffrey J. DiGiovanni
- Auditory Psychophysics and Signal Processing Lab, Division of Communication Sciences and Disorders, Ohio University, Athens
- Department of Communication Sciences and Disorders, University of Cincinnati, OH
| | - Dennis T. Ries
- Department of Physical Medicine and Rehabilitation, University of Colorado–Anschutz Medical Campus, Aurora
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14
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Colmenárez-Raga AC, Díaz I, Pernia M, Pérez-González D, Delgado-García JM, Carro J, Plaza I, Merchán MA. Reversible Functional Changes Evoked by Anodal Epidural Direct Current Electrical Stimulation of the Rat Auditory Cortex. Front Neurosci 2019; 13:356. [PMID: 31031588 PMCID: PMC6473088 DOI: 10.3389/fnins.2019.00356] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/28/2018] [Accepted: 03/28/2019] [Indexed: 12/26/2022] Open
Abstract
Rat auditory cortex was subjected to 0.1 mA anodal direct current in seven 10-min sessions on alternate days. Based on the well-known auditory cortex control of olivocochlear regulation through corticofugal projections, auditory brainstem responses (ABRs) were recorded as an indirect test of the effectiveness and reversibility of the multisession protocol of epidural stimulation. Increases of 20-30 dB ABR auditory thresholds shown after epidural stimulation reverted back to control levels 10 min after a single session. However, increases in thresholds revert 4 days after multisession stimulation. Less changes in wave amplitudes and threshold shifts were shown in ABR recorded contralaterally to the electrically stimulated side of the brain. To assess tissue effects of epidural electric stimulation on the brain cortex, well characterized functional anatomical markers of glial cells (GFAP/astrocytes and Iba1/microglial cells) and neurons (c-Fos) were analyzed in alternate serial sections by quantitative immunocytochemistry. Restricted astroglial and microglial reactivity was observed within the cytoarchitectural limits of the auditory cortex. However, interstitial GFAP overstaining was also observed in the ventricular surface and around blood vessels, thus supporting a potential global electrolytic stimulation of the brain. These results correlate with extensive changes in the distribution of c-Fos immunoreactive neurons among layers along sensory cortices after multisession stimulation. Quantitative immunocytochemical analysis supported this idea by showing a significant increase in the number of positive neurons in supragranular layers and a decrease in layer 6 with no quantitative changes detected in layer 5. Our data indicate that epidural stimulation of the auditory cortex induces a reversible decrease in hearing sensitivity due to local, restricted epidural stimulation. A global plastic response of the sensory cortices, also reported here, may be related to electrolytic effects of electric currents.
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Affiliation(s)
| | - Iván Díaz
- Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca, Spain
| | - Marianny Pernia
- Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca, Spain
| | - David Pérez-González
- Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca, Spain
| | | | - Juan Carro
- Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca, Spain
| | - Ignacio Plaza
- Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca, Spain
| | - Miguel A. Merchán
- Instituto de Neurociencias de Castilla y León, University of Salamanca, Salamanca, Spain
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15
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Liu X, Zhang O, Qi J, Chen A, Hu K, Yan J. The onset and post-onset auditory responses of cochlear nucleus neurons are modulated differently by cortical activation. Hear Res 2019; 373:96-102. [DOI: 10.1016/j.heares.2018.12.013] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/05/2018] [Revised: 12/13/2018] [Accepted: 12/28/2018] [Indexed: 01/14/2023]
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16
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Dragicevic CD, Marcenaro B, Navarrete M, Robles L, Delano PH. Oscillatory infrasonic modulation of the cochlear amplifier by selective attention. PLoS One 2019; 14:e0208939. [PMID: 30615632 PMCID: PMC6322828 DOI: 10.1371/journal.pone.0208939] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/28/2018] [Accepted: 11/26/2018] [Indexed: 11/18/2022] Open
Abstract
Evidence shows that selective attention to visual stimuli modulates the gain of cochlear responses, probably through auditory-cortex descending pathways. At the cerebral cortex level, amplitude and phase changes of neural oscillations have been proposed as a correlate of selective attention. However, whether sensory receptors are also influenced by the oscillatory network during attention tasks remains unknown. Here, we searched for oscillatory attention-related activity at the cochlear receptor level in humans. We used an alternating visual/auditory selective attention task and measured electroencephalographic activity simultaneously to distortion product otoacoustic emissions (a measure of cochlear receptor-cell activity). In order to search for cochlear oscillatory activity, the otoacoustic emission signal, was included as an additional channel in the electroencephalogram analyses. This method allowed us to evaluate dynamic changes in cochlear oscillations within the same range of frequencies (1–35 Hz) in which cognitive effects are commonly observed in electroencephalogram works. We found the presence of low frequency (<10 Hz) brain and cochlear amplifier oscillations during selective attention to visual and auditory stimuli. Notably, switching between auditory and visual attention modulates the amplitude and the temporal order of brain and inner ear oscillations. These results extend the role of the oscillatory activity network during cognition in neural systems to the receptor level.
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Affiliation(s)
| | - Bruno Marcenaro
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Marcela Navarrete
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Luis Robles
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Paul H. Delano
- Neuroscience Department, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Otolaryngology Department, Clinical Hospital, Universidad de Chile, Santiago, Chile
- Biomedical Neuroscience Institute, Universidad de Chile, Santiago, Chile
- * E-mail:
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17
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Lewis JD. Synchronized Spontaneous Otoacoustic Emissions Provide a Signal-to-Noise Ratio Advantage in Medial-Olivocochlear Reflex Assays. J Assoc Res Otolaryngol 2017; 19:53-65. [PMID: 29134475 DOI: 10.1007/s10162-017-0645-5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/20/2017] [Accepted: 10/23/2017] [Indexed: 11/28/2022] Open
Abstract
Detection of medial olivocochlear-induced (MOC) changes to transient-evoked otoacoustic emissions (TEOAE) requires high signal-to-noise ratios (SNR). TEOAEs associated with synchronized spontaneous (SS) OAEs exhibit higher SNRs than TEOAEs in the absence of SSOAEs, potentially making the former well suited for MOC assays. Although SSOAEs may complicate interpretation of MOC-induced changes to TEOAE latency, recent work suggests SSOAEs are not a problem in non-latency-dependent MOC assays. The current work examined the potential benefit of SSOAEs in TEOAE-based assays of the MOC efferents. It was hypothesized that the higher SNR afforded by SSOAEs would permit detection of smaller changes to the TEOAE upon activation of the MOC reflex. TEOAEs were measured in 24 female subjects in the presence and absence of contralateral broadband noise. Frequency bands with and without SSOAEs were identified for each subject. The prevalence of TEOAEs and statistically significant MOC effects were highest in frequency bands that also contained SSOAEs. The median TEOAE SNR in frequency bands with SSOAEs was approximately 8 dB higher than the SNR in frequency bands lacking SSOAEs. After normalizing by TEOAE amplitude, MOC-induced changes to the TEOAE were similar between frequency bands with and without SSOAEs. Smaller MOC effects were detectable across a subset of the frequency bands with SSOAEs, presumably due to a higher TEOAE SNR. These findings demonstrate that SSOAEs are advantageous in assays of the MOC reflex.
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Affiliation(s)
- James D Lewis
- Department of Audiology and Speech Pathology, University of Tennessee Health Science Center, 578 South Stadium Hall, Knoxville, TN, 37996, USA.
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18
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Jorratt P, Delano PH, Delgado C, Dagnino-Subiabre A, Terreros G. Difference in Perseverative Errors during a Visual Attention Task with Auditory Distractors in Alpha-9 Nicotinic Receptor Subunit Wild Type and Knock-Out Mice. Front Cell Neurosci 2017; 11:357. [PMID: 29163062 PMCID: PMC5676050 DOI: 10.3389/fncel.2017.00357] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/18/2017] [Accepted: 10/27/2017] [Indexed: 12/14/2022] Open
Abstract
The auditory efferent system is a neural network that originates in the auditory cortex and projects to the cochlear receptor through olivocochlear (OC) neurons. Medial OC neurons make cholinergic synapses with outer hair cells (OHCs) through nicotinic receptors constituted by α9 and α10 subunits. One of the physiological functions of the α9 nicotinic receptor subunit (α9-nAChR) is the suppression of auditory distractors during selective attention to visual stimuli. In a recent study we demonstrated that the behavioral performance of alpha-9 nicotinic receptor knock-out (KO) mice is altered during selective attention to visual stimuli with auditory distractors since they made less correct responses and more omissions than wild type (WT) mice. As the inhibition of the behavioral responses to irrelevant stimuli is an important mechanism of the selective attention processes, behavioral errors are relevant measures that can reflect altered inhibitory control. Errors produced during a cued attention task can be classified as premature, target and perseverative errors. Perseverative responses can be considered as an inability to inhibit the repetition of an action already planned, while premature responses can be considered as an index of the ability to wait or retain an action. Here, we studied premature, target and perseverative errors during a visual attention task with auditory distractors in WT and KO mice. We found that α9-KO mice make fewer perseverative errors with longer latencies than WT mice in the presence of auditory distractors. In addition, although we found no significant difference in the number of target error between genotypes, KO mice made more short-latency target errors than WT mice during the presentation of auditory distractors. The fewer perseverative error made by α9-KO mice could be explained by a reduced motivation for reward and an increased impulsivity during decision making with auditory distraction in KO mice.
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Affiliation(s)
- Pascal Jorratt
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Paul H Delano
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Departamento de Otorrinolaringología, Hospital Clínico de la Universidad de Chile, Santiago, Chile
| | - Carolina Delgado
- Departamento de Neurociencia, Facultad de Medicina, Universidad de Chile, Santiago, Chile.,Departamento Neurología y Neurocirugía, Hospital Clínico de la Universidad de Chile, Santiago, Chile
| | - Alexies Dagnino-Subiabre
- Laboratorio de Neurobiología del Stress, Centro de Neurobiología y Plasticidad Cerebral (CNPC), Instituto de Fisiología, Facultad de Ciencias, Universidad de Valparaíso, Valparaíso, Chile
| | - Gonzalo Terreros
- Instituto de Ciencias de la Salud, Universidad de O'Higgins, Rancagua, Chile
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19
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Lamas V, Estévez S, Pernía M, Plaza I, Merchán MA. Stereotactically-guided Ablation of the Rat Auditory Cortex, and Localization of the Lesion in the Brain. J Vis Exp 2017. [PMID: 29053697 PMCID: PMC5752406 DOI: 10.3791/56429] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
The rat auditory cortex (AC) is becoming popular among auditory neuroscience investigators who are interested in experience-dependence plasticity, auditory perceptual processes, and cortical control of sound processing in the subcortical auditory nuclei. To address new challenges, a procedure to accurately locate and surgically expose the auditory cortex would expedite this research effort. Stereotactic neurosurgery is routinely used in pre-clinical research in animal models to engraft a needle or electrode at a pre-defined location within the auditory cortex. In the following protocol, we use stereotactic methods in a novel way. We identify four coordinate points over the surface of the temporal bone of the rat to define a window that, once opened, accurately exposes both the primary (A1) and secondary (Dorsal and Ventral) cortices of the AC. Using this method, we then perform a surgical ablation of the AC. After such a manipulation is performed, it is necessary to assess the localization, size, and extension of the lesions made in the cortex. Thus, we also describe a method to easily locate the AC ablation postmortem using a coordinate map constructed by transferring the cytoarchitectural limits of the AC to the surface of the brain.The combination of the stereotactically-guided location and ablation of the AC with the localization of the injured area in a coordinate map postmortem facilitates the validation of information obtained from the animal, and leads to a better analysis and comprehension of the data.
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Affiliation(s)
- Verónica Lamas
- Institute of Neuroscience of Castilla y León, University of Salamanca; Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, Department of Otolaryngology, Harvard Medical School;
| | - Sheila Estévez
- Institute of Neuroscience of Castilla y León, University of Salamanca
| | - Marianni Pernía
- Institute of Neuroscience of Castilla y León, University of Salamanca
| | - Ignacio Plaza
- Institute of Neuroscience of Castilla y León, University of Salamanca
| | - Miguel A Merchán
- Institute of Neuroscience of Castilla y León, University of Salamanca
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20
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Selective Attention to Visual Stimuli Using Auditory Distractors Is Altered in Alpha-9 Nicotinic Receptor Subunit Knock-Out Mice. J Neurosci 2017; 36:7198-209. [PMID: 27383594 DOI: 10.1523/jneurosci.4031-15.2016] [Citation(s) in RCA: 40] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/09/2015] [Accepted: 05/26/2016] [Indexed: 12/28/2022] Open
Abstract
UNLABELLED During selective attention, subjects voluntarily focus their cognitive resources on a specific stimulus while ignoring others. Top-down filtering of peripheral sensory responses by higher structures of the brain has been proposed as one of the mechanisms responsible for selective attention. A prerequisite to accomplish top-down modulation of the activity of peripheral structures is the presence of corticofugal pathways. The mammalian auditory efferent system is a unique neural network that originates in the auditory cortex and projects to the cochlear receptor through the olivocochlear bundle, and it has been proposed to function as a top-down filter of peripheral auditory responses during attention to cross-modal stimuli. However, to date, there is no conclusive evidence of the involvement of olivocochlear neurons in selective attention paradigms. Here, we trained wild-type and α-9 nicotinic receptor subunit knock-out (KO) mice, which lack cholinergic transmission between medial olivocochlear neurons and outer hair cells, in a two-choice visual discrimination task and studied the behavioral consequences of adding different types of auditory distractors. In addition, we evaluated the effects of contralateral noise on auditory nerve responses as a measure of the individual strength of the olivocochlear reflex. We demonstrate that KO mice have a reduced olivocochlear reflex strength and perform poorly in a visual selective attention paradigm. These results confirm that an intact medial olivocochlear transmission aids in ignoring auditory distraction during selective attention to visual stimuli. SIGNIFICANCE STATEMENT The auditory efferent system is a neural network that originates in the auditory cortex and projects to the cochlear receptor through the olivocochlear system. It has been proposed to function as a top-down filter of peripheral auditory responses during attention to cross-modal stimuli. However, to date, there is no conclusive evidence of the involvement of olivocochlear neurons in selective attention paradigms. Here, we studied the behavioral consequences of adding different types of auditory distractors in a visual selective attention task in wild-type and α-9 nicotinic receptor knock-out (KO) mice. We demonstrate that KO mice perform poorly in the selective attention paradigm and that an intact medial olivocochlear transmission aids in ignoring auditory distractors during attention.
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21
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Maruthy S, Kumar UA, Gnanateja GN. Functional Interplay Between the Putative Measures of Rostral and Caudal Efferent Regulation of Speech Perception in Noise. J Assoc Res Otolaryngol 2017; 18:635-648. [PMID: 28447225 DOI: 10.1007/s10162-017-0623-y] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2016] [Accepted: 03/22/2017] [Indexed: 01/23/2023] Open
Abstract
Efferent modulation has been demonstrated to be very important for speech perception, especially in the presence of noise. We examined the functional relationship between two efferent systems: the rostral and caudal efferent pathways and their individual influences on speech perception in noise. Earlier studies have shown that these two efferent mechanisms were correlated with speech perception in noise. However, previously, these mechanisms were studied in isolation, and their functional relationship with each other was not investigated. We used a correlational design to study the relationship if any, between these two mechanisms in young and old normal hearing individuals. We recorded context-dependent brainstem encoding as an index of rostral efferent function and contralateral suppression of otoacoustic emissions as an index of caudal efferent function in groups with good and poor speech perception in noise. These efferent mechanisms were analysed for their relationship with each other and with speech perception in noise. We found that the two efferent mechanisms did not show any functional relationship. Interestingly, both the efferent mechanisms correlated with speech perception in noise and they even emerged as significant predictors. Based on the data, we posit that the two efferent mechanisms function relatively independently but with a common goal of fine-tuning the afferent input and refining auditory perception in degraded listening conditions.
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Affiliation(s)
- Sandeep Maruthy
- Electrophysiology Laboratory, Department of Audiology, All India Institute of Speech and Hearing, Manasagangothri, Mysore, Karnataka, IN-570006, India
| | - U Ajith Kumar
- Electrophysiology Laboratory, Department of Audiology, All India Institute of Speech and Hearing, Manasagangothri, Mysore, Karnataka, IN-570006, India
| | - G Nike Gnanateja
- Electrophysiology Laboratory, Department of Audiology, All India Institute of Speech and Hearing, Manasagangothri, Mysore, Karnataka, IN-570006, India.
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22
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Ablation of the auditory cortex results in changes in the expression of neurotransmission-related mRNAs in the cochlea. Hear Res 2017; 346:71-80. [PMID: 28216123 DOI: 10.1016/j.heares.2017.02.011] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Revised: 02/09/2017] [Accepted: 02/14/2017] [Indexed: 01/02/2023]
Abstract
The auditory cortex (AC) dynamically regulates responses of the Organ of Corti to sound through descending connections to both the medial (MOC) and lateral (LOC) olivocochlear efferent systems. We have recently provided evidence that AC has a reinforcement role in the responses to sound of the auditory brainstem nuclei. In a molecular level, we have shown that descending inputs from AC are needed to regulate the expression of molecules involved in outer hair cell (OHC) electromotility control, such as prestin and the α10 nicotinic acetylcholine receptor (nAchR). In this report, we show that descending connections from AC to olivocochlear neurons are necessary to regulate the expression of molecules involved in cochlear afferent signaling. RT-qPCR was performed in rats at 1, 7 and 15 days after unilateral ablation of the AC, and analyzed the time course changes in gene transcripts involved in neurotransmission at the first auditory synapse. This included the glutamate metabolism enzyme glutamate decarboxylase 1 (glud1) and AMPA glutamate receptor subunits GluA2-4. In addition, gene transcripts involved in efferent regulation of type I spiral ganglion neuron (SGN) excitability mediated by LOC, such as the α7 nAchR, the D2 dopamine receptor, and the α1, and γ2 GABAA receptor subunits, were also investigated. Unilateral AC ablation induced up-regulation of GluA3 receptor subunit transcripts, whereas both GluA2 and GluA4 mRNA receptors were down-regulated already at 1 day after the ablation. Unilateral removal of the AC also resulted in up-regulation of the transcripts for α7 nAchR subunit, D2 dopamine receptor, and α1 GABAA receptor subunit at 1 day after the ablation. Fifteen days after the injury, AC ablations induced an up-regulation of glud1 transcripts.
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23
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Saldaña E. All the way from the cortex: a review of auditory corticosubcollicular pathways. THE CEREBELLUM 2016; 14:584-96. [PMID: 26142291 DOI: 10.1007/s12311-015-0694-4] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Enrico Mugnaini has devoted part of his long and fruitful neuroscientific career to investigating the structural similarities between the cerebellar cortex and one of the first relay stations of the mammalian auditory pathway: the dorsal cochlear nucleus. The hypothesis of the cerebellar-like nature of the superficial layers of the dorsal cochlear nucleus received definitive support with the discovery and extensive characterization in his laboratory of unipolar brush cells, a neuron type unique to certain regions of the cerebellar cortex and to the granule cell domains of the cochlear nuclei. Paradoxically, a different line of research carried out in his laboratory revealed that, unlike the mammalian cerebellar cortex, the dorsal cochlear nucleus receives direct projections from the cerebral cortex, a fact that constitutes one of the main differences between the cerebellum and the dorsal cochlear nucleus. In an article published in 1995, Mugnaini's group described in detail the novel direct projections from the rat auditory neocortex to various subcollicular auditory centers, including the nucleus sagulum, the paralemniscal regions, the superior olivary complex, and the cochlear nuclei (Feliciano et al., Auditory Neuroscience 1995; 1:287-308). This review gives Enrico Mugnaini credit for his seminal contribution to the knowledge of auditory corticosubcollicular projections and summarizes how this growing field has evolved in the last 20 years.
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Affiliation(s)
- Enrique Saldaña
- Neurohistology Laboratory, Neuroscience Institute of Castilla y León (INCyL), University of Salamanca, 37007, Salamanca, Spain. .,Department of Cell Biology and Pathology, Medical School, University of Salamanca, 37007, Salamanca, Spain. .,Institute of Biomedical Research of Salamanca (IBSAL), 37007, Salamanca, Spain.
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24
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Aedo C, Terreros G, León A, Delano PH. The Corticofugal Effects of Auditory Cortex Microstimulation on Auditory Nerve and Superior Olivary Complex Responses Are Mediated via Alpha-9 Nicotinic Receptor Subunit. PLoS One 2016; 11:e0155991. [PMID: 27195498 PMCID: PMC4873184 DOI: 10.1371/journal.pone.0155991] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/15/2016] [Accepted: 05/06/2016] [Indexed: 02/06/2023] Open
Abstract
Background and Objective The auditory efferent system is a complex network of descending pathways, which mainly originate in the primary auditory cortex and are directed to several auditory subcortical nuclei. These descending pathways are connected to olivocochlear neurons, which in turn make synapses with auditory nerve neurons and outer hair cells (OHC) of the cochlea. The olivocochlear function can be studied using contralateral acoustic stimulation, which suppresses auditory nerve and cochlear responses. In the present work, we tested the proposal that the corticofugal effects that modulate the strength of the olivocochlear reflex on auditory nerve responses are produced through cholinergic synapses between medial olivocochlear (MOC) neurons and OHCs via alpha-9/10 nicotinic receptors. Methods We used wild type (WT) and alpha-9 nicotinic receptor knock-out (KO) mice, which lack cholinergic transmission between MOC neurons and OHC, to record auditory cortex evoked potentials and to evaluate the consequences of auditory cortex electrical microstimulation in the effects produced by contralateral acoustic stimulation on auditory brainstem responses (ABR). Results Auditory cortex evoked potentials at 15 kHz were similar in WT and KO mice. We found that auditory cortex microstimulation produces an enhancement of contralateral noise suppression of ABR waves I and III in WT mice but not in KO mice. On the other hand, corticofugal modulations of wave V amplitudes were significant in both genotypes. Conclusion These findings show that the corticofugal modulation of contralateral acoustic suppressions of auditory nerve (ABR wave I) and superior olivary complex (ABR wave III) responses are mediated through MOC synapses.
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Affiliation(s)
- Cristian Aedo
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Gonzalo Terreros
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Alex León
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
| | - Paul H Delano
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile, Santiago, Chile
- Departamento de Otorrinolaringología, Hospital Clínico de la Universidad de Chile, Santiago, Chile
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Ubiali T, Sanfins MD, Borges LR, Colella-Santos MF. Contralateral Noise Stimulation Delays P300 Latency in School-Aged Children. PLoS One 2016; 11:e0148360. [PMID: 26849224 PMCID: PMC4744065 DOI: 10.1371/journal.pone.0148360] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2015] [Accepted: 01/19/2016] [Indexed: 11/18/2022] Open
Abstract
Background and Objective The auditory cortex modulates auditory afferents through the olivocochlear system, which innervates the outer hair cells and the afferent neurons under the inner hair cells in the cochlea. Most of the studies that investigated the efferent activity in humans focused on evaluating the suppression of the otoacoustic emissions by stimulating the contralateral ear with noise, which assesses the activation of the medial olivocochlear bundle. The neurophysiology and the mechanisms involving efferent activity on higher regions of the auditory pathway, however, are still unknown. Also, the lack of studies investigating the effects of noise on human auditory cortex, especially in peadiatric population, points to the need for recording the late auditory potentials in noise conditions. Assessing the auditory efferents in schoolaged children is highly important due to some of its attributed functions such as selective attention and signal detection in noise, which are important abilities related to the development of language and academic skills. For this reason, the aim of the present study was to evaluate the effects of noise on P300 responses of children with normal hearing. Methods P300 was recorded in 27 children aged from 8 to 14 years with normal hearing in two conditions: with and whitout contralateral white noise stimulation. Results P300 latencies were significantly longer at the presence of contralateral noise. No significant changes were observed for the amplitude values. Conclusion Contralateral white noise stimulation delayed P300 latency in a group of school-aged children with normal hearing. These results suggest a possible influence of the medial olivocochlear activation on P300 responses under noise condition.
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Affiliation(s)
- Thalita Ubiali
- Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil
- * E-mail:
| | | | - Leticia Reis Borges
- Faculty of Medical Sciences, State University of Campinas, Campinas, São Paulo, Brazil
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Abdul Wahab NA, Wahab S, Abdul Rahman AH, Sidek D, Zakaria MN. The Hyperactivity of Efferent Auditory System in Patients with Schizophrenia: A Transient Evoked Otoacoustic Emissions Study. Psychiatry Investig 2016; 13:82-8. [PMID: 26766950 PMCID: PMC4701690 DOI: 10.4306/pi.2016.13.1.82] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2015] [Revised: 05/18/2015] [Accepted: 05/30/2015] [Indexed: 02/07/2023] Open
Abstract
OBJECTIVE Electrophysiological studies, which are mostly focused on afferent pathway, have proven that auditory processing deficits exist in patients with schizophrenia. Nevertheless, reports on the suppressive effect of efferent auditory pathway on cochlear outer hair cells among schizophrenia patients are limited. The present, case-control, study examined the contralateral suppression of transient evoked otoacoustic emissions (TEOAEs) in patients with schizophrenia. METHODS Participants were twenty-three healthy controls and sixteen schizophrenia patients with normal hearing, middle ear and cochlear outer hair cells function. Absolute non-linear and linear TEOAEs were measured in both ears by delivering clicks stimuli at 80 dB SPL and 60 dB SPL respectively. Subsequently, contralateral suppression was determined by subtracting the absolute TEOAEs response obtained at 60 dBpe SPL during the absence and presence of contralateral white noise delivered at 65 dB HL. No attention tasks were conducted during measurements. RESULTS We found no significant difference in absolute TEOAEs responses at 80 dB SPL, in either diagnosis or ear groups (p>0.05). However, the overall contralateral suppression was significantly larger in schizophrenia patients (p<0.05). Specifically, patients with schizophrenia demonstrated significantly increased right ear contralateral suppression compared to healthy control (p<0.05). CONCLUSION The present findings suggest increased inhibitory effect of efferent auditory pathway especially on the right cochlear outer hair cells. Further studies to investigate increased suppressive effects are crucial to expand the current understanding of auditory hallucination mechanisms in schizophrenia patients.
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Affiliation(s)
- Noor Alaudin Abdul Wahab
- Audiology Programme, School of Health Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
- Audiology Programme, School of Rehabilitation Sciences, Faculty of Health Sciences, Universiti Kebangsaan Malaysia, Wilayah Persekutuan, Malaysia
| | - Suzaily Wahab
- Department of Psychiatry, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Center, Wilayah Persekutuan, Malaysia
| | - Abdul Hamid Abdul Rahman
- Department of Psychiatry, Faculty of Medicine, Universiti Kebangsaan Malaysia Medical Center, Wilayah Persekutuan, Malaysia
| | - Dinsuhaimi Sidek
- Department of Otorhinolaryngology, School of Medicine, Universiti Sains Malaysia, Kelantan, Malaysia
| | - Mohd. Normani Zakaria
- Audiology Programme, School of Health Sciences, Universiti Sains Malaysia, Kelantan, Malaysia
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Jäger K, Kössl M. Corticofugal Modulation of DPOAEs in Gerbils. Hear Res 2015; 332:61-72. [PMID: 26619750 DOI: 10.1016/j.heares.2015.11.008] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 07/13/2015] [Revised: 10/20/2015] [Accepted: 11/09/2015] [Indexed: 01/13/2023]
Abstract
Efferent auditory feedback on cochlear hair cells is well studied regarding olivocochlear brainstem mechanisms. Less is known about how the descending corticofugal system may shape efferent feedback and modulate cochlear mechanics. Distortion-product otoacoustic emissions (DPOAEs) are a suitable tool to assess outer hair cell function, as they are by-products of the nonlinear cochlear amplification process. The present project investigates the effects of cortical activity on cubic and quadratic DPOAEs in mongolian gerbils, Meriones unguiculatus, through cortical deactivation using the sodium-channel blocker lidocaine. Contralateral cortical microinjections of lidocaine can lead to either an increase or decrease of median DPOAE levels of up to 10.95 dB. The effects are reversible and comparable at all tested frequencies (0.5-40 kHz). They are not restricted to the preferred frequency of the cortical site of injection. Recovery times are between 20 and 120 min depending on stimulation levels and emission type. When the injection is performed in the ipsilateral hemisphere, DPOAE level shifts are lower in amplitude compared to those after injection in the contralateral hemisphere. No significant changes in DPOAE levels are obtained after saline microinjections. Results indicate that deactivation of auditory cortex activity through lidocaine has a considerable impact on peripheral auditory responses in form of DPOAEs, probably through cortico-olivocochlear pathways.
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Affiliation(s)
- K Jäger
- Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, Max-von-Laue Str. 13, 60438 Frankfurt, Germany.
| | - M Kössl
- Institute for Cell Biology and Neuroscience, Goethe University Frankfurt, Max-von-Laue Str. 13, 60438 Frankfurt, Germany.
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Terreros G, Delano PH. Corticofugal modulation of peripheral auditory responses. Front Syst Neurosci 2015; 9:134. [PMID: 26483647 PMCID: PMC4588004 DOI: 10.3389/fnsys.2015.00134] [Citation(s) in RCA: 81] [Impact Index Per Article: 9.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2015] [Accepted: 09/15/2015] [Indexed: 01/17/2023] Open
Abstract
The auditory efferent system originates in the auditory cortex and projects to the medial geniculate body (MGB), inferior colliculus (IC), cochlear nucleus (CN) and superior olivary complex (SOC) reaching the cochlea through olivocochlear (OC) fibers. This unique neuronal network is organized in several afferent-efferent feedback loops including: the (i) colliculo-thalamic-cortico-collicular; (ii) cortico-(collicular)-OC; and (iii) cortico-(collicular)-CN pathways. Recent experiments demonstrate that blocking ongoing auditory-cortex activity with pharmacological and physical methods modulates the amplitude of cochlear potentials. In addition, auditory-cortex microstimulation independently modulates cochlear sensitivity and the strength of the OC reflex. In this mini-review, anatomical and physiological evidence supporting the presence of a functional efferent network from the auditory cortex to the cochlear receptor is presented. Special emphasis is given to the corticofugal effects on initial auditory processing, that is, on CN, auditory nerve and cochlear responses. A working model of three parallel pathways from the auditory cortex to the cochlea and auditory nerve is proposed.
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Affiliation(s)
- Gonzalo Terreros
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile Santiago, Chile
| | - Paul H Delano
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile Santiago, Chile ; Departamento de Otorrinolaringología, Hospital Clínico de la Universidad de Chile Santiago, Chile
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Moreno-Gómez FN, León A, Velásquez NA, Penna M, Delano PH. Individual and sex distinctiveness in bark calls of domestic chinchillas elicited in a distress context. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2015; 138:1614-1622. [PMID: 26428799 DOI: 10.1121/1.4929750] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
Animals obtain information about their social environment by means of communication signals, which provide relevant subtle cues for individual recognition. An important requisite for this process is the existence of larger between- than within-emitter signal variation. Acoustic signals are complex traits susceptible of variation in their spectral and temporal components, implying that signal distinctiveness can result from differences in single or various acoustic components. In this study, domestic chinchillas were induced to vocalize in a distress context to describe the acoustic characteristics of the bark calls, and to determine features that denote the potential value of this vocalization for individual and/or sexual recognition. The results demonstrate that the variation in spectral and temporal components of the bark calls of chinchillas elicited under a distress context is larger between than within individuals, suggesting the potential of these signals for distinctiveness between individual signalers, although the potential of this call type for sex distinctiveness is quite limited. These results combined with previous studies on auditory capabilities of chinchillas contribute to position this rodent as a valuable model species for studying auditory-vocal interactions.
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Affiliation(s)
- Felipe N Moreno-Gómez
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 70005, Correo 7, Santiago, Chile
| | - Alex León
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 70005, Correo 7, Santiago, Chile
| | - Nelson A Velásquez
- Departamento de Biología y Química, Facultad de Ciencias Básicas, Universidad Católica del Maule, Casilla 617, Talca, Chile
| | - Mario Penna
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 70005, Correo 7, Santiago, Chile
| | - Paul H Delano
- Programa de Fisiología y Biofísica, Instituto de Ciencias Biomédicas, Facultad de Medicina, Universidad de Chile, Casilla 70005, Correo 7, Santiago, Chile
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Aedo C, Tapia E, Pavez E, Elgueda D, Delano PH, Robles L. Stronger efferent suppression of cochlear neural potentials by contralateral acoustic stimulation in awake than in anesthetized chinchilla. Front Syst Neurosci 2015; 9:21. [PMID: 25784861 PMCID: PMC4345911 DOI: 10.3389/fnsys.2015.00021] [Citation(s) in RCA: 21] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2014] [Accepted: 02/08/2015] [Indexed: 11/18/2022] Open
Abstract
There are two types of sensory cells in the mammalian cochlea, inner hair cells, which make synaptic contact with auditory-nerve afferent fibers, and outer hair cells that are innervated by crossed and uncrossed medial olivocochlear (MOC) efferent fibers. Contralateral acoustic stimulation activates the uncrossed efferent MOC fibers reducing cochlear neural responses, thus modifying the input to the central auditory system. The chinchilla, among all studied mammals, displays the lowest percentage of uncrossed MOC fibers raising questions about the strength and frequency distribution of the contralateral-sound effect in this species. On the other hand, MOC effects on cochlear sensitivity have been mainly studied in anesthetized animals and since the MOC-neuron activity depends on the level of anesthesia, it is important to assess the influence of anesthesia in the strength of efferent effects. Seven adult chinchillas (Chinchilla laniger) were chronically implanted with round-window electrodes in both cochleae. We compared the effect of contralateral sound in awake and anesthetized condition. Compound action potentials (CAP) and cochlear microphonics (CM) were measured in the ipsilateral cochlea in response to tones in absence and presence of contralateral sound. Control measurements performed after middle-ear muscles section in one animal discarded any possible middle-ear reflex activation. Contralateral sound produced CAP amplitude reductions in all chinchillas, with suppression effects greater by about 1–3 dB in awake than in anesthetized animals. In contrast, CM amplitude increases of up to 1.9 dB were found in only three awake chinchillas. In both conditions the strongest efferent effects were produced by contralateral tones at frequencies equal or close to those of ipsilateral tones. Contralateral CAP suppressions for 1–6 kHz ipsilateral tones corresponded to a span of uncrossed MOC fiber innervation reaching at least the central third of the chinchilla cochlea.
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Affiliation(s)
- Cristian Aedo
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile Santiago, Chile ; Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile Santiago, RM, Chile
| | - Eduardo Tapia
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile Santiago, Chile ; Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile Santiago, RM, Chile
| | - Elizabeth Pavez
- Departamento de Tecnología Médica, Facultad de Medicina, Universidad de Chile Santiago, Chile ; Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile Santiago, RM, Chile
| | - Diego Elgueda
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile Santiago, RM, Chile
| | - Paul H Delano
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile Santiago, RM, Chile ; Departamento de Otorrinolaringología, Hospital Clínico, Universidad de Chile Santiago, Chile
| | - Luis Robles
- Programa de Fisiología y Biofísica, ICBM, Facultad de Medicina, Universidad de Chile Santiago, RM, Chile
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The olivocochlear reflex strength and cochlear sensitivity are independently modulated by auditory cortex microstimulation. J Assoc Res Otolaryngol 2015; 16:223-40. [PMID: 25663383 DOI: 10.1007/s10162-015-0509-9] [Citation(s) in RCA: 48] [Impact Index Per Article: 5.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/15/2014] [Accepted: 01/21/2015] [Indexed: 12/20/2022] Open
Abstract
In mammals, efferent projections to the cochlear receptor are constituted by olivocochlear (OC) fibers that originate in the superior olivary complex. Medial and lateral OC neurons make synapses with outer hair cells and with auditory nerve fibers, respectively. In addition to the OC system, there are also descending projections from the auditory cortex that are directed towards the thalamus, inferior colliculus, cochlear nucleus, and superior olivary complex. Olivocochlear function can be assessed by measuring a brainstem reflex mediated by auditory nerve fibers, cochlear nucleus neurons, and OC fibers. Although it is known that the OC reflex is activated by contralateral acoustic stimulation and produces a suppression of cochlear responses, the influence of cortical descending pathways in the OC reflex is largely unknown. Here, we used auditory cortex electrical microstimulation in chinchillas to study a possible cortical modulation of cochlear and auditory nerve responses to tones in the absence and presence of contralateral noise. We found that cortical microstimulation produces two different peripheral modulations: (i) changes in cochlear sensitivity evidenced by amplitude modulation of cochlear microphonics and auditory nerve compound action potentials and (ii) enhancement or suppression of the OC reflex strength as measured by auditory nerve responses, which depended on the intersubject variability of the OC reflex. Moreover, both corticofugal effects were not correlated, suggesting the presence of two functionally different efferent pathways. These results demonstrate that auditory cortex electrical microstimulation independently modulates the OC reflex strength and cochlear sensitivity.
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Lamas V, Arévalo JC, Juiz JM, Merchán MA. Acoustic input and efferent activity regulate the expression of molecules involved in cochlear micromechanics. Front Syst Neurosci 2015; 8:253. [PMID: 25653600 PMCID: PMC4299405 DOI: 10.3389/fnsys.2014.00253] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/21/2014] [Accepted: 12/24/2014] [Indexed: 11/13/2022] Open
Abstract
Electromotile activity in auditory outer hair cells (OHCs) is essential for sound amplification. It relies on the highly specialized membrane motor protein prestin, and its interactions with the cytoskeleton. It is believed that the expression of prestin and related molecules involved in OHC electromotility may be dynamically regulated by signals from the acoustic environment. However little is known about the nature of such signals and how they affect the expression of molecules involved in electromotility in OHCs. We show evidence that prestin oligomerization is regulated, both at short and relatively long term, by acoustic input and descending efferent activity originating in the cortex, likely acting in concert. Unilateral removal of the middle ear ossicular chain reduces levels of trimeric prestin, particularly in the cochlea from the side of the lesion, whereas monomeric and dimeric forms are maintained or even increased in particular in the contralateral side, as shown in Western blots. Unilateral removal of the auditory cortex (AC), which likely causes an imbalance in descending efferent activity on the cochlea, also reduces levels of trimeric and tetrameric forms of prestin in the side ipsilateral to the lesion, whereas in the contralateral side prestin remains unaffected, or even increased in the case of trimeric and tetrameric forms. As far as efferent inputs are concerned, unilateral ablation of the AC up-regulates the expression of α10 nicotinic Ach receptor (nAChR) transcripts in the cochlea, as shown by RT-Quantitative real-time PCR (qPCR). This suggests that homeostatic synaptic scaling mechanisms may be involved in dynamically regulating OHC electromotility by medial olivocochlear efferents. Limited, unbalanced efferent activity after unilateral AC removal, also affects prestin and β-actin mRNA levels. These findings support that the concerted action of acoustic and efferent inputs to the cochlea is needed to regulate the expression of major molecules involved in OHC electromotility, both at the transcriptional and posttranscriptional levels.
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Affiliation(s)
- Veronica Lamas
- Laboratory of Neurobiology of Hearing, Institute for Neuroscience of Castilla y Leon, University of Salamanca Salamanca, Spain
| | - Juan C Arévalo
- Laboratory of Neurobiology of Hearing, Institute for Neuroscience of Castilla y Leon, University of Salamanca Salamanca, Spain
| | - José M Juiz
- Facultad de Medicina de Albacete, Instituto de Investigación en Discapacidades Neurológicas (IDINE), Universidad de Castilla La Mancha Albacete, Spain
| | - Miguel A Merchán
- Laboratory of Neurobiology of Hearing, Institute for Neuroscience of Castilla y Leon, University of Salamanca Salamanca, Spain
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Srinivasan S, Keil A, Stratis K, Osborne AF, Cerwonka C, Wong J, Rieger BL, Polcz V, Smith DW. Interaural attention modulates outer hair cell function. Eur J Neurosci 2014; 40:3785-92. [PMID: 25302959 DOI: 10.1111/ejn.12746] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2014] [Revised: 09/03/2014] [Accepted: 09/05/2014] [Indexed: 11/27/2022]
Abstract
Mounting evidence suggests that auditory attention tasks may modulate the sensitivity of the cochlea by way of the corticofugal and the medial olivocochlear (MOC) efferent pathways. Here, we studied the extent to which a separate efferent tract, the 'uncrossed' MOC, which functionally connects the two ears, mediates inter-aural selective attention. We compared distortion product otoacoustic emissions (DPOAEs) in one ear with binaurally presented primaries, using an intermodal target detection task in which participants were instructed to report the occurrence of brief target events (visual changes, tones). Three tasks were compared under identical physical stimulation: (i) report brief tones in the ear in which DPOAE responses were recorded; (ii) report brief tones presented to the contralateral, non-recorded ear; and (iii) report brief phase shifts of a visual grating at fixation. Effects of attention were observed as parallel shifts in overall DPOAE contour level, with DPOAEs relatively higher in overall level when subjects ignored the auditory stimuli and attended to the visual stimulus, compared with both of the auditory-attending conditions. Importantly, DPOAE levels were statistically lowest when attention was directed to the ipsilateral ear in which the DPOAE recordings were made. These data corroborate notions that top-down mechanisms, via the corticofugal and medial efferent pathways, mediate cochlear responses during intermodal attention. New findings show attending to one ear can significantly alter the physiological response of the contralateral, unattended ear, probably through the uncrossed-medial olivocochlear efferent fibers connecting the two ears.
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Affiliation(s)
- Sridhar Srinivasan
- Program in Behavioral and Cognitive Neuroscience, Department of Psychology, University of Florida, Gainesville, FL, 32611, USA
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Masking level differences--a diffusion tensor imaging and functional MRI study. PLoS One 2014; 9:e88466. [PMID: 24558392 PMCID: PMC3928251 DOI: 10.1371/journal.pone.0088466] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/22/2013] [Accepted: 01/07/2014] [Indexed: 11/26/2022] Open
Abstract
In our previous study we investigated Masking Level Differences (MLD) using functional Magnetic Resonance Imaging (fMRI), but were unable to confirm neural correlations for the MLD within the auditory cortex and inferior colliculus. Here we have duplicated conditions from our previous study, but have included more participants and changed the study site to a new location with a newer scanner and presentation system. Additionally, Diffusion Tensor Imaging (DTI) is included to allow investigation of fiber tracts that may be involved with MLDs. Twenty participants were included and underwent audiometric testing and MRI scanning. The current study revealed regions of increased and decreased activity within the auditory cortex when comparing the combined noise and signal of the dichotic MLD stimuli (N0Sπ and NπS0) with N0S0. Furthermore, we found evidence of inferior colliculus involvement. Our DTI findings show strong correlations between DTI measures within the brainstem and signal detection threshold levels. Patterns of correlation when the signal was presented only to the right ear showed an extensive network in the left hemisphere; however, the opposite was not true for the signal presented only to the left ear. Our current study was able to confirm what we had previously hypothesized using fMRI, while extending our investigation of MLDs to include the characteristics of connecting neural pathways.
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Shastri U, Mythri HM, Kumar UA. Descending auditory pathway and identification of phonetic contrast by native listeners. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2014; 135:896-905. [PMID: 25234897 DOI: 10.1121/1.4861350] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The present study investigated the ability of native listeners to identify subtle phonetic contrasts in nonsense words and its relationship with the contralateral inhibition of transient evoked otoacoustic emissions (TEOAE). A group of 45 young adults with normal hearing sensitivity who were native speakers of Malayalam participated in the behavioral experiment. Phone identification score and reaction time for four phonetic pairs in nonsense words were measured for each participant. Based on the phone identification score, the participants were divided into high and low performers. Twelve participants randomly selected from each group were evaluated for contralateral inhibition of TEOAEs. Phone identification score and global contralateral inhibition amplitude of TEOAE were significantly higher and reaction time was significantly shorter in high performers than that of low performers. Significant correlation was found between the phone identification score and contralateral inhibition of TEOAE. Strength of the medial olivocochlear bundle activity explained about 30% of the variance in the phone identification scores providing evidence for the involvement of the descending auditory pathways in identifying the phonetic contrasts that are acoustically similar. These results support the emerging view that top down influences from higher centers shapes the responses of lower centers.
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Affiliation(s)
- Usha Shastri
- Department of Audiology, All India Institute of Speech and Hearing, Mysore 570 006, Karnataka, India
| | - H M Mythri
- Department of Audiology, All India Institute of Speech and Hearing, Mysore 570 006, Karnataka, India
| | - U Ajith Kumar
- Department of Audiology, All India Institute of Speech and Hearing, Mysore 570 006, Karnataka, India
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Antunes FM, Malmierca MS. An Overview of Stimulus-Specific Adaptation in the Auditory Thalamus. Brain Topogr 2013; 27:480-99. [DOI: 10.1007/s10548-013-0342-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/01/2013] [Accepted: 12/05/2013] [Indexed: 12/30/2022]
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Lamas V, Alvarado JC, Carro J, Merchán MA. Long-term evolution of brainstem electrical evoked responses to sound after restricted ablation of the auditory cortex. PLoS One 2013; 8:e73585. [PMID: 24066057 PMCID: PMC3774800 DOI: 10.1371/journal.pone.0073585] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2013] [Accepted: 07/25/2013] [Indexed: 11/19/2022] Open
Abstract
INTRODUCTION This study aimed to assess the top-down control of sound processing in the auditory brainstem of rats. Short latency evoked responses were analyzed after unilateral or bilateral ablation of auditory cortex. This experimental paradigm was also used towards analyzing the long-term evolution of post-lesion plasticity in the auditory system and its ability to self-repair. METHOD Auditory cortex lesions were performed in rats by stereotactically guided fine-needle aspiration of the cerebrocortical surface. Auditory Brainstem Responses (ABR) were recorded at post-surgery day (PSD) 1, 7, 15 and 30. Recordings were performed under closed-field conditions, using click trains at different sound intensity levels, followed by statistical analysis of threshold values and ABR amplitude and latency variables. Subsequently, brains were sectioned and immunostained for GAD and parvalbumin to assess the location and extent of lesions accurately. RESULTS Alterations in ABR variables depended on the type of lesion and post-surgery time of ABR recordings. Accordingly, bilateral ablations caused a statistically significant increase in thresholds at PSD1 and 7 and a decrease in waves amplitudes at PSD1 that recover at PSD7. No effects on latency were noted at PSD1 and 7, whilst recordings at PSD15 and 30 showed statistically significant decreases in latency. Conversely, unilateral ablations had no effect on auditory thresholds or latencies, while wave amplitudes only decreased at PSD1 strictly in the ipsilateral ear. CONCLUSION Post-lesion plasticity in the auditory system acts in two time periods: short-term period of decreased sound sensitivity (until PSD7), most likely resulting from axonal degeneration; and a long-term period (up to PSD7), with changes in latency responses and recovery of thresholds and amplitudes values. The cerebral cortex may have a net positive gain on the auditory pathway response to sound.
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Affiliation(s)
- Verónica Lamas
- Instituto de Neurociencias de Castilla y León, Universidad de Salamanca, Salamanca, Spain
| | - Juan C. Alvarado
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina de Albacete, Universidad de castilla-La Mancha, Campus in Albacete, Albacete, Spain
| | - Juan Carro
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina de Albacete, Universidad de castilla-La Mancha, Campus in Albacete, Albacete, Spain
| | - Miguel A. Merchán
- Instituto de Investigación en Discapacidades Neurológicas (IDINE), Facultad de Medicina de Albacete, Universidad de castilla-La Mancha, Campus in Albacete, Albacete, Spain
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Perrot X, Collet L. Function and plasticity of the medial olivocochlear system in musicians: a review. Hear Res 2013; 308:27-40. [PMID: 23994434 DOI: 10.1016/j.heares.2013.08.010] [Citation(s) in RCA: 34] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/23/2013] [Revised: 08/11/2013] [Accepted: 08/21/2013] [Indexed: 10/26/2022]
Abstract
The outer hair cells of the organ of Corti are the target of abundant efferent projections from the olivocochlear system. This peripheral efferent auditory subsystem is currently thought to be modulated by central activity via corticofugal descending auditory system, and to modulate active cochlear micromechanics. Although the function of this efferent subsystem remains unclear, physiological, psychophysical, and modeling data suggest that it may be involved in ear protection against noise damage and auditory perception, especially in the presence of background noise. Moreover, there is mounting evidence that its activity is modulated by auditory and visual attention. A commonly used approach to measure olivocochlear activity noninvasively in humans relies on the suppression of otoacoustic emissions by contralateral noise. Previous studies have found substantial interindividual variability in this effect, and statistical differences have been observed between professional musicians and non-musicians, with stronger bilateral suppression effects in the former. In this paper, we review these studies and discuss various possible interpretations for these findings, including experience-dependent neuroplasticity. We ask whether differences in olivocochlear function between musicians and non-musicians reflect differences in peripheral auditory function or in more central factors, such as top-down attentional modulation.
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Affiliation(s)
- Xavier Perrot
- Université de Lyon, Lyon F-69000, France; INSERM U1028, CNRS UMR5292, Université Lyon 1, Lyon Neuroscience Research Center, Brain Dynamics and Cognition Team, Lyon F-69000, France; Claude Bernard Lyon 1 University, Lyon F-69500, France; Hospices Civils de Lyon, Lyon Sud Teaching Hospital, Department of Audiology and Orofacial Explorations, Pierre-Bénite F-69310, France.
| | - Lionel Collet
- Université de Lyon, Lyon F-69000, France; INSERM U1028, CNRS UMR5292, Université Lyon 1, Lyon Neuroscience Research Center, Brain Dynamics and Cognition Team, Lyon F-69000, France; Claude Bernard Lyon 1 University, Lyon F-69500, France; Hospices Civils de Lyon, Lyon Sud Teaching Hospital, Department of Audiology and Orofacial Explorations, Pierre-Bénite F-69310, France.
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