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Choi MH, Li N, Popelka G, Butts Pauly K. Development and validation of a computational method to predict unintended auditory brainstem response during transcranial ultrasound neuromodulation in mice. Brain Stimul 2023; 16:1362-1370. [PMID: 37690602 DOI: 10.1016/j.brs.2023.09.004] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/20/2023] [Revised: 08/03/2023] [Accepted: 09/06/2023] [Indexed: 09/12/2023] Open
Abstract
BACKGROUND Transcranial ultrasound stimulation (TUS) is a promising noninvasive neuromodulation modality. The inadvertent and unpredictable activation of the auditory system in response to TUS obfuscates the interpretation of non-auditory neuromodulatory responses. OBJECTIVE The objective was to develop and validate a computational metric to quantify the susceptibility to unintended auditory brainstem response (ABR) in mice premised on time frequency analyses of TUS signals and auditory sensitivity. METHODS Ultrasound pulses with varying amplitudes, pulse repetition frequencies (PRFs), envelope smoothing profiles, and sinusoidal modulation frequencies were selected. Each pulse's time-varying frequency spectrum was differentiated across time, weighted by the mouse hearing sensitivity, then summed across frequencies. The resulting time-varying function, computationally predicting the ABR, was validated against experimental ABR in mice during TUS with the corresponding pulse. RESULTS There was a significant correlation between experimental ABRs and the computational predictions for 19 TUS signals (R2 = 0.97). CONCLUSIONS To reduce ABR in mice during in vivo TUS studies, 1) reduce the amplitude of a rectangular continuous wave envelope, 2) increase the rise/fall times of a smoothed continuous wave envelope, and/or 3) change the PRF and/or duty cycle of a rectangular or sinusoidal pulsed wave to reduce the gap between pulses and increase the rise/fall time of the overall envelope. This metric can aid researchers performing in vivo mouse studies in selecting TUS signal parameters that minimize unintended ABR. The methods for developing this metric can be adapted to other animal models.
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Affiliation(s)
- Mi Hyun Choi
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA.
| | - Ningrui Li
- Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA
| | - Gerald Popelka
- Department of Otolaryngology, Stanford School of Medicine, Stanford, CA, 94305, USA; Department of Radiology, Stanford School of Medicine, Stanford, CA, 94305, USA
| | - Kim Butts Pauly
- Department of Bioengineering, Stanford University, Stanford, CA, 94305, USA; Department of Electrical Engineering, Stanford University, Stanford, CA, 94305, USA; Department of Radiology, Stanford School of Medicine, Stanford, CA, 94305, USA.
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Simon JZ, Commuri V, Kulasingham JP. Time-locked auditory cortical responses in the high-gamma band: A window into primary auditory cortex. Front Neurosci 2022; 16:1075369. [PMID: 36570848 PMCID: PMC9773383 DOI: 10.3389/fnins.2022.1075369] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 11/24/2022] [Indexed: 12/13/2022] Open
Abstract
Primary auditory cortex is a critical stage in the human auditory pathway, a gateway between subcortical and higher-level cortical areas. Receiving the output of all subcortical processing, it sends its output on to higher-level cortex. Non-invasive physiological recordings of primary auditory cortex using electroencephalography (EEG) and magnetoencephalography (MEG), however, may not have sufficient specificity to separate responses generated in primary auditory cortex from those generated in underlying subcortical areas or neighboring cortical areas. This limitation is important for investigations of effects of top-down processing (e.g., selective-attention-based) on primary auditory cortex: higher-level areas are known to be strongly influenced by top-down processes, but subcortical areas are often assumed to perform strictly bottom-up processing. Fortunately, recent advances have made it easier to isolate the neural activity of primary auditory cortex from other areas. In this perspective, we focus on time-locked responses to stimulus features in the high gamma band (70-150 Hz) and with early cortical latency (∼40 ms), intermediate between subcortical and higher-level areas. We review recent findings from physiological studies employing either repeated simple sounds or continuous speech, obtaining either a frequency following response (FFR) or temporal response function (TRF). The potential roles of top-down processing are underscored, and comparisons with invasive intracranial EEG (iEEG) and animal model recordings are made. We argue that MEG studies employing continuous speech stimuli may offer particular benefits, in that only a few minutes of speech generates robust high gamma responses from bilateral primary auditory cortex, and without measurable interference from subcortical or higher-level areas.
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Affiliation(s)
- Jonathan Z. Simon
- Department of Electrical and Computer Engineering, University of Maryland, College Park, College Park, MD, United States,Department of Biology, University of Maryland, College Park, College Park, MD, United States,Institute for Systems Research, University of Maryland, College Park, College Park, MD, United States,*Correspondence: Jonathan Z. Simon,
| | - Vrishab Commuri
- Department of Electrical and Computer Engineering, University of Maryland, College Park, College Park, MD, United States
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McChesney N, Barth JL, Rumschlag JA, Tan J, Harrington AJ, Noble KV, McClaskey CM, Elvis P, Vaena SG, Romeo MJ, Harris KC, Cowan CW, Lang H. Peripheral Auditory Nerve Impairment in a Mouse Model of Syndromic Autism. J Neurosci 2022; 42:8002-8018. [PMID: 36180228 PMCID: PMC9617620 DOI: 10.1523/jneurosci.0253-22.2022] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Revised: 07/27/2022] [Accepted: 08/13/2022] [Indexed: 11/21/2022] Open
Abstract
Dysfunction of the peripheral auditory nerve (AN) contributes to dynamic changes throughout the central auditory system, resulting in abnormal auditory processing, including hypersensitivity. Altered sound sensitivity is frequently observed in autism spectrum disorder (ASD), suggesting that AN deficits and changes in auditory information processing may contribute to ASD-associated symptoms, including social communication deficits and hyperacusis. The MEF2C transcription factor is associated with risk for several neurodevelopmental disorders, and mutations or deletions of MEF2C produce a haploinsufficiency syndrome characterized by ASD, language, and cognitive deficits. A mouse model of this syndromic ASD (Mef2c-Het) recapitulates many of the MEF2C haploinsufficiency syndrome-linked behaviors, including communication deficits. We show here that Mef2c-Het mice of both sexes exhibit functional impairment of the peripheral AN and a modest reduction in hearing sensitivity. We find that MEF2C is expressed during development in multiple AN and cochlear cell types; and in Mef2c-Het mice, we observe multiple cellular and molecular alterations associated with the AN, including abnormal myelination, neuronal degeneration, neuronal mitochondria dysfunction, and increased macrophage activation and cochlear inflammation. These results reveal the importance of MEF2C function in inner ear development and function and the engagement of immune cells and other non-neuronal cells, which suggests that microglia/macrophages and other non-neuronal cells might contribute, directly or indirectly, to AN dysfunction and ASD-related phenotypes. Finally, our study establishes a comprehensive approach for characterizing AN function at the physiological, cellular, and molecular levels in mice, which can be applied to animal models with a wide range of human auditory processing impairments.SIGNIFICANCE STATEMENT This is the first report of peripheral auditory nerve (AN) impairment in a mouse model of human MEF2C haploinsufficiency syndrome that has well-characterized ASD-related behaviors, including communication deficits, hyperactivity, repetitive behavior, and social deficits. We identify multiple underlying cellular, subcellular, and molecular abnormalities that may contribute to peripheral AN impairment. Our findings also highlight the important roles of immune cells (e.g., cochlear macrophages) and other non-neuronal elements (e.g., glial cells and cells in the stria vascularis) in auditory impairment in ASD. The methodological significance of the study is the establishment of a comprehensive approach for evaluating peripheral AN function and impact of peripheral AN deficits with minimal hearing loss.
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Affiliation(s)
- Nathan McChesney
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Jeremy L Barth
- Department of Regenerative Medicine and Cell Biology, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Jeffrey A Rumschlag
- Department of Otolaryngology & Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Junying Tan
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Adam J Harrington
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kenyaria V Noble
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Carolyn M McClaskey
- Department of Otolaryngology & Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Phillip Elvis
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Silvia G Vaena
- Hollings Cancer Institute, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Martin J Romeo
- Hollings Cancer Institute, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Kelly C Harris
- Department of Otolaryngology & Head and Neck Surgery, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Christopher W Cowan
- Department of Neuroscience, Medical University of South Carolina, Charleston, South Carolina 29425
| | - Hainan Lang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, Charleston, South Carolina 29425
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Signatures of cochlear processing in neuronal coding of auditory information. Mol Cell Neurosci 2022; 120:103732. [PMID: 35489636 DOI: 10.1016/j.mcn.2022.103732] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2021] [Revised: 04/19/2022] [Accepted: 04/21/2022] [Indexed: 11/22/2022] Open
Abstract
The vertebrate ear is endowed with remarkable perceptual capabilities. The faintest sounds produce vibrations of magnitudes comparable to those generated by thermal noise and can nonetheless be detected through efficient amplification of small acoustic stimuli. Two mechanisms have been proposed to underlie such sound amplification in the mammalian cochlea: somatic electromotility and active hair-bundle motility. These biomechanical mechanisms may work in concert to tune auditory sensitivity. In addition to amplitude sensitivity, the hearing system shows exceptional frequency discrimination allowing mammals to distinguish complex sounds with great accuracy. For instance, although the wide hearing range of humans encompasses frequencies from 20 Hz to 20 kHz, our frequency resolution extends to one-thirtieth of the interval between successive keys on a piano. In this article, we review the different cochlear mechanisms underlying sound encoding in the auditory system, with a particular focus on the frequency decomposition of sounds. The relation between peak frequency of activation and location along the cochlea - known as tonotopy - arises from multiple gradients in biophysical properties of the sensory epithelium. Tonotopic mapping represents a major organizational principle both in the peripheral hearing system and in higher processing levels and permits the spectral decomposition of complex tones. The ribbon synapses connecting sensory hair cells to auditory afferents and the downstream spiral ganglion neurons are also tuned to process periodic stimuli according to their preferred frequency. Though sensory hair cells and neurons necessarily filter signals beyond a few kHz, many animals can hear well beyond this range. We finally describe how the cochlear structure shapes the neural code for further processing in order to send meaningful information to the brain. Both the phase-locked response of auditory nerve fibers and tonotopy are key to decode sound frequency information and place specific constraints on the downstream neuronal network.
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Bao J, Jegede SL, Hawks JW, Dade B, Guan Q, Middaugh S, Qiu Z, Levina A, Tsai TH. Detecting Cochlear Synaptopathy Through Curvature Quantification of the Auditory Brainstem Response. Front Cell Neurosci 2022; 16:851500. [PMID: 35356798 PMCID: PMC8959412 DOI: 10.3389/fncel.2022.851500] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2022] [Accepted: 02/14/2022] [Indexed: 11/13/2022] Open
Abstract
The sound-evoked electrical compound potential known as auditory brainstem response (ABR) represents the firing of a heterogenous population of auditory neurons in response to sound stimuli, and is often used for clinical diagnosis based on wave amplitude and latency. However, recent ABR applications to detect human cochlear synaptopathy have led to inconsistent results, mainly due to the high variability of ABR wave-1 amplitude. Here, rather than focusing on the amplitude of ABR wave 1, we evaluated the use of ABR wave curvature to detect cochlear synaptic loss. We first compared four curvature quantification methods using simulated ABR waves, and identified that the cubic spline method using five data points produced the most accurate quantification. We next evaluated this quantification method with ABR data from an established mouse model with cochlear synaptopathy. The data clearly demonstrated that curvature measurement is more sensitive and consistent in identifying cochlear synaptic loss in mice compared to the amplitude and latency measurements. We further tested this curvature method in a different mouse model presenting with otitis media. The change in curvature profile due to middle ear infection in otitis media is different from the profile of mice with cochlear synaptopathy. Thus, our study suggests that curvature quantification can be used to address the current ABR variability issue, and may lead to additional applications in the clinic diagnosis of hearing disorders.
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Affiliation(s)
- Jianxin Bao
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
- *Correspondence: Jianxin Bao,
| | - Segun Light Jegede
- Department of Mathematical Sciences, Kent State University, Kent, OH, United States
| | - John W. Hawks
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
| | - Bethany Dade
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
| | - Qiang Guan
- Department of Computer Science, Kent State University, Kent, OH, United States
| | - Samantha Middaugh
- Department of Anatomy and Neurobiology, Northeast Ohio Medical University, Rootstown, OH, United States
| | - Ziyu Qiu
- Department of Research and Development, Gateway Biotechnology Inc., Rootstown, OH, United States
| | - Anna Levina
- Department of Mathematical Sciences, Kent State University, Kent, OH, United States
| | - Tsung-Heng Tsai
- Department of Mathematical Sciences, Kent State University, Kent, OH, United States
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Nishimura M, Song WJ. Region-dependent Millisecond Time-scale Sensitivity in Spectrotemporal Integrations in Guinea Pig Primary Auditory Cortex. Neuroscience 2022; 480:229-245. [PMID: 34762984 DOI: 10.1016/j.neuroscience.2021.10.030] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/19/2021] [Revised: 10/28/2021] [Accepted: 10/29/2021] [Indexed: 11/18/2022]
Abstract
Spectrotemporal integration is a key function of our auditory system for discriminating spectrotemporally complex sounds, such as words. Response latency in the auditory cortex is known to change with the millisecond time-scale depending on acoustic parameters, such as sound frequency and intensity. The functional significance of the millisecond-range latency difference in the integration remains unclear. Actually, whether the auditory cortex has a sensitivity to the millisecond-range difference has not been systematically examined. Herein, we examined the sensitivity in the primary auditory cortex (A1) using voltage-sensitive dye imaging techniques in guinea pigs. Bandpass noise bursts in two different bands (band-noises), centered at 1 and 16 kHz, respectively, were used for the examination. Onset times of individual band-noises (spectral onset-times) were varied to virtually cancel or magnify the latency difference observed with the band-noises. Conventionally defined nonlinear effects in integration were analyzed at A1 with varying sound intensities (or response latencies) and/or spectral onset-times of the two band-noises. The nonlinear effect measured in the high-frequency region of the A1 linearly changed depending on the millisecond difference of the response onset-times, which were estimated from the spatially-local response latencies and spectral onset-times. In contrast, the low-frequency region of the A1 had no significant sensitivity to the millisecond difference. The millisecond-range latency difference may have functional significance in the spectrotemporal integration with the millisecond time-scale sensitivity at the high-frequency region of A1 but not at the low-frequency region.
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Affiliation(s)
- Masataka Nishimura
- Department of Sensory and Cognitive Physiology, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 8608556, Japan.
| | - Wen-Jie Song
- Department of Sensory and Cognitive Physiology, Faculty of Life Sciences, Kumamoto University, 1-1-1 Honjo, Kumamoto 8608556, Japan; Program for Leading Graduate Schools HIGO Program, Kumamoto University, Kumamoto, Japan
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Rutherford MA, von Gersdorff H, Goutman JD. Encoding sound in the cochlea: from receptor potential to afferent discharge. J Physiol 2021; 599:2527-2557. [PMID: 33644871 PMCID: PMC8127127 DOI: 10.1113/jp279189] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2020] [Accepted: 02/22/2021] [Indexed: 12/17/2022] Open
Abstract
Ribbon-class synapses in the ear achieve analog to digital transformation of a continuously graded membrane potential to all-or-none spikes. In mammals, several auditory nerve fibres (ANFs) carry information from each inner hair cell (IHC) to the brain in parallel. Heterogeneity of transmission among synapses contributes to the diversity of ANF sound-response properties. In addition to the place code for sound frequency and the rate code for sound level, there is also a temporal code. In series with cochlear amplification and frequency tuning, neural representation of temporal cues over a broad range of sound levels enables auditory comprehension in noisy multi-speaker settings. The IHC membrane time constant introduces a low-pass filter that attenuates fluctuations of the receptor potential above 1-2 kHz. The ANF spike generator adds a high-pass filter via its depolarization-rate threshold that rejects slow changes in the postsynaptic potential and its phasic response property that ensures one spike per depolarization. Synaptic transmission involves several stochastic subcellular processes between IHC depolarization and ANF spike generation, introducing delay and jitter that limits the speed and precision of spike timing. ANFs spike at a preferred phase of periodic sounds in a process called phase-locking that is limited to frequencies below a few kilohertz by both the IHC receptor potential and the jitter in synaptic transmission. During phase-locking to periodic sounds of increasing intensity, faster and facilitated activation of synaptic transmission and spike generation may be offset by presynaptic depletion of synaptic vesicles, resulting in relatively small changes in response phase. Here we review encoding of spike-timing at cochlear ribbon synapses.
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Affiliation(s)
- Mark A. Rutherford
- Department of Otolaryngology, Washington University School of Medicine, St. Louis, Missouri 63110
| | - Henrique von Gersdorff
- Vollum Institute, Oregon Hearing Research Center, Oregon Health and Sciences University, Portland, Oregon 97239
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McClaskey CM, Panganiban CH, Noble KV, Dias JW, Lang H, Harris KC. A multi-metric approach to characterizing mouse peripheral auditory nerve function using the auditory brainstem response. J Neurosci Methods 2020; 346:108937. [PMID: 32910925 PMCID: PMC7957964 DOI: 10.1016/j.jneumeth.2020.108937] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 09/03/2020] [Accepted: 09/03/2020] [Indexed: 11/30/2022]
Abstract
BACKGROUND The auditory brainstem response (ABR), specifically wave I, is widely used to noninvasively measure auditory nerve (AN) function. Recent work in humans has introduced novel electrocochleographic measures to comprehensively characterize AN function that emphasize suprathreshold processing and estimate neural synchrony. NEW METHOD This study establishes new tools for evaluating AN function in vivo in adult mice using tone-evoked ABRs obtained from young-adult CBA/CaJ mice, adapting the approach previously introduced in humans. Six metrics are obtained from ABR wave I at suprathreshold stimulus levels. RESULTS Change-point analyses show that the metrics' rate of change with stimulus level differs between moderate and high suprathreshold levels, suggesting that this approach can potentially characterize the presence of heterogeneous AN fiber types. COMPARISON WITH EXISTING METHODS Traditional ABR approaches focus on response thresholds and averaged amplitudes/latencies. In contrast, our multi-metric approach, which uses single-trial data and suprathreshold stimuli, provides novel information and identifies evidence of neural synchrony deficits and changes in the heterogeneity of AN fibers underlying AN behavior. CONCLUSION The techniques reported here provide a novel tool to assess changes in AN function in vivo in a commonly used animal model. A benchmark of most current hearing research is the transition from animal to human studies. Here we established a translational objective approach, applying methods that were first developed in humans to animals. This approach enables researchers to identify changes in AN function arising from the animal models with well-characterized pathology, and predict similar pathological changes in human AN dysfunction and hearing loss.
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Affiliation(s)
- Carolyn M McClaskey
- Department of Otolaryngology, Head & Neck Surgery, Medical University of South Carolina, 135 Rutledge Ave, MSC 550, Charleston, SC, 29425, United States.
| | - Clarisse H Panganiban
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Avenue, MSC 908, Charleston, SC, 29425, United States.
| | - Kenyaria V Noble
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Avenue, MSC 908, Charleston, SC, 29425, United States.
| | - James W Dias
- Department of Otolaryngology, Head & Neck Surgery, Medical University of South Carolina, 135 Rutledge Ave, MSC 550, Charleston, SC, 29425, United States.
| | - Hainan Lang
- Department of Pathology and Laboratory Medicine, Medical University of South Carolina, 171 Ashley Avenue, MSC 908, Charleston, SC, 29425, United States.
| | - Kelly C Harris
- Department of Otolaryngology, Head & Neck Surgery, Medical University of South Carolina, 135 Rutledge Ave, MSC 550, Charleston, SC, 29425, United States.
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Macias S, Bakshi K, Garcia-Rosales F, Hechavarria JC, Smotherman M. Temporal coding of echo spectral shape in the bat auditory cortex. PLoS Biol 2020; 18:e3000831. [PMID: 33170833 PMCID: PMC7678962 DOI: 10.1371/journal.pbio.3000831] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/22/2020] [Revised: 11/20/2020] [Accepted: 10/01/2020] [Indexed: 01/26/2023] Open
Abstract
Echolocating bats rely upon spectral interference patterns in echoes to reconstruct fine details of a reflecting object’s shape. However, the acoustic modulations required to do this are extremely brief, raising questions about how their auditory cortex encodes and processes such rapid and fine spectrotemporal details. Here, we tested the hypothesis that biosonar target shape representation in the primary auditory cortex (A1) is more reliably encoded by changes in spike timing (latency) than spike rates and that latency is sufficiently precise to support a synchronization-based ensemble representation of this critical auditory object feature space. To test this, we measured how the spatiotemporal activation patterns of A1 changed when naturalistic spectral notches were inserted into echo mimic stimuli. Neurons tuned to notch frequencies were predicted to exhibit longer latencies and lower mean firing rates due to lower signal amplitudes at their preferred frequencies, and both were found to occur. Comparative analyses confirmed that significantly more information was recoverable from changes in spike times relative to concurrent changes in spike rates. With this data, we reconstructed spatiotemporal activation maps of A1 and estimated the level of emerging neuronal spike synchrony between cortical neurons tuned to different frequencies. The results support existing computational models, indicating that spectral interference patterns may be efficiently encoded by a cascading tonotopic sequence of neural synchronization patterns within an ensemble of network activity that relates to the physical features of the reflecting object surface. Echolocating bats rely upon spectral interference patterns in echoes to reconstruct fine details of a reflecting object’s shape. This study shows that the latency shifts induced by spectral notch patterns can provide the foundation for an avalanche of neuronal synchrony that is sufficient to support encoding of auditory object shape features during active biosonar.
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Affiliation(s)
- Silvio Macias
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
- * E-mail:
| | - Kushal Bakshi
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
| | | | - Julio C. Hechavarria
- Institut für Zellbiologie und Neurowissenschaft, Goethe-Universität, Frankfurt/M., Germany
| | - Michael Smotherman
- Department of Biology, Texas A&M University, College Station, Texas, United States of America
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Finneran JJ, Mulsow J, Strahan MG, Houser DS, Burkard RF. Role of the temporal window in dolphin auditory brainstem response onset. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2020; 148:3360. [PMID: 33261407 DOI: 10.1121/10.0002703] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/17/2020] [Accepted: 11/03/2020] [Indexed: 06/12/2023]
Abstract
Auditory brainstem responses (ABRs) to linear-enveloped, broadband noisebursts were measured in six bottlenose dolphins to examine relationships between sound onset envelope properties and the ABR peak amplitude. Two stimulus manipulations were utilized: (1) stimulus onset envelope pressure rate-of-change was held constant while plateau pressure and risetime were varied and (2) plateau duration was varied while plateau pressure and risetime were held constant. When the stimulus onset envelope pressure rate-of-change was held constant, ABR amplitudes increased with risetime and were fit well with an exponential growth model. The model best-fit time constants for ABR peaks P1 and N5 were 55 and 64 μs, respectively, meaning ABRs reached 99% of their maximal amplitudes for risetimes of 275-320 μs. When plateau pressure and risetime were constant, ABR amplitudes increased linearly with stimulus sound exposure level up to durations of ∼250 μs. The results highlight the relationship between ABR amplitude and the integral of some quantity related to the stimulus pressure envelope over the first ∼250 μs following stimulus onset-a time interval consistent with prior estimates of the dolphin auditory temporal window, also known as the "critical interval" in hearing.
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Affiliation(s)
- James J Finneran
- United States Navy Marine Mammal Program, Naval Information Warfare Center Pacific Code 56710, 53560 Hull Street, San Diego, California 92152, USA
| | - Jason Mulsow
- National Marine Mammal Foundation, 2240 Shelter Island Drive Number 200, San Diego, California 92106, USA
| | - Madelyn G Strahan
- National Marine Mammal Foundation, 2240 Shelter Island Drive Number 200, San Diego, California 92106, USA
| | - Dorian S Houser
- National Marine Mammal Foundation, 2240 Shelter Island Drive Number 200, San Diego, California 92106, USA
| | - Robert F Burkard
- Department of Rehabilitation Science, University at Buffalo, 626 Kimball Tower, Buffalo, New York 14214, USA
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Egorova MA, Akimov AG, Khorunzhii GD, Ehret G. Frequency response areas of neurons in the mouse inferior colliculus. III. Time-domain responses: Constancy, dynamics, and precision in relation to spectral resolution, and perception in the time domain. PLoS One 2020; 15:e0240853. [PMID: 33104718 PMCID: PMC7588072 DOI: 10.1371/journal.pone.0240853] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/28/2020] [Accepted: 10/04/2020] [Indexed: 11/23/2022] Open
Abstract
The auditory midbrain (central nucleus of inferior colliculus, ICC) receives multiple brainstem projections and recodes auditory information for perception in higher centers. Many neural response characteristics are represented in gradients (maps) in the three-dimensional ICC space. Map overlap suggests that neurons, depending on their ICC location, encode information in several domains simultaneously by different aspects of their responses. Thus, interdependence of coding, e.g. in spectral and temporal domains, seems to be a general ICC principle. Studies on covariation of response properties and possible impact on sound perception are, however, rare. Here, we evaluated tone-evoked single neuron activity from the mouse ICC and compared shapes of excitatory frequency-response areas (including strength and shape of inhibition within and around the excitatory area; classes I, II, III) with types of temporal response patterns and first-spike response latencies. Analyses showed covariation of sharpness of frequency tuning with constancy and precision of responding to tone onsets. Highest precision (first-spike latency jitter < 1 ms) and stable phasic responses throughout frequency-response areas were the quality mainly of class III neurons with broad frequency tuning, least influenced by inhibition. Class II neurons with narrow frequency tuning and dominating inhibitory influence were unsuitable for time domain coding with high precision. The ICC center seems specialized rather for high spectral resolution (class II presence), lateral parts for constantly precise responding to sound onsets (class III presence). Further, the variation of tone-response latencies in the frequency-response areas of individual neurons with phasic, tonic, phasic-tonic, or pauser responses gave rise to the definition of a core area, which represented a time window of about 20 ms from tone onset for tone-onset responding of the whole ICC. This time window corresponds to the roughly 20 ms shortest time interval that was found critical in several auditory perceptual tasks in humans and mice.
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Affiliation(s)
- Marina A. Egorova
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Alexander G. Akimov
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Gleb D. Khorunzhii
- Sechenov Institute of Evolutionary Physiology and Biochemistry, Russian Academy of Sciences, St. Petersburg, Russia
| | - Günter Ehret
- Institute of Neurobiology, University of Ulm, Ulm, Germany
- * E-mail:
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Band-Limited Chirp-Evoked Compound Action Potential in Guinea Pig: Comprehensive Neural Measure for Cochlear Implantation Monitoring. Ear Hear 2020; 42:142-162. [PMID: 32665481 DOI: 10.1097/aud.0000000000000910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES Patients with severely impaired high-frequency hearing and sufficient residual low-frequency hearing can be provided with a cochlear implant (CI), thereby facilitating ipsilateral electric and acoustic stimulation with established advantages over electric stimulation alone. However, partial or complete hearing loss often occurred after implantation due to, inter alia, acute mechanical trauma to cochlear structures during electrode insertion. Possibilities of intraoperative monitoring using electrocochleography (ECochG) have recently been studied in CI patients, primarily using the ongoing response to low-frequency tone bursts consisting of the cochlear microphonic (CM) and the auditory nerve neurophonic. By contrast, the transient neural response to tone bursts, that is, compound action potential (CAP), was generally less detectable or less sensitive as a monitoring measure, thus falling short of providing useful contribution to electrocochleography analysis. In this study, we investigate using chirps to evoke more robust CAP responses in a limited frequency band by synchronizing neural firing, and thereby improving CAP sensitivity to mechanical trauma in a guinea pig model of cochlear implantation. DESIGN Stimuli were band-limited between 100 Hz and 10 kHz to investigate their frequency range selectivity as a preliminary model for low-frequency hearing. They were constructed by adding a harmonic series either with zero phase delay (click) or by adjusting the phase delay at a rate that is inversely related to a traveling wave delay model (chirp), with three different parameters to examine level-dependent delay compression. The amplitude spectrum was thus identical between stimuli with differences only in phase. In Experiment 1, we compared input-output functions recorded at the round window in normal-hearing guinea pigs and implemented a high-pass noise masking paradigm to infer neural contribution to the CAP. In Experiment 2, guinea pigs were implanted with a custom-built CI electrode using a motorized micromanipulator. Acute mechanical trauma was simulated during the electrode insertion. At each insertion step, CAP and CM responses were measured at the round window for the following stimuli: broad-band click, band-limited click, and band-limited chirps (3 parameters), and tone bursts at frequencies 1, 2, 4, and 8 kHz. RESULTS Chirps compared with the equal-band click showed significantly lower thresholds and steeper slopes of sigmoid-fitted input-output functions. The shorter chirp evoked significantly larger amplitudes than click when compared at equal sensation level. However, the click evoked larger amplitudes than chirps at higher levels and correspondingly achieved larger saturation amplitudes. The results of the high-pass noise masking paradigm suggest that chirps could efficiently synchronize neural firing in their targeted frequency band, while the click recruited more basal fibers outside its limited band. Finally, monitoring sensitivity during electrode insertion, defined as relative amplitude change per unit distance, was higher for chirp-evoked CAP and tone burst-evoked CM, but smaller for CAP responses evoked by clicks or tone bursts. CONCLUSION The chirp was shown to be an efficient stimulus in synchronizing neural firing for a limited frequency band in the guinea pig model. This study provides a proof of principle for using chirp-evoked CAP as a comprehensive neural measure in CI patients with residual hearing.
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Dieter A, Keppeler D, Moser T. Towards the optical cochlear implant: optogenetic approaches for hearing restoration. EMBO Mol Med 2020; 12:e11618. [PMID: 32227585 PMCID: PMC7136966 DOI: 10.15252/emmm.201911618] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2019] [Revised: 01/08/2020] [Accepted: 01/28/2020] [Indexed: 12/30/2022] Open
Abstract
Cochlear implants (CIs) are considered the most successful neuroprosthesis as they enable speech comprehension in the majority of half a million CI users suffering from sensorineural hearing loss. By electrically stimulating the auditory nerve, CIs constitute an interface re-connecting the brain and the auditory scene, providing the patient with information regarding the latter. However, since electric current is hard to focus in conductive environments such as the cochlea, the precision of electrical sound encoding-and thus quality of artificial hearing-is limited. Recently, optogenetic stimulation of the cochlea has been suggested as an alternative approach for hearing restoration. Cochlear optogenetics promises increased spectral selectivity of artificial sound encoding, hence improved hearing, as light can conveniently be confined in space to activate the auditory nerve within smaller tonotopic ranges. In this review, we discuss the latest experimental and technological developments of cochlear optogenetics and outline the remaining challenges on the way to clinical translation.
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Affiliation(s)
- Alexander Dieter
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Göttingen Graduate School for Neurosciences, Biophysics and Molecular Biosciences, University of Göttingen, Göttingen, Germany
| | - Daniel Keppeler
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany
| | - Tobias Moser
- Institute for Auditory Neuroscience and InnerEarLab, University Medical Center Göttingen, Göttingen, Germany.,Auditory Neuroscience and Optogenetics Laboratory, German Primate Center, Göttingen, Germany.,Auditory Neuroscience Group, Max Planck Institute of Experimental Medicine, Göttingen, Germany.,Cluster of Excellence "Multiscale Bioimaging: from Molecular Machines to Networks of Excitable Cells" (MBExC), University of Göttingen, Göttingen, Germany
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14
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Zulfiqar I, Moerel M, Formisano E. Spectro-Temporal Processing in a Two-Stream Computational Model of Auditory Cortex. Front Comput Neurosci 2020; 13:95. [PMID: 32038212 PMCID: PMC6987265 DOI: 10.3389/fncom.2019.00095] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2019] [Accepted: 12/23/2019] [Indexed: 12/14/2022] Open
Abstract
Neural processing of sounds in the dorsal and ventral streams of the (human) auditory cortex is optimized for analyzing fine-grained temporal and spectral information, respectively. Here we use a Wilson and Cowan firing-rate modeling framework to simulate spectro-temporal processing of sounds in these auditory streams and to investigate the link between neural population activity and behavioral results of psychoacoustic experiments. The proposed model consisted of two core (A1 and R, representing primary areas) and two belt (Slow and Fast, representing rostral and caudal processing respectively) areas, differing in terms of their spectral and temporal response properties. First, we simulated the responses to amplitude modulated (AM) noise and tones. In agreement with electrophysiological results, we observed an area-dependent transition from a temporal (synchronization) to a rate code when moving from low to high modulation rates. Simulated neural responses in a task of amplitude modulation detection suggested that thresholds derived from population responses in core areas closely resembled those of psychoacoustic experiments in human listeners. For tones, simulated modulation threshold functions were found to be dependent on the carrier frequency. Second, we simulated the responses to complex tones with missing fundamental stimuli and found that synchronization of responses in the Fast area accurately encoded pitch, with the strength of synchronization depending on number and order of harmonic components. Finally, using speech stimuli, we showed that the spectral and temporal structure of the speech was reflected in parallel by the modeled areas. The analyses highlighted that the Slow stream coded with high spectral precision the aspects of the speech signal characterized by slow temporal changes (e.g., prosody), while the Fast stream encoded primarily the faster changes (e.g., phonemes, consonants, temporal pitch). Interestingly, the pitch of a speaker was encoded both spatially (i.e., tonotopically) in Slow area and temporally in Fast area. Overall, performed simulations showed that the model is valuable for generating hypotheses on how the different cortical areas/streams may contribute toward behaviorally relevant aspects of auditory processing. The model can be used in combination with physiological models of neurovascular coupling to generate predictions for human functional MRI experiments.
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Affiliation(s)
- Isma Zulfiqar
- Maastricht Centre for Systems Biology, Maastricht University, Maastricht, Netherlands
| | - Michelle Moerel
- Maastricht Centre for Systems Biology, Maastricht University, Maastricht, Netherlands.,Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands.,Maastricht Brain Imaging Center, Maastricht, Netherlands
| | - Elia Formisano
- Maastricht Centre for Systems Biology, Maastricht University, Maastricht, Netherlands.,Department of Cognitive Neuroscience, Faculty of Psychology and Neuroscience, Maastricht University, Maastricht, Netherlands.,Maastricht Brain Imaging Center, Maastricht, Netherlands
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15
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Macias S, Bakshi K, Smotherman M. Laminar Organization of FM Direction Selectivity in the Primary Auditory Cortex of the Free-Tailed Bat. Front Neural Circuits 2019; 13:76. [PMID: 31827425 PMCID: PMC6890848 DOI: 10.3389/fncir.2019.00076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/13/2019] [Indexed: 01/18/2023] Open
Abstract
We studied the columnar and layer-specific response properties of neurons in the primary auditory cortex (A1) of six (four females, two males) anesthetized free-tailed bats, Tadarida brasiliensis, in response to pure tones and down and upward frequency modulated (FM; 50 kHz bandwidth) sweeps. In addition, we calculated current source density (CSD) to test whether lateral intracortical projections facilitate neuronal activation in response to FM echoes containing spectrally distant frequencies from the excitatory frequency response area (FRA). Auditory responses to a set of stimuli changing in frequency and level were recorded along 64 penetrations in the left A1 of six free-tailed bats. FRA shapes were consistent across the cortical depth within a column and there were no obvious differences in tuning properties. Generally, response latencies were shorter (<10 ms) for cortical depths between 500 and 600 μm, which might correspond to thalamocortical input layers IIIb-IV. Most units showed a stronger response to downward FM sweeps, and direction selectivity did not vary across cortical depth. CSD profiles calculated in response to the CF showed a current sink located at depths between 500 and 600 μm. Frequencies lower than the frequency range eliciting a spike response failed to evoke any visible current sink. Frequencies higher than the frequency range producing a spike response evoked layer IV sinks at longer latencies that increased with spectral distance. These data support the hypothesis that a progressive downward relay of spectral information spreads along the tonotopic axis of A1 via lateral connections, contributing to the neural processing of FM down sweeps used in biosonar.
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Affiliation(s)
- Silvio Macias
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Kushal Bakshi
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Michael Smotherman
- Department of Biology, Texas A&M University, College Station, TX, United States
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16
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Van Canneyt J, Hofmann M, Wouters J, Francart T. The effect of stimulus envelope shape on the auditory steady-state response. Hear Res 2019; 380:22-34. [DOI: 10.1016/j.heares.2019.05.007] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/09/2018] [Revised: 04/23/2019] [Accepted: 05/23/2019] [Indexed: 01/01/2023]
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17
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Jones R, Finneran JJ, Mulsow J, Burkard RF. Effects of stimulus cosine onset properties on bottlenose dolphin (Tursiops truncatus) auditory brainstem responses. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 145:2994. [PMID: 31153333 DOI: 10.1121/1.5108613] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 04/25/2019] [Indexed: 06/09/2023]
Abstract
Although the auditory brainstem response (ABR) is known to be an onset response, the specific relationship between stimulus onset properties and the resulting ABR is not well understood. In this study, the effects of stimulus onset on dolphin ABR were examined by measuring ABRs in six bottlenose dolphins while systematically manipulating rise time and plateau sound pressure of cosine-enveloped noise bursts. Noise bursts were spectrally "pink" with frequency content from 10 to 160 kHz, rise times from 32 μs to 4 ms, and plateau sound pressure levels from 102 to 138 dB re 1 μPa. Envelope rise time and plateau sound pressure alone were found to be poor predictors for ABR peak amplitudes and latencies. Peak amplitudes were well described by the envelope sound pressure at the end of a 260-μs window; however, best-fits to the data across ABR peaks were obtained when the window start time was allowed to vary. Peak latencies were best described by the maximum value of the second derivative of the pressure envelope. These results are consistent with single-unit and nearfield response data for terrestrial mammals and indicate that stimuli with rise times greater than 260 μs are non-optimal with respect to maximizing ABR amplitudes.
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Affiliation(s)
- Ryan Jones
- National Marine Mammal Foundation, 2240 Shelter Island Drive #200, San Diego, California 92106, USA
| | - James J Finneran
- US Navy Marine Mammal Program, Naval Information Warfare Center Pacific, Code 56710, 53560 Hull Street, San Diego, California 92152, USA
| | - Jason Mulsow
- National Marine Mammal Foundation, 2240 Shelter Island Drive #200, San Diego, California 92106, USA
| | - Robert F Burkard
- Department of Rehabilitation Science, University of Buffalo, 626 Kimball Tower, Buffalo, New York 14214, USA
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18
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Phase Locking of Auditory-Nerve Fibers Reveals Stereotyped Distortions and an Exponential Transfer Function with a Level-Dependent Slope. J Neurosci 2019; 39:4077-4099. [PMID: 30867259 DOI: 10.1523/jneurosci.1801-18.2019] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/16/2018] [Revised: 02/28/2019] [Accepted: 03/07/2019] [Indexed: 12/16/2022] Open
Abstract
Phase locking of auditory-nerve-fiber (ANF) responses to the fine structure of acoustic stimuli is a hallmark of the auditory system's temporal precision and is important for many aspects of hearing. Period histograms from phase-locked ANF responses to low-frequency tones exhibit spike-rate and temporal asymmetries, but otherwise retain an approximately sinusoidal shape as stimulus level increases, even beyond the level at which the mean spike rate saturates. This is intriguing because apical cochlear mechanical vibrations show little compression, and mechanoelectrical transduction in the receptor cells is thought to obey a static sigmoidal nonlinearity, which might be expected to produce peak clipping at moderate and high stimulus levels. Here we analyze phase-locked responses of ANFs from cats of both sexes. We show that the lack of peak clipping is due neither to ANF refractoriness nor to spike-rate adaptation on time scales longer than the stimulus period. We demonstrate that the relationship between instantaneous pressure and instantaneous rate is well described by an exponential function whose slope decreases with increasing stimulus level. Relatively stereotyped harmonic distortions in the input to the exponential can account for the temporal asymmetry of the period histograms, including peak splitting. We show that the model accounts for published membrane-potential waveforms when assuming a power-of-three, but not a power-of-one, relationship to exocytosis. Finally, we demonstrate the relationship between the exponential transfer functions and the sigmoidal pseudotransducer functions obtained in the literature by plotting the maxima and minima of the voltage responses against the maxima and minima of the stimuli.SIGNIFICANCE STATEMENT Phase locking of auditory-nerve-fiber responses to the temporal fine structure of acoustic stimuli is important for many aspects of hearing, but the mechanisms underlying phase locking are not fully understood. Intriguingly, period histograms retain an approximately sinusoidal shape across sound levels, even when the mean rate has saturated. We find that neither refractoriness nor spike-rate adaptation is responsible for this behavior. Instead, the peripheral auditory system operates as though it contains an exponential transfer function whose slope changes with stimulus level. The underlying mechanism is distinct from the comparatively weak cochlear mechanical compression in the cochlear apex, and likely resides in the receptor cells.
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19
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Siveke I, Lingner A, Ammer JJ, Gleiss SA, Grothe B, Felmy F. A Temporal Filter for Binaural Hearing Is Dynamically Adjusted by Sound Pressure Level. Front Neural Circuits 2019; 13:8. [PMID: 30814933 PMCID: PMC6381077 DOI: 10.3389/fncir.2019.00008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2018] [Accepted: 01/24/2019] [Indexed: 12/02/2022] Open
Abstract
In natural environments our auditory system is exposed to multiple and diverse signals of fluctuating amplitudes. Therefore, to detect, localize, and single out individual sounds the auditory system has to process and filter spectral and temporal information from both ears. It is known that the overall sound pressure level affects sensory signal transduction and therefore the temporal response pattern of auditory neurons. We hypothesize that the mammalian binaural system utilizes a dynamic mechanism to adjust the temporal filters in neuronal circuits to different overall sound pressure levels. Previous studies proposed an inhibitory mechanism generated by the reciprocally coupled dorsal nuclei of the lateral lemniscus (DNLL) as a temporal neuronal-network filter that suppresses rapid binaural fluctuations. Here we investigated the consequence of different sound levels on this filter during binaural processing. Our in vivo and in vitro electrophysiology in Mongolian gerbils shows that the integration of ascending excitation and contralateral inhibition defines the temporal properties of this inhibitory filter. The time course of this filter depends on the synaptic drive, which is modulated by the overall sound pressure level and N-methyl-D-aspartate receptor (NMDAR) signaling. In psychophysical experiments we tested the temporal perception of humans and show that detection and localization of two subsequent tones changes with the sound pressure level consistent with our physiological results. Together our data support the hypothesis that mammals dynamically adjust their time window for sound detection and localization within the binaural system in a sound level dependent manner.
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Affiliation(s)
- Ida Siveke
- Department Biology II, Division of Neurobiology, Ludwig-Maximilians-Universität München, Munich, Germany.,Institute of Zoology and Neurobiology, Ruhr-Universität Bochum, Bochum, Germany
| | - Andrea Lingner
- Department Biology II, Division of Neurobiology, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Julian J Ammer
- Department Biology II, Division of Neurobiology, Ludwig-Maximilians-Universität München, Munich, Germany.,Graduate School for Systemic Neurosciences, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Sarah A Gleiss
- Department Biology II, Division of Neurobiology, Ludwig-Maximilians-Universität München, Munich, Germany.,Graduate School for Systemic Neurosciences, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Benedikt Grothe
- Department Biology II, Division of Neurobiology, Ludwig-Maximilians-Universität München, Munich, Germany.,Graduate School for Systemic Neurosciences, Ludwig-Maximilians-Universität München, Munich, Germany
| | - Felix Felmy
- Department Biology II, Division of Neurobiology, Ludwig-Maximilians-Universität München, Munich, Germany.,Institute of Zoology, University of Veterinary Medicine Hannover, Hannover, Germany
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20
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Krause BM, Murphy CA, Uhlrich DJ, Banks MI. PV+ Cells Enhance Temporal Population Codes but not Stimulus-Related Timing in Auditory Cortex. Cereb Cortex 2019; 29:627-647. [PMID: 29300837 PMCID: PMC6319178 DOI: 10.1093/cercor/bhx345] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/25/2017] [Revised: 11/30/2017] [Accepted: 12/05/2017] [Indexed: 01/05/2023] Open
Abstract
Spatio-temporal cortical activity patterns relative to both peripheral input and local network activity carry information about stimulus identity and context. GABAergic interneurons are reported to regulate spiking at millisecond precision in response to sensory stimulation and during gamma oscillations; their role in regulating spike timing during induced network bursts is unclear. We investigated this issue in murine auditory thalamo-cortical (TC) brain slices, in which TC afferents induced network bursts similar to previous reports in vivo. Spike timing relative to TC afferent stimulation during bursts was poor in pyramidal cells and SOM+ interneurons. It was more precise in PV+ interneurons, consistent with their reported contribution to spiking precision in pyramidal cells. Optogenetic suppression of PV+ cells unexpectedly improved afferent-locked spike timing in pyramidal cells. In contrast, our evidence suggests that PV+ cells do regulate the spatio-temporal spike pattern of pyramidal cells during network bursts, whose organization is suited to ensemble coding of stimulus information. Simulations showed that suppressing PV+ cells reduces the capacity of pyramidal cell networks to produce discriminable spike patterns. By dissociating temporal precision with respect to a stimulus versus internal cortical activity, we identified a novel role for GABAergic cells in regulating information processing in cortical networks.
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Affiliation(s)
- Bryan M Krause
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA
- Neuroscience Training Program, University of Wisconsin, Madison, WI, USA
| | - Caitlin A Murphy
- Physiology Graduate Training Program, University of Wisconsin, Madison, WI, USA
| | - Daniel J Uhlrich
- Department of Neuroscience, University of Wisconsin, Madison, WI, USA
| | - Matthew I Banks
- Department of Anesthesiology, University of Wisconsin, Madison, WI, USA
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21
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Lee C, Guinan JJ, Rutherford MA, Kaf WA, Kennedy KM, Buchman CA, Salt AN, Lichtenhan JT. Cochlear compound action potentials from high-level tone bursts originate from wide cochlear regions that are offset toward the most sensitive cochlear region. J Neurophysiol 2019; 121:1018-1033. [PMID: 30673362 DOI: 10.1152/jn.00677.2018] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023] Open
Abstract
Little is known about the spatial origins of auditory nerve (AN) compound action potentials (CAPs) evoked by moderate to intense sounds. We studied the spatial origins of AN CAPs evoked by 2- to 16-kHz tone bursts at several sound levels by slowly injecting kainic acid solution into the cochlear apex of anesthetized guinea pigs. As the solution flowed from apex to base, it sequentially reduced CAP responses from low- to high-frequency cochlear regions. The times at which CAPs were reduced, combined with the cochlear location traversed by the solution at that time, showed the cochlear origin of the removed CAP component. For low-level tone bursts, the CAP origin along the cochlea was centered at the characteristic frequency (CF). As sound level increased, the CAP center shifted basally for low-frequency tone bursts but apically for high-frequency tone bursts. The apical shift was surprising because it is opposite the shift expected from AN tuning curve and basilar membrane motion asymmetries. For almost all high-level tone bursts, CAP spatial origins extended over 2 octaves along the cochlea. Surprisingly, CAPs evoked by high-level low-frequency (including 2 kHz) tone bursts showed little CAP contribution from CF regions ≤ 2 kHz. Our results can be mostly explained by spectral splatter from the tone-burst rise times, excitation in AN tuning-curve "tails," and asynchronous AN responses to high-level energy ≤ 2 kHz. This is the first time CAP origins have been identified by a spatially specific technique. Our results show the need for revising the interpretation of the cochlear origins of high-level CAPs-ABR wave 1. NEW & NOTEWORTHY Cochlear compound action potentials (CAPs) and auditory brain stem responses (ABRs) are routinely used in laboratories and clinics. They are typically interpreted as arising from the cochlear region tuned to the stimulus frequency. However, as sound level is increased, the cochlear origins of CAPs from tone bursts of all frequencies become very wide and their centers shift toward the most sensitive cochlear region. The standard interpretation of CAPs and ABRs from moderate to intense stimuli needs revision.
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Affiliation(s)
- C Lee
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri
| | - J J Guinan
- Eaton-Peabody Laboratories, Massachusetts Eye and Ear, and Department of Otolaryngology, Harvard Medical School , Boston, Massachusetts
| | - M A Rutherford
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri
| | - W A Kaf
- Communication Sciences and Disorders Department, Missouri State University , Springfield, Missouri
| | - K M Kennedy
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri.,Communication Sciences and Disorders Department, Missouri State University , Springfield, Missouri
| | - C A Buchman
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri
| | - A N Salt
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri
| | - J T Lichtenhan
- Department of Otolaryngology, Washington University School of Medicine in St. Louis , St. Louis, Missouri
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22
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Improved Neural Coding of ITD with Bilateral Cochlear Implants by Introducing Short Inter-pulse Intervals. J Assoc Res Otolaryngol 2018; 19:681-702. [PMID: 30191423 DOI: 10.1007/s10162-018-00693-0] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2016] [Accepted: 07/17/2018] [Indexed: 10/28/2022] Open
Abstract
Bilateral cochlear implant (CI) users have poor perceptual sensitivity to interaural time differences (ITDs), which limits their ability to localize sounds and understand speech in noisy environments. This is especially true for high-rate (> 300 pps) periodic pulse trains, which are used as carriers in CI processors. Here, we investigate a novel stimulation strategy in which extra pulses are added to high-rate periodic pulse trains to introduce short inter-pulse intervals (SIPIs). We hypothesized that SIPIs can improve neural ITD sensitivity similarly to the effect observed by randomly jittering IPIs (Hancock et al., J. Neurophysiol. 108:714-28, 2012). To test this hypothesis, we measured ITD sensitivity of single units in the inferior colliculus (IC) of unanesthetized rabbits with bilateral CIs. Introducing SIPIs into high-rate pulse trains significantly increased firing rates for ~ 60 % of IC neurons, and the extra spikes tended to be synchronized to the SIPIs. The additional firings produced by SIPIs uncovered latent ITD sensitivity that was comparable to that observed with low-rate pulse trains. In some neurons, high spontaneous firing rates masked the ITD sensitivity introduced by SIPIs. ITD sensitivity in these neurons could be revealed by emphasizing stimulus-synchronized spikes with a coincidence detection analysis. Overall, these results with SIPIs are consistent with the effects observed previously with jittered pulse trains, with the added benefit of retaining control over the timing and number of SIPIs. A novel CI processing strategy could incorporate SIPIs by inserting them at selected times to high-rate pulse train carriers. Such a strategy could potentially improve ITD perception without degrading speech intelligibility and thereby improve outcomes for bilateral CI users.
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23
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Henry KS, Abrams KS. Persistent Auditory Nerve Damage Following Kainic Acid Excitotoxicity in the Budgerigar (Melopsittacus undulatus). J Assoc Res Otolaryngol 2018; 19:435-449. [PMID: 29744730 DOI: 10.1007/s10162-018-0671-y] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/29/2017] [Accepted: 04/22/2018] [Indexed: 11/30/2022] Open
Abstract
Permanent loss of auditory nerve (AN) fibers occurs with increasing age and sound overexposure, sometimes without hair cell damage or associated audiometric threshold elevation. Rodent studies suggest effects of AN damage on central processing and behavior, but these species have limited capacity to discriminate low-frequency speech-like sounds. Here, we introduce a new animal model of AN damage in an avian communication specialist, the budgerigar (Melopsittacus undulatus). The budgerigar is a vocal learner and speech mimic with sensitive low-frequency hearing and human-like behavioral sensitivity to many complex signals including speech components. Excitotoxic AN damage was induced through bilateral cochlear infusions of kainic acid (KA). Acute KA effects on cochlear function were assessed using AN compound action potentials (CAPs) and hair cell cochlear microphonics (CMs). Long-term KA effects were assessed using auditory brainstem response (ABR) measurements for up to 31 weeks post-KA exposure. KA infusion immediately abolished AN CAPs while having mild impact on the CM. ABR wave I, the far-field AN response, showed a pronounced 40-75 % amplitude reduction at moderate-to-high sound levels that persisted for the duration of the study. In contrast, wave I latency and the amplitude of wave V were nearly unaffected by KA, and waves II-IV were less reduced than wave I. ABR thresholds, calculated based on complete response waveforms, showed no impairment following KA. These results demonstrate that KA exposure in the budgerigar causes irreversible AN damage, most likely through excitotoxic injury to afferent fibers or synapses as in other species, while sparing ABR thresholds. Normal wave V amplitude, assumed to originate centrally, may persist through compensatory mechanisms that restore central response amplitude by downregulating inhibition. Future studies in this new animal model of AN damage can explore effects of this neural lesion, in isolation from hair cell trauma and threshold elevation, on central processing and perception of complex sounds.
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Affiliation(s)
- Kenneth S Henry
- Department of Otolaryngology, University of Rochester, 601 Elmwood Ave., Box 629, Rochester, NY, 14642, USA.
| | - Kristina S Abrams
- Department of Otolaryngology, University of Rochester, 601 Elmwood Ave., Box 629, Rochester, NY, 14642, USA.,Department of Neuroscience, University of Rochester, Rochester, NY, USA
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24
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Finneran JJ, Mulsow J, Houser DS, Burkard RF. Effects of noise burst rise time and level on bottlenose dolphin (Tursiops truncatus) auditory brainstem responses. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2018; 143:2914. [PMID: 29857708 DOI: 10.1121/1.5037586] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/08/2023]
Abstract
Although the auditory brainstem response (ABR) is known to be an onset response, specific features of acoustic stimuli that affect the morphology of the ABR are not well understood. In this study, the effects of stimulus onset properties were investigated by measuring ABRs in seven bottlenose dolphins while systematically manipulating stimulus rise time and the amplitude of the sound pressure temporal envelope plateau. Stimuli consisted of spectrally pink (i.e., equal mean-square pressure in proportional frequency bands) noise bursts with linear rise (and fall) envelopes and frequency content from 10 to 160 kHz. Noise burst rise times varied from 32 μs to 4 ms and plateau sound pressure levels varied from 96 to 150 dB re 1 μPa. ABR peak latency was found to be a function of the rate of change of the sound pressure envelope, while ABR peak amplitude was a function of the envelope sound pressure at the end of a fixed integration window. The data support previous single-unit and nearfield response data from terrestrial mammals and a model where the rate of change of envelope sound pressure is integrated across a time window aligned with stimulus onset.
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Affiliation(s)
- James J Finneran
- U.S. Navy Marine Mammal Program, Space and Naval Warfare Systems Center Pacific Code 71510, 53560 Hull Street, San Diego, California 92152, USA
| | - Jason Mulsow
- National Marine Mammal Foundation, 2240 Shelter Island Drive #200, San Diego, California 92106, USA
| | - Dorian S Houser
- National Marine Mammal Foundation, 2240 Shelter Island Drive #200, San Diego, California 92106, USA
| | - Robert F Burkard
- Department of Rehabilitation Science, University at Buffalo, 626 Kimball Tower, Buffalo, New York 14214, USA
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Khatami F, Wöhr M, Read HL, Escabí MA. Origins of scale invariance in vocalization sequences and speech. PLoS Comput Biol 2018; 14:e1005996. [PMID: 29659561 PMCID: PMC5919684 DOI: 10.1371/journal.pcbi.1005996] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2017] [Revised: 04/26/2018] [Accepted: 01/23/2018] [Indexed: 11/18/2022] Open
Abstract
To communicate effectively animals need to detect temporal vocalization cues that vary over several orders of magnitude in their amplitude and frequency content. This large range of temporal cues is evident in the power-law scale-invariant relationship between the power of temporal fluctuations in sounds and the sound modulation frequency (f). Though various forms of scale invariance have been described for natural sounds, the origins and implications of scale invariant phenomenon remain unknown. Using animal vocalization sequences, including continuous human speech, and a stochastic model of temporal amplitude fluctuations we demonstrate that temporal acoustic edges are the primary acoustic cue accounting for the scale invariant phenomenon. The modulation spectrum of vocalization sequences and the model both exhibit a dual regime lowpass structure with a flat region at low modulation frequencies and scale invariant 1/f2 trend for high modulation frequencies. Moreover, we find a time-frequency tradeoff between the average vocalization duration of each vocalization sequence and the cutoff frequency beyond which scale invariant behavior is observed. These results indicate that temporal edges are universal features responsible for scale invariance in vocalized sounds. This is significant since temporal acoustic edges are salient perceptually and the auditory system could exploit such statistical regularities to minimize redundancies and generate compact neural representations of vocalized sounds. The efficient coding hypothesis posits that the brain encodes sensory signals efficiently in order to reduce metabolic cost and preserve behaviorally relevant environment information. In audition, recognition and coding depends on the brain’s ability to accurately and efficiently encode statistical regularities that are prevalent in natural sounds. Similarly, efficient audio coding and compression schemes attempt to preserve salient sound qualities while minimizing data bandwidth. A widely observed statistical regularity in nearly all natural sounds is the presence of scale invariance where the power of amplitude fluctuations is inversely related to the sound amplitude modulation frequency. In this study, we explore the physical sound cues responsible for the scale invariant phenomenon previously observed. We demonstrate that for animal vocalizations, including human speech, the scale invariant behavior is fully accounted by the presence of temporal acoustic edges that are largely created by opening and closing of the oral cavity and which mark the beginning and end of isolated vocalizations. The findings thus identify a single physical cue responsible for the universal scale invariant phenomenon that the brain can exploit to optimize coding and perception of vocalized sounds.
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Affiliation(s)
- Fatemeh Khatami
- Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States of America
| | - Markus Wöhr
- Behavioral Neuroscience, Experimental and Biological Psychology, Faculty of Psychology, Philipps-University of Marburg, Marburg, Germany
- Center for Mind, Brain, and Behavior (CMBB), Philipps-University of Marburg, Marburg, Germany
| | - Heather L. Read
- Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States of America
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut, United States of America
| | - Monty A. Escabí
- Biomedical Engineering, University of Connecticut, Storrs, Connecticut, United States of America
- Department of Psychological Sciences, University of Connecticut, Storrs, Connecticut, United States of America
- Electrical and Computer Engineering, University of Connecticut, Storrs, Connecticut, United States of America
- * E-mail:
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26
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Harris KC, Vaden KI, McClaskey CM, Dias JW, Dubno JR. Complementary metrics of human auditory nerve function derived from compound action potentials. J Neurophysiol 2017; 119:1019-1028. [PMID: 29187555 DOI: 10.1152/jn.00638.2017] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Declines in auditory nerve (AN) function contribute to suprathreshold auditory processing and communication deficits in individuals with normal hearing, hearing loss, hyperacusis, and tinnitus. Procedures to characterize AN loss or dysfunction in humans are limited. We report several novel complementary metrics using the compound action potential (CAP), a direct measure of summated AN activity. Together, these metrics may be used to characterize AN function noninvasively in humans. We examined how these metrics change with stimulus intensity and interpreted these changes within a framework of known physiological properties of the basilar membrane and AN. Our results reveal how neural synchrony and the recruitment of AN fibers with longer first-spike latencies likely contribute to the CAP, affect auditory processing, and differ with noise exposure history in younger adults with normal pure-tone thresholds. Moving forward, this new battery of metrics provides a crucial step toward new diagnostics of AN function in humans. NEW & NOTEWORTHY Loss or inactivity of auditory nerve (AN) fibers is thought to contribute to suprathreshold auditory processing deficits, but evidence-based methods to assess these effects are not available. We describe several novel metrics that together may be used to quantify neural synchrony and characterize AN function in humans.
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Affiliation(s)
- Kelly C Harris
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina , Charleston, South Carolina
| | - Kenneth I Vaden
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina , Charleston, South Carolina
| | - Carolyn M McClaskey
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina , Charleston, South Carolina
| | - James W Dias
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina , Charleston, South Carolina
| | - Judy R Dubno
- Department of Otolaryngology-Head and Neck Surgery, Medical University of South Carolina , Charleston, South Carolina
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27
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Peng K, Peng YJ, Wang J, Yang MJ, Fu ZY, Tang J, Chen QC. Latency modulation of collicular neurons induced by electric stimulation of the auditory cortex in Hipposideros pratti: In vivo intracellular recording. PLoS One 2017; 12:e0184097. [PMID: 28863144 PMCID: PMC5580910 DOI: 10.1371/journal.pone.0184097] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2017] [Accepted: 08/17/2017] [Indexed: 11/18/2022] Open
Abstract
In the auditory pathway, the inferior colliculus (IC) receives and integrates excitatory and inhibitory inputs from the lower auditory nuclei, contralateral IC, and auditory cortex (AC), and then uploads these inputs to the thalamus and cortex. Meanwhile, the AC modulates the sound signal processing of IC neurons, including their latency (i.e., first-spike latency). Excitatory and inhibitory corticofugal projections to the IC may shorten and prolong the latency of IC neurons, respectively. However, the synaptic mechanisms underlying the corticofugal latency modulation of IC neurons remain unclear. Thus, this study probed these mechanisms via in vivo intracellular recording and acoustic and focal electric stimulation. The AC latency modulation of IC neurons is possibly mediated by pre-spike depolarization duration, pre-spike hyperpolarization duration, and spike onset time. This study suggests an effective strategy for the timing sequence determination of auditory information uploaded to the thalamus and cortex.
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Affiliation(s)
- Kang Peng
- School of Life Sciences and Hubei Key Lab of Genetic Regulation & Integrative Biology, Central China Normal University, Wuhan, China
| | - Yu-Jie Peng
- School of Life Sciences and Hubei Key Lab of Genetic Regulation & Integrative Biology, Central China Normal University, Wuhan, China
| | - Jing Wang
- School of Life Sciences and Hubei Key Lab of Genetic Regulation & Integrative Biology, Central China Normal University, Wuhan, China
| | - Ming-Jian Yang
- School of Life Sciences and Hubei Key Lab of Genetic Regulation & Integrative Biology, Central China Normal University, Wuhan, China
| | - Zi-Ying Fu
- School of Life Sciences and Hubei Key Lab of Genetic Regulation & Integrative Biology, Central China Normal University, Wuhan, China
| | - Jia Tang
- School of Life Sciences and Hubei Key Lab of Genetic Regulation & Integrative Biology, Central China Normal University, Wuhan, China
| | - Qi-Cai Chen
- School of Life Sciences and Hubei Key Lab of Genetic Regulation & Integrative Biology, Central China Normal University, Wuhan, China
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28
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Krächan EG, Fischer AU, Franke J, Friauf E. Synaptic reliability and temporal precision are achieved via high quantal content and effective replenishment: auditory brainstem versus hippocampus. J Physiol 2017; 595:839-864. [PMID: 27673320 PMCID: PMC5285727 DOI: 10.1113/jp272799] [Citation(s) in RCA: 23] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2016] [Accepted: 09/07/2016] [Indexed: 12/11/2022] Open
Abstract
KEY POINTS Auditory brainstem neurons involved in sound source localization are equipped with several morphological and molecular features that enable them to compute interaural level and time differences. As sound source localization works continually, synaptic transmission between these neurons should be reliable and temporally precise, even during sustained periods of high-frequency activity. Using patch-clamp recordings in acute brain slices, we compared synaptic reliability and temporal precision in the seconds-minute range between auditory and two types of hippocampal synapses; the latter are less confronted with temporally precise high-frequency transmission than the auditory ones. We found striking differences in synaptic properties (e.g. continually high quantal content) that allow auditory synapses to reliably release vesicles at much higher rate than their hippocampal counterparts. Thus, they are indefatigable and also in a position to transfer information with exquisite temporal precision and their performance appears to be supported by very efficient replenishment mechanisms. ABSTRACT At early stations of the auditory pathway, information is encoded by precise signal timing and rate. Auditory synapses must maintain the relative timing of events with submillisecond precision even during sustained and high-frequency stimulation. In non-auditory brain regions, e.g. telencephalic ones, synapses are activated at considerably lower frequencies. Central to understanding the heterogeneity of synaptic systems is the elucidation of the physical, chemical and biological factors that determine synapse performance. In this study, we used slice recordings from three synapse types in the mouse auditory brainstem and hippocampus. Whereas the auditory brainstem nuclei experience high-frequency activity in vivo, the hippocampal circuits are activated at much lower frequencies. We challenged the synapses with sustained high-frequency stimulation (up to 200 Hz for 60 s) and found significant performance differences. Our results show that auditory brainstem synapses differ considerably from their hippocampal counterparts in several aspects, namely resistance to synaptic fatigue, low failure rate and exquisite temporal precision. Their high-fidelity performance supports the functional demands and appears to be due to the large size of the readily releasable pool and a high release probability, which together result in a high quantal content. In conjunction with very efficient vesicle replenishment mechanisms, these properties provide extremely rapid and temporally precise signalling required for neuronal communication at early stations of the auditory system, even during sustained activation in the minute range.
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Affiliation(s)
- Elisa G Krächan
- Animal Physiology Group, Department of BiologyUniversity of KaiserslauternD‐67663KaiserslauternGermany
| | - Alexander U Fischer
- Animal Physiology Group, Department of BiologyUniversity of KaiserslauternD‐67663KaiserslauternGermany
| | - Jürgen Franke
- Chair for Applied Mathematical Statistics, Department of MathematicsUniversity of KaiserslauternD‐67663KaiserslauternGermany
| | - Eckhard Friauf
- Animal Physiology Group, Department of BiologyUniversity of KaiserslauternD‐67663KaiserslauternGermany
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29
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Harper NS, Schoppe O, Willmore BDB, Cui Z, Schnupp JWH, King AJ. Network Receptive Field Modeling Reveals Extensive Integration and Multi-feature Selectivity in Auditory Cortical Neurons. PLoS Comput Biol 2016; 12:e1005113. [PMID: 27835647 PMCID: PMC5105998 DOI: 10.1371/journal.pcbi.1005113] [Citation(s) in RCA: 43] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/12/2015] [Accepted: 08/22/2016] [Indexed: 11/28/2022] Open
Abstract
Cortical sensory neurons are commonly characterized using the receptive field, the linear dependence of their response on the stimulus. In primary auditory cortex neurons can be characterized by their spectrotemporal receptive fields, the spectral and temporal features of a sound that linearly drive a neuron. However, receptive fields do not capture the fact that the response of a cortical neuron results from the complex nonlinear network in which it is embedded. By fitting a nonlinear feedforward network model (a network receptive field) to cortical responses to natural sounds, we reveal that primary auditory cortical neurons are sensitive over a substantially larger spectrotemporal domain than is seen in their standard spectrotemporal receptive fields. Furthermore, the network receptive field, a parsimonious network consisting of 1-7 sub-receptive fields that interact nonlinearly, consistently better predicts neural responses to auditory stimuli than the standard receptive fields. The network receptive field reveals separate excitatory and inhibitory sub-fields with different nonlinear properties, and interaction of the sub-fields gives rise to important operations such as gain control and conjunctive feature detection. The conjunctive effects, where neurons respond only if several specific features are present together, enable increased selectivity for particular complex spectrotemporal structures, and may constitute an important stage in sound recognition. In conclusion, we demonstrate that fitting auditory cortical neural responses with feedforward network models expands on simple linear receptive field models in a manner that yields substantially improved predictive power and reveals key nonlinear aspects of cortical processing, while remaining easy to interpret in a physiological context.
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Affiliation(s)
- Nicol S. Harper
- Dept. of Physiology, Anatomy and Genetics (DPAG), Sherrington Building, University of Oxford, United Kingdom
- Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Headington, United Kingdom
| | - Oliver Schoppe
- Dept. of Physiology, Anatomy and Genetics (DPAG), Sherrington Building, University of Oxford, United Kingdom
- Bio-Inspired Information Processing, Technische Universität München, Germany
| | - Ben D. B. Willmore
- Dept. of Physiology, Anatomy and Genetics (DPAG), Sherrington Building, University of Oxford, United Kingdom
| | - Zhanfeng Cui
- Institute of Biomedical Engineering, Department of Engineering Science, Old Road Campus Research Building, University of Oxford, Headington, United Kingdom
| | - Jan W. H. Schnupp
- Dept. of Physiology, Anatomy and Genetics (DPAG), Sherrington Building, University of Oxford, United Kingdom
- Department of Biomedical Science, City University of Hong Kong, Kowloon Tong, Hong Kong
| | - Andrew J. King
- Dept. of Physiology, Anatomy and Genetics (DPAG), Sherrington Building, University of Oxford, United Kingdom
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30
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Neural response differences in the rat primary auditory cortex under anesthesia with ketamine versus the mixture of medetomidine, midazolam and butorphanol. Hear Res 2016; 339:69-79. [DOI: 10.1016/j.heares.2016.06.012] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/25/2016] [Revised: 06/08/2016] [Accepted: 06/15/2016] [Indexed: 11/18/2022]
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31
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Heil P, Peterson AJ. Spike timing in auditory-nerve fibers during spontaneous activity and phase locking. Synapse 2016; 71:5-36. [DOI: 10.1002/syn.21925] [Citation(s) in RCA: 28] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/01/2015] [Revised: 07/20/2016] [Accepted: 07/24/2016] [Indexed: 12/22/2022]
Affiliation(s)
- Peter Heil
- Department of Systems Physiology of Learning; Leibniz Institute for Neurobiology; Magdeburg 39118 Germany
- Center for Behavioral Brain Sciences; Magdeburg Germany
| | - Adam J. Peterson
- Department of Systems Physiology of Learning; Leibniz Institute for Neurobiology; Magdeburg 39118 Germany
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32
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Lee CM, Osman AF, Volgushev M, Escabí MA, Read HL. Neural spike-timing patterns vary with sound shape and periodicity in three auditory cortical fields. J Neurophysiol 2016; 115:1886-904. [PMID: 26843599 DOI: 10.1152/jn.00784.2015] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/10/2015] [Accepted: 01/29/2016] [Indexed: 11/22/2022] Open
Abstract
Mammals perceive a wide range of temporal cues in natural sounds, and the auditory cortex is essential for their detection and discrimination. The rat primary (A1), ventral (VAF), and caudal suprarhinal (cSRAF) auditory cortical fields have separate thalamocortical pathways that may support unique temporal cue sensitivities. To explore this, we record responses of single neurons in the three fields to variations in envelope shape and modulation frequency of periodic noise sequences. Spike rate, relative synchrony, and first-spike latency metrics have previously been used to quantify neural sensitivities to temporal sound cues; however, such metrics do not measure absolute spike timing of sustained responses to sound shape. To address this, in this study we quantify two forms of spike-timing precision, jitter, and reliability. In all three fields, we find that jitter decreases logarithmically with increase in the basis spline (B-spline) cutoff frequency used to shape the sound envelope. In contrast, reliability decreases logarithmically with increase in sound envelope modulation frequency. In A1, jitter and reliability vary independently, whereas in ventral cortical fields, jitter and reliability covary. Jitter time scales increase (A1 < VAF < cSRAF) and modulation frequency upper cutoffs decrease (A1 > VAF > cSRAF) with ventral progression from A1. These results suggest a transition from independent encoding of shape and periodicity sound cues on short time scales in A1 to a joint encoding of these same cues on longer time scales in ventral nonprimary cortices.
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Affiliation(s)
- Christopher M Lee
- Department of Psychology, University of Connecticut, Storrs, Connecticut
| | - Ahmad F Osman
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; and
| | - Maxim Volgushev
- Department of Psychology, University of Connecticut, Storrs, Connecticut
| | - Monty A Escabí
- Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; and Department of Electrical and Computer Engineering, University of Connecticut, Storrs, Connecticut
| | - Heather L Read
- Department of Psychology, University of Connecticut, Storrs, Connecticut; Department of Biomedical Engineering, University of Connecticut, Storrs, Connecticut; and
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33
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Rutherford MA, Moser T. The Ribbon Synapse Between Type I Spiral Ganglion Neurons and Inner Hair Cells. THE PRIMARY AUDITORY NEURONS OF THE MAMMALIAN COCHLEA 2016. [DOI: 10.1007/978-1-4939-3031-9_5] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
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34
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Keller CH, Takahashi TT. Spike timing precision changes with spike rate adaptation in the owl's auditory space map. J Neurophysiol 2015; 114:2204-19. [PMID: 26269555 PMCID: PMC4600961 DOI: 10.1152/jn.00442.2015] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2015] [Accepted: 08/07/2015] [Indexed: 11/22/2022] Open
Abstract
Spike rate adaptation (SRA) is a continuing change of responsiveness to ongoing stimuli, which is ubiquitous across species and levels of sensory systems. Under SRA, auditory responses to constant stimuli change over time, relaxing toward a long-term rate often over multiple timescales. With more variable stimuli, SRA causes the dependence of spike rate on sound pressure level to shift toward the mean level of recent stimulus history. A model based on subtractive adaptation (Benda J, Hennig RM. J Comput Neurosci 24: 113-136, 2008) shows that changes in spike rate and level dependence are mechanistically linked. Space-specific neurons in the barn owl's midbrain, when recorded under ketamine-diazepam anesthesia, showed these classical characteristics of SRA, while at the same time exhibiting changes in spike timing precision. Abrupt level increases of sinusoidally amplitude-modulated (SAM) noise initially led to spiking at higher rates with lower temporal precision. Spike rate and precision relaxed toward their long-term values with a time course similar to SRA, results that were also replicated by the subtractive model. Stimuli whose amplitude modulations (AMs) were not synchronous across carrier frequency evoked spikes in response to stimulus envelopes of a particular shape, characterized by the spectrotemporal receptive field (STRF). Again, abrupt stimulus level changes initially disrupted the temporal precision of spiking, which then relaxed along with SRA. We suggest that shifts in latency associated with stimulus level changes may differ between carrier frequency bands and underlie decreased spike precision. Thus SRA is manifest not simply as a change in spike rate but also as a change in the temporal precision of spiking.
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35
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Levakova M, Tamborrino M, Ditlevsen S, Lansky P. A review of the methods for neuronal response latency estimation. Biosystems 2015; 136:23-34. [PMID: 25939679 DOI: 10.1016/j.biosystems.2015.04.008] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2015] [Accepted: 04/14/2015] [Indexed: 11/29/2022]
Abstract
Neuronal response latency is usually vaguely defined as the delay between the stimulus onset and the beginning of the response. It contains important information for the understanding of the temporal code. For this reason, the detection of the response latency has been extensively studied in the last twenty years, yielding different estimation methods. They can be divided into two classes, one of them including methods based on detecting an intensity change in the firing rate profile after the stimulus onset and the other containing methods based on detection of spikes evoked by the stimulation using interspike intervals and spike times. The aim of this paper is to present a review of the main techniques proposed in both classes, highlighting their advantages and shortcomings.
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Affiliation(s)
- Marie Levakova
- Institute of Physiology, The Czech Academy of Sciences, Videnska 1083, 14220 Prague 4, Czech Republic.
| | - Massimiliano Tamborrino
- Institute for Stochastics, Johannes Kepler University Linz, Altenbergerstraße 69, 4040 Linz, Austria.
| | - Susanne Ditlevsen
- Department of Mathematical Sciences, University of Copenhagen, Universitetsparken 5, 2100 Copenhagen, Denmark.
| | - Petr Lansky
- Institute of Physiology, The Czech Academy of Sciences, Videnska 1083, 14220 Prague 4, Czech Republic.
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36
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Heil P, Peterson AJ. Basic response properties of auditory nerve fibers: a review. Cell Tissue Res 2015; 361:129-58. [PMID: 25920587 DOI: 10.1007/s00441-015-2177-9] [Citation(s) in RCA: 68] [Impact Index Per Article: 7.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Accepted: 03/19/2015] [Indexed: 01/26/2023]
Abstract
All acoustic information from the periphery is encoded in the timing and rates of spikes in the population of spiral ganglion neurons projecting to the central auditory system. Considerable progress has been made in characterizing the physiological properties of type-I and type-II primary auditory afferents and understanding the basic properties of type-I afferents in response to sounds. Here, we review some of these properties, with emphasis placed on issues such as the stochastic nature of spike timing during spontaneous and driven activity, frequency tuning curves, spike-rate-versus-level functions, dynamic-range and spike-rate adaptation, and phase locking to stimulus fine structure and temporal envelope. We also review effects of acoustic trauma on some of these response properties.
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Affiliation(s)
- Peter Heil
- Leibniz Institute for Neurobiology, Brenneckestrasse 6, 39118, Magdeburg, Germany,
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37
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Huang EI, Durrant JD, Boston JR. Will diminishing cochlear delay affect speech perception in noise? Int J Audiol 2015; 54:562-7. [PMID: 25735205 DOI: 10.3109/14992027.2014.1002582] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
OBJECTIVE Normal auditory systems appear well habituated to time/phase delays inherent to sound encoding along the hearing organ, sending frequency information non-simultaneously to the central auditory system. Eliminating, or simply perturbing, the cochlear delay might be expected to decrease speech recognition ability, especially under demanding listening conditions. Resources of a larger-scale investigation permitted a preliminary examination of this issue, particularly on a relevant timescale of empirically demonstrated cochlear delays. DESIGN In a randomized controlled trial study, word recognition was tested for mono-syllabic tokens treated digitally to exacerbate, if not diminish/nullify, such delays. Speech-weighted noise was used to interfere with listening to time-frequency reversed (nominally no delay) versus non-reversed (natural timing) transforms under three treatments of speech tokens: (1) original-digitally recorded; digitally processed to emphasize (2) transient versus (3) quasi-steady-state components. STUDY SAMPLE Ten normal-hearing young-adult females. RESULTS The findings failed to demonstrate statistically significant differences between delay conditions for any of the three speech-token treatments. CONCLUSIONS An algorithm putatively diminishing frequency-dependent cochlear delays failed to systematically deteriorate performance in all subjects for the fixed time-frequency transform, stimulus parameters, and test materials employed. Yet, trends were evident such that some effect of perturbing cochlear delays could not be ruled out completely.
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Affiliation(s)
- Ethan I Huang
- * Department of Communication Science and Disorders, University of Pittsburgh , Pennsylvania , USA
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38
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Eggermont JJ. Animal models of auditory temporal processing. Int J Psychophysiol 2015; 95:202-15. [DOI: 10.1016/j.ijpsycho.2014.03.011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2013] [Revised: 03/27/2014] [Accepted: 03/27/2014] [Indexed: 10/25/2022]
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39
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Wang N, Wang X, Yang X, Tang J, Xiao Z. Interdependent effects of sound duration and amplitude on neuronal onset response in mice inferior colliculus. Brain Res 2014; 1543:209-22. [PMID: 24201024 DOI: 10.1016/j.brainres.2013.10.040] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2013] [Revised: 10/10/2013] [Accepted: 10/21/2013] [Indexed: 11/30/2022]
Abstract
In this study, we adopted iso-frequency pure tone bursts to investigate the interdependent effects of sound amplitude/intensity and duration on mice inferior colliculus (IC) neuronal onset responses. On the majority of the sampled neurons (n=57, 89.1%), sound amplitude and duration had effects on the neuronal response to each other by showing complex changes of the rat-intensity function/duration selectivity types and/or best amplitudes (BAs)/durations (BDs), evaluated by spike counts. These results suggested that the balance between the excitatory and inhibitory inputs set by one acoustic parameter, amplitude or duration, affected the neuronal spike counts responses to the other. Neuronal duration selectivity types were altered easily by the low-amplitude sounds while the changes of rate-intensity function types had no obvious preferred stimulus durations. However, the first spike latencies (FSLs) of the onset response neurons were relative stable to iso-amplitude sound durations and changing systematically along with the sound levels. The superimposition of FSL and duration threshold (DT) as a function of stimulus amplitude after normalization indicated that the effects of the sound levels on FSLs are considered on DT actually.
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Affiliation(s)
- Ningqian Wang
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou 510515, China
| | - Xiao Wang
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou 510515, China
| | - Xiaoli Yang
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou 510515, China
| | - Jie Tang
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou 510515, China
| | - Zhongju Xiao
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou 510515, China.
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Musical expertise affects attention as reflected by auditory-evoked gamma-band activity in human EEG. Neuroreport 2013; 24:445-50. [PMID: 23660630 DOI: 10.1097/wnr.0b013e328360abdb] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
Musical expertise has been shown to induce widespread structural and functional alterations in the brain, even-handedly affecting top-down and bottom-up factors. At the same time, it is known that the early evoked gamma-band response (GBR) can be modulated by top-down as well as bottom-up factors such as attention and sound intensity. In this study, we examined the effects of musicianship and attention on the intensity modulation of the auditory-evoked GBR. We compared the electroencephalogram of 17 professional musicians with that of 17 musical laymen obtained during either a forced-choice discrimination task (active) or a passive listening condition. Pure 1000 Hz sine tones were presented at three systematically varied sound intensities (40, 60, and 80 dB sound pressure levels). The results of auditory-evoked potentials and evoked GBRs obtained in the active condition predominantly corresponded to the findings of previous studies. Besides the already known augmentation of the early evoked GBR because of enhanced intertrial phase coherence with increasing sound intensity, we also observed stronger GBRs and enhanced phase locking under the active condition compared with passive listening, whereas the general shape of intensity modulation was comparable between the two conditions. In addition, phase locking to stimulus onset was increased for stimuli of all three intensities when attended, whereas in musicians, only stimuli of the highest intensity (80 dB) induced significantly increased phase locking under the active condition. Taken together, our results suggest that musical expertise influences attention effects on the intensity-modulated early auditory-evoked GBR with respect to intertrial phase coherence.
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41
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Raghavan M, Amrutur B, Narayanan R, Sikdar SK. Synconset waves and chains: spiking onsets in synchronous populations predict and are predicted by network structure. PLoS One 2013; 8:e74910. [PMID: 24116018 PMCID: PMC3792941 DOI: 10.1371/journal.pone.0074910] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2013] [Accepted: 08/07/2013] [Indexed: 11/30/2022] Open
Abstract
Synfire waves are propagating spike packets in synfire chains, which are feedforward chains embedded in random networks. Although synfire waves have proved to be effective quantification for network activity with clear relations to network structure, their utilities are largely limited to feedforward networks with low background activity. To overcome these shortcomings, we describe a novel generalisation of synfire waves, and define ‘synconset wave’ as a cascade of first spikes within a synchronisation event. Synconset waves would occur in ‘synconset chains’, which are feedforward chains embedded in possibly heavily recurrent networks with heavy background activity. We probed the utility of synconset waves using simulation of single compartment neuron network models with biophysically realistic conductances, and demonstrated that the spread of synconset waves directly follows from the network connectivity matrix and is modulated by top-down inputs and the resultant oscillations. Such synconset profiles lend intuitive insights into network organisation in terms of connection probabilities between various network regions rather than an adjacency matrix. To test this intuition, we develop a Bayesian likelihood function that quantifies the probability that an observed synfire wave was caused by a given network. Further, we demonstrate it's utility in the inverse problem of identifying the network that caused a given synfire wave. This method was effective even in highly subsampled networks where only a small subset of neurons were accessible, thus showing it's utility in experimental estimation of connectomes in real neuronal-networks. Together, we propose synconset chains/waves as an effective framework for understanding the impact of network structure on function, and as a step towards developing physiology-driven network identification methods. Finally, as synconset chains extend the utilities of synfire chains to arbitrary networks, we suggest utilities of our framework to several aspects of network physiology including cell assemblies, population codes, and oscillatory synchrony.
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Affiliation(s)
- Mohan Raghavan
- Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore, Karnataka, India
- * E-mail:
| | - Bharadwaj Amrutur
- Department of Electrical Communication Engineering, Indian Institute of Science, Bangalore, Karnataka, India
| | - Rishikesh Narayanan
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
| | - Sujit Kumar Sikdar
- Molecular Biophysics Unit, Indian Institute of Science, Bangalore, Karnataka, India
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42
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Zheng Y, Escabí MA. Proportional spike-timing precision and firing reliability underlie efficient temporal processing of periodicity and envelope shape cues. J Neurophysiol 2013; 110:587-606. [PMID: 23636724 DOI: 10.1152/jn.01080.2010] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Temporal sound cues are essential for sound recognition, pitch, rhythm, and timbre perception, yet how auditory neurons encode such cues is subject of ongoing debate. Rate coding theories propose that temporal sound features are represented by rate tuned modulation filters. However, overwhelming evidence also suggests that precise spike timing is an essential attribute of the neural code. Here we demonstrate that single neurons in the auditory midbrain employ a proportional code in which spike-timing precision and firing reliability covary with the sound envelope cues to provide an efficient representation of the stimulus. Spike-timing precision varied systematically with the timescale and shape of the sound envelope and yet was largely independent of the sound modulation frequency, a prominent cue for pitch. In contrast, spike-count reliability was strongly affected by the modulation frequency. Spike-timing precision extends from sub-millisecond for brief transient sounds up to tens of milliseconds for sounds with slow-varying envelope. Information theoretic analysis further confirms that spike-timing precision depends strongly on the sound envelope shape, while firing reliability was strongly affected by the sound modulation frequency. Both the information efficiency and total information were limited by the firing reliability and spike-timing precision in a manner that reflected the sound structure. This result supports a temporal coding strategy in the auditory midbrain where proportional changes in spike-timing precision and firing reliability can efficiently signal shape and periodicity temporal cues.
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Affiliation(s)
- Y Zheng
- Department of Biomedical Engineering, University of Connecticut, Storrs, CT 06269, USA
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43
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Rasetshwane DM, Argenyi M, Neely ST, Kopun JG, Gorga MP. Latency of tone-burst-evoked auditory brain stem responses and otoacoustic emissions: level, frequency, and rise-time effects. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 133:2803-2817. [PMID: 23654387 PMCID: PMC3663861 DOI: 10.1121/1.4798666] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/13/2012] [Revised: 03/05/2013] [Accepted: 03/11/2013] [Indexed: 05/29/2023]
Abstract
Simultaneous measurement of auditory brain stem response (ABR) and otoacoustic emission (OAE) delays may provide insights into effects of level, frequency, and stimulus rise-time on cochlear delay. Tone-burst-evoked ABRs and OAEs (TBOAEs) were measured simultaneously in normal-hearing human subjects. Stimuli included a wide range of frequencies (0.5-8 kHz), levels (20-90 dB SPL), and tone-burst rise times. ABR latencies have orderly dependence on these three parameters, similar to previously reported data by Gorga et al. [J. Speech Hear. Res. 31, 87-97 (1988)]. Level dependence of ABR and TBOAE latencies was similar across a wide range of stimulus conditions. At mid-frequencies, frequency dependence of ABR and TBOAE latencies were similar. The dependence of ABR latency on both rise time and level was significant; however, the interaction was not significant, suggesting independent effects. Comparison between ABR and TBOAE latencies reveals that the ratio of TBOAE latency to ABR forward latency (the level-dependent component of ABR total latency) is close to one below 1.5 kHz, but greater than two above 1.5 kHz. Despite the fact that the current experiment was designed to test compatibility with models of reverse-wave propagation, existing models do not completely explain the current data.
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Affiliation(s)
- Daniel M Rasetshwane
- Boys Town National Research Hospital, 555 North 30th Street, Omaha, Nebraska 68131, USA.
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44
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Wojtczak M, Beim JA, Micheyl C, Oxenham AJ. Effects of temporal stimulus properties on the perception of across-frequency asynchrony. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2013; 133:982-997. [PMID: 23363115 PMCID: PMC3574076 DOI: 10.1121/1.4773350] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/04/2012] [Revised: 11/24/2012] [Accepted: 12/11/2012] [Indexed: 06/01/2023]
Abstract
The role of temporal stimulus parameters in the perception of across-frequency synchrony and asynchrony was investigated using pairs of 500-ms tones consisting of a 250-Hz tone and a tone with a higher frequency of 1, 2, 4, or 6 kHz. Subjective judgments suggested veridical perception of across-frequency synchrony but with greater sensitivity to changes in asynchrony for pairs in which the lower-frequency tone was leading than for pairs in which it was lagging. Consistent with the subjective judgments, thresholds for the detection of asynchrony measured in a three-alternative forced-choice task were lower when the signal interval contained a pair with the low-frequency tone leading than a pair with a high-frequency tone leading. A similar asymmetry was observed for asynchrony discrimination when the standard asynchrony was relatively small (≤20 ms) but not for larger standard asynchronies. Independent manipulation of onset and offset ramp durations indicated a dominant role of onsets in the perception of across-frequency asynchrony. A physiologically inspired model, involving broadly tuned monaural coincidence detectors that receive inputs from frequency-selective onset detectors, was able to accurately reproduce the asymmetric distributions of synchrony judgments. The model provides testable predictions for future physiological investigations of responses to broadband stimuli with across-frequency delays.
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Affiliation(s)
- Magdalena Wojtczak
- Department of Psychology, University of Minnesota, 75 East River Road, Minneapolis, Minnesota 55455, USA.
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45
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Nourski KV, Brugge JF, Reale RA, Kovach CK, Oya H, Kawasaki H, Jenison RL, Howard MA. Coding of repetitive transients by auditory cortex on posterolateral superior temporal gyrus in humans: an intracranial electrophysiology study. J Neurophysiol 2012; 109:1283-95. [PMID: 23236002 DOI: 10.1152/jn.00718.2012] [Citation(s) in RCA: 54] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Evidence regarding the functional subdivisions of human auditory cortex has been slow to converge on a definite model. In part, this reflects inadequacies of current understanding of how the cortex represents temporal information in acoustic signals. To address this, we investigated spatiotemporal properties of auditory responses in human posterolateral superior temporal (PLST) gyrus to acoustic click-train stimuli using intracranial recordings from neurosurgical patients. Subjects were patients undergoing chronic invasive monitoring for refractory epilepsy. The subjects listened passively to acoustic click-train stimuli of varying durations (160 or 1,000 ms) and rates (4-200 Hz), delivered diotically via insert earphones. Multicontact subdural grids placed over the perisylvian cortex recorded intracranial electrocorticographic responses from PLST and surrounding areas. Analyses focused on averaged evoked potentials (AEPs) and high gamma (70-150 Hz) event-related band power (ERBP). Responses to click trains featured prominent AEP waveforms and increases in ERBP. The magnitude of AEPs and ERBP typically increased with click rate. Superimposed on the AEPs were frequency-following responses (FFRs), most prominent at 50-Hz click rates but still detectable at stimulus rates up to 200 Hz. Loci with the largest high gamma responses on PLST were often different from those sites that exhibited the strongest FFRs. The data indicate that responses of non-core auditory cortex of PLST represent temporal stimulus features in multiple ways. These include an isomorphic representation of periodicity (as measured by the FFR), a representation based on increases in non-phase-locked activity (as measured by high gamma ERBP), and spatially distributed patterns of activity.
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Affiliation(s)
- Kirill V Nourski
- Dept. of Neurosurgery, The Univ. of Iowa, Iowa City, IA 52242, USA.
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Ongoing temporal coding of a stochastic stimulus as a function of intensity: time-intensity trading. J Neurosci 2012; 32:9517-27. [PMID: 22787037 DOI: 10.1523/jneurosci.0103-12.2012] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Stimulus-locked temporal codes are increasingly seen as relevant to perception. The timing of action potentials typically varies with stimulus intensity, and the invariance of temporal representations with intensity is therefore an issue. We examine the timing of action potentials in cat auditory nerve to broadband noise presented at different intensities, using an analysis inspired by coincidence detection and by the binaural "latency hypothesis." It is known that the two cues for azimuthal sound localization, interaural intensity or level differences and interaural time differences (ITDs), interact perceptually. According to the latency hypothesis, the increase in intensity for the ear nearest to a sound source off the midline causes a decrease in response latency in that ear relative to the other ear. We found that changes in intensity cause small but systematic shifts in the ongoing timing of responses in the auditory nerve, generally but not always resulting in shorter delays between stimulus onset and neural response for increasing intensity. The size of the temporal shifts depends on characteristic frequency with a pattern indicating a fine-structure and an envelope response regime. Overall, the results show that ongoing timing is remarkably stable with intensity at the most peripheral neural level. The results are not consistent in a simple way with the latency hypothesis, but because of the acute sensitivity to ITDs, the subtle effects of intensity on timing may nevertheless have perceptual consequences.
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47
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Neurons with stereotyped and rapid responses provide a reference frame for relative temporal coding in primate auditory cortex. J Neurosci 2012; 32:2998-3008. [PMID: 22378873 DOI: 10.1523/jneurosci.5435-11.2012] [Citation(s) in RCA: 41] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The precise timing of spikes of cortical neurons relative to stimulus onset carries substantial sensory information. To access this information the sensory systems would need to maintain an internal temporal reference that reflects the precise stimulus timing. Whether and how sensory systems implement such reference frames to decode time-dependent responses, however, remains debated. Studying the encoding of naturalistic sounds in primate (Macaca mulatta) auditory cortex we here investigate potential intrinsic references for decoding temporally precise information. Within the population of recorded neurons, we found one subset responding with stereotyped fast latencies that varied little across trials or stimuli, while the remaining neurons had stimulus-modulated responses with longer and variable latencies. Computational analysis demonstrated that the neurons with stereotyped short latencies constitute an effective temporal reference for relative coding. Using the response onset of a simultaneously recorded stereotyped neuron allowed decoding most of the stimulus information carried by onset latencies and the full spike train of stimulus-modulated neurons. Computational modeling showed that few tens of such stereotyped reference neurons suffice to recover nearly all information that would be available when decoding the same responses relative to the actual stimulus onset. These findings reveal an explicit neural signature of an intrinsic reference for decoding temporal response patterns in the auditory cortex of alert animals. Furthermore, they highlight a role for apparently unselective neurons as an early saliency signal that provides a temporal reference for extracting stimulus information from other neurons.
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48
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Wojtczak M, Beim JA, Micheyl C, Oxenham AJ. Perception of across-frequency asynchrony and the role of cochlear delays. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2012; 131:363-377. [PMID: 22280598 PMCID: PMC3272712 DOI: 10.1121/1.3665995] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/12/2011] [Revised: 11/10/2011] [Accepted: 11/10/2011] [Indexed: 05/29/2023]
Abstract
Cochlear filtering results in earlier responses to high than to low frequencies. This study examined potential perceptual correlates of cochlear delays by measuring the perception of relative timing between tones of different frequencies. A brief 250-Hz tone was combined with a brief 1-, 2-, 4-, or 6-kHz tone. Two experiments were performed, one involving subjective judgments of perceived synchrony, the other involving asynchrony detection and discrimination. The functions relating the proportion of "synchronous" responses to the delay between the tones were similar for all tone pairs. Perceived synchrony was maximal when the tones in a pair were gated synchronously. The perceived-synchrony function slopes were asymmetric, being steeper on the low-frequency-leading side. In the second experiment, asynchrony-detection thresholds were lower for low-frequency rather than for high-frequency leading pairs. In contrast with previous studies, but consistent with the first experiment, thresholds did not depend on frequency separation between the tones, perhaps because of the elimination of within-channel cues. The results of the two experiments were related quantitatively using a decision-theoretic model, and were found to be highly correlated. Overall the results suggest that frequency-dependent cochlear group delays are compensated for at higher processing stages, resulting in veridical perception of timing relationships across frequency.
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Affiliation(s)
- Magdalena Wojtczak
- Department of Psychology, University of Minnesota, 75 East River Road, Minneapolis, Minnesota 55455, USA.
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49
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Sharpee TO, Nagel KI, Doupe AJ. Two-dimensional adaptation in the auditory forebrain. J Neurophysiol 2011; 106:1841-61. [PMID: 21753019 PMCID: PMC3296429 DOI: 10.1152/jn.00905.2010] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2010] [Accepted: 07/07/2011] [Indexed: 11/22/2022] Open
Abstract
Sensory neurons exhibit two universal properties: sensitivity to multiple stimulus dimensions, and adaptation to stimulus statistics. How adaptation affects encoding along primary dimensions is well characterized for most sensory pathways, but if and how it affects secondary dimensions is less clear. We studied these effects for neurons in the avian equivalent of primary auditory cortex, responding to temporally modulated sounds. We showed that the firing rate of single neurons in field L was affected by at least two components of the time-varying sound log-amplitude. When overall sound amplitude was low, neural responses were based on nonlinear combinations of the mean log-amplitude and its rate of change (first time differential). At high mean sound amplitude, the two relevant stimulus features became the first and second time derivatives of the sound log-amplitude. Thus a strikingly systematic relationship between dimensions was conserved across changes in stimulus intensity, whereby one of the relevant dimensions approximated the time differential of the other dimension. In contrast to stimulus mean, increases in stimulus variance did not change relevant dimensions, but selectively increased the contribution of the second dimension to neural firing, illustrating a new adaptive behavior enabled by multidimensional encoding. Finally, we demonstrated theoretically that inclusion of time differentials as additional stimulus features, as seen so prominently in the single-neuron responses studied here, is a useful strategy for encoding naturalistic stimuli, because it can lower the necessary sampling rate while maintaining the robustness of stimulus reconstruction to correlated noise.
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Affiliation(s)
- Tatyana O Sharpee
- The Crick-Jacobs Center for Theoretical and Computational Biology, Computational Neurobiology Laboratory, The Salk Institute for Biological Studies, and the Center for Theoretical Biological Physics, University of California, San Diego, La Jolla, CA, USA.
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50
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Laback B, Zimmermann I, Majdak P, Baumgartner WD, Pok SM. Effects of envelope shape on interaural envelope delay sensitivity in acoustic and electric hearing. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2011; 130:1515-29. [PMID: 21895091 DOI: 10.1121/1.3613704] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The envelope shape is important for the perception of interaural time difference (ITD) in the envelope as supported by the improved sensitivity for transposed tones compared to sinusoidally amplitude-modulated (SAM) tones. The present study investigated the effects of specific envelope parameters in nine normal-hearing (NH) and seven cochlear-implant (CI) listeners, using high-rate carriers with 27-Hz trapezoidal modulation. In NH listeners, increasing the off time (the silent interval in each modulation cycle) up to 12 ms, increasing the envelope slope from 6 to 8 dB/ms, and increasing the peak level improved ITD sensitivity. The combined effect of the off time and slope accounts for the gain in sensitivity for transposed tones relative to SAM tones. In CI listeners, increasing the off time up to 20 ms improved sensitivity, but increasing the slope showed no systematic effect. A 27-pulses/s electric pulse train, representing a special case of modulation with infinitely steep slopes and maximum possible off time, yielded considerably higher sensitivity compared to the best condition with trapezoidal modulation. Overall, the results of this study indicate that envelope-ITD sensitivity could be improved by using CI processing schemes that simultaneously increase the off time and the peak level of the signal envelope.
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Affiliation(s)
- Bernhard Laback
- Acoustics Research Institute, Austrian Academy of Sciences, Wohllebengasse 12-14, A-1040 Vienna, Austria.
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