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Alamatsaz N, Rosen MJ, Ihlefeld A. Increased reliance on temporal coding when target sound is softer than the background. Sci Rep 2024; 14:4457. [PMID: 38396044 PMCID: PMC10891139 DOI: 10.1038/s41598-024-54865-5] [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: 06/14/2023] [Accepted: 02/17/2024] [Indexed: 02/25/2024] Open
Abstract
Everyday environments often contain multiple concurrent sound sources that fluctuate over time. Normally hearing listeners can benefit from high signal-to-noise ratios (SNRs) in energetic dips of temporally fluctuating background sound, a phenomenon called dip-listening. Specialized mechanisms of dip-listening exist across the entire auditory pathway. Both the instantaneous fluctuating and the long-term overall SNR shape dip-listening. An unresolved issue regarding cortical mechanisms of dip-listening is how target perception remains invariant to overall SNR, specifically, across different tone levels with an ongoing fluctuating masker. Equivalent target detection over both positive and negative overall SNRs (SNR invariance) is reliably achieved in highly-trained listeners. Dip-listening is correlated with the ability to resolve temporal fine structure, which involves temporally-varying spike patterns. Thus the current work tests the hypothesis that at negative SNRs, neuronal readout mechanisms need to increasingly rely on decoding strategies based on temporal spike patterns, as opposed to spike count. Recordings from chronically implanted electrode arrays in core auditory cortex of trained and awake Mongolian gerbils that are engaged in a tone detection task in 10 Hz amplitude-modulated background sound reveal that rate-based decoding is not SNR-invariant, whereas temporal coding is informative at both negative and positive SNRs.
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Affiliation(s)
- Nima Alamatsaz
- Graduate School of Biomedical Sciences, Rutgers University, Newark, NJ, USA
- Department of Biomedical Engineering, New Jersey Institute of Technology, Newark, NJ, USA
| | - Merri J Rosen
- Northeast Ohio Medical University (NEOMED), Rootstown, OH, USA.
- University Hospitals Hearing Research Center at NEOMED, Rootstown, OH, USA.
- Brain Health Research Institute, Kent State University, Kent, OH, USA.
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Faraji L, Pourbakht A, Haghani H. Comodulation Masking Release in Tinnitus Frequency and One Lower Octave of Tinnitus Frequency. Indian J Otolaryngol Head Neck Surg 2023; 75:363-371. [PMID: 37206848 PMCID: PMC10188682 DOI: 10.1007/s12070-022-03452-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/01/2022] [Accepted: 12/25/2022] [Indexed: 01/19/2023] Open
Abstract
Inhibitory function is the basis of many perceptual and non-perceptual abilities in the auditory system. In people with tinnitus, decreased inhibitory function in the central auditory system has been proven. This disorder is caused by an increase in neural activity caused by an imbalance between stimulation and inhibition. The aim of this study was to evaluate and compare inhibitory function in persons who had tinnitus, at and one octave lower than the tinnitus frequency. Studies show that inhibition has very important role in comodulation masking release. According to inhibitory dysfunction in people with tinnitus, in this study we assessed comodulation masking release in tinnitus frequency and one lower octave. Participants were divided into two groups. Group 1 consisted of 7 individuals with unilateral tonal tinnitus at 4 kHz and group 2 included 7 individuals with unilateral tonal tinnitus at 6 kHz. Paired test, in each group separately, showed that the comodulation masking release and Across Frequency comodulation masking release differed significantly between tinnitus frequency and one octave lower in each group (p < 0.05). In fact, the disinhibition in the area around the frequency of the tinnitus seems to be greater than the tinnitus frequency area. It seems that the results of CMRs can be used in planning and managing the treatment of people with tinnitus (such as sound therapy, etc.).
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Affiliation(s)
- Leila Faraji
- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Akram Pourbakht
- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Hamid Haghani
- Statistics Department, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
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Anderson SR, Kan A, Litovsky RY. Asymmetric temporal envelope sensitivity: Within- and across-ear envelope comparisons in listeners with bilateral cochlear implants. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2022; 152:3294. [PMID: 36586876 PMCID: PMC9731674 DOI: 10.1121/10.0016365] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/17/2022] [Revised: 11/14/2022] [Accepted: 11/16/2022] [Indexed: 06/17/2023]
Abstract
For listeners with bilateral cochlear implants (BiCIs), patient-specific differences in the interface between cochlear implant (CI) electrodes and the auditory nerve can lead to degraded temporal envelope information, compromising the ability to distinguish between targets of interest and background noise. It is unclear how comparisons of degraded temporal envelope information across spectral channels (i.e., electrodes) affect the ability to detect differences in the temporal envelope, specifically amplitude modulation (AM) rate. In this study, two pulse trains were presented simultaneously via pairs of electrodes in different places of stimulation, within and/or across ears, with identical or differing AM rates. Results from 11 adults with BiCIs indicated that sensitivity to differences in AM rate was greatest when stimuli were paired between different places of stimulation in the same ear. Sensitivity from pairs of electrodes was predicted by the poorer electrode in the pair or the difference in fidelity between both electrodes in the pair. These findings suggest that electrodes yielding poorer temporal fidelity act as a bottleneck to comparisons of temporal information across frequency and ears, limiting access to the cues used to segregate sounds, which has important implications for device programming and optimizing patient outcomes with CIs.
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Affiliation(s)
- Sean R Anderson
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
| | - Alan Kan
- School of Engineering, Macquarie University, Sydney, New South Wales 2109, Australia
| | - Ruth Y Litovsky
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
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Anderson SR, Kan A, Litovsky RY. Asymmetric temporal envelope encoding: Implications for within- and across-ear envelope comparison. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2019; 146:1189. [PMID: 31472559 PMCID: PMC7051005 DOI: 10.1121/1.5121423] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/25/2018] [Revised: 07/24/2019] [Accepted: 07/24/2019] [Indexed: 05/17/2023]
Abstract
Separating sound sources in acoustic environments relies on making ongoing, highly accurate spectro-temporal comparisons. However, listeners with hearing impairment may have varying quality of temporal encoding within or across ears, which may limit the listeners' ability to make spectro-temporal comparisons between places-of-stimulation. In this study in normal hearing listeners, depth of amplitude modulation (AM) for sinusoidally amplitude modulated (SAM) tones was manipulated in an effort to reduce the coding of periodicity in the auditory nerve. The ability to judge differences in AM rates was studied for stimuli presented to different cochlear places-of-stimulation, within- or across-ears. It was hypothesized that if temporal encoding was poorer for one tone in a pair, then sensitivity to differences in AM rate of the pair would decrease. Results indicated that when the depth of AM was reduced from 50% to 20% for one SAM tone in a pair, sensitivity to differences in AM rate decreased. Sensitivity was greatest for AM rates near 90 Hz and depended upon the places-of-stimulation being compared. These results suggest that degraded temporal representations in the auditory nerve for one place-of-stimulation could lead to deficits comparing that temporal information with other places-of-stimulation.
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Affiliation(s)
- Sean R Anderson
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
| | - Alan Kan
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
| | - Ruth Y Litovsky
- Waisman Center, University of Wisconsin-Madison, Madison, Wisconsin 53705, USA
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Pourbakht A, Faraji L. Asymmetric Flankers in Comodulation Masking Release. J Audiol Otol 2018; 23:27-32. [PMID: 30126261 PMCID: PMC6348304 DOI: 10.7874/jao.2018.00192] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/08/2018] [Accepted: 06/18/2018] [Indexed: 11/22/2022] Open
Abstract
Background and Objectives Detection of auditory signals may be improved when maskers far from the frequency of the target signal are coherently amplitude-modulated. This improvement of signal detection is called comodulation masking release (CMR). In the CMR experiments, flankers have been usually arranged symmetrically. In practice, we will be confronted with a problem by using symmetric flankers due to the limited output of clinical audiometers, especially at high-frequency. We aimed to check whether flanker arrangement has any effect on the amount of CMR, especially when there is no flankers with a frequency higher than the signal. Subjects and Methods Eighteen normal hearing listeners ranging in age from 20 to 46 years old participated. Symmetric (2-2) and asymmetric (3-1 and 4-0) flankers were used and then the amount of CMR compared among them. Results Our results showed in the same numbers of flankers, there were no statistically CMR differences between symmetric and asymmetric arrangement. Also when we did not have a flanker at a frequency higher than the signal and all flankers were placed below the signal, there was no statistically difference with the symmetric arrangement. Conclusions The asymmetry of the flankers and also omitting the flankers with a frequency higher than the signal, have no effect on CMR results. We concluded that CMR can be considered by using clinical audiometer.
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Affiliation(s)
- Akram Pourbakht
- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
| | - Leila Faraji
- Department of Audiology, School of Rehabilitation Sciences, Iran University of Medical Sciences, Tehran, Iran
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Hershenhoren I, Nelken I. Detection of Tones Masked by Fluctuating Noise in Rat Auditory Cortex. Cereb Cortex 2017; 27:5130-5143. [PMID: 28334090 DOI: 10.1093/cercor/bhw295] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2016] [Accepted: 08/25/2016] [Indexed: 11/13/2022] Open
Abstract
Sounds in natural settings always appear over a noisy background. The masked threshold of a pure tone in white noise (the lowest sound level at which the tone can be detected in the presence of masking noise) is largely determined by energy masking in the peripheral auditory system: when the signal-to-noise ratio within a frequency band centered at the target tone frequency is large enough, the tone can be detected. However, when additional information is supplied to the auditory system, for example in the presence of slow and coherent modulations of a broadband masker (often found in natural sounds), masked thresholds can be reduced substantially below the values expected from pure energy masking. Here, we used intracellular recordings in vivo in rat auditory cortex in order to study neuronal responses to pure tones masked by broadband maskers and amplitude-modulated broadband maskers. When tones were embedded in amplitude-modulated noise, detection thresholds were substantially lower than when embedded in unmodulated noise. The main cue for tone detection in modulated noise consisted of the suppression of the locking of the neuronal responses to the amplitude modulation of the noise by low-level tones.
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Affiliation(s)
- Itai Hershenhoren
- The Edmond and Lily Safra Center for Brain Sciences and the Department of Neuroscience, The Alexander Silberman Institute of Life Sciences, Hebrew University, Edmond J. Safra Campus, Jerusalem 91904, Israel
| | - Israel Nelken
- The Edmond and Lily Safra Center for Brain Sciences and the Department of Neuroscience, The Alexander Silberman Institute of Life Sciences, Hebrew University, Edmond J. Safra Campus, Jerusalem 91904, Israel
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Comodulation Enhances Signal Detection via Priming of Auditory Cortical Circuits. J Neurosci 2017; 36:12299-12311. [PMID: 27927950 PMCID: PMC5148223 DOI: 10.1523/jneurosci.0656-16.2016] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/29/2016] [Revised: 08/25/2016] [Accepted: 08/29/2016] [Indexed: 11/21/2022] Open
Abstract
Acoustic environments are composed of complex overlapping sounds that the auditory system is required to segregate into discrete perceptual objects. The functions of distinct auditory processing stations in this challenging task are poorly understood. Here we show a direct role for mouse auditory cortex in detection and segregation of acoustic information. We measured the sensitivity of auditory cortical neurons to brief tones embedded in masking noise. By altering spectrotemporal characteristics of the masker, we reveal that sensitivity to pure tone stimuli is strongly enhanced in coherently modulated broadband noise, corresponding to the psychoacoustic phenomenon comodulation masking release. Improvements in detection were largest following priming periods of noise alone, indicating that cortical segregation is enhanced over time. Transient opsin-mediated silencing of auditory cortex during the priming period almost completely abolished these improvements, suggesting that cortical processing may play a direct and significant role in detection of quiet sounds in noisy environments. SIGNIFICANCE STATEMENT Auditory systems are adept at detecting and segregating competing sound sources, but there is little direct evidence of how this process occurs in the mammalian auditory pathway. We demonstrate that coherent broadband noise enhances signal representation in auditory cortex, and that prolonged exposure to noise is necessary to produce this enhancement. Using optogenetic perturbation to selectively silence auditory cortex during early noise processing, we show that cortical processing plays a crucial role in the segregation of competing sounds.
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Grose JH, Buss E, Hall JW. Within- and across-channel factors in the multiband comodulation masking release paradigm. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2009; 125:282-293. [PMID: 19173415 PMCID: PMC2677279 DOI: 10.1121/1.3023067] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2007] [Revised: 10/20/2008] [Accepted: 10/21/2008] [Indexed: 05/27/2023]
Abstract
Maskers made up of comodulated narrow bands of noise can result in a signal detection advantage due to both within- and across-channel processes. The purpose of this study was to determine whether contributions from these processes could be differentiated on the basis of two stimulus manipulations: (1) onset/offset asynchrony across bands and (2) introduction of a random temporal fringe surrounding the comodulated bands. The hypothesis was that only masking release due to across-channel processing would be disrupted by these manipulations. Five-band comodulated maskers were constructed, and the availability of within- and across-channel cues was varied by adjusting the frequency spacing of the bands; both logarithmic and linear spacings were tested. The signal was a 1 kHz pure tone. Onset/offset asynchrony had different effects depending on the characteristics of the asynchrony. The results were consistent with an interpretation that across-channel, but not within-channel, masking release was disrupted when the flanking bands were presented continuously and the on-signal band was gated. However, the results suggested that both the across-channel and the within-channel masking release were disrupted in conditions where the on-signal band was continuous and the flanking bands were gated on, as well as in conditions where a random temporal fringe was present.
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Affiliation(s)
- John H Grose
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7070, USA.
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Grose JH, Buss E, Hall JW. Gap detection in modulated noise: across-frequency facilitation and interference. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2008; 123:998-1007. [PMID: 18247902 PMCID: PMC2290824 DOI: 10.1121/1.2828058] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This study tested the hypothesis that a detection advantage for gaps in comodulated noise relative to random noise can be demonstrated in conditions of continuous noise and salient envelope fluctuations. Experiment 1 used five 25-Hz-wide bands of Gaussian noise, low-fluctuation noise, and a noise with increased salience of the inherent fluctuations (staccato noise). The bands were centered at 444, 667, 1000, 1500, and 2250 Hz, with the gap signal always inserted in the 1000-Hz band. Results indicated that a gap detection advantage existed in continuous comodulated noise only for Gaussian and staccato noise. Experiment 2 demonstrated that the advantage did not exist for gated presentation. This experiment also showed that the advantage bore some similarity to comodulation masking release. However, differences were also noted in terms of the effects of the number of flanking bands and the absence of a detection advantage in gated conditions. The detrimental effect of a gated flanking band was less pronounced for a comodulated band than for a random band. This study indicates that, under some conditions, a detection advantage for gaps carried by a narrow band of noise can occur in the presence of comodulated flanking bands of noise.
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Affiliation(s)
- John H Grose
- Department of Otolaryngology-Head & Neck Surgery, University of North Carolina at Chapel Hill, Chapel Hill, North Carolina 27599-7070, USA.
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Jensen KK. Comodulation detection differences in the hooded crow (Corvus corone cornix), with direct comparison to human subjects. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2007; 121:1783-9. [PMID: 17407915 DOI: 10.1121/1.2434246] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/14/2023]
Abstract
Envelope modulations have been shown important in determining the effectiveness of masking noises. For example, the threshold for detecting a signal flanked by maskers is lower if the maskers and the signal are modulated with different envelopes, rather than the same envelope (comodulation). This threshold change is called the comodulation detection difference (CDD). CDDs were studied in two wild-caught hooded crows, using a 1.5 kHz signal and two maskers at 0.9 and 2.1 kHz, presented at an overall level of 55 dB SPL (re 20 microPa). For direct comparison with human psychophysics, three human subjects were tested in the same setup. CDDs averaged 15 dB for the two crow subjects and 11 dB for the human subjects. The species difference between average CDDs was insignificant. The significance of the CDD effect in a natural setting is discussed.
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Affiliation(s)
- Kenneth Kragh Jensen
- Institute of Biology, University of Southern Denmark, Campusvej 55, DK-5230 Odense M, Denmark.
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Hall JW, Buss E, Grose JH. Binaural comodulation masking release: effects of masker interaural correlation. THE JOURNAL OF THE ACOUSTICAL SOCIETY OF AMERICA 2006; 120:3878-88. [PMID: 17225415 PMCID: PMC1994906 DOI: 10.1121/1.2357989] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/13/2023]
Abstract
Binaural detection was examined for a signal presented in a narrow band of noise centered on the on-signal masking band (OSB) or in the presence of flanking noise bands that were random or comodulated with respect to the OSB. The noise had an interaural correlation of 1.0 (No), 0.99 or 0.95. In No noise, random flanking bands worsened Spi detection and comodulated bands improved Spi detection for some listeners but had no effect for other listeners. For the 0.99 or 0.95 interaural correlation conditions, random flanking bands were less detrimental to Spi detection and comodulated flanking bands improved Spi detection for all listeners. Analyses based on signal detection theory indicated that the improvement in Spi thresholds obtained with comodulated bands was not compatible with an optimal combination of monaural and binaural cues or to across-frequency analyses of dynamic interaural phase differences. Two accounts consistent with the improvement in Spi thresholds in comodulated noise were (1) envelope information carried by the flanking bands improves the weighting of binaural cues associated with the signal; (2) the auditory system is sensitive to across-frequency differences in ongoing interaural correlation.
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Affiliation(s)
- Joseph W Hall
- Department of Otolaryngology/Head and Neck Surgery, University of North Carolina School of Medicine, Chapel Hill, North Carolina 27599, USA.
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