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Liu X, Zhang O, Chen A, Hu K, Ehret G, Yan J. Corticofugal Augmentation of the Auditory Brainstem Response With Respect to Cortical Preference. Front Syst Neurosci 2019; 13:39. [PMID: 31496941 PMCID: PMC6713121 DOI: 10.3389/fnsys.2019.00039] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2019] [Accepted: 08/02/2019] [Indexed: 11/30/2022] Open
Abstract
Physiological studies documented highly specific corticofugal modulations making subcortical centers focus processing on sounds that the auditory cortex (AC) has experienced to be important. Here, we show the effects of focal conditioning (FC) of the primary auditory cortex (FCAI) on auditory brainstem response (ABR) amplitudes and latencies in house mice. FCAI significantly increased ABR peak amplitudes (peaks I–V), decreased thresholds, and shortened peak latencies in responses to the frequency tuned by conditioned cortical neurons. The amounts of peak amplitude increases and latency decreases were specific for each processing level up to the auditory midbrain. The data provide new insights into possible corticofugal modulation of inner hair cell synapses and new corticofugal effects as neuronal enhancement of processing in the superior olivary complex (SOC) and lateral lemniscus (LL). Thus, our comprehensive ABR approach confirms the role of the AC as instructor of lower auditory levels and extends this role specifically to the cochlea, SOC, and LL. The whole pathway from the cochlea to the inferior colliculus appears, in a common mode, instructed in a very similar way.
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Affiliation(s)
- Xiuping Liu
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Oliver Zhang
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Amber Chen
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Kaili Hu
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Günter Ehret
- Institute of Neurobiology, University of Ulm, Ulm, Germany
| | - Jun Yan
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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2
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Geissler DB, Weiler E, Ehret G. Adaptation and spectral enhancement at auditory temporal perceptual boundaries - Measurements via temporal precision of auditory brainstem responses. PLoS One 2018; 13:e0208935. [PMID: 30571726 PMCID: PMC6301773 DOI: 10.1371/journal.pone.0208935] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2018] [Accepted: 11/26/2018] [Indexed: 12/21/2022] Open
Abstract
In human and animal auditory perception the perceived quality of sound streams changes depending on the duration of inter-sound intervals (ISIs). Here, we studied whether adaptation and the precision of temporal coding in the auditory periphery reproduce general perceptual boundaries in the time domain near 20, 100, and 400 ms ISIs, the physiological origin of which are unknown. In four experiments, we recorded auditory brainstem responses with five wave peaks (P1 –P5) in response to acoustic models of communication calls of house mice, who perceived these calls with the mentioned boundaries. The newly introduced measure of average standard deviations of wave latencies of individual animals indicate the waves’ temporal precision (latency jitter) mostly in the range of 30–100 μs, very similar to latency jitter of single neurons. Adaptation effects of response latencies and latency jitter were measured for ISIs of 10–1000 ms. Adaptation decreased with increasing ISI duration following exponential or linear (on a logarithmic scale) functions in the range of up to about 200 ms ISIs. Adaptation effects were specific for each processing level in the auditory system. The perceptual boundaries near 20–30 and 100 ms ISIs were reflected in significant adaptation of latencies together with increases of latency jitter at P2-P5 for ISIs < ~30 ms and at P5 for ISIs < ~100 ms, respectively. Adaptation effects occurred when frequencies in a sound stream were within the same critical band. Ongoing low-frequency components/formants in a sound enhanced (decrease of latencies) coding of high-frequency components/formants when the frequencies concerned different critical bands. The results are discussed in the context of coding multi-harmonic sounds and stop-consonants-vowel pairs in the auditory brainstem. Furthermore, latency data at P1 (cochlea level) offer a reasonable value for the base-to-apex cochlear travel time in the mouse (0.342 ms) that has not been determined experimentally.
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Affiliation(s)
| | - Elke Weiler
- Institute of Neurobiology, University of Ulm, Ulm, Germany
| | - Günter Ehret
- Institute of Neurobiology, University of Ulm, Ulm, Germany
- * E-mail:
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3
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An Overrepresentation of High Frequencies in the Mouse Inferior Colliculus Supports the Processing of Ultrasonic Vocalizations. PLoS One 2015; 10:e0133251. [PMID: 26244986 PMCID: PMC4526676 DOI: 10.1371/journal.pone.0133251] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/22/2014] [Accepted: 06/25/2015] [Indexed: 12/15/2022] Open
Abstract
Mice are of paramount importance in biomedical research and their vocalizations are a subject of interest for researchers across a wide range of health-related disciplines due to their increasingly important value as a phenotyping tool in models of neural, speech and language disorders. However, the mechanisms underlying the auditory processing of vocalizations in mice are not well understood. The mouse audiogram shows a peak in sensitivity at frequencies between 15-25 kHz, but weaker sensitivity for the higher ultrasonic frequencies at which they typically vocalize. To investigate the auditory processing of vocalizations in mice, we measured evoked potential, single-unit, and multi-unit responses to tones and vocalizations at three different stages along the auditory pathway: the auditory nerve and the cochlear nucleus in the periphery, and the inferior colliculus in the midbrain. Auditory brainstem response measurements suggested stronger responses in the midbrain relative to the periphery for frequencies higher than 32 kHz. This result was confirmed by single- and multi-unit recordings showing that high ultrasonic frequency tones and vocalizations elicited responses from only a small fraction of cells in the periphery, while a much larger fraction of cells responded in the inferior colliculus. These results suggest that the processing of communication calls in mice is supported by a specialization of the auditory system for high frequencies that emerges at central stations of the auditory pathway.
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4
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King J, Insanally M, Jin M, Martins ARO, D'amour JA, Froemke RC. Rodent auditory perception: Critical band limitations and plasticity. Neuroscience 2015; 296:55-65. [PMID: 25827498 DOI: 10.1016/j.neuroscience.2015.03.053] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2014] [Revised: 03/20/2015] [Accepted: 03/22/2015] [Indexed: 10/23/2022]
Abstract
What do animals hear? While it remains challenging to adequately assess sensory perception in animal models, it is important to determine perceptual abilities in model systems to understand how physiological processes and plasticity relate to perception, learning, and cognition. Here we discuss hearing in rodents, reviewing previous and recent behavioral experiments querying acoustic perception in rats and mice, and examining the relation between behavioral data and electrophysiological recordings from the central auditory system. We focus on measurements of critical bands, which are psychoacoustic phenomena that seem to have a neural basis in the functional organization of the cochlea and the inferior colliculus. We then discuss how behavioral training, brain stimulation, and neuropathology impact auditory processing and perception.
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Affiliation(s)
- J King
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA; Center for Neural Science, New York University, New York, NY, USA
| | - M Insanally
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA; Center for Neural Science, New York University, New York, NY, USA
| | - M Jin
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA; Center for Neural Science, New York University, New York, NY, USA
| | - A R O Martins
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA; Center for Neural Science, New York University, New York, NY, USA; PhD Programme in Experimental Biology and Biomedicine, Center for Neurosciences and Cell Biology, University of Coimbra, Portugal
| | - J A D'amour
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA; Center for Neural Science, New York University, New York, NY, USA
| | - R C Froemke
- Skirball Institute for Biomolecular Medicine, New York University School of Medicine, New York, NY, USA; Department of Otolaryngology, New York University School of Medicine, New York, NY, USA; Department of Neuroscience and Physiology, New York University School of Medicine, New York, NY, USA; Center for Neural Science, New York University, New York, NY, USA.
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5
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Liang F, Bai L, Tao HW, Zhang LI, Xiao Z. Thresholding of auditory cortical representation by background noise. Front Neural Circuits 2014; 8:133. [PMID: 25426029 PMCID: PMC4226155 DOI: 10.3389/fncir.2014.00133] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2014] [Accepted: 10/21/2014] [Indexed: 11/13/2022] Open
Abstract
It is generally thought that background noise can mask auditory information. However, how the noise specifically transforms neuronal auditory processing in a level-dependent manner remains to be carefully determined. Here, with in vivo loose-patch cell-attached recordings in layer 4 of the rat primary auditory cortex (A1), we systematically examined how continuous wideband noise of different levels affected receptive field properties of individual neurons. We found that the background noise, when above a certain critical/effective level, resulted in an elevation of intensity threshold for tone-evoked responses. This increase of threshold was linearly dependent on the noise intensity above the critical level. As such, the tonal receptive field (TRF) of individual neurons was translated upward as an entirety toward high intensities along the intensity domain. This resulted in preserved preferred characteristic frequency (CF) and the overall shape of TRF, but reduced frequency responding range and an enhanced frequency selectivity for the same stimulus intensity. Such translational effects on intensity threshold were observed in both excitatory and fast-spiking inhibitory neurons, as well as in both monotonic and nonmonotonic (intensity-tuned) A1 neurons. Our results suggest that in a noise background, fundamental auditory representations are modulated through a background level-dependent linear shifting along intensity domain, which is equivalent to reducing stimulus intensity.
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Affiliation(s)
- Feixue Liang
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou Guangdong, China ; Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California Los Angeles, CA, USA
| | - Lin Bai
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou Guangdong, China ; Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California Los Angeles, CA, USA
| | - Huizhong W Tao
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California Los Angeles, CA, USA
| | - Li I Zhang
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California Los Angeles, CA, USA
| | - Zhongju Xiao
- Department of Physiology, School of Basic Medicine, Southern Medical University, Guangzhou Guangdong, China
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6
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Muniak MA, Rivas A, Montey KL, May BJ, Francis HW, Ryugo DK. 3D model of frequency representation in the cochlear nucleus of the CBA/J mouse. J Comp Neurol 2013; 521:1510-32. [PMID: 23047723 PMCID: PMC3992438 DOI: 10.1002/cne.23238] [Citation(s) in RCA: 48] [Impact Index Per Article: 4.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2012] [Revised: 08/29/2012] [Accepted: 10/02/2012] [Indexed: 02/02/2023]
Abstract
The relationship between structure and function is an invaluable context with which to explore biological mechanisms of normal and dysfunctional hearing. The systematic and topographic representation of frequency originates at the cochlea, and is retained throughout much of the central auditory system. The cochlear nucleus (CN), which initiates all ascending auditory pathways, represents an essential link for understanding frequency organization. A model of the CN that maps frequency representation in 3D would facilitate investigations of possible frequency specializations and pathologic changes that disturb frequency organization. Toward this goal, we reconstructed in 3D the trajectories of labeled auditory nerve (AN) fibers following multiunit recordings and dye injections in the anteroventral CN of the CBA/J mouse. We observed that each injection produced a continuous sheet of labeled AN fibers. Individual cases were normalized to a template using 3D alignment procedures that revealed a systematic and tonotopic arrangement of AN fibers in each subdivision with a clear indication of isofrequency laminae. The combined dataset was used to mathematically derive a 3D quantitative map of frequency organization throughout the entire volume of the CN. This model, available online (http://3D.ryugolab.com/), can serve as a tool for quantitatively testing hypotheses concerning frequency and location in the CN.
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Affiliation(s)
- Michael A Muniak
- Department of Neuroscience, Johns Hopkins University, Baltimore, Maryland 21205, USA.
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7
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Early postnatal development of spontaneous and acoustically evoked discharge activity of principal cells of the medial nucleus of the trapezoid body: an in vivo study in mice. J Neurosci 2009; 29:9510-20. [PMID: 19641114 DOI: 10.1523/jneurosci.1377-09.2009] [Citation(s) in RCA: 107] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
The calyx of Held synapse in the medial nucleus of the trapezoid body of the auditory brainstem has become an established in vitro model to study the development of fast glutamatergic transmission in the mammalian brain. However, we still lack in vivo data at this synapse on the maturation of spontaneous and sound-evoked discharge activity before and during the early phase of acoustically evoked signal processing (i.e., before and after hearing onset). Here we report in vivo single-unit recordings in mice from postnatal day 8 (P8) to P28 with a specific focus on developmental changes around hearing onset (P12). Data were obtained from two mouse strains commonly used in brain slice recordings: CBA/J and C57BL/6J. Spontaneous discharge rates progressively increased from P8 to P13, initially showing bursting patterns and large coefficients of variation (CVs), which changed to more continuous and random discharge activity accompanied by gradual decrease of CV around hearing onset. From P12 on, sound-evoked activity yielded phasic-tonic discharge patterns with discharge rates increasing up to P28. Response thresholds and shapes of tuning curves were adult-like by P14. A gradual shortening in response latencies was observed up to P18. The three-dimensional tonotopic organization of the medial nucleus of the trapezoid body yielded a high-to-low frequency gradient along the mediolateral and dorsoventral but not in the rostrocaudal axes. These data emphasize that models of signal transmission at the calyx of Held based on in vitro data have to take developmental changes in firing rates and response latencies up to the fourth postnatal week into account.
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8
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Unmasking effects of olivocochlear efferent activation on responses of inferior colliculus neurons. Hear Res 2008; 243:35-46. [DOI: 10.1016/j.heares.2008.05.004] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 12/11/2007] [Revised: 05/12/2008] [Accepted: 05/14/2008] [Indexed: 11/19/2022]
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9
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Egorova M, Ehret G. Tonotopy and inhibition in the midbrain inferior colliculus shape spectral resolution of sounds in neural critical bands. Eur J Neurosci 2008; 28:675-92. [DOI: 10.1111/j.1460-9568.2008.06376.x] [Citation(s) in RCA: 28] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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10
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Russell IJ, Legan PK, Lukashkina VA, Lukashkin AN, Goodyear RJ, Richardson GP. Sharpened cochlear tuning in a mouse with a genetically modified tectorial membrane. Nat Neurosci 2007; 10:215-23. [PMID: 17220887 PMCID: PMC3388746 DOI: 10.1038/nn1828] [Citation(s) in RCA: 121] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2006] [Accepted: 12/12/2006] [Indexed: 11/09/2022]
Abstract
Frequency tuning in the cochlea is determined by the passive mechanical properties of the basilar membrane and active feedback from the outer hair cells, sensory-effector cells that detect and amplify sound-induced basilar membrane motions. The sensory hair bundles of the outer hair cells are imbedded in the tectorial membrane, a sheet of extracellular matrix that overlies the cochlea's sensory epithelium. The tectorial membrane contains radially organized collagen fibrils that are imbedded in an unusual striated-sheet matrix formed by two glycoproteins, alpha-tectorin (Tecta) and beta-tectorin (Tectb). In Tectb(-/-) mice the structure of the striated-sheet matrix is disrupted. Although these mice have a low-frequency hearing loss, basilar-membrane and neural tuning are both significantly enhanced in the high-frequency regions of the cochlea, with little loss in sensitivity. These findings can be attributed to a reduction in the acting mass of the tectorial membrane and reveal a new function for this structure in controlling interactions along the cochlea.
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MESH Headings
- Animals
- Basilar Membrane/abnormalities
- Basilar Membrane/metabolism
- Basilar Membrane/ultrastructure
- Cells, Cultured
- Chimera
- Cochlea/abnormalities
- Cochlea/metabolism
- Cochlea/ultrastructure
- Collagen/metabolism
- Extracellular Matrix/metabolism
- Extracellular Matrix Proteins/genetics
- GPI-Linked Proteins
- Hair Cells, Auditory, Outer/cytology
- Hair Cells, Auditory, Outer/metabolism
- Hearing/genetics
- Hearing Loss, Sensorineural/genetics
- Hearing Loss, Sensorineural/metabolism
- Hearing Loss, Sensorineural/physiopathology
- Membrane Glycoproteins/genetics
- Membrane Proteins/genetics
- Mice
- Mice, Inbred C57BL
- Mice, Knockout
- Mutation/genetics
- Pitch Perception
- Tectorial Membrane/abnormalities
- Tectorial Membrane/metabolism
- Tectorial Membrane/ultrastructure
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Affiliation(s)
- Ian J. Russell
- School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK
| | - P. Kevin Legan
- School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK
| | | | - Andrei N. Lukashkin
- School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK
| | - Richard J. Goodyear
- School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK
| | - Guy. P Richardson
- School of Life Sciences, University of Sussex, Falmer, Brighton, BN1 9QG, UK
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11
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Müller M, von Hünerbein K, Hoidis S, Smolders JWT. A physiological place–frequency map of the cochlea in the CBA/J mouse. Hear Res 2005; 202:63-73. [PMID: 15811700 DOI: 10.1016/j.heares.2004.08.011] [Citation(s) in RCA: 311] [Impact Index Per Article: 16.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/29/2004] [Accepted: 08/17/2004] [Indexed: 11/26/2022]
Abstract
Genetically manipulated mice have gained a prominent role in in vivo research on development and function of the auditory system. A prerequisite for the interpretation of normal and abnormal structural and functional features of the inner ear is the exact knowledge of the cochlear place-frequency map. Using a stereotaxic approach to the projection site of the auditory nerve fibers in the cochlear nucleus, we succeeded in labelling physiologically characterized auditory nerve afferents and determined their peripheral innervation site in the cochlea. From the neuronal characteristic frequency (CF) and the innervation site in the organ of Corti a place-frequency map was established for characteristic frequencies between 7.2 and 61.8 kHz, corresponding to locations between 90% and 10% basilar membrane length (base = 0%, apex = 100%, mean length measured under the inner hair cells 5.13 mm). The relation between normalized distance from the base (d) and frequency (kHz) can be described by a simple logarithmic function: d(%) = 156.5-82.5 x log(f), with a slope of 1.25 mm/octave of frequency. The present map, recorded under physiological conditions, differs from earlier maps determined with different methods. The simple logarithmic place-frequency relation found in the mouse indicates that mice are acoustic generalists rather than specialists.
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Affiliation(s)
- Marcus Müller
- Physiologisches Institut II, J.W. Goethe-Universität Frankfurt, Germany
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12
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Abstract
The availability of transgenic and mutant lines makes the mouse a valuable model for study of the inner ear, and a powerful window into cochlear function can be obtained by recordings from single auditory nerve (AN) fibers. This study provides the first systematic description of spontaneous and sound-evoked discharge properties of AN fibers in mouse, specifically in CBA/CaJ and C57BL/6 strains, both commonly used in auditory research. Response properties of 196 AN fibers from CBA/CaJ and 58 from C57BL/6 were analyzed, including spontaneous rates (SR), tuning curves, rate versus level functions, dynamic range, response adaptation, phase-locking, and the relation between SR and these response properties. The only significant interstrain difference was the elevation of high-frequency thresholds in C57BL/6. In general, mouse AN fibers showed similar responses to other mammals: sharpness of tuning increased with characteristic frequency, which ranged from 2.5 to 70 kHz; SRs ranged from 0 to 120 sp/s, and fibers with low SR (<1 sp/s) had higher thresholds, and wider dynamic ranges than fibers with high SR. Dynamic ranges for mouse high-SR fibers were smaller (<20 dB) than those seen in other mammals. Phase-locking was seen for tone frequencies <4 kHz. Maximum synchronization indices were lower than those in cat but similar to those found in guinea pig.
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Affiliation(s)
- Annette M Taberner
- Eaton-Peabody Laboratory, Massachusetts Eye and Ear Infirmary, 243 Charles St., Boston, MA 02114, USA
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13
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Chiu TW, Poon PWF, Chan WY, Yew DTW. Long-term changes of response in the inferior colliculus of senescence accelerated mice after early sound exposure. J Neurol Sci 2003; 216:143-51. [PMID: 14607316 DOI: 10.1016/s0022-510x(03)00230-2] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
Early sound exposure could alter auditory sensitivity in young animals. For example, the distribution of frequency tuning at the midbrain inferior colliculus (IC) is altered following early exposure to a tone at a moderate intensity level. Whether such neonatal change is still present in the old animals remains unknown. We studied the long-term effects of early sound exposure using a mutant strain of mice expressing accelerated senescence (SAM). Experimental animals were first exposed to a 9-kHz tone (53 dB sound pressure level (SPL)) for 30 days (10 h/day) after birth. Control animals received no tones. At the age of 15 months, responses of single IC units to sounds were studied electrophysiologically under urethane anesthesia. In the control group, we found an overall reduction in sensitivity to tones particularly at high frequencies, in comparison with normal non-senescent mice. Moreover, neurons exhibited increased spontaneous activities. These signs are consistent with accelerated senescence. Early sound exposure produced two effects in the experimental group. Firstly, IC units showed an apparent 'clustering' of best frequencies towards the frequency of the exposing tone (i.e., 9 kHz). Secondly, there was a further loss in sensitivity to tones particularly at high frequencies. Results suggest that early sound exposure has produced a long-lasting effect on frequency tuning of IC neurons. Acoustic overstimulation early in life may also accelerate the senescence of neurons or structures in the auditory system.
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Affiliation(s)
- T W Chiu
- Institute of Basic Medical Sciences, College of Medicine, National Cheng Kung University, Tainan, Taiwan
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14
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Barsz K, Wilson WW, Walton JP. Background noise differentially effects temporal coding by tonic units in the mouse inferior colliculus. Hear Res 2000; 150:149-60. [PMID: 11077200 DOI: 10.1016/s0378-5955(00)00186-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
Abstract
In natural environments, temporally complex signals often occur in a background of noise. The neural mechanisms underlying the preservation of temporal sensitivity in background noise are poorly understood. In the present study, we examined the ability of inferior colliculus (IC) units with primary-like and sustained response patterns ('tonic units') to encode silent gaps in quiet and in background noise. Minimum gap thresholds (MGTs), the shortest silent gap in a noise burst evoking a neural response, were measured in quiet and background noise for 34 IC units. Units were classified as background noise resistant (BNR; MGT did not change in background noise) or background noise sensitive (BNS; MGTs became elevated in background noise). In quiet, the MGTs of BNR and BNS units were comparable and both types of units encoded the gap by a cessation of activity during the gap. The addition of background noise had little effect on the response rate of BNR units either during or after the gap stimulus. In contrast, for BNS units, background noise reduced the response rate during the gap stimulus while increasing the response rate after the gap stimulus. Background noise also altered the first spike latency of BNS units. For BNS units, the mean first spike latency was no longer inversely related to BF, but this relationship was maintained in BNR units. These results suggest that the response of BNS units to background noise obliterates their response to the gap stimulus.
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Affiliation(s)
- K Barsz
- Otolaryngology Division, Department of Surgery, P.O. Box 629, University of Rochester School of Medicine and Dentistry, Rochester, NY 14642-8629, USA
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15
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Parham K, Bonaiuto G, Carlson S, Turner JG, D'Angelo WR, Bross LS, Fox A, Willott JF, Kim DO. Purkinje cell degeneration and control mice: responses of single units in the dorsal cochlear nucleus and the acoustic startle response. Hear Res 2000; 148:137-52. [PMID: 10978831 DOI: 10.1016/s0378-5955(00)00147-7] [Citation(s) in RCA: 16] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/01/2022]
Abstract
The cartwheel cell is the most numerous inhibitory interneuron of the dorsal cochlear nucleus (DCN). It is expected to be an important determinant of DCN function. To assess the contribution of the cartwheel cell, we examined the discharge characteristics of DCN neurons and behavioral measures in the Purkinje cell degeneration (pcd) mice, which lack cartwheel cells, and compared them to those of the control mice. Distortion product otoacoustic emissions and auditory brainstem-evoked response thresholds were similar between the two groups. Extracellularly recorded DCN single units in ketamine/xylazine-anesthetized mice were classified according to post-stimulus time histogram (PSTH) and excitatory-inhibitory response area (EI-area) schemes. PSTHs recorded in mouse DCN included chopper, pauser/buildup, onset, inhibited and nondescript types. EI-areas recorded included Types I, II, III, I/III, IV and V. There were no significant differences in the proportions of various unit types between the pcd and control mice. The pcd units had slightly lower thresholds to characteristic frequency tones; however, they had spontaneous rates, thresholds to noise, and maximum driven rates to noise that were similar to those of the control units. Pcd mice had smaller startle amplitudes, but startle latency, prepulse inhibition/augmentation and facilitation by a background tone were comparable between the two groups. From these results, we conclude that DCN function in response to relatively simple acoustic stimuli is minimally affected by the absence of the cartwheel cells. Future studies employing more complex and/or multimodal stimuli should help assess the role of the cartwheel cells.
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Affiliation(s)
- K Parham
- Division of Otolarynology, Department of Surgery, University of Connecticut Health Center, Farmington, 06030-1110, USA
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Schreiner CE, Read HL, Sutter ML. Modular organization of frequency integration in primary auditory cortex. Annu Rev Neurosci 2000; 23:501-29. [PMID: 10845073 DOI: 10.1146/annurev.neuro.23.1.501] [Citation(s) in RCA: 198] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
Two fundamental aspects of frequency analysis shape the functional organization of primary auditory cortex. For one, the decomposition of complex sounds into different frequency components is reflected in the tonotopic organization of auditory cortical fields. Second, recent findings suggest that this decomposition is carried out in parallel for a wide range of frequency resolutions by neurons with frequency receptive fields of different sizes (bandwidths). A systematic representation of the range of frequency resolution and, equivalently, spectral integration shapes the functional organization of the iso-frequency domain. Distinct subregions, or "modules," along the iso-frequency domain can be demonstrated with various measures of spectral integration, including pure-tone tuning curves, noise masking, and electrical cochlear stimulation. This modularity in the representation of spectral integration is expressed by intrinsic cortical connections. This organization has implications for our understanding of psychophysical spectral integration measures such as the critical band and general cortical coding strategies.
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Affiliation(s)
- C E Schreiner
- Coleman Memorial Laboratory, W.M. Keck Center for Integrative Neuroscience, University of California, San Francisco 94143-0732, USA.
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Diesch E, Luce T. Topographic and temporal indices of vowel spectral envelope extraction in the human auditory cortex. J Cogn Neurosci 2000; 12:878-93. [PMID: 11054929 DOI: 10.1162/089892900562480] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022]
Abstract
The auditory-evoked neuromagnetic field elicited by single vowel formants and two-formant vowels was recorded under active listening conditions using a 37-channel magnetometer. There were three single formants with formant frequencies of 200, 400, and 800 Hz, another single formant with a formant frequency of 2600 Hz, and three vowels that were constructed by linear superimposition of the high- onto one of the low-frequency formants. P50 m and N100 m latency values were inversely correlated with the formant frequency of single formants. A strong effect of formant frequency on source location was obtained along the postero-anterior axis, which is orthogonal to the well-established latero-medial tonotopic gradient. Regardless of whether single formants or first formants of vowels were considered, N100 m sources were more anterior and sustained field sources were more posterior for higher-frequency than for lower-frequency formants. The velocity of the apparent posterior-to-anterior movement across cortical surface of N100 m sources first reported by Rogers et al. [Rogers, R. L., Papanicolaou, A. C., Baumann, S. B., Saydjari, C., & Eisenberg, H. M. (1990). Neuromagnetic evidence of a dynamic excitation pattern generating the N100 auditory response. Electroencephalography and Clinical Neurophysiology,77, 237-240] decreased as a function of latency. The amount of deceleration was positively correlated with formant frequency. Responses to the vowels were superadditive, indicating that the processes elicited by the constituents of composite stimuli interact at one or more stages of the afferent auditory pathway. Such interaction may account for the absence of a lateral-to-medial tonotopic mapping of first formant frequency. The source topography found may reflect activity in auditory fields adjacent to AI with the strength of the contribution varying with formant frequency. Alternatively, it may reflect sharpness-of-tuning and inhibitory response-area asymmetry gradients along isofrequency stripes within AI. Either alternative may be interpreted in terms of a spectral blurring mechanism that abstracts spectral envelope information from the details of spectral composition, an important step towards the formation of invariant phonetic percepts.
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Affiliation(s)
- E Diesch
- Institute of Medical Psychology and Neurobiology, University of Tübingen, Germany.
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18
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Abstract
Regional differences in spectral integration of neurons in cat primary auditory cortex (AI) suggest that regions differ in effects of background noise on operating characteristics of neurons. Therefore, tone-response threshold, best level (peak-rate intensity), dynamic range, and sharpness of tuning in quiet and in continuous broadband noise were mapped for single neurons along the isofrequency domain of AI. Neurons did not show an excitatory response to the noise. Noise invariably increased the tone-response threshold and best levels. Consequently, the dynamic ranges and receptive fields shifted to higher intensity levels without changes of average sharpness of tuning. These shifts were linearly related to noise level and showed little inter-neuronal variability for neurons in the central, mostly sharply tuned part of AI. In more dorsal and ventral parts of AI, neurons were more variable in tone-response threshold, dynamic range and best level, and no systematic relationship between increase in noise level, threshold increase and best-level increase was observed. We conclude that linear shifts in the operating range of neurons in central AI in the presence of continuous noise backgrounds do not affect other response properties and may relate to the unaltered analysis and representation of spectral components of sounds. In contrast, neurons in dorsal and ventral AI change response properties in a non-predictable way in the presence of noise in accordance with the more complex receptive field properties in those areas.
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Affiliation(s)
- G Ehret
- Department of Neurobiology, University of Ulm, D-89069, Ulm, Germany.
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Burkard R, Palmer AR. Responses of chopper units in the ventral cochlear nucleus of the anaesthetised guinea pig to clicks-in-noise and click trains. Hear Res 1997; 110:234-50. [PMID: 9282906 DOI: 10.1016/s0378-5955(97)00084-1] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 02/05/2023]
Abstract
Auditory brainstem responses (ABRs) have been measured with clicks, clicks masked by noise, click trains and pseudorandom maximum length sequences (MLS) of clicks. To investigate the neuronal populations contributing to the ABR under these stimulation conditions, we measured the extracellular responses of ventral cochlear nucleus (VCN) units in the urethane-anaesthetised guinea pig. We studied 23 chopper, 7 primary-like and 7 onset units. This report focuses on the responses from chopper units. The probability of discharge for chopper units increased with increasing click level reaching nearly 100% in many units, over a range of about 20-30 dB. Following each response to a click there was a 5-10 ms suppression of the spontaneous or noise evoked activity. As the level of the noise was increased over a range of 20-30 dB, the response to the clicks gradually decreased leading to a complete abolition of the click response at high noise levels. In a few units, low level noise produced a facilitation of the response to single clicks. In response to constant level equally spaced click trains, discharge probability increased with increasing minimum pulse interval (MPI), approaching 100% for MPIs of 4-8 ms in some units. The recovery afforded by the gaps in the MLS train often resulted in higher discharge probability for MLS than click trains with the same MPI, while response probabilities for MLS and click trains were similar when compared at equivalent average click rates. At short MPIs (0.5 and 1.0 ms), peri stimulus time histograms in response to click trains resembled those to best frequency (BF) tones and noisebursts, with chopping peaks unrelated to unit BF. VCN units show highly synchronised and reliable responses to click trains, MLS trains and clicks masked by noise. The decrease in discharge rate and increase in latency of chopper units with decreasing click level, increasing click rate and increasing masker level parallel the peak amplitude and latency changes observed in the auditory brainstem response.
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Affiliation(s)
- R Burkard
- The Center for Hearing and Deafness, University of Buffalo, NY 14214, USA
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20
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Schreiner CE, Langner G. Laminar fine structure of frequency organization in auditory midbrain. Nature 1997; 388:383-6. [PMID: 9237756 DOI: 10.1038/41106] [Citation(s) in RCA: 153] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023]
Abstract
The perception of sound is based on signal processing by a bank of frequency-selective auditory filters, the so-called critical bands. Here we investigate how the internal frequency organization of the main auditory midbrain station, the central nucleus of the inferior colliculus (ICC), might contribute to the generation of the critical-band behaviour of its neurons. We find a unique spatial arrangement of the frequency distribution in the ICC that correlates with psychophysical critical-band characteristics. Systematic frequency discontinuities along the main tonotopic axis, in combination with a smooth frequency gradient orthogonal to the main tonotopic organization of cat ICC, reflect a layering of the frequency organization paralleling its anatomical laminae. This layered frequency organization is characterized by constant frequency ratios of corresponding locations on neighbouring laminae and may provide a spatial framework for the generation of critical bands and for signal processing within and across frequency bands for the analysis of sound.
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Affiliation(s)
- C E Schreiner
- W. M. Keck Center for Integrative Neuroscience, Sloan Center for Theoretical Neuroscience, Coleman Laboratory, University of California at San Francisco, 94143-0732, USA.
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21
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McFadden SL, Willott JF. Responses of inferior colliculus neurons in C57BL/6J mice with and without sensorineural hearing loss: effects of changing the azimuthal location of a continuous noise masker on responses to contralateral tones. Hear Res 1994; 78:132-48. [PMID: 7982807 DOI: 10.1016/0378-5955(94)90019-1] [Citation(s) in RCA: 24] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/28/2023]
Abstract
Extracellular recordings were obtained from inferior colliculus neurons of young adult (2-month-old) C57 mice with normal hearing and middle-aged (6-month-old) C57 mice with sensorineural hearing loss as they responded to best frequency (BF) tones (signal) in the presence of a continuous background noise (masker). Rate/level functions were obtained for the signal alone, noise bursts alone, and the signal in continuous noise as a function of masker location. For both groups of mice, thresholds for BF tones were significantly elevated in the presence of noise at all three noise locations. Separating the signal and masker sources significantly improved masked tone thresholds of 2-month-old mice but not hearing-impaired mice. The decreased ability of middle-aged mice to benefit from separation of the signal and masker sources may reflect alterations in binaural processing as a result of sensorineural hearing loss.
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Affiliation(s)
- S L McFadden
- Department of Psychology, Northern Illinois University, DeKalb 60115
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Gerken GM. Evoked potentials recorded from brain-stem nuclei in awake cat: interaction of tone bursts and continuous tone. ELECTROENCEPHALOGRAPHY AND CLINICAL NEUROPHYSIOLOGY 1991; 80:73-9. [PMID: 1703953 DOI: 10.1016/0168-5597(91)90046-z] [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: 12/28/2022]
Abstract
Previous work indicated that components of the auditory thalamocortical potential evoked by a brief binaural tone burst could be enhanced by certain stimulus combinations, e.g., a brief tone burst in the presence of a continuous tone. The principal questions of the present study were whether enhanced components could be obtained caudal to thalamocortex and whether monaural stimuli would be effective in producing enhancement. Eight cats received permanent electrodes in cochlear nucleus and the nucleus of the inferior colliculus. Custom earmolds were made for each ear of each animal. The median attenuation produced by the earmolds was 35 dB and the use of a single earmold approximated monaural stimulation. Auditory evoked potentials were recorded from the electrodes while the animals were unanesthetized but comfortably restrained. Brief 6.25 kHz tone bursts were presented against a background of silence or of a 4.96 kHz continuous tone. In the presence of the continuous tone, enhanced components were obtained from a majority of the electrodes in inferior colliculus but from none of the electrodes in cochlear nucleus. The late negative component in the colliculus potential was increased in amplitude while other components were reduced in amplitude by the continuous tone. The latencies of all components from all electrodes were increased by the presence of the continuous tone. It was concluded that enhancement effects could be obtained at the level of inferior colliculus, and that binaural stimulation does not appear to be necessary to produce enhanced components.
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Affiliation(s)
- G M Gerken
- Dept. of Otorhinolaryngology, University of Texas Southwestern Medical Center, Dallas 75235
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Ehret G, Merzenich MM. Complex sound analysis (frequency resolution, filtering and spectral integration) by single units of the inferior colliculus of the cat. Brain Res 1988; 472:139-63. [PMID: 3289688 DOI: 10.1016/0165-0173(88)90018-5] [Citation(s) in RCA: 145] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/05/2023]
Abstract
The central nucleus of the inferior colliculus (ICC) is a center of convergence of brainstem input and is critical for auditory information processing. Here, the analysis of complex sound spectra by single neurons in the ICC is investigated. Several measures of frequency resolution (excitatory/inhibitory tuning curves, effective bandwidths, critical ratio bands, critical bands derived using narrowband masking and two-tone separation paradigms) have been obtained from the responses of these neurons at sound pressure levels (SPL) up to 80 dB above the units' response thresholds (nearly 110 dB SPL). Among our results are the following: (1) Narrowband masking measures of critical bands from ICC neurons closely parallel behavioral measures using the same stimulus paradigm. (2) Frequency resolution power as measured by critical bandwidths varies little as a function of stimulus intensity. (3) Tuning curves of ICC neurons provide no simple basis for predicting the frequency filtering of the same neurons excited by complex sound spectra. (4) There is a frequency dependence of all measures of frequency resolution similar to that found in psychophysical determinations of critical bandwidths. That is, spatial frequency resolution in the cochlea is the origin for the resolution found in the ICC and in behavioral tests. (5) Lateral inhibition at the level of the ICC clearly plays a role in frequency resolution. (6) Frequency resolution is encoded by response rate changes of ICC neurons and is independent of tone response threshold, response latency, spontaneous activity, tone response type, binaural response type. It is concluded that spectral analysis of sound is established by processes, including lateral inhibition, independent of other basic response properties of neurons at the level of the ICC.
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Affiliation(s)
- G Ehret
- Fakultät für Biologie, Universität Konstanz, F.R.G
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Abstract
Resolving the frequency components of complex sound spectra including speech is an inherent, important accomplishment of the auditory nervous systems of vertebrates. The critical perceptual unit in the frequency domain, the critical bandwidth, has a simple functional equivalent within the principal midbrain auditory nucleus--the central nucleus of the inferior colliculus.
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Ehret G, Moffat AJM. Inferior colliculus of the house mouse. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1985. [DOI: 10.1007/bf00619111] [Citation(s) in RCA: 39] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
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26
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Ehret G, Moffat AJM. Inferior colliculus of the house mouse. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 1985. [DOI: 10.1007/bf00619112] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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