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Ma Y, Shu WC, Lin L, Cao XJ, Oertel D, Smith PH, Jackson MB. Imaging Voltage Globally and in Isofrequency Lamina in Slices of Mouse Ventral Cochlear Nucleus. eNeuro 2023; 10:ENEURO.0465-22.2023. [PMID: 36792362 PMCID: PMC9997695 DOI: 10.1523/eneuro.0465-22.2023] [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: 11/15/2022] [Revised: 02/02/2023] [Accepted: 02/06/2023] [Indexed: 02/17/2023] Open
Abstract
The cochlear nuclei (CNs) receive sensory information from the ear and perform fundamental computations before relaying this information to higher processing centers. These computations are performed by distinct types of neurons interconnected in circuits dedicated to the specialized roles of the auditory system. In the present study, we explored the use of voltage imaging to investigate CN circuitry. We tested two approaches based on fundamentally different voltage sensing technologies. Using a voltage-sensitive dye we recorded glutamate receptor-independent signals arising predominantly from axons. The mean conduction velocity of these fibers of 0.27 m/s was rapid but in range with other unmyelinated axons. We then used a genetically-encoded hybrid voltage sensor (hVOS) to image voltage from a specific population of neurons. Probe expression was controlled using Cre recombinase linked to c-fos activation. This activity-induced gene enabled targeting of neurons that are activated when a mouse hears a pure 15-kHz tone. In CN slices from these animals auditory nerve fiber stimulation elicited a glutamate receptor-dependent depolarization in hVOS probe-labeled neurons. These cells resided within a band corresponding to an isofrequency lamina, and responded with a high degree of synchrony. In contrast to the axonal origin of voltage-sensitive dye signals, hVOS signals represent predominantly postsynaptic responses. The introduction of voltage imaging to the CN creates the opportunity to investigate auditory processing circuitry in populations of neurons targeted on the basis of their genetic identity and their roles in sensory processing.
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Affiliation(s)
- Yihe Ma
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Wen-Chi Shu
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Lin Lin
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Xiao-Jie Cao
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Donata Oertel
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Philip H Smith
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
| | - Meyer B Jackson
- Department of Neuroscience, University of Wisconsin School of Medicine and Public Health, Madison, WI 53705
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Stoner ZA, Ketchum EM, Sheltz-Kempf S, Blinkiewicz PV, Elliott KL, Duncan JS. Fzd3 Expression Within Inner Ear Afferent Neurons Is Necessary for Central Pathfinding. Front Neurosci 2022; 15:779871. [PMID: 35153658 PMCID: PMC8828977 DOI: 10.3389/fnins.2021.779871] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2021] [Accepted: 12/29/2021] [Indexed: 11/29/2022] Open
Abstract
During development the afferent neurons of the inner ear make precise wiring decisions in the hindbrain reflective of their topographic distribution in the periphery. This is critical for the formation of sensory maps capable of faithfully processing both auditory and vestibular input. Disorganized central projections of inner ear afferents in Fzd3 null mice indicate Wnt/PCP signaling is involved in this process and ear transplantation in Xenopus indicates that Fzd3 is necessary in the ear but not the hindbrain for proper afferent navigation. However, it remains unclear in which cell type of the inner ear Fzd3 expression is influencing the guidance of inner ear afferents to their proper synaptic targets in the hindbrain. We utilized Atoh1-cre and Neurod1-cre mouse lines to conditionally knockout Fzd3 within the mechanosensory hair cells of the organ of Corti and within the inner ear afferents, respectively. Following conditional deletion of Fzd3 within the hair cells, the central topographic distribution of inner ear afferents was maintained with no gross morphological defects. In contrast, conditional deletion of Fzd3 within inner ear afferents leads to central pathfinding defects of both cochlear and vestibular afferents. Here, we show that Fzd3 is acting in a cell autonomous manner within inner ear afferents to regulate central pathfinding within the hindbrain.
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Affiliation(s)
- Zachary A. Stoner
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, United States
| | - Elizabeth M. Ketchum
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, United States
| | - Sydney Sheltz-Kempf
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, United States
| | - Paige V. Blinkiewicz
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, United States
| | - Karen L. Elliott
- Department of Biology, University of Iowa, Iowa City, IA, United States
- *Correspondence: Karen L. Elliott,
| | - Jeremy S. Duncan
- Department of Biological Sciences, Western Michigan University, Kalamazoo, MI, United States
- Department of Biomedical Sciences, Western Michigan University Homer Stryker MD School of Medicine, Kalamazoo, MI, United States
- Jeremy S. Duncan,
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3
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Mathematical framework for place coding in the auditory system. PLoS Comput Biol 2021; 17:e1009251. [PMID: 34339409 PMCID: PMC8360601 DOI: 10.1371/journal.pcbi.1009251] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2020] [Revised: 08/12/2021] [Accepted: 07/06/2021] [Indexed: 11/18/2022] Open
Abstract
In the auditory system, tonotopy is postulated to be the substrate for a place code, where sound frequency is encoded by the location of the neurons that fire during the stimulus. Though conceptually simple, the computations that allow for the representation of intensity and complex sounds are poorly understood. Here, a mathematical framework is developed in order to define clearly the conditions that support a place code. To accommodate both frequency and intensity information, the neural network is described as a space with elements that represent individual neurons and clusters of neurons. A mapping is then constructed from acoustic space to neural space so that frequency and intensity are encoded, respectively, by the location and size of the clusters. Algebraic operations -addition and multiplication- are derived to elucidate the rules for representing, assembling, and modulating multi-frequency sound in networks. The resulting outcomes of these operations are consistent with network simulations as well as with electrophysiological and psychophysical data. The analyses show how both frequency and intensity can be encoded with a purely place code, without the need for rate or temporal coding schemes. The algebraic operations are used to describe loudness summation and suggest a mechanism for the critical band. The mathematical approach complements experimental and computational approaches and provides a foundation for interpreting data and constructing models.
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Qi J, Zhang Z, He N, Liu X, Zhang C, Yan J. Cortical Stimulation Induces Excitatory Postsynaptic Potentials of Inferior Colliculus Neurons in a Frequency-Specific Manner. Front Neural Circuits 2020; 14:591986. [PMID: 33192337 PMCID: PMC7649762 DOI: 10.3389/fncir.2020.591986] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/05/2020] [Accepted: 09/24/2020] [Indexed: 11/30/2022] Open
Abstract
Corticofugal modulation of auditory responses in subcortical nuclei has been extensively studied whereas corticofugal synaptic transmission must still be characterized. This study examined postsynaptic potentials of the corticocollicular system, i.e., the projections from the primary auditory cortex (AI) to the central nucleus of the inferior colliculus (ICc) of the midbrain, in anesthetized C57 mice. We used focal electrical stimulation at the microampere level to activate the AI (ESAI) and in vivo whole-cell current-clamp to record the membrane potentials of ICc neurons. Following the whole-cell patch-clamp recording of 88 ICc neurons, 42 ICc neurons showed ESAI-evoked changes in the membrane potentials. We found that the ESAI induced inhibitory postsynaptic potentials in 6 out of 42 ICc neurons but only when the stimulus current was 96 μA or higher. In the remaining 36 ICc neurons, excitatory postsynaptic potentials (EPSPs) were induced at a much lower stimulus current. The 36 ICc neurons exhibiting EPSPs were categorized into physiologically matched neurons (n = 12) when the characteristic frequencies of the stimulated AI and recorded ICc neurons were similar (≤1 kHz) and unmatched neurons (n = 24) when they were different (>1 kHz). Compared to unmatched neurons, matched neurons exhibited a significantly lower threshold of evoking noticeable EPSP, greater EPSP amplitude, and shorter EPSP latency. Our data allow us to propose that corticocollicular synaptic transmission is primarily excitatory and that synaptic efficacy is dependent on the relationship of the frequency tunings between AI and ICc neurons.
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Affiliation(s)
- Jiyao Qi
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Zizhen Zhang
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Na He
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Xiuping Liu
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Caseng Zhang
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
| | - Jun Yan
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, AB, Canada
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5
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Xiong C, Liu X, Kong L, Yan J. Thalamic gating contributes to forward suppression in the auditory cortex. PLoS One 2020; 15:e0236760. [PMID: 32726372 PMCID: PMC7390390 DOI: 10.1371/journal.pone.0236760] [Citation(s) in RCA: 4] [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: 04/20/2020] [Accepted: 07/11/2020] [Indexed: 11/18/2022] Open
Abstract
The neural mechanisms underlying forward suppression in the auditory cortex remain a puzzle. Little attention is paid to thalamic contribution despite the important fact that the thalamus gates upstreaming information to the auditory cortex. This study compared the time courses of forward suppression in the auditory thalamus, thalamocortical inputs and cortex using the two-tone stimulus paradigm. The preceding and succeeding tones were 20-ms long. Their frequency and amplitude were set at the characteristic frequency and 20 dB above the minimum threshold of given neurons, respectively. In the ventral division of the medial geniculate body of the thalamus, we found that the duration of complete forward suppression was about 75 ms and the duration of partial suppression was from 75 ms to about 300 ms after the onset of the preceding tone. We also found that during the partial suppression period, the responses to the succeeding tone were further suppressed in the primary auditory cortex. The forward suppression of thalamocortical field excitatory postsynaptic potentials was between those of thalamic and cortical neurons but much closer to that of thalamic ones. Our results indicate that early suppression in the cortex could result from complete suppression in the thalamus whereas later suppression may involve thalamocortical and intracortical circuitry. This suggests that the complete suppression that occurs in the thalamus provides the cortex with a "silence" window that could potentially benefit cortical processing and/or perception of the information carried by the preceding sound.
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Affiliation(s)
- Colin Xiong
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Xiuping Liu
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Lingzhi Kong
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
| | - Jun Yan
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, Calgary, Alberta, Canada
- * E-mail:
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Singla S, Dempsey C, Warren R, Enikolopov AG, Sawtell NB. A cerebellum-like circuit in the auditory system cancels responses to self-generated sounds. Nat Neurosci 2017; 20:943-950. [PMID: 28530663 PMCID: PMC5525154 DOI: 10.1038/nn.4567] [Citation(s) in RCA: 62] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/15/2016] [Accepted: 04/19/2017] [Indexed: 12/15/2022]
Abstract
The dorsal cochlear nucleus (DCN) integrates auditory nerve input with a
diverse array of sensory and motor signals processed within circuity similar to
the cerebellum. Yet how the DCN contributes to early auditory processing has
been a longstanding puzzle. Using electrophysiological recordings in mice during
licking behavior we show that DCN neurons are largely unaffected by
self-generated sounds while remaining sensitive to external acoustic stimuli.
Recordings in deafened mice, together with neural activity manipulations,
indicate that self-generated sounds are cancelled by non-auditory signals
conveyed by mossy fibers. In addition, DCN neurons exhibit gradual reductions in
their responses to acoustic stimuli that are temporally correlated with licking.
Together, these findings suggest that DCN may act as an adaptive filter for
cancelling self-generated sounds. Adaptive filtering has been established
previously for cerebellum-like sensory structures in fish suggesting a conserved
function for such structures across vertebrates.
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Affiliation(s)
- Shobhit Singla
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, New York, USA
| | - Conor Dempsey
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, New York, USA
| | - Richard Warren
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, New York, USA
| | - Armen G Enikolopov
- Department of Biological Sciences, Columbia University, New York, New York, USA
| | - Nathaniel B Sawtell
- Department of Neuroscience and Kavli Institute for Brain Science, Columbia University Medical Center, New York, New York, USA
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7
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Liu X, Zhou L, Ding F, Wang Y, Yan J. Local field potentials are local events in the mouse auditory cortex. Eur J Neurosci 2015; 42:2289-97. [PMID: 26112462 PMCID: PMC5014213 DOI: 10.1111/ejn.13003] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2015] [Revised: 06/05/2015] [Accepted: 06/18/2015] [Indexed: 11/30/2022]
Abstract
Local field potentials (LFPs) and spikes (SPKs) sampled at the thalamocortical recipient layers represent the inputs from the thalamus and outputs to other layers. Previous studies have shown that SPK‐constructed receptive fields (RFSPK) of cortical neurons are much smaller than LFP‐constructed RFs (RFLFP). The difference in cortical RFLFP and RFSPK is therefore a plausible indication of local networking. The presence of a boarder RFLFP appears due to contamination, to some degree, from remote sites. Our studies of the mouse primary auditory cortex show that the best frequencies and minimum thresholds of RFSPK and RFLFP were similar. We also observed that the RFLFP area was only slightly larger than the RFSPK area, a very different finding from previous reports. The bandwidth of RFLFP was slightly broader than that of RFSPK at all levels. These data do not support the explanation that bioelectrical signals from distant sites impact on cortical LFP through volume conduction. That the cortical LFP represents a local event is further supported by comparisons of RFSPK and RFLFP after cortical inhibition by muscimol and cortical disinhibition by bicuculine. We conclude that the difference between RFSPK (output of cortical neurons) and RFLFP (input of cortical neurons) results from intracortical processing, including cortical lateral inhibition and excitation.
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Affiliation(s)
- Xiuping Liu
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Linran Zhou
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Fangchao Ding
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Yehan Wang
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
| | - Jun Yan
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Cumming School of Medicine, University of Calgary, 3330 Hospital Drive NW, Calgary, AB, T2N 4N1, Canada
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8
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Kong L, Xiong C, Li L, Yan J. Frequency-specific corticofugal modulation of the dorsal cochlear nucleus in mice. Front Syst Neurosci 2014; 8:125. [PMID: 25071477 PMCID: PMC4076887 DOI: 10.3389/fnsys.2014.00125] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/18/2014] [Accepted: 06/16/2014] [Indexed: 01/03/2023] Open
Abstract
The primary auditory cortex (AI) modulates the sound information processing in the lemniscal subcortical nuclei, including the anteroventral cochlear nucleus (AVCN), in a frequency-specific manner. The dorsal cochlear nucleus (DCN) is a non-lemniscal subcortical nucleus but it is tonotopically organized like the AVCN. However, it remains unclear how the AI modulates the sound information processing in the DCN. This study examined the impact of focal electrical stimulation of AI on the auditory responses of the DCN neurons in mice. We found that the electrical stimulation induced significant changes in the best frequency (BF) of DCN neurons. The changes in the BFs were highly specific to the BF differences between the stimulated AI neurons and the recorded DCN neurons. The DCN BFs shifted higher when the AI BFs were higher than the DCN BFs and the DCN BFs shifted lower when the AI BFs were lower than the DCN BFs. The DCN BFs showed no change when the AI and DCN BFs were similar. Moreover, the BF shifts were linearly correlated to the BF differences. Thus, our data suggest that corticofugal modulation of the DCN is also highly specific to frequency information, similar to the corticofugal modulation of the AVCN. The frequency-specificity of corticofugal modulation does not appear limited to the lemniscal ascending pathway.
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Affiliation(s)
- Lingzhi Kong
- Department of Physiology and Pharmacology, Faculty of Medicine, Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada
| | - Colin Xiong
- Department of Physiology and Pharmacology, Faculty of Medicine, Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada
| | - Liang Li
- Department of Psychology, Department of Machine Intelligence, Speech and Hearing Research Center, Key Laboratory on Machine Perception (Ministry of Education), PKU-IDG/McGovern Institute for Brain Research, Peking University Beijing, China
| | - Jun Yan
- Department of Physiology and Pharmacology, Faculty of Medicine, Hotchkiss Brain Institute, University of Calgary Calgary, AB, Canada
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Guenthner CJ, Miyamichi K, Yang HH, Heller HC, Luo L. Permanent genetic access to transiently active neurons via TRAP: targeted recombination in active populations. Neuron 2013; 78:773-84. [PMID: 23764283 DOI: 10.1016/j.neuron.2013.03.025] [Citation(s) in RCA: 402] [Impact Index Per Article: 36.5] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 03/19/2013] [Indexed: 12/16/2022]
Abstract
Targeting genetically encoded tools for neural circuit dissection to relevant cellular populations is a major challenge in neurobiology. We developed an approach, targeted recombination in active populations (TRAP), to obtain genetic access to neurons that were activated by defined stimuli. This method utilizes mice in which the tamoxifen-dependent recombinase CreER(T2) is expressed in an activity-dependent manner from the loci of the immediate early genes Arc and Fos. Active cells that express CreER(T2) can only undergo recombination when tamoxifen is present, allowing genetic access to neurons that are active during a time window of less than 12 hr. We show that TRAP can provide selective access to neurons activated by specific somatosensory, visual, and auditory stimuli and by experience in a novel environment. When combined with tools for labeling, tracing, recording, and manipulating neurons, TRAP offers a powerful approach for understanding how the brain processes information and generates behavior.
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Affiliation(s)
- Casey J Guenthner
- Howard Hughes Medical Institute, Stanford University, Stanford, CA 94305, USA
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10
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Luo F, Yan J. Sound-specific plasticity in the primary auditory cortex as induced by the cholinergic pedunculopontine tegmental nucleus. Eur J Neurosci 2013; 37:393-9. [PMID: 23373690 DOI: 10.1111/ejn.12046] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2012] [Revised: 09/23/2012] [Accepted: 10/01/2012] [Indexed: 11/30/2022]
Abstract
Brain cholinergic modulation is essential for learning-induced plasticity of the auditory cortex. The pedunculopontine tegmental nucleus (PPTg) is an important cholinergic nucleus in the brainstem, and appears to be involved in learning and subcortical plasticity. This study confirms the involvement of the PPTg in the plasticity of the auditory cortex in mice. We show here that electrical stimulation of the PPTg paired with a tone induced drastic changes in the frequency tunings of auditory cortical neurons. Importantly, the changes in frequency tuning were highly specific to the frequency of the paired tone; the best frequency of auditory cortical neurons shifted towards the frequency of the paired tone. We further demonstrated that such frequency-specific plasticity was largely eliminated by either thalamic or cortical application of the muscarinic acetylcholine receptor antagonist atropine. Our finding suggests that the PPTg significantly contributes to auditory cortical plasticity via the auditory thalamus and cholinergic basal forebrain.
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Affiliation(s)
- Feng Luo
- Hubei Key Laboratory of Genetic Regulation and Integrative Biology, School of Life Sciences, Central China Normal University, Wuhan, Hubei, China.
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11
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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: 45] [Impact Index Per Article: 4.1] [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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12
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Green SH, Bailey E, Wang Q, Davis RL. The Trk A, B, C's of Neurotrophins in the Cochlea. Anat Rec (Hoboken) 2012; 295:1877-95. [DOI: 10.1002/ar.22587] [Citation(s) in RCA: 75] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/24/2012] [Accepted: 07/24/2012] [Indexed: 12/20/2022]
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13
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Roos MJ, May BJ. Classification of unit types in the anteroventral cochlear nucleus of laboratory mice. Hear Res 2012; 289:13-26. [PMID: 22579638 DOI: 10.1016/j.heares.2012.04.019] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/12/2012] [Revised: 04/16/2012] [Accepted: 04/23/2012] [Indexed: 10/28/2022]
Abstract
This report introduces a system for the objective physiological classification of single-unit activity in the anteroventral cochlear nucleus (AVCN) of anesthetized CBA/129 and CBA/CaJ mice. As in previous studies, the decision criteria are based on the temporal properties of responses to short tone bursts that are visualized in the form of peri-stimulus time histograms (PSTHs). Individual unit types are defined by the statistical distribution of quantifiable metrics that relate to the onset latency, regularity, and adaptation of sound-driven discharge rates. Variations of these properties reflect the unique synaptic organizations and intrinsic membrane properties that dictate the selective tuning of sound coding in the AVCN. When these metrics are applied to the mouse AVCN, responses to best frequency (BF) tones reproduce the major PSTH patterns that have been previously demonstrated in other mammalian species. The consistency of response types in two genetically diverse strains of laboratory mice suggests that the present classification system is appropriate for additional strains with normal peripheral function. The general agreement of present findings to established classifications validates laboratory mice as an adequate model for general principles of mammalian sound coding. Nevertheless, important differences are noted for the reliability of specialized endbulb transmission within the AVCN, suggesting less secure temporal coding in this high-frequency species.
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Affiliation(s)
- Matthew J Roos
- Department of Neuroscience, The Johns Hopkins University School of Medicine, Baltimore, MD, USA
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14
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Cleland TA, Chen SYT, Hozer KW, Ukatu HN, Wong KJ, Zheng F. Sequential mechanisms underlying concentration invariance in biological olfaction. FRONTIERS IN NEUROENGINEERING 2012; 4:21. [PMID: 22287949 PMCID: PMC3251820 DOI: 10.3389/fneng.2011.00021] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 10/03/2011] [Accepted: 12/19/2011] [Indexed: 11/13/2022]
Abstract
Concentration invariance-the capacity to recognize a given odorant (analyte) across a range of concentrations-is an unusually difficult problem in the olfactory modality. Nevertheless, humans and other animals are able to recognize known odors across substantial concentration ranges, and this concentration invariance is a highly desirable property for artificial systems as well. Several properties of olfactory systems have been proposed to contribute to concentration invariance, but none of these alone can plausibly achieve full concentration invariance. We here propose that the mammalian olfactory system uses at least six computational mechanisms in series to reduce the concentration-dependent variance in odor representations to a level at which different concentrations of odors evoke reasonably similar representations, while preserving variance arising from differences in odor quality. We suggest that the residual variance then is treated like any other source of stimulus variance, and categorized appropriately into "odors" via perceptual learning. We further show that naïve mice respond to different concentrations of an odorant just as if they were differences in quality, suggesting that, prior to odor categorization, the learning-independent compensatory mechanisms are limited in their capacity to achieve concentration invariance.
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Affiliation(s)
- Thomas A Cleland
- Computational Physiology Laboratory, Department of Psychology, Cornell University, Ithaca NY, USA
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15
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Ma WLD, Brenowitz SD. Single-neuron recordings from unanesthetized mouse dorsal cochlear nucleus. J Neurophysiol 2011; 107:824-35. [PMID: 22072506 DOI: 10.1152/jn.00427.2011] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Because of the availability of disease and genetic models, the mouse has become a valuable species for auditory neuroscience that will facilitate long-term goals of understanding neuronal mechanisms underlying the perception and processing of sounds. The goal of this study was to define the basic sound-evoked response properties of single neurons in the mouse dorsal cochlear nucleus (DCN). Neurons producing complex spikes were distinguished as cartwheel cells (CWCs), and other neurons were classified according to the response map scheme previously developed in DCN. Similar to observations in other rodent species, neurons of the mouse DCN exhibit relatively little sound-driven inhibition. As a result, type III was the most commonly observed response. Our findings are generally consistent with the model of DCN function that has been developed in the cat and the gerbil, suggesting that this in vivo mouse preparation will be a useful tool for future studies of auditory physiology.
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Affiliation(s)
- Wei-Li Diana Ma
- Section on Synaptic Transmission, National Institute on Deafness and Other Communication Disorders, National Institutes of Health, Bethesda, Maryland, USA
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Luo F, Liu X, Wang C, Yan J. The Pedunculopontine Tegmental Nucleus: A Second Cholinergic Source for Frequency-Specific Auditory Plasticity. J Neurophysiol 2011; 105:107-16. [DOI: 10.1152/jn.00546.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cholinergic modulation is essential for many brain functions and is an indispensable component of the prevalent models attempting to understand the neural mechanism responsible for learning-induced auditory plasticity. Unlike the cholinergic basal forebrain, the cholinergic pedunculopontine tegmental nucleus (PPTg) has received little attention. This study was designed to confirm whether the PPTg enables frequency-specific plasticity in the ventral division of the medial geniculate body of the thalamus (MGBv). Using the mouse model, we paired electrical stimulation of the PPTg with tone stimulation to help define the role of the PPTg. The receptive fields of MGBv neurons were examined before and after the paired stimulation; they were quantified in this study by best frequency (BF), response threshold, dynamic range, and spike number. We found that the electrical stimulation of the PPTg together with a tone presentation shifted the BFs of MGBv neurons upward when the frequency of the paired tone was higher than that of the control BF. Similarly, the BFs shifted downward when the frequency of the paired tone was lower than that of the control BF. The BFs of MGBv neurons, however, remained unchanged when the frequency of the paired tone was the same as that of the control BF. There was a linear relationship between the BF shift of MGBv neurons and the difference between the frequency of the paired tone and the control BF of MGBv neurons. Highly frequency specific changes were also observed in the response threshold, dynamic range, and spike number. This frequency-specific plasticity was largely eliminated by the microinjection of the muscarinic receptor antagonist atropine into the MGBv before the paired stimulation. Our findings suggest that the PPTg, like the cholinergic basal forebrain, is an important cholinergic source that enables frequency-specific plasticity in the central auditory system.
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Affiliation(s)
- Feng Luo
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada; and
| | - Xiuping Liu
- Health Science Centre, Hebei University, Baoding, Hebei, China
| | - Carol Wang
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada; and
| | - Jun Yan
- Department of Physiology and Pharmacology, Hotchkiss Brain Institute, Faculty of Medicine, University of Calgary, Calgary, Alberta, Canada; and
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Corticofugal modulation of initial neural processing of sound information from the ipsilateral ear in the mouse. PLoS One 2010; 5:e14038. [PMID: 21124980 PMCID: PMC2987806 DOI: 10.1371/journal.pone.0014038] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/16/2010] [Accepted: 10/30/2010] [Indexed: 12/04/2022] Open
Abstract
Background Cortical neurons implement a high frequency-specific modulation of subcortical nuclei that includes the cochlear nucleus. Anatomical studies show that corticofugal fibers terminating in the auditory thalamus and midbrain are mostly ipsilateral. Differently, corticofugal fibers terminating in the cochlear nucleus are bilateral, which fits to the needs of binaural hearing that improves hearing quality. This leads to our hypothesis that corticofugal modulation of initial neural processing of sound information from the contralateral and ipsilateral ears could be equivalent or coordinated at the first sound processing level. Methodology/Principal Findings With the focal electrical stimulation of the auditory cortex and single unit recording, this study examined corticofugal modulation of the ipsilateral cochlear nucleus. The same methods and procedures as described in our previous study of corticofugal modulation of contralateral cochlear nucleus were employed simply for comparison. We found that focal electrical stimulation of cortical neurons induced substantial changes in the response magnitude, response latency and receptive field of ipsilateral cochlear nucleus neurons. Cortical stimulation facilitated auditory response and shortened the response latency of physiologically matched neurons whereas it inhibited auditory response and lengthened the response latency of unmatched neurons. Finally, cortical stimulation shifted the best frequencies of cochlear neurons towards those of stimulated cortical neurons. Conclusion Our data suggest that cortical neurons enable a high frequency-specific remodelling of sound information processing in the ipsilateral cochlear nucleus in the same manner as that in the contralateral cochlear nucleus.
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Schwarz J, Burguet J, Rampin O, Fromentin G, Andrey P, Tomé D, Maurin Y, Darcel N. Three-dimensional macronutrient-associated Fos expression patterns in the mouse brainstem. PLoS One 2010; 5:e8974. [PMID: 20126542 PMCID: PMC2813867 DOI: 10.1371/journal.pone.0008974] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/06/2009] [Accepted: 01/06/2010] [Indexed: 12/03/2022] Open
Abstract
Background The caudal brainstem plays an important role in short-term satiation and in the control of meal termination. Meal-related stimuli sensed by the gastrointestinal (GI) tract are transmitted to the area postrema (AP) via the bloodstream, or to the nucleus tractus solitarii (NTS) via the vagus nerve. Little is known about the encoding of macronutrient-specific signals in the caudal brainstem. We hypothesized that sucrose and casein peptone activate spatially distinct sub-populations of NTS neurons and thus characterized the latter using statistical three-dimensional modeling. Methodology/Principal Findings Using immunolabeling of the proto-oncogene Fos as a marker of neuronal activity, in combination with a statistical three-dimensional modeling approach, we have shown that NTS neurons activated by sucrose or peptone gavage occupy distinct, although partially overlapping, positions. Specifically, when compared to their homologues in peptone-treated mice, three-dimensional models calculated from neuronal density maps following sucrose gavage showed that Fos-positive neurons occupy a more lateral position at the rostral end of the NTS, and a more dorsal position at the caudal end. Conclusion/Significance To our knowledge, this is the first time that subpopulations of NTS neurons have be distinguished according to the spatial organization of their functional response. Such neuronal activity patterns may be of particular relevance to understanding the mechanisms that support the central encoding of signals related to the presence of macronutrients in the GI tract during digestion. Finally, this finding also illustrates the usefulness of statistical three-dimensional modeling to functional neuroanatomical studies.
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Affiliation(s)
- Jessica Schwarz
- AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
- INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - Jasmine Burguet
- INRA, UMR 1197 Neurobiologie de l'Olfaction et de la Prise Alimentaire, Domaine de Vilvert, Jouy-en-Josas, France
- Université Paris-Sud 11, UMR 1197, Orsay, France
- IFR 144 Neuro-Sud Paris, Paris, France
| | - Olivier Rampin
- INRA, UMR 1197 Neurobiologie de l'Olfaction et de la Prise Alimentaire, Domaine de Vilvert, Jouy-en-Josas, France
- Université Paris-Sud 11, UMR 1197, Orsay, France
- IFR 144 Neuro-Sud Paris, Paris, France
| | - Gilles Fromentin
- AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
- INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - Philippe Andrey
- INRA, UMR 1197 Neurobiologie de l'Olfaction et de la Prise Alimentaire, Domaine de Vilvert, Jouy-en-Josas, France
- Université Paris-Sud 11, UMR 1197, Orsay, France
- IFR 144 Neuro-Sud Paris, Paris, France
- UPMC Univ. Paris 06, Paris, France
| | - Daniel Tomé
- AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
- INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
| | - Yves Maurin
- INRA, UMR 1197 Neurobiologie de l'Olfaction et de la Prise Alimentaire, Domaine de Vilvert, Jouy-en-Josas, France
- Université Paris-Sud 11, UMR 1197, Orsay, France
- IFR 144 Neuro-Sud Paris, Paris, France
| | - Nicolas Darcel
- AgroParisTech, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
- INRA, CRNH-IdF, UMR914 Nutrition Physiology and Ingestive Behavior, Paris, France
- * E-mail:
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