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Yeo XY, Kwon S, Rinai KR, Lee S, Jung S, Park R. A Consolidated Understanding of the Contribution of Redox Dysregulation in the Development of Hearing Impairment. Antioxidants (Basel) 2024; 13:598. [PMID: 38790703 PMCID: PMC11118506 DOI: 10.3390/antiox13050598] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/22/2024] [Revised: 04/26/2024] [Accepted: 05/09/2024] [Indexed: 05/26/2024] Open
Abstract
The etiology of hearing impairment is multifactorial, with contributions from both genetic and environmental factors. Although genetic studies have yielded valuable insights into the development and function of the auditory system, the contribution of gene products and their interaction with alternate environmental factors for the maintenance and development of auditory function requires further elaboration. In this review, we provide an overview of the current knowledge on the role of redox dysregulation as the converging factor between genetic and environmental factor-dependent development of hearing loss, with a focus on understanding the interaction of oxidative stress with the physical components of the peripheral auditory system in auditory disfunction. The potential involvement of molecular factors linked to auditory function in driving redox imbalance is an important promoter of the development of hearing loss over time.
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Affiliation(s)
- Xin Yi Yeo
- Department of Psychological Medicine, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 119228, Singapore;
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Soohyun Kwon
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
- Department of BioNanotechnology, Gachon University, Seongnam 13120, Republic of Korea
| | - Kimberley R. Rinai
- Department of Life Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Sungsu Lee
- Department of Otolaryngology-Head and Neck Surgery, Chonnam National University Hospital and Medical School, Gwangju 61469, Republic of Korea;
| | - Sangyong Jung
- Department of Medical Science, College of Medicine, CHA University, Seongnam 13488, Republic of Korea;
| | - Raekil Park
- Department of Biomedical Science and Engineering, Gwangju Institute of Science & Technology (GIST), Gwangju 61005, Republic of Korea
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Delavari F, Sandini C, Kojovic N, Saccaro LF, Eliez S, Van De Ville D, Bolton TAW. Thalamic contributions to psychosis susceptibility: Evidence from co-activation patterns accounting for intra-seed spatial variability (μCAPs). Hum Brain Mapp 2024; 45:e26649. [PMID: 38520364 PMCID: PMC10960557 DOI: 10.1002/hbm.26649] [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: 07/23/2023] [Revised: 02/20/2024] [Accepted: 02/22/2024] [Indexed: 03/25/2024] Open
Abstract
The temporal variability of the thalamus in functional networks may provide valuable insights into the pathophysiology of schizophrenia. To address the complexity of the role of the thalamic nuclei in psychosis, we introduced micro-co-activation patterns (μCAPs) and employed this method on the human genetic model of schizophrenia 22q11.2 deletion syndrome (22q11.2DS). Participants underwent resting-state functional MRI and a data-driven iterative process resulting in the identification of six whole-brain μCAPs with specific activity patterns within the thalamus. Unlike conventional methods, μCAPs extract dynamic spatial patterns that reveal partially overlapping and non-mutually exclusive functional subparts. Thus, the μCAPs method detects finer foci of activity within the initial seed region, retaining valuable and clinically relevant temporal and spatial information. We found that a μCAP showing co-activation of the mediodorsal thalamus with brain-wide cortical regions was expressed significantly less frequently in patients with 22q11.2DS, and its occurrence negatively correlated with the severity of positive psychotic symptoms. Additionally, activity within the auditory-visual cortex and their respective geniculate nuclei was expressed in two different μCAPs. One of these auditory-visual μCAPs co-activated with salience areas, while the other co-activated with the default mode network (DMN). A significant shift of occurrence from the salience+visuo-auditory-thalamus to the DMN + visuo-auditory-thalamus μCAP was observed in patients with 22q11.2DS. Thus, our findings support existing research on the gatekeeping role of the thalamus for sensory information in the pathophysiology of psychosis and revisit the evidence of geniculate nuclei hyperconnectivity with the audio-visual cortex in 22q11.2DS in the context of dynamic functional connectivity, seen here as the specific hyper-occurrence of these circuits with the task-negative brain networks.
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Affiliation(s)
- Farnaz Delavari
- Developmental Imaging and Psychopathology LaboratoryUniversity of Geneva School of MedicineGenevaSwitzerland
- Neuro‐X InstituteÉcole Polytechnique FÉdÉrale de LausanneGenevaSwitzerland
| | - Corrado Sandini
- Developmental Imaging and Psychopathology LaboratoryUniversity of Geneva School of MedicineGenevaSwitzerland
| | - Nada Kojovic
- Autism Brain and Behavior Lab, Faculty of MedicineUniversity of GenevaGenevaSwitzerland
| | - Luigi F. Saccaro
- Faculty of Medicine, Psychiatry DepartmentUniversity of GenevaGenevaSwitzerland
- Psychiatry DepartmentGeneva University HospitalGenevaSwitzerland
| | - Stephan Eliez
- Developmental Imaging and Psychopathology LaboratoryUniversity of Geneva School of MedicineGenevaSwitzerland
- Department of Genetic Medicine and DevelopmentUniversity of Geneva School of MedicineGenevaSwitzerland
| | - Dimitri Van De Ville
- Neuro‐X InstituteÉcole Polytechnique FÉdÉrale de LausanneGenevaSwitzerland
- Department of Radiology and Medical InformaticsUniversity of Geneva (UNIGE)GenevaSwitzerland
| | - Thomas A. W. Bolton
- Neuro‐X InstituteÉcole Polytechnique FÉdÉrale de LausanneGenevaSwitzerland
- Connectomics Laboratory, Department of RadiologyCentre Hospitalier Universitaire Vaudois (CHUV)LausanneSwitzerland
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Zhou W, Ye C, Wang H, Mao Y, Zhang W, Liu A, Yang CL, Li T, Hayashi L, Zhao W, Chen L, Liu Y, Tao W, Zhang Z. Sound induces analgesia through corticothalamic circuits. Science 2022; 377:198-204. [PMID: 35857536 PMCID: PMC9636983 DOI: 10.1126/science.abn4663] [Citation(s) in RCA: 28] [Impact Index Per Article: 14.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 07/30/2023]
Abstract
Sound-including music and noise-can relieve pain in humans, but the underlying neural mechanisms remain unknown. We discovered that analgesic effects of sound depended on a low (5-decibel) signal-to-noise ratio (SNR) relative to ambient noise in mice. Viral tracing, microendoscopic calcium imaging, and multitetrode recordings in freely moving mice showed that low-SNR sounds inhibited glutamatergic inputs from the auditory cortex (ACxGlu) to the thalamic posterior (PO) and ventral posterior (VP) nuclei. Optogenetic or chemogenetic inhibition of the ACxGlu→PO and ACxGlu→VP circuits mimicked the low-SNR sound-induced analgesia in inflamed hindpaws and forepaws, respectively. Artificial activation of these two circuits abolished the sound-induced analgesia. Our study reveals the corticothalamic circuits underlying sound-promoted analgesia by deciphering the role of the auditory system in pain processing.
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Affiliation(s)
- Wenjie Zhou
- Department of Anesthesiology and Pain Medicine, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - Chonghuan Ye
- Department of Anesthesiology and Pain Medicine, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - Haitao Wang
- Auditory Research Laboratory, Department of Neurobiology and Biophysics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
- School of Integrated Chinese and Western Medicine, Anhui University of Chinese Medicine, Hefei, PR China
| | - Yu Mao
- Department of Anesthesiology and Pain Medicine, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
- Department of Anesthesiology and Pain Management, The First Affiliated Hospital of Anhui Medical University, Hefei, PR China
| | - Weijia Zhang
- Department of Anesthesiology and Pain Medicine, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - An Liu
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, PR China
| | - Chen-Ling Yang
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, PR China
| | - Tianming Li
- Somatosensation and Pain Unit, National Institute of Dental and Craniofacial Research (NIDCR), National Center for Complementary and Integrative Health (NCCIH), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Lauren Hayashi
- Somatosensation and Pain Unit, National Institute of Dental and Craniofacial Research (NIDCR), National Center for Complementary and Integrative Health (NCCIH), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Wan Zhao
- Department of Otolaryngology, The First Affiliated Hospital of USTC, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - Lin Chen
- Auditory Research Laboratory, Department of Neurobiology and Biophysics, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
| | - Yuanyuan Liu
- Somatosensation and Pain Unit, National Institute of Dental and Craniofacial Research (NIDCR), National Center for Complementary and Integrative Health (NCCIH), National Institutes of Health (NIH), Bethesda, MD, USA
| | - Wenjuan Tao
- Department of Physiology, School of Basic Medical Sciences, Anhui Medical University, Hefei, PR China
| | - Zhi Zhang
- Department of Anesthesiology and Pain Medicine, The First Affiliated Hospital of USTC, Hefei National Laboratory for Physical Sciences at the Microscale, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, PR China
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Kiwitz K, Brandstetter A, Schiffer C, Bludau S, Mohlberg H, Omidyeganeh M, Massicotte P, Amunts K. Cytoarchitectonic Maps of the Human Metathalamus in 3D Space. Front Neuroanat 2022; 16:837485. [PMID: 35350721 PMCID: PMC8957853 DOI: 10.3389/fnana.2022.837485] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2021] [Accepted: 01/18/2022] [Indexed: 11/13/2022] Open
Abstract
The human metathalamus plays an important role in processing visual and auditory information. Understanding its layers and subdivisions is important to gain insights in its function as a subcortical relay station and involvement in various pathologies. Yet, detailed histological references of the microanatomy in 3D space are still missing. We therefore aim at providing cytoarchitectonic maps of the medial geniculate body (MGB) and its subdivisions in the BigBrain – a high-resolution 3D-reconstructed histological model of the human brain, as well as probabilistic cytoarchitectonic maps of the MGB and lateral geniculate body (LGB). Therefore, histological sections of ten postmortem brains were studied. Three MGB subdivisions (MGBv, MGBd, MGBm) were identified on every 5th BigBrain section, and a deep-learning based tool was applied to map them on every remaining section. The maps were 3D-reconstructed to show the shape and extent of the MGB and its subdivisions with cellular precision. The LGB and MGB were additionally identified in nine other postmortem brains. Probabilistic cytoarchitectonic maps in the MNI “Colin27” and MNI ICBM152 reference spaces were computed which reveal an overall low interindividual variability in topography and extent. The probabilistic maps were included into the Julich-Brain atlas, and are freely available. They can be linked to other 3D data of human brain organization and serve as an anatomical reference for diagnostic, prognostic and therapeutic neuroimaging studies of healthy brains and patients. Furthermore, the high-resolution MGB BigBrain maps provide a basis for data integration, brain modeling and simulation to bridge the larger scale involvement of thalamocortical and local subcortical circuits.
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Affiliation(s)
- Kai Kiwitz
- Cécile and Oskar Vogt Institute of Brain Research, University Hospital Düsseldorf, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
- Max Planck School of Cognition, Stephanstraße 1a, Leipzig, Germany
- *Correspondence: Kai Kiwitz,
| | - Andrea Brandstetter
- Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, Jülich, Germany
| | - Christian Schiffer
- Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, Jülich, Germany
- Helmholtz AI, Forschungszentrum Jülich, Jülich, Germany
| | - Sebastian Bludau
- Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, Jülich, Germany
| | - Hartmut Mohlberg
- Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, Jülich, Germany
| | - Mona Omidyeganeh
- McGill Centre for Integrative Neuroscience, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
- National Research Council of Canada, Ottawa, ON, Canada
| | - Philippe Massicotte
- McGill Centre for Integrative Neuroscience, McConnell Brain Imaging Center, Montreal Neurological Institute, McGill University, Montreal, QC, Canada
| | - Katrin Amunts
- Cécile and Oskar Vogt Institute of Brain Research, University Hospital Düsseldorf, Medical Faculty, Heinrich Heine University, Düsseldorf, Germany
- Max Planck School of Cognition, Stephanstraße 1a, Leipzig, Germany
- Institute of Neuroscience and Medicine (INM-1), Forschungszentrum Jülich, Jülich, Germany
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Pagella S, Deussing JM, Kopp-Scheinpflug C. Expression Patterns of the Neuropeptide Urocortin 3 and Its Receptor CRFR2 in the Mouse Central Auditory System. Front Neural Circuits 2021; 15:747472. [PMID: 34867212 PMCID: PMC8633543 DOI: 10.3389/fncir.2021.747472] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 10/18/2021] [Indexed: 11/16/2022] Open
Abstract
Sensory systems have to be malleable to context-dependent modulations occurring over different time scales, in order to serve their evolutionary function of informing about the external world while also eliciting survival-promoting behaviors. Stress is a major context-dependent signal that can have fast and delayed effects on sensory systems, especially on the auditory system. Urocortin 3 (UCN3) is a member of the corticotropin-releasing factor family. As a neuropeptide, UCN3 regulates synaptic activity much faster than the classic steroid hormones of the hypothalamic-pituitary-adrenal axis. Moreover, due to the lack of synaptic re-uptake mechanisms, UCN3 can have more long-lasting and far-reaching effects. To date, a modest number of studies have reported the presence of UCN3 or its receptor CRFR2 in the auditory system, particularly in the cochlea and the superior olivary complex, and have highlighted the importance of this stress neuropeptide for protecting auditory function. However, a comprehensive map of all neurons synthesizing UCN3 or CRFR2 within the auditory pathway is lacking. Here, we utilize two reporter mouse lines to elucidate the expression patterns of UCN3 and CRFR2 in the auditory system. Additional immunolabelling enables further characterization of the neurons that synthesize UCN3 or CRFR2. Surprisingly, our results indicate that within the auditory system, UCN3 is expressed predominantly in principal cells, whereas CRFR2 expression is strongest in non-principal, presumably multisensory, cell types. Based on the presence or absence of overlap between UCN3 and CRFR2 labeling, our data suggest unusual modes of neuromodulation by UCN3, involving volume transmission and autocrine signaling.
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Affiliation(s)
- Sara Pagella
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
| | - Jan M Deussing
- Research Group Molecular Neurogenetics, Max Planck Institute of Psychiatry, Munich, Germany
| | - Conny Kopp-Scheinpflug
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilians-University Munich, Munich, Germany
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6
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Souffi S, Nodal FR, Bajo VM, Edeline JM. When and How Does the Auditory Cortex Influence Subcortical Auditory Structures? New Insights About the Roles of Descending Cortical Projections. Front Neurosci 2021; 15:690223. [PMID: 34413722 PMCID: PMC8369261 DOI: 10.3389/fnins.2021.690223] [Citation(s) in RCA: 10] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/02/2021] [Accepted: 06/14/2021] [Indexed: 12/28/2022] Open
Abstract
For decades, the corticofugal descending projections have been anatomically well described but their functional role remains a puzzling question. In this review, we will first describe the contributions of neuronal networks in representing communication sounds in various types of degraded acoustic conditions from the cochlear nucleus to the primary and secondary auditory cortex. In such situations, the discrimination abilities of collicular and thalamic neurons are clearly better than those of cortical neurons although the latter remain very little affected by degraded acoustic conditions. Second, we will report the functional effects resulting from activating or inactivating corticofugal projections on functional properties of subcortical neurons. In general, modest effects have been observed in anesthetized and in awake, passively listening, animals. In contrast, in behavioral tasks including challenging conditions, behavioral performance was severely reduced by removing or transiently silencing the corticofugal descending projections. This suggests that the discriminative abilities of subcortical neurons may be sufficient in many acoustic situations. It is only in particularly challenging situations, either due to the task difficulties and/or to the degraded acoustic conditions that the corticofugal descending connections bring additional abilities. Here, we propose that it is both the top-down influences from the prefrontal cortex, and those from the neuromodulatory systems, which allow the cortical descending projections to impact behavioral performance in reshaping the functional circuitry of subcortical structures. We aim at proposing potential scenarios to explain how, and under which circumstances, these projections impact on subcortical processing and on behavioral responses.
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Affiliation(s)
- Samira Souffi
- Department of Integrative and Computational Neurosciences, Paris-Saclay Institute of Neuroscience (NeuroPSI), UMR CNRS 9197, Paris-Saclay University, Orsay, France
| | - Fernando R Nodal
- Department of Physiology, Anatomy and Genetics, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Victoria M Bajo
- Department of Physiology, Anatomy and Genetics, Medical Sciences Division, University of Oxford, Oxford, United Kingdom
| | - Jean-Marc Edeline
- Department of Integrative and Computational Neurosciences, Paris-Saclay Institute of Neuroscience (NeuroPSI), UMR CNRS 9197, Paris-Saclay University, Orsay, France
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7
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Gilad A, Maor I, Mizrahi A. Learning-related population dynamics in the auditory thalamus. eLife 2020; 9:56307. [PMID: 32639231 PMCID: PMC7371423 DOI: 10.7554/elife.56307] [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: 02/24/2020] [Accepted: 07/07/2020] [Indexed: 12/20/2022] Open
Abstract
Learning to associate sensory stimuli with a chosen action involves a dynamic interplay between cortical and thalamic circuits. While the cortex has been widely studied in this respect, how the thalamus encodes learning-related information is still largely unknown. We studied learning-related activity in the medial geniculate body (MGB; Auditory thalamus), targeting mainly the dorsal and medial regions. Using fiber photometry, we continuously imaged population calcium dynamics as mice learned a go/no-go auditory discrimination task. The MGB was tuned to frequency and responded to cognitive features like the choice of the mouse within several hundred milliseconds. Encoding of choice in the MGB increased with learning, and was highly correlated with the learning curves of the mice. MGB also encoded motor parameters of the mouse during the task. These results provide evidence that the MGB encodes task- motor- and learning-related information.
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Affiliation(s)
- Ariel Gilad
- Department of Medical Neurobiology, Institute for Medical Research Israel Canada, Faculty of Medicine, The Hebrew University, Jerusalem, Israel.,The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Ido Maor
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel
| | - Adi Mizrahi
- The Edmond and Lily Safra Center for Brain Sciences, The Hebrew University of Jerusalem, Jerusalem, Israel.,Department of Neurobiology, The Hebrew University of Jerusalem, Jerusalem, Israel
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Macias S, Bakshi K, Smotherman M. Laminar Organization of FM Direction Selectivity in the Primary Auditory Cortex of the Free-Tailed Bat. Front Neural Circuits 2019; 13:76. [PMID: 31827425 PMCID: PMC6890848 DOI: 10.3389/fncir.2019.00076] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2019] [Accepted: 11/13/2019] [Indexed: 01/18/2023] Open
Abstract
We studied the columnar and layer-specific response properties of neurons in the primary auditory cortex (A1) of six (four females, two males) anesthetized free-tailed bats, Tadarida brasiliensis, in response to pure tones and down and upward frequency modulated (FM; 50 kHz bandwidth) sweeps. In addition, we calculated current source density (CSD) to test whether lateral intracortical projections facilitate neuronal activation in response to FM echoes containing spectrally distant frequencies from the excitatory frequency response area (FRA). Auditory responses to a set of stimuli changing in frequency and level were recorded along 64 penetrations in the left A1 of six free-tailed bats. FRA shapes were consistent across the cortical depth within a column and there were no obvious differences in tuning properties. Generally, response latencies were shorter (<10 ms) for cortical depths between 500 and 600 μm, which might correspond to thalamocortical input layers IIIb-IV. Most units showed a stronger response to downward FM sweeps, and direction selectivity did not vary across cortical depth. CSD profiles calculated in response to the CF showed a current sink located at depths between 500 and 600 μm. Frequencies lower than the frequency range eliciting a spike response failed to evoke any visible current sink. Frequencies higher than the frequency range producing a spike response evoked layer IV sinks at longer latencies that increased with spectral distance. These data support the hypothesis that a progressive downward relay of spectral information spreads along the tonotopic axis of A1 via lateral connections, contributing to the neural processing of FM down sweeps used in biosonar.
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Affiliation(s)
- Silvio Macias
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Kushal Bakshi
- Department of Biology, Texas A&M University, College Station, TX, United States
| | - Michael Smotherman
- Department of Biology, Texas A&M University, College Station, TX, United States
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Quraishe S, Newman T, Anderson L. Auditory temporal acuity improves with age in the male mouse auditory thalamus: A role for perineuronal nets? J Neurosci Res 2019; 98:1780-1799. [PMID: 31562661 DOI: 10.1002/jnr.24537] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 09/13/2019] [Accepted: 09/15/2019] [Indexed: 11/09/2022]
Abstract
The ability to perceive and interpret environmental sound accurately is conserved across many species and is fundamental for understanding communication via vocalizations. Auditory acuity and temporally controlled neuronal firing underpin this ability. Deterioration in neuronal firing precision likely contributes to poorer hearing performance, yet the role of neural processing by key nuclei in the central auditory pathways is not fully understood. Here, we record from the auditory thalamus (medial geniculate body [MGB]) of young and middle-aged, normally hearing male CBA/Ca mice. We report changes in temporal processing of auditory stimuli, with neurons recorded from ventral and medial MGB subdivisions of older animals more likely to synchronize to rapid temporally varying stimuli. MGB subdivisions also showed increased probability of neuronal firing and shorter response latencies to clicks in older animals. Histological investigation of neuronal extracellular specializations, perineuronal nets (PNNs) and axonal coats, in the MGB identified greater organization of PNNs around MGB neurons and the presence of axonal coats within older animals. This supports the observation that neural responses recorded from ventral and medial MGB of older mice were more likely to synchronize to temporally varying stimuli presented at faster repetition rates than those recorded from young adult animals. These changes are observed in animals with normal hearing thresholds, confirming that neural processing differs between the MGB subdivisions and such processing is associated with age-related changes to PNNs. Understanding these age-related changes and how they occur have important implications for the design of effective therapeutic interventions to improve speech intelligibility into later life.
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Affiliation(s)
- Shmma Quraishe
- School of Biological Sciences, B85, University of Southampton, Southampton, UK
| | - Tracey Newman
- Clinical and Experimental Sciences, B85, University of Southampton, Southampton, UK
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Mai JK, Majtanik M. Toward a Common Terminology for the Thalamus. Front Neuroanat 2019; 12:114. [PMID: 30687023 PMCID: PMC6336698 DOI: 10.3389/fnana.2018.00114] [Citation(s) in RCA: 47] [Impact Index Per Article: 9.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2018] [Accepted: 11/27/2018] [Indexed: 01/08/2023] Open
Abstract
The wealth of competing parcellations with limited cross-correspondence between atlases of the human thalamus raises problems in a time when the usefulness of neuroanatomical methods is increasingly appreciated for modern computational analyses of the brain. An unequivocal nomenclature is, however, compulsory for the understanding of the organization of the thalamus. This situation cannot be improved by renewed discussion but with implementation of neuroinformatics tools. We adopted a new volumetric approach to characterize the significant subdivisions and determined the relationships between the parcellation schemes of nine most influential atlases of the human thalamus. The volumes of each atlas were 3d-reconstructed and spatially registered to the standard MNI/ICBM2009b reference volume of the Human Brain Atlas in the MNI (Montreal Neurological Institute) space (Mai and Majtanik, 2017). This normalization of the individual thalamus shapes allowed for the comparison of the nuclear regions delineated by the different authors. Quantitative cross-comparisons revealed the extent of predictability of territorial borders for 11 area clusters. In case of discordant parcellations we re-analyzed the underlying histological features and the original descriptions. The final scheme of the spatial organization provided the frame for the selected terms for the subdivisions of the human thalamus using on the (modified) terminology of the Federative International Programme for Anatomical Terminology (FIPAT). Waiving of exact individual definition of regional boundaries in favor of the statistical representation within the open MNI platform provides the common and objective (standardized) ground to achieve concordance between results from different sources (microscopy, imaging etc.).
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Affiliation(s)
- Jürgen K. Mai
- Institute for Anatomy, Heinrich-Heine-University, Duesseldorf, Germany
| | - Milan Majtanik
- Institute of Informatics, Heinrich-Heine-University, Duesseldorf, Germany
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Clarke BA, Lee CC. Inhibitory Projections in the Mouse Auditory Tectothalamic System. Brain Sci 2018; 8:E103. [PMID: 29890716 PMCID: PMC6025108 DOI: 10.3390/brainsci8060103] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/11/2018] [Revised: 05/30/2018] [Accepted: 06/07/2018] [Indexed: 12/24/2022] Open
Abstract
The medial geniculate body (MGB) is the target of excitatory and inhibitory inputs from several neural sources. Among these, the inferior colliculus (IC) is an important nucleus in the midbrain that acts as a nexus for auditory projections, ascending and descending, throughout the rest of the central auditory system and provides both excitatory and inhibitory inputs to the MGB. In our study, we assessed the relative contribution from presumed excitatory and inhibitory IC neurons to the MGB in mice. Using retrograde tract tracing with cholera toxin beta subunit (CTβ)-Alexa Fluor 594 injected into the MGB of transgenic, vesicular GABA transporter (VGAT)-Venus mice, we quantitatively analyzed the projections from both the ipsilateral and contralateral IC to the MGB. Our results demonstrate inhibitory projections from both ICs to the MGB that likely play a significant role in shaping auditory processing. These results complement prior studies in other species, which suggest that the inhibitory tectothalamic pathway is important in the regulation of neuronal activity in the auditory forebrain.
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Affiliation(s)
- Blaise A Clarke
- Department of Comparative Biomedical Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA 70803, USA.
| | - Charles C Lee
- Department of Comparative Biomedical Sciences, LSU School of Veterinary Medicine, Baton Rouge, LA 70803, USA.
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13
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Berger C, Kühne D, Scheper V, Kral A. Congenital deafness affects deep layers in primary and secondary auditory cortex. J Comp Neurol 2017; 525. [PMID: 28643417 PMCID: PMC5599951 DOI: 10.1002/cne.24267] [Citation(s) in RCA: 29] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/23/2022]
Abstract
Congenital deafness leads to functional deficits in the auditory cortex for which early cochlear implantation can effectively compensate. Most of these deficits have been demonstrated functionally. Furthermore, the majority of previous studies on deafness have involved the primary auditory cortex; knowledge of higher-order areas is limited to effects of cross-modal reorganization. In this study, we compared the cortical cytoarchitecture of four cortical areas in adult hearing and congenitally deaf cats (CDCs): the primary auditory field A1, two secondary auditory fields, namely the dorsal zone and second auditory field (A2); and a reference visual association field (area 7) in the same section stained either using Nissl or SMI-32 antibodies. The general cytoarchitectonic pattern and the area-specific characteristics in the auditory cortex remained unchanged in animals with congenital deafness. Whereas area 7 did not differ between the groups investigated, all auditory fields were slightly thinner in CDCs, this being caused by reduced thickness of layers IV-VI. The study documents that, while the cytoarchitectonic patterns are in general independent of sensory experience, reduced layer thickness is observed in both primary and higher-order auditory fields in layer IV and infragranular layers. The study demonstrates differences in effects of congenital deafness between supragranular and other cortical layers, but similar dystrophic effects in all investigated auditory fields.
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Affiliation(s)
- Christoph Berger
- Institute of AudioNeuroTechnology & Department of Experimental OtologyENT Clinics, School of Medicine, Hannover Medical UniversityHannoverGermany
| | - Daniela Kühne
- Institute of AudioNeuroTechnology & Department of Experimental OtologyENT Clinics, School of Medicine, Hannover Medical UniversityHannoverGermany
| | - Verena Scheper
- Institute of AudioNeuroTechnology & Department of Experimental OtologyENT Clinics, School of Medicine, Hannover Medical UniversityHannoverGermany
| | - Andrej Kral
- Institute of AudioNeuroTechnology & Department of Experimental OtologyENT Clinics, School of Medicine, Hannover Medical UniversityHannoverGermany
- School of Behavioral and Brain SciencesThe University of TexasDallasUSA
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Sottile SY, Ling L, Cox BC, Caspary DM. Impact of ageing on postsynaptic neuronal nicotinic neurotransmission in auditory thalamus. J Physiol 2017; 595:5375-5385. [PMID: 28585699 PMCID: PMC5538226 DOI: 10.1113/jp274467] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2017] [Accepted: 05/24/2017] [Indexed: 11/08/2022] Open
Abstract
KEY POINTS Neuronal nicotinic acetylcholine receptors (nAChRs) play a fundamental role in the attentional circuitry throughout the mammalian CNS. In the present study, we report a novel finding that ageing negatively impacts nAChR efficacy in auditory thalamus, and this is probably the result of a loss of nAChR density (Bmax ) and changes in the subunit composition of nAChRs. Our data support the hypothesis that age-related maladaptive changes involving nAChRs within thalamocortical circuits partially underpin the difficulty that elderly adults experience with respect to attending to speech and other salient acoustic signals. ABSTRACT The flow of auditory information through the medial geniculate body (MGB) is regulated, in part, by cholinergic projections from the pontomesencephalic tegmentum. The functional significance of these projections is not fully established, although they have been strongly implicated in the allocation of auditory attention. Using in vitro slice recordings, we have analysed postsynaptic function and pharmacology of neuronal nicotinic ACh receptors (nAChRs) in young adult and the aged rat MGB. We find that ACh produces significant excitatory postsynaptic actions on young MGB neurons, probably mediated by β2-containing heteromeric nAChRs. Radioligand binding studies show a significant age-related loss of heteromeric nAChR receptor number, which supports patch clamp data showing an age-related loss in ACh efficacy in evoking postsynaptic responses. Use of the β2-selective nAChR antagonist, dihydro-β-erythroidine, suggests that loss of cholinergic efficacy may also be the result of an age-related subunit switch from high affinity β2-containing nAChRs to low affinity β4-containing nAChRs, in addition to the loss of total nAChR number. This age-related nAChR dysfunction may partially underpin the attentional deficits that contribute to the loss of speech understanding in the elderly.
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Affiliation(s)
| | | | - Brandon C. Cox
- Department of Pharmacology
- Department of Surgery, Division of OtolaryngologySouthern Illinois University School of MedicineSpringfieldILUSA
| | - Donald M. Caspary
- Department of Pharmacology
- Department of Surgery, Division of OtolaryngologySouthern Illinois University School of MedicineSpringfieldILUSA
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15
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Todd TP, Mehlman ML, Keene CS, DeAngeli NE, Bucci DJ. Retrosplenial cortex is required for the retrieval of remote memory for auditory cues. ACTA ACUST UNITED AC 2016; 23:278-88. [PMID: 27194795 PMCID: PMC4880149 DOI: 10.1101/lm.041822.116] [Citation(s) in RCA: 57] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/26/2016] [Accepted: 03/07/2016] [Indexed: 11/25/2022]
Abstract
The restrosplenial cortex (RSC) has a well-established role in contextual and spatial learning and memory, consistent with its known connectivity with visuo-spatial association areas. In contrast, RSC appears to have little involvement with delay fear conditioning to an auditory cue. However, all previous studies have examined the contribution of the RSC to recently acquired auditory fear memories. Since neocortical regions have been implicated in the permanent storage of remote memories, we examined the contribution of the RSC to remotely acquired auditory fear memories. In Experiment 1, retrieval of a remotely acquired auditory fear memory was impaired when permanent lesions (either electrolytic or neurotoxic) were made several weeks after initial conditioning. In Experiment 2, using a chemogenetic approach, we observed impairments in the retrieval of remote memory for an auditory cue when the RSC was temporarily inactivated during testing. In Experiment 3, after injection of a retrograde tracer into the RSC, we observed labeled cells in primary and secondary auditory cortices, as well as the claustrum, indicating that the RSC receives direct projections from auditory regions. Overall our results indicate the RSC has a critical role in the retrieval of remotely acquired auditory fear memories, and we suggest this is related to the quality of the memory, with less precise memories being RSC dependent.
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Affiliation(s)
- Travis P Todd
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Max L Mehlman
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Christopher S Keene
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - Nicole E DeAngeli
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
| | - David J Bucci
- Department of Psychological and Brain Sciences, Dartmouth College, Hanover, New Hampshire 03755, USA
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16
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Lee CC. Exploring functions for the non-lemniscal auditory thalamus. Front Neural Circuits 2015; 9:69. [PMID: 26582978 PMCID: PMC4631820 DOI: 10.3389/fncir.2015.00069] [Citation(s) in RCA: 32] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2015] [Accepted: 10/15/2015] [Indexed: 01/15/2023] Open
Abstract
The functions of the medial geniculate body (MGB) in normal hearing still remain somewhat enigmatic, in part due to the relatively unexplored properties of the non-lemniscal MGB nuclei. Indeed, the canonical view of the thalamus as a simple relay for transmitting ascending information to the cortex belies a role in higher-order forebrain processes. However, recent anatomical and physiological findings now suggest important information and affective processing roles for the non-primary auditory thalamic nuclei. The non-lemniscal nuclei send and receive feedforward and feedback projections among a wide constellation of midbrain, cortical, and limbic-related sites, which support potential conduits for auditory information flow to higher auditory cortical areas, mediators for transitioning among arousal states, and synchronizers of activity across expansive cortical territories. Considered here is a perspective on the putative and unresolved functional roles of the non-lemniscal nuclei of the MGB.
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Affiliation(s)
- Charles C Lee
- Department of Comparative Biomedical Sciences, Louisiana State University, School of Veterinary Medicine Baton Rouge, LA, USA
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17
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Deviance detection in auditory subcortical structures: what can we learn from neurochemistry and neural connectivity? Cell Tissue Res 2015; 361:215-32. [DOI: 10.1007/s00441-015-2134-7] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/11/2014] [Accepted: 01/22/2015] [Indexed: 12/18/2022]
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18
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Carrasco A, Brown TA, Lomber SG. Spectral and Temporal Acoustic Features Modulate Response Irregularities within Primary Auditory Cortex Columns. PLoS One 2014; 9:e114550. [PMID: 25494365 PMCID: PMC4262427 DOI: 10.1371/journal.pone.0114550] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2014] [Accepted: 11/05/2014] [Indexed: 11/18/2022] Open
Abstract
Assemblies of vertically connected neurons in the cerebral cortex form information processing units (columns) that participate in the distribution and segregation of sensory signals. Despite well-accepted models of columnar architecture, functional mechanisms of inter-laminar communication remain poorly understood. Hence, the purpose of the present investigation was to examine the effects of sensory information features on columnar response properties. Using acute recording techniques, extracellular response activity was collected from the right hemisphere of eight mature cats (felis catus). Recordings were conducted with multichannel electrodes that permitted the simultaneous acquisition of neuronal activity within primary auditory cortex columns. Neuronal responses to simple (pure tones), complex (noise burst and frequency modulated sweeps), and ecologically relevant (con-specific vocalizations) acoustic signals were measured. Collectively, the present investigation demonstrates that despite consistencies in neuronal tuning (characteristic frequency), irregularities in discharge activity between neurons of individual A1 columns increase as a function of spectral (signal complexity) and temporal (duration) acoustic variations.
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Affiliation(s)
- Andres Carrasco
- Cerebral Systems Laboratory, University of Western Ontario, London, Ontario, Canada
- Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Trecia A. Brown
- Cerebral Systems Laboratory, University of Western Ontario, London, Ontario, Canada
- Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
| | - Stephen G. Lomber
- Cerebral Systems Laboratory, University of Western Ontario, London, Ontario, Canada
- Brain and Mind Institute, University of Western Ontario, London, Ontario, Canada
- Department of Physiology and Pharmacology, University of Western Ontario, London, Ontario, Canada
- Department of Psychology, University of Western Ontario, London, Ontario, Canada
- National Centre for Audiology, University of Western Ontario, London, Ontario, Canada
- * E-mail:
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19
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Imaizumi K, Lee CC. Frequency transformation in the auditory lemniscal thalamocortical system. Front Neural Circuits 2014; 8:75. [PMID: 25071456 PMCID: PMC4086294 DOI: 10.3389/fncir.2014.00075] [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: 02/01/2014] [Accepted: 06/16/2014] [Indexed: 12/02/2022] Open
Abstract
The auditory lemniscal thalamocortical (TC) pathway conveys information from the ventral division of the medial geniculate body to the primary auditory cortex (A1). Although their general topographic organization has been well characterized, functional transformations at the lemniscal TC synapse still remain incompletely codified, largely due to the need for integration of functional anatomical results with the variability observed with various animal models and experimental techniques. In this review, we discuss these issues with classical approaches, such as in vivo extracellular recordings and tracer injections to physiologically identified areas in A1, and then compare these studies with modern approaches, such as in vivo two-photon calcium imaging, in vivo whole-cell recordings, optogenetic methods, and in vitro methods using slice preparations. A surprising finding from a comparison of classical and modern approaches is the similar degree of convergence from thalamic neurons to single A1 neurons and clusters of A1 neurons, although, thalamic convergence to single A1 neurons is more restricted from areas within putative thalamic frequency lamina. These comparisons suggest that frequency convergence from thalamic input to A1 is functionally limited. Finally, we consider synaptic organization of TC projections and future directions for research.
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Affiliation(s)
- Kazuo Imaizumi
- Department of Comparative Biomedical Sciences, Louisiana State University, School of Veterinary Medicine Baton Rouge, LA, USA
| | - Charles C Lee
- Department of Comparative Biomedical Sciences, Louisiana State University, School of Veterinary Medicine Baton Rouge, LA, USA
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20
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Saldeitis K, Happel MF, Ohl FW, Scheich H, Budinger E. Anatomy of the auditory thalamocortical system in the mongolian gerbil: Nuclear origins and cortical field-, layer-, and frequency-specificities. J Comp Neurol 2014; 522:2397-430. [DOI: 10.1002/cne.23540] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2013] [Revised: 01/03/2014] [Accepted: 01/10/2014] [Indexed: 01/24/2023]
Affiliation(s)
- Katja Saldeitis
- Department of Auditory Learning & Speech; Leibniz Institute for Neurobiology; D-39118 Magdeburg Germany
| | - Max F.K. Happel
- Department of Systems Physiology of Learning; Leibniz Institute for Neurobiology; D-39118 Magdeburg Germany
- Institute of Biology, Otto-von-Guericke University; D-39120 Magdeburg Germany
| | - Frank W. Ohl
- Department of Systems Physiology of Learning; Leibniz Institute for Neurobiology; D-39118 Magdeburg Germany
- Institute of Biology, Otto-von-Guericke University; D-39120 Magdeburg Germany
- Center for Behavioral Brain Sciences; Magdeburg Universitätsplatz 2, D-39106 Germany
| | - Henning Scheich
- Department of Auditory Learning & Speech; Leibniz Institute for Neurobiology; D-39118 Magdeburg Germany
- Center for Behavioral Brain Sciences; Magdeburg Universitätsplatz 2, D-39106 Germany
| | - Eike Budinger
- Department of Auditory Learning & Speech; Leibniz Institute for Neurobiology; D-39118 Magdeburg Germany
- Clinic of Neurology; Otto-von-Guericke-University Magdeburg; D-39120 Magdeburg Germany
- Center for Behavioral Brain Sciences; Magdeburg Universitätsplatz 2, D-39106 Germany
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21
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Henschke JU, Noesselt T, Scheich H, Budinger E. Possible anatomical pathways for short-latency multisensory integration processes in primary sensory cortices. Brain Struct Funct 2014; 220:955-77. [DOI: 10.1007/s00429-013-0694-4] [Citation(s) in RCA: 61] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/19/2013] [Accepted: 12/17/2013] [Indexed: 01/25/2023]
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22
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Atencio CA, Shih JY, Schreiner CE, Cheung SW. Primary auditory cortical responses to electrical stimulation of the thalamus. J Neurophysiol 2013; 111:1077-87. [PMID: 24335216 DOI: 10.1152/jn.00749.2012] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Cochlear implant electrical stimulation of the auditory system to rehabilitate deafness has been remarkably successful. Its deployment requires both an intact auditory nerve and a suitably patent cochlear lumen. When disease renders prerequisite conditions impassable, such as in neurofibromatosis type II and cochlear obliterans, alternative treatment targets are considered. Electrical stimulation of the cochlear nucleus and midbrain in humans has delivered encouraging clinical outcomes, buttressing the promise of central auditory prostheses to mitigate deafness in those who are not candidates for cochlear implantation. In this study we explored another possible implant target: the auditory thalamus. In anesthetized cats, we first presented pure tones to determine frequency preferences of thalamic and cortical sites. We then electrically stimulated tonotopically organized thalamic sites while recording from primary auditory cortical sites using a multichannel recording probe. Cathode-leading biphasic thalamic stimulation thresholds that evoked cortical responses were much lower than published accounts of cochlear and midbrain stimulation. Cortical activation dynamic ranges were similar to those reported for cochlear stimulation, but they were narrower than those found through midbrain stimulation. Our results imply that thalamic stimulation can activate auditory cortex at low electrical current levels and suggest an auditory thalamic implant may be a viable central auditory prosthesis.
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Affiliation(s)
- Craig A Atencio
- Coleman Memorial Laboratory, Department of Otolaryngology-Head and Neck Surgery, University of California, San Francisco, California
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23
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Mylius J, Brosch M, Scheich H, Budinger E. Subcortical auditory structures in the Mongolian gerbil: I. Golgi architecture. J Comp Neurol 2013; 521:1289-321. [PMID: 23047461 DOI: 10.1002/cne.23232] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2012] [Revised: 08/25/2012] [Accepted: 10/02/2012] [Indexed: 12/17/2022]
Abstract
By means of the Golgi-Cox and Nissl methods we investigated the cyto- and fiberarchitecture as well as the morphology of neurons in the subcortical auditory structures of the Mongolian gerbil (Meriones unguiculatus), a frequently used animal model in auditory neuroscience. We describe the divisions and subdivisions of the auditory thalamus including the medial geniculate body, suprageniculate nucleus, and reticular thalamic nucleus, as well as of the inferior colliculi, nuclei of the lateral lemniscus, superior olivary complex, and cochlear nuclear complex. In this study, we 1) confirm previous results about the organization of the gerbil's subcortical auditory pathway using other anatomical staining methods (e.g., Budinger et al. [2000] Eur J Neurosci 12:2452-2474); 2) add substantially to the knowledge about the laminar and cellular organization of the gerbil's subcortical auditory structures, in particular about the orientation of their fibrodendritic laminae and about the morphology of their most distinctive neuron types; and 3) demonstrate that the cellular organization of these structures, as seen by the Golgi technique, corresponds generally to that of other mammalian species, in particular to that of rodents.
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Affiliation(s)
- Judith Mylius
- Special Laboratory Primate Neurobiology, Leibniz Institute for Neurobiology, D-39118 Magdeburg, Germany
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24
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Identification of inputs to olivocochlear neurons using transneuronal labeling with pseudorabies virus (PRV). J Assoc Res Otolaryngol 2013; 14:703-17. [PMID: 23728891 DOI: 10.1007/s10162-013-0400-5] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/30/2013] [Accepted: 05/14/2013] [Indexed: 10/26/2022] Open
Abstract
Olivocochlear (OC) neurons respond to sound and provide descending input that controls processing in the cochlea. The identities of neurons in the pathways providing inputs to OC neurons are incompletely understood. To explore these pathways, the retrograde transneuronal tracer pseudorabies virus (Bartha strain, expressing green fluorescent protein) was used to label OC neurons and their inputs in guinea pigs. Labeling of OC neurons began 1 day after injection into the cochlea. On day 2 (and for longer survival times), transneuronal labeling spread to the cochlear nucleus, inferior colliculus, and other brainstem areas. There was a correlation between the numbers of these transneuronally labeled neurons and the number of labeled medial (M) OC neurons, suggesting that the spread of labeling proceeds mainly via synapses on MOC neurons. In the cochlear nucleus, the transneuronally labeled neurons were multipolar cells including the subtype known as planar cells. In the central nucleus of the inferior colliculus, transneuronally labeled neurons were of two principal types: neurons with disc-shaped dendritic fields and neurons with dendrites in a stellate pattern. Transneuronal labeling was also observed in pyramidal cells in the auditory cortex and in centers not typically associated with the auditory pathway such as the pontine reticular formation, subcoerulean nucleus, and the pontine dorsal raphe. These data provide information on the identity of neurons providing input to OC neurons, which are located in auditory as well as non-auditory centers.
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25
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Geis HRA, Borst JGG. Large GABAergic neurons form a distinct subclass within the mouse dorsal cortex of the inferior colliculus with respect to intrinsic properties, synaptic inputs, sound responses, and projections. J Comp Neurol 2012; 521:189-202. [DOI: 10.1002/cne.23170] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/02/2012] [Revised: 04/18/2012] [Accepted: 06/07/2012] [Indexed: 11/10/2022]
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26
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Kuwabara N. Neuroanatomical technique for studying long axonal projections in the central nervous system: combined axonal staining and pre-labeling in parasagittal gerbil brain slices. Biotech Histochem 2012; 87:413-22. [PMID: 22712444 DOI: 10.3109/10520295.2012.688868] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
A method is described for studying the morphological features of extensive axonal projections within the central nervous system of the gerbil, Meriones anguiculatus. Potentially long descending axonal projections between the auditory thalamus and lower brainstem were used as a model. The inferior colliculus (IC) in the tectum was injected in vivo with a fluorescent retrograde tracer, Fluoro-Gold, to label cells in the medial geniculate body (MGB) that had descending projections to the IC, and cells in the superior olivary complex (SOC) that had ascending projections to the IC. Another fluorescent retrograde tracer, fast blue, was injected into the cochlea to label olivocochlear (OC) cells in the SOC. Inferomedially curved parasagittal slices containing ipsilateral auditory cell groups from the thalamus to the brainstem were cut and descending axons of the pre-labeled MGB cells were traced anterogradely with Biocytin. After visualizing histologically the injected Biocytin, discretely labeled IC-projecting axons of the MGB cells were traced including their collaterals that extended further into the SOC. In the SOC, these axons terminated on pre-labeled cells including OC cells. The combination of anterograde and retrograde tracing in the slice preparations described here demonstrated extensive descending axonal projections from the thalamus to their targets in the lower brainstem that had known ascending/descending projections within the auditory system.
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Affiliation(s)
- N Kuwabara
- Department of Anatomical Sciences and Neurobiology, University of Louisville School of Medicine, Health Sciences Center, Kentucky 40292, USA.
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27
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Calixto R, Lenarz M, Neuheiser A, Scheper V, Lenarz T, Lim HH. Coactivation of different neurons within an isofrequency lamina of the inferior colliculus elicits enhanced auditory cortical activation. J Neurophysiol 2012; 108:1199-210. [PMID: 22623485 DOI: 10.1152/jn.00111.2012] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The phenomenal success of the cochlear implant (CI) is attributed to its ability to provide sufficient temporal and spectral cues for speech understanding. Unfortunately, the CI is ineffective for those without a functional auditory nerve or an implantable cochlea required for CI implementation. As an alternative, our group developed and implanted in deaf patients a new auditory midbrain implant (AMI) to stimulate the central nucleus of the inferior colliculus (ICC). Although the AMI can provide frequency cues, it appears to insufficiently transmit temporal cues for speech understanding. The three-dimensional ICC consists of two-dimensional isofrequency laminae. The single-shank AMI only stimulates one site in any given ICC lamina and does not exhibit enhanced activity (i.e., louder percepts or lower thresholds) for repeated pulses on the same site with intervals <2-5 ms, as occurs for CI pulse or acoustic click stimulation. This enhanced activation, related to short-term temporal integration, is important for tracking the rapid temporal fluctuations of a speech signal. Therefore, we investigated the effects of coactivation of different regions within an ICC lamina on primary auditory cortex activity in ketamine-anesthetized guinea pigs. Interestingly, our findings reveal an enhancement mechanism for integrating converging inputs from an ICC lamina on a fast scale (<6-ms window) that is compromised when stimulating just a single ICC location. Coactivation of two ICC regions also reduces the strong and long-term (>100 ms) suppressive effects induced by repeated stimulation of just a single location. Improving AMI performance may require at least two shanks implanted along the tonotopic gradient of the ICC that enables coactivation of multiple regions along an ICC lamina with the appropriate interstimulus delays.
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Affiliation(s)
- Roger Calixto
- Institute of Audioneurotechnology and Department of Experimental Otology, Hannover Medical University, Hannover, Germany
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28
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Atencio CA, Sharpee TO, Schreiner CE. Receptive field dimensionality increases from the auditory midbrain to cortex. J Neurophysiol 2012; 107:2594-603. [PMID: 22323634 DOI: 10.1152/jn.01025.2011] [Citation(s) in RCA: 45] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
In the primary auditory cortex, spectrotemporal receptive fields (STRFs) are composed of multiple independent components that capture the processing of disparate stimulus aspects by any given neuron. The origin of these multidimensional stimulus filters in the central auditory system is unknown. To determine whether multicomponent STRFs emerge prior to the forebrain, we recorded from single neurons in the main obligatory station of the auditory midbrain, the inferior colliculus. By comparing results of different spike-triggered techniques, we found that the neural responses in the inferior colliculus can be accounted for by a single stimulus filter. This was observed for all temporal response patterns, from strongly phasic to tonic. Our results reveal that spectrotemporal stimulus encoding undergoes a fundamental transformation along the auditory neuraxis, with the emergence of multidimensional receptive fields beyond the auditory midbrain.
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Affiliation(s)
- Craig A Atencio
- The UCSF Center for Integrative Neuroscience, Department of Otolaryngology-Headand Neck Surgery, University of California, San Francisco, CA, USA.
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29
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Froemke RC, Martins ARO. Spectrotemporal dynamics of auditory cortical synaptic receptive field plasticity. Hear Res 2011; 279:149-61. [PMID: 21426927 PMCID: PMC3138852 DOI: 10.1016/j.heares.2011.03.005] [Citation(s) in RCA: 26] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/03/2011] [Revised: 03/07/2011] [Accepted: 03/15/2011] [Indexed: 01/10/2023]
Abstract
The nervous system must dynamically represent sensory information in order for animals to perceive and operate within a complex, changing environment. Receptive field plasticity in the auditory cortex allows cortical networks to organize around salient features of the sensory environment during postnatal development, and then subsequently refine these representations depending on behavioral context later in life. Here we review the major features of auditory cortical receptive field plasticity in young and adult animals, focusing on modifications to frequency tuning of synaptic inputs. Alteration in the patterns of acoustic input, including sensory deprivation and tonal exposure, leads to rapid adjustments of excitatory and inhibitory strengths that collectively determine the suprathreshold tuning curves of cortical neurons. Long-term cortical plasticity also requires co-activation of subcortical neuromodulatory control nuclei such as the cholinergic nucleus basalis, particularly in adults. Regardless of developmental stage, regulation of inhibition seems to be a general mechanism by which changes in sensory experience and neuromodulatory state can remodel cortical receptive fields. We discuss recent findings suggesting that the microdynamics of synaptic receptive field plasticity unfold as a multi-phase set of distinct phenomena, initiated by disrupting the balance between excitation and inhibition, and eventually leading to wide-scale changes to many synapses throughout the cortex. These changes are coordinated to enhance the representations of newly-significant stimuli, possibly for improved signal processing and language learning in humans.
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Affiliation(s)
- Robert C Froemke
- Molecular Neurobiology Program, The Helen and Martin Kimmel Center for Biology and Medicine at the Skirball Institute for Biomolecular Medicine, Department of Otolaryngology, New York University School of Medicine, New York, NY, USA.
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30
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Pienkowski M, Eggermont JJ. Sound frequency representation in primary auditory cortex is level tolerant for moderately loud, complex sounds. J Neurophysiol 2011; 106:1016-27. [DOI: 10.1152/jn.00291.2011] [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
The distribution of neuronal characteristic frequencies over the area of primary auditory cortex (AI) roughly reflects the tonotopic organization of the cochlea. However, because the area of AI activated by any given sound frequency increases erratically with sound level, it has generally been proposed that frequency is represented in AI not with a rate-place code but with some more complex, distributed code. Here, on the basis of both spike and local field potential (LFP) recordings in the anesthetized cat, we show that the tonotopic representation in AI is much more level tolerant when mapped with spectrotemporally dense tone pip ensembles rather than with individually presented tone pips. That is, we show that the tuning properties of individual unit and LFP responses are less variable with sound level under dense compared with sparse stimulation, and that the spatial frequency resolution achieved by the AI neural population at moderate stimulus levels (65 dB SPL) is better with densely than with sparsely presented sounds. This implies that nonlinear processing in the central auditory system can compensate (in part) for the level-dependent coding of sound frequency in the cochlea, and suggests that there may be a functional role for the cortical tonotopic map in the representation of complex sounds.
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Affiliation(s)
- Martin Pienkowski
- Department of Physiology and Pharmacology,
- Department of Psychology, and
| | - Jos J. Eggermont
- Department of Physiology and Pharmacology,
- Department of Psychology, and
- Hotchkiss Brain Institute, University of Calgary, Calgary, Alberta, Canada
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Lee CC, Sherman SM. On the classification of pathways in the auditory midbrain, thalamus, and cortex. Hear Res 2010; 276:79-87. [PMID: 21184817 DOI: 10.1016/j.heares.2010.12.012] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/11/2010] [Revised: 12/10/2010] [Accepted: 12/13/2010] [Indexed: 01/24/2023]
Abstract
Auditory forebrain pathways exhibit several morphological and physiological properties that underlie their specific neurobiological roles in auditory processing. Anatomically, such projections can be distinguished by their terminal size, arborization patterns, and postsynaptic dendritic locations. These structural features correlate with several postsynaptic physiological properties, such as EPSP amplitude, short-term plasticity, and postsynaptic receptor types. Altogether, these synaptic properties segregate into two main classes that are associated with either primarily information-bearing (Class 1) or modulatory (Class 2) roles, and have been used to delineate the principle routes of information flow through the auditory midbrain, thalamus, and cortex. Moreover, these synaptic properties engender as yet unexplored issues regarding the neuronal processing of auditory information, such as the convergent integration and long-term plasticity of auditory forebrain inputs.
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Affiliation(s)
- Charles C Lee
- Department of Neurobiology, University of Chicago, Chicago, IL 60637, USA
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32
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Bizley JK, Walker KMM. Sensitivity and selectivity of neurons in auditory cortex to the pitch, timbre, and location of sounds. Neuroscientist 2010; 16:453-69. [PMID: 20530254 DOI: 10.1177/1073858410371009] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
We are able to rapidly recognize and localize the many sounds in our environment. We can describe any of these sounds in terms of various independent "features" such as their loudness, pitch, or position in space. However, we still know surprisingly little about how neurons in the auditory brain, specifically the auditory cortex, might form representations of these perceptual characteristics from the information that the ear provides about sound acoustics. In this article, the authors examine evidence that the auditory cortex is necessary for processing the pitch, timbre, and location of sounds, and document how neurons across multiple auditory cortical fields might represent these as trains of action potentials. They conclude by asking whether neurons in different regions of the auditory cortex might not be simply sensitive to each of these three sound features but whether they might be selective for one of them. The few studies that have examined neural sensitivity to multiple sound attributes provide only limited support for neural selectivity within auditory cortex. Providing an explanation of the neural basis of feature invariance is thus one of the major challenges to sensory neuroscience obtaining the ultimate goal of understanding how neural firing patterns in the brain give rise to perception.
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Affiliation(s)
- Jennifer K Bizley
- Department of Physiology, Anatomy and Genetics, University of Oxford, Oxford, United Kingdom.
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33
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Atencio CA, Schreiner CE. Laminar diversity of dynamic sound processing in cat primary auditory cortex. J Neurophysiol 2010; 103:192-205. [PMID: 19864440 PMCID: PMC2807218 DOI: 10.1152/jn.00624.2009] [Citation(s) in RCA: 60] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/17/2009] [Accepted: 10/24/2009] [Indexed: 11/22/2022] Open
Abstract
For primary auditory cortex (AI) laminae, there is little evidence of functional specificity despite clearly expressed cellular and connectional differences. Natural sounds are dominated by dynamic temporal and spectral modulations and we used these properties to evaluate local functional differences or constancies across laminae. To examine the layer-specific processing of acoustic modulation information, we simultaneously recorded from multiple AI laminae in the anesthetized cat. Neurons were challenged with dynamic moving ripple stimuli and we subsequently computed spectrotemporal receptive fields (STRFs). From the STRFs, temporal and spectral modulation transfer functions (tMTFs, sMTFs) were calculated and compared across layers. Temporal and spectral modulation properties often differed between layers. On average, layer II/III and VI neurons responded to lower temporal modulations than those in layer IV. tMTFs were mainly band-pass in granular layer IV and became more low-pass in infragranular layers. Compared with layer IV, spectral MTFs were broader and their upper cutoff frequencies higher in layers V and VI. In individual penetrations, temporal modulation preference was similar across layers for roughly 70% of the penetrations, suggesting a common, columnar functional characteristic. By contrast, only about 30% of penetrations showed consistent spectral modulation preferences across layers, indicative of functional laminar diversity or specialization. Since local laminar differences in stimulus preference do not always parallel the main flow of information in the columnar cortical microcircuit, this indicates the influence of additional horizontal or thalamocortical inputs. AI layers that express differing modulation properties may serve distinct roles in the extraction of dynamic sound information, with the differing information specific to the targeted stations of each layer.
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Affiliation(s)
- Craig A Atencio
- University of California-Berkeley and San Francisco Joint Graduate Group in Bioengineering, University of California-San Francisco, 513 Parnassus Avenue, San Francisco, CA 94143-0732, USA.
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34
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Topography and physiology of ascending streams in the auditory tectothalamic pathway. Proc Natl Acad Sci U S A 2009; 107:372-7. [PMID: 20018757 DOI: 10.1073/pnas.0907873107] [Citation(s) in RCA: 71] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Auditory information is relayed from the cochlea along parallel pathways and reaches the inferior colliculus (IC) and the medial geniculate body (MGB) en route to the cortex. Although the ascending tectothalamic pathway to the ventral division of the MGB is regarded as a high-fidelity information-bearing channel, the roles of the pathways to the dorsal and medial divisions are more opaque. Here, we show fundamental differences between these ascending pathways using an in vitro slice preparation. Using photostimulation, we found three main patterns of input (excitatory, inhibitory, and mixed) that differed in each pathway. Furthermore, electrical stimulation of the central nucleus of the IC evoked a depressing response in the MGB with no metabotropic glutamate (mGlu) receptor component, whereas stimulation of the lateral cortex of the IC evoked a facilitating response with an mGlu receptor component. These data suggest that the ascending tectothalamic pathways are functionally distinct from one another.
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35
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Hierarchical computation in the canonical auditory cortical circuit. Proc Natl Acad Sci U S A 2009; 106:21894-9. [PMID: 19918079 DOI: 10.1073/pnas.0908383106] [Citation(s) in RCA: 87] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Sensory cortical anatomy has identified a canonical microcircuit underlying computations between and within layers. This feed-forward circuit processes information serially from granular to supragranular and to infragranular layers. How this substrate correlates with an auditory cortical processing hierarchy is unclear. We recorded simultaneously from all layers in cat primary auditory cortex (AI) and estimated spectrotemporal receptive fields (STRFs) and associated nonlinearities. Spike-triggered averaged STRFs revealed that temporal precision, spectrotemporal separability, and feature selectivity varied with layer according to a hierarchical processing model. STRFs from maximally informative dimension (MID) analysis confirmed hierarchical processing. Of two cooperative MIDs identified for each neuron, the first comprised the majority of stimulus information in granular layers. Second MID contributions and nonlinear cooperativity increased in supragranular and infragranular layers. The AI microcircuit provides a valid template for three independent hierarchical computation principles. Increases in processing complexity, STRF cooperativity, and nonlinearity correlate with the synaptic distance from granular layers.
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36
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Zeng SJ, Lin YT, Tian CP, Song KJ, Zhang XW, Zuo MX. Evolutionary significance of delayed neurogenesis in the core versus shell auditory areas of Mus musculus. J Comp Neurol 2009; 515:600-13. [PMID: 19480001 DOI: 10.1002/cne.22076] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
Early comparative embryogenesis can reflect the organization and evolutionary origins of brain areas. Neurogenesis in the auditory areas of sauropsids displays a clear core-to-shell distinction, but it remains unclear in mammals. To address this issue, [3H]-thymidine was injected into pregnant mice on consecutive embryonic (E) days (E10-E19) to date neuronal birthdays. Immunohistochemistry for substance P, calbindin, and parvalbumin was conducted to distinguish the core and shell auditory regions. The results showed that: 1) cell generation began at E13 in the external or dorsal nucleus of the inferior colliculus (IC), but it did not start in the caudomedial portion of the central nucleus of IC, and significantly fewer cells were produced in the medial and rostromedial portions of the central nucleus of IC; 2) cells were generated at E11 in the dorsal and medial divisions of the medial geniculate complex (MGd and MGm, respectively), whereas cell generation was absent in the medial and rostromedial portions of the ventral medial geniculate complex (MGv), and fewer cells were produced in the caudomedial portion of MGv; 3) in the telencephalic auditory cortex, cells were produced at E11 or E12 in layer I and the subplate, which receive projections from the MGd and MGm. However, cell generation occurred at E13-E18 in layers II-VI, including the area receiving projections from the MGv. The core-to-shell distinction of neurogenesis is thus present in the mesencephalic to telencephalic auditory areas in the mouse. This distinction of neurogenesis is discussed from an evolutionary perspective.
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Affiliation(s)
- Shao-Ju Zeng
- Beijing Key Lab of Gene Engineering Drugs & Biological Technology, Beijing Normal University, Beijing, P.R. China.
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37
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Poulsen C, Picton TW, Paus T. Age-related changes in transient and oscillatory brain responses to auditory stimulation during early adolescence. Dev Sci 2009; 12:220-35. [DOI: 10.1111/j.1467-7687.2008.00760.x] [Citation(s) in RCA: 38] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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38
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Kim SJ, Badi AN, Normann RA. Selective Activation of Cat Primary Auditory Cortex by way of Direct Intraneural Auditory Nerve Stimulation. Laryngoscope 2009; 117:1053-62. [PMID: 17545868 DOI: 10.1097/mlg.0b013e31804714a7] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES/HYPOTHESIS Although cochlear implants have been successfully used by many individuals with profound hearing impairment, limitations still remain with this approach to hearing restoration, including poor stimulation selectivity because of cross-talk between electrodes and poor low-frequency percepts. These limitations may be mitigated by direct intraneural stimulation of the auditory nerve by way of an array of penetrating microelectrodes. Such an approach should provide focal stimulation and selective activation of the nerve fibers, thereby minimizing cross-talk among implanted stimulating electrodes and evoking narrow-band frequency percepts. STUDY DESIGN We investigated the activation of primary auditory cortex evoked by such direct intraneural electrical stimulation of the auditory nerve. METHODS We implanted 11 penetrating microelectrodes in the cat auditory nerve, simulated the nerve by way of these electrodes, and recorded the evoked neuronal activity patterns in cat primary auditory cortex. We compared these activation patterns with acoustically evoked cortical activity patterns obtained in a different animal. RESULTS Our results showed that direct stimulation of the auditory nerve evoked localized activity patterns in primary auditory cortex similar in spatial extent to those evoked by acoustic stimulation and that the extent of cortical activation by both acoustic and electrical stimuli was graded with stimulus intensity. These results suggest that the implanted electrodes can excite independent and small populations of nerve fibers. CONCLUSION This study demonstrates the functional feasibility of direct intraneural auditory nerve stimulation with an array of penetrating microelectrodes and that such an approach could form the foundation for an auditory prosthesis with improved frequency coding.
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Affiliation(s)
- Seung-Jae Kim
- Department of Bioengineering, University of Utah, Salt Lake City, Utah 84112, USA
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39
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Lee CC, Sherman SM. Synaptic properties of thalamic and intracortical inputs to layer 4 of the first- and higher-order cortical areas in the auditory and somatosensory systems. J Neurophysiol 2008; 100:317-26. [PMID: 18436628 DOI: 10.1152/jn.90391.2008] [Citation(s) in RCA: 120] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
The thalamus is an essential structure in the mammalian forebrain conveying information topographically from the sensory periphery to primary neocortical areas. Beyond this initial processing stage, "higher-order" thalamocortical connections have been presumed to serve only a modulatory role, or are otherwise functionally disregarded. Here we demonstrate that these "higher-order" thalamic nuclei share similar synaptic properties with the "first-order" thalamic nuclei. Using whole cell recordings from layer 4 neurons in thalamocortical slice preparations in the mouse somatosensory and auditory systems, we found that electrical stimulation in all thalamic nuclei elicited large, glutamatergic excitatory postsynaptic potentials (EPSPs) that depress in response to repetitive stimulation and that fail to activate a metabotropic glutamate response. In contrast, the intracortical inputs from layer 6 to layer 4 exhibit facilitating EPSPs. These data suggest that higher-order thalamocortical projections may serve a functional role similar to the first-order nuclei, whereas both are physiologically distinct from the intracortical layer 6 inputs. These results suggest an alternate route for information transfer between cortical areas via a corticothalamocortical pathway.
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Affiliation(s)
- Charles C Lee
- Department of Neurobiology, University of Chicago, Chicago, Illinois 60637, USA.
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40
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Wallace MN, Palmer AR. Laminar differences in the response properties of cells in the primary auditory cortex. Exp Brain Res 2007; 184:179-91. [PMID: 17828392 DOI: 10.1007/s00221-007-1092-z] [Citation(s) in RCA: 69] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2007] [Accepted: 07/31/2007] [Indexed: 11/25/2022]
Abstract
In visual and somatosensory cortex there are important functional differences between layers. Although it is difficult to identify laminar borders in the primary auditory cortex (AI) laminar differences in functional processing are still present. We have used electrodes inserted orthogonal to the cortical surface to compare the response properties of cells in all six layers of AI in anaesthetised guinea pigs. Cells were stimulated with short tone pips and two conspecific vocalizations. When frequency response areas were measured for 248 units the tuning bandwidth was broader for units in the deep layers. The mean Q (10) value for tuning in layers IV-VI was significantly smaller (Mann-Whitney test P < 0.001) than for layers I-III. When response latencies were measured, the shortest latencies were found in layer V and the mean latency in this layer was shorter than in any of the more superficial layers (I-IV) when compared with a Tukey analysis of variance (P < 0.005). There were also laminar differences in the best threshold with layer V having the highest mean value. The mean best threshold for layer V (32.7 dB SPL) was significantly different from the means for layers II (25.5 dB SPL) and III (26.3 dB SPL). The responses to two vocalizations also varied between layers: the response to the first phrase of a chutter was smaller and about 10 ms later in the deep layers than in layers II and III. By contrast, the response to an example of whistle was stronger in the deep layers. These results are consistent with a model of AI that involves separate inputs to different layers and descending outputs from layers V/VI (to thalamus and brainstem) that are different from the output from layers II/III (to ipsilateral cortex).
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Affiliation(s)
- M N Wallace
- MRC Institute of Hearing Research, University Park, Nottingham NG7 2RD, UK.
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41
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Cant NB, Benson CG. Multiple topographically organized projections connect the central nucleus of the inferior colliculus to the ventral division of the medial geniculate nucleus in the gerbil, Meriones unguiculatus. J Comp Neurol 2007; 503:432-53. [PMID: 17503483 DOI: 10.1002/cne.21391] [Citation(s) in RCA: 53] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/27/2022]
Abstract
The ventral division of the medial geniculate nucleus (MGv) receives almost all of its ascending input from the ipsilateral central nucleus of the inferior colliculus (CNIC). In a previous study (Cant and Benson [2006] J. Comp. Neurol. 495:511-528), we made injections of biotinylated dextran amine into the CNIC of the gerbil and demonstrated that it can be divided into two parts. One part (zone 1) receives almost all of its ascending input from the cochlear nuclei, the nuclei of the lateral lemniscus, and the main nuclei of the superior olivary complex; the other part (zone 2) receives inputs from the cochlear nuclei and nuclei of the lateral lemniscus but few or no inputs from the main olivary nuclei. Here we show that these two parts of the CNIC project differentially to the MGv. Axons labeled anterogradely by injections in zone 1 project throughout the rostral two-thirds of the MGv, whereas axons from zone 2 project to the caudal third of the MGv. Throughout much of their extent, the terminal fields do not appear to overlap, although both parts of the CNIC project to medial and dorsal parts of the MGv, and there may be overlap in the most ventral part as well. The results indicate that two parallel pathways arising in the CNIC remain largely separate in the medial geniculate nucleus of the gerbil. It seems most likely that the neurons in the two terminal zones in the MGv perform different functions in audition.
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Affiliation(s)
- Nell B Cant
- Department of Neurobiology, Duke University Medical Center, Durham, North Carolina 27710, USA.
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42
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Campolattaro MM, Halverson HE, Freeman JH. Medial auditory thalamic stimulation as a conditioned stimulus for eyeblink conditioning in rats. Learn Mem 2007; 14:152-9. [PMID: 17351138 PMCID: PMC1838556 DOI: 10.1101/lm.465507] [Citation(s) in RCA: 37] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/08/2006] [Accepted: 01/23/2007] [Indexed: 11/25/2022]
Abstract
The neural pathways that convey conditioned stimulus (CS) information to the cerebellum during eyeblink conditioning have not been fully delineated. It is well established that pontine mossy fiber inputs to the cerebellum convey CS-related stimulation for different sensory modalities (e.g., auditory, visual, tactile). Less is known about the sources of sensory input to the pons that are important for eyeblink conditioning. The first experiment of the current study was designed to determine whether electrical stimulation of the medial auditory thalamic nuclei is a sufficient CS for establishing eyeblink conditioning in rats. The second experiment used anterograde and retrograde tract tracing techniques to assess neuroanatomical connections between the medial auditory thalamus and pontine nuclei. Stimulation of the medial auditory thalamus was a very effective CS for eyeblink conditioning in rats, and the medial auditory thalamus has direct ipsilateral projections to the pontine nuclei. The results suggest that the medial auditory thalamic nuclei and their projections to the pontine nuclei are components of the auditory CS pathway in eyeblink conditioning.
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Affiliation(s)
| | | | - John H. Freeman
- Department of Psychology, University of Iowa, Iowa City, Iowa 52242, USA
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43
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Abstract
A synthesis of cat auditory cortex (AC) organization is presented in which the extrinsic and intrinsic connections interact to derive a unified profile of the auditory stream and use it to direct and modify cortical and subcortical information flow. Thus, the thalamocortical input provides essential sensory information about peripheral stimulus events, which AC redirects locally for feature extraction, and then conveys to parallel auditory, multisensory, premotor, limbic, and cognitive centers for further analysis. The corticofugal output influences areas as remote as the pons and the cochlear nucleus, structures whose effects upon AC are entirely indirect, and it has diverse roles in the transmission of information through the medial geniculate body and inferior colliculus. The distributed AC is thus construed as a functional network in which the auditory percept is assembled for subsequent redistribution in sensory, premotor, and cognitive streams contingent on the derived interpretation of the acoustic events. The confluence of auditory and multisensory streams likely precedes cognitive processing of sound. The distributed AC constitutes the largest and arguably the most complete representation of the auditory world. Many facets of this scheme may apply in rodent and primate AC as well. We propose that the distributed auditory cortex contributes to local processing regimes in regions as disparate as the frontal pole and the cochlear nucleus to construct the acoustic percept.
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Affiliation(s)
- Jeffery A Winer
- Division of Neurobiology, Department of Molecular and Cell Biology, Life Sciences Addition, University of California at Berkeley, Berkeley, CA 94720-3200, USA.
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Anderson LA, Malmierca MS, Wallace MN, Palmer AR. Evidence for a direct, short latency projection from the dorsal cochlear nucleus to the auditory thalamus in the guinea pig. Eur J Neurosci 2006; 24:491-8. [PMID: 16836634 DOI: 10.1111/j.1460-9568.2006.04930.x] [Citation(s) in RCA: 52] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The auditory thalamus (medial geniculate body, MGB) receives its main ascending input from the inferior colliculus (IC), which was considered to be an obligatory relay for all auditory inputs to the MGB. However, recent anatomical evidence in the rat [ (Malmierca et al. 2002) J. Neurosci., 22, 10891-10897] has confirmed the presence of a direct pathway from the dorsal cochlear nucleus (DCN) to the medial MGB, bypassing the IC, as previously suggested in the chimpanzee [ (Strominger et al. 1977) J. Comp. Neurol., 172, 349-366]. We show that this direct pathway is also present in the guinea pig and apparently results in short latency responses in the thalamus. Injection of anterograde tracer into the DCN of five adult guinea pigs revealed terminal boutons and axonal swellings distributed throughout the medial MGB, but absent from all other MGB subdivisions. Electrophysiological recordings made from 39 adult guinea pigs (24 male & 15 female) showed neurons in the medial MGB responded with significantly shorter latencies to acoustic clicks (7.8 ms) than those from the ventral (11.0 ms), dorsal (14.4 ms), or shell (16.5 ms) MGB, consistent with the direct pathway from the DCN. The function of the direct pathway is not known but may be related to the fast responses and the role of the medial MGB in integrating combined somatosensory and auditory inputs. Short latency responses may be important in priming the auditory cortex to prepare it for rapid analysis and in recruiting the amygdala for rapid emotional responses such as fear.
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Affiliation(s)
- L A Anderson
- MRC Institute of Hearing Research, University Park, Nottingham, NG7 2RD, UK.
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45
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Schofield BR, Coomes DL, Schofield RM. Cells in auditory cortex that project to the cochlear nucleus in guinea pigs. J Assoc Res Otolaryngol 2006; 7:95-109. [PMID: 16557424 PMCID: PMC2504579 DOI: 10.1007/s10162-005-0025-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2004] [Accepted: 12/07/2005] [Indexed: 11/28/2022] Open
Abstract
Fluorescent retrograde tracers were used to identify the cells in auditory cortex that project directly to the cochlear nucleus (CN). Following injection of a tracer into the CN, cells were labeled bilaterally in primary auditory cortex and the dorsocaudal auditory field as well as several surrounding fields. On both sides, the cells were limited to layer V. The size of labeled cell bodies varied considerably, suggesting that different cell types may project to the CN. Cells ranging from small to medium in size were present bilaterally, whereas the largest cells were labeled only ipsilaterally. In optimal cases, the extent of dendritic labeling was sufficient to identify the morphologic class. Many cells had an apical dendrite that could be traced to a terminal tuft in layer I. Such "tufted" pyramidal cells were identified both ipsilateral and contralateral to the injected CN. The results suggest that the direct pathway from auditory cortex to the cochlear nucleus is substantial and is likely to play a role in modulating the way the cochlear nucleus processes acoustic stimuli.
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Affiliation(s)
- Brett R Schofield
- Department of Neurobiology, Northeastern Ohio Universities College of Medicine, 4209 St. Rt. 44, P.O. Box 95, Rootstown, OH 44272, USA.
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Abstract
The status of the organization of the auditory corticofugal systems is summarized. These are among the largest pathways in the brain, with descending connections to auditory and non-auditory thalamic, midbrain, and medullary regions. Auditory corticofugal influence thus reaches sites immediately presynaptic to the cortex, sites remote from the cortex, as in periolivary regions that may have a centrifugal role, and to the cochlear nucleus, which could influence early central events in hearing. Other targets include the striatum (possible premotor functions), the amygdala and central gray (prospective limbic and motivational roles), and the pontine nuclei (for precerebellar control). The size, specificity, laminar origins, and morphologic diversity of auditory corticofugal axons is consonant with an interpretation of multiple roles in parallel descending systems.
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Affiliation(s)
- Jeffery A Winer
- Division of Neurobiology, Department of Molecular and Cell Biology, University of California at Berkeley, 94720-3200, USA.
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47
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Abstract
The status of the organization of the auditory corticofugal systems is summarized. These are among the largest pathways in the brain, with descending connections to auditory and non-auditory thalamic, midbrain, and medullary regions. Auditory corticofugal influence thus reaches sites immediately presynaptic to the cortex, sites remote from the cortex, as in perolivary regions that may have a centrifugal role, and to the cochlear nucleus, which could influence early central events in hearing. Other targets include the striatum (possible premotor functions), the amygdala and central gray (prospective limbic and motivational roles), and the pontine nuclei (for precerebellar control). The size, specificity, laminar origins, and morphologic diversity of auditory corticofugal axons is consonant with an interpretation of multiple roles in parallel descending systems.
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Affiliation(s)
- Jeffery A Winer
- Division of Neurobiology, Department of Molecular and Cell Biology, University of California at Berkeley, Room 289 Life Sciences Addition, Berkeley, CA 94720-3200, USA.
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48
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Abstract
Layer-V pyramidal cells comprise a major output of primary auditory cortex (A1). At least two cell types displaying different morphology, projections and in vitro physiology have been previously identified in layer-V. The focus of the present study was to characterize extracellular receptive field properties of layer-V neurons to determine whether a similar breakdown of responses can be found in vivo. Recordings from 105 layer-V neurons revealed two predominant receptive field types. Thirty-two percent displayed strong excitatory V/U-shaped receptive field maps and spiking patterns with shorter stimulus-driven interspike intervals (ISIs), reminiscent of the bursting cells discussed in the in vitro literature. V/U-shaped maps remained relatively unchanged across the three sequential repetitions of the map run on each neuron. Neurons with V/U-shaped maps were also easily depolarized with extracellular current pulse stimulation. In contrast, 47% of the neurons displayed Complex receptive field maps characterized by weak and/or inconsistent excitatory regions and were difficult to depolarize with current pulses. These findings suggest that V/U-shaped receptive fields could correspond to previously described intrinsic bursting (IB) cells with corticotectal projections, and that neurons with Complex receptive fields might represent the regular spiking (RS) cells with their greater inhibitory input and corticocortical/corticostriatal projection pattern.
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Affiliation(s)
- Jeremy G Turner
- Department of Pharmacology, School of Medicine, Southern Illinois University, Springfield, 62794-9629, USA
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Winer JA, Miller LM, Lee CC, Schreiner CE. Auditory thalamocortical transformation: structure and function. Trends Neurosci 2005; 28:255-63. [PMID: 15866200 DOI: 10.1016/j.tins.2005.03.009] [Citation(s) in RCA: 138] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Communicative, predatory, and reproductive behaviors rely on the auditory thalamocortical system, a key nexus that combines, transforms, and distributes virtually all acoustic information relevant to survival. The rules of connectivity for this complex network, both anatomically and functionally, are only beginning to be uncovered. Although the auditory thalamocortical system shares many features with other modalities, its connectivity and information processing principles differ from those of other modalities in many ways. Some physiological and anatomical bases for these differences are the subject of this review.
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Affiliation(s)
- Jeffery A Winer
- Division of Neurobiology, Department of Molecular and Cell Biology, University of California, Berkeley, CA 94720-3200, USA.
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Abstract
Topographic maps are common constituents of the primary auditory, visual, and somatic sensory cortex. However, in most cortical areas, no such maps have yet been identified, posing a conceptual problem for theories of cortical function centered on topography. What principle guides the organization of these other areas? We investigated this issue in cat auditory cortex. The connectional topography of five tonotopic areas and eight non-tonotopic areas was assessed using retrograde tract tracing and quantified by three metrics: clustering, dispersion, and separation. Clustering measures the spatial density of labeled neurons, dispersion provides an index of their spread, and separation serves as a scaling metric. These parameters each show that all auditory cortical regions receive precise and equally topographic connections from thalamic, corticocortical, and commissural sources. This isotropic principle suggests a common substrate for coordinating communication across the cortex and may reflect common mechanisms related to the developmental patterning of connections. This unifying principle extends to auditory and prefrontal cortex, and perhaps to other neocortical areas.
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Affiliation(s)
- Charles C Lee
- Division of Neurobiology, Department of Molecular and Cell Biology, University of California at Berkeley, Berkeley, CA 94720-3200, USA.
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