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Robertson A, Miller DJ, Hull A, Butler BE. Quantifying myelin density in the feline auditory cortex. Brain Struct Funct 2024:10.1007/s00429-024-02821-4. [PMID: 38981886 DOI: 10.1007/s00429-024-02821-4] [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: 11/07/2023] [Accepted: 06/12/2024] [Indexed: 07/11/2024]
Abstract
The cerebral cortex comprises many distinct regions that differ in structure, function, and patterns of connectivity. Current approaches to parcellating these regions often take advantage of functional neuroimaging approaches that can identify regions involved in a particular process with reasonable spatial resolution. However, neuroanatomical biomarkers are also very useful in identifying distinct cortical regions either in addition to, or in place of functional measures. For example, differences in myelin density are thought to relate to functional differences between regions, are sensitive to individual patterns of experience, and have been shown to vary across functional hierarchies in a predictable manner. Accordingly, the current study provides quantitative stereological estimates of myelin density for each of the 13 regions that make up the feline auditory cortex. We demonstrate that significant differences can be observed between auditory cortical regions, with the highest myelin density observed in the regions that comprise the auditory core (i.e., the primary auditory cortex and anterior auditory field). Moreover, our myeloarchitectonic map suggests that myelin density varies in a hierarchical fashion that conforms to the traditional model of spatial organization in auditory cortex. Taken together, these results establish myelin as a useful biomarker for parcellating auditory cortical regions, and provide detailed estimates against which other, less invasive methods of quantifying cortical myelination may be compared.
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Affiliation(s)
- Austin Robertson
- Graduate Program in Neuroscience, University of Western Ontario, London, ON, Canada
| | - Daniel J Miller
- Department of Psychology, University of Western Ontario, 1151 Richmond Street N, London, ON, N6A5C1, Canada
- Department of Evolution, Ecology, and Behavior, University of Illinois Urbana-Champagne, Urbana, IL, USA
| | - Adam Hull
- Undergraduate Program in Neuroscience, University of Western Ontario, London, ON, Canada
| | - Blake E Butler
- Department of Psychology, University of Western Ontario, 1151 Richmond Street N, London, ON, N6A5C1, Canada.
- Western Institute for Neuroscience, University of Western Ontario, London, ON, Canada.
- National Centre for Audiology, University of Western Ontario, London, ON, Canada.
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Singh S, Sutkus L, Li Z, Baker S, Bear J, Dilger RN, Miller DJ. Standardization of a silver stain to reveal mesoscale myelin in histological preparations of the mammalian brain. J Neurosci Methods 2024; 407:110139. [PMID: 38626852 DOI: 10.1016/j.jneumeth.2024.110139] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/18/2024] [Revised: 03/26/2024] [Accepted: 04/12/2024] [Indexed: 04/29/2024]
Abstract
BACKGROUND The brain is built of neurons supported by myelin, a fatty substance that improves cellular communication. Noninvasive magnetic resonance imaging (MRI) is now able to measure brain structure like myelin and requires histological validation. NEW METHOD Here we present work in small and large biomedical model mammals to standardize a silver impregnation method as a high-throughput histological myelin visualization procedure. Specifically, we built a new staining well plate to increase batch size, and then systematically varied the staining and clearing cycles to describe the staining response curve across taxa and conditions. We compared tissues fixed by immersion or perfusion, mounted versus free-floating, and cut as thicker or thinner slices, with two-weeks of post-fixation. RESULTS The staining response curves show optimal staining with a single exposure across taxa when incubation and clearing epochs are held to within 3-9 min. We show that clearing was slower in mounted vs free-floating tissue, and that staining was faster and caused fracturing earlier in thinner sliced and smaller volumes of tissue. COMPARISON WITH EXISTING METHODS We developed a batch processing approach to increase throughput while ensuring reproducibility and demonstrate the optimal conditions for fine myelinated fiber morphology visualization with short cycles (<9 minutes). CONCLUSIONS We present our optimized protocol to reveal mesoscale neuroanatomical myelin content in histology across mammals. This standard staining procedure will facilitate multiscale analyses of myelin content across development as well as in the presence of injury or disease.
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Affiliation(s)
- S Singh
- Department of Evolution, Ecology, and Behavior, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America
| | - L Sutkus
- Neuroscience Program, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America
| | - Z Li
- Neuroscience Program, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America
| | - S Baker
- Machine Shop, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America
| | - J Bear
- Machine Shop, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America
| | - R N Dilger
- Department of Animal Sciences, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America; Neuroscience Program, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America; Beckman Institute for Advanced Science and Technology, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America
| | - D J Miller
- Department of Evolution, Ecology, and Behavior, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America; Neuroscience Program, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America; Beckman Institute for Advanced Science and Technology, at the University of Illinois at Urbana-Champaign, 505 South Goodwin Ave, Urbana, IL 61801, United States of America.
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Kim EJ, Nip K, Blanco C, Kim JH. Structural Refinement of the Auditory Brainstem Neurons in Baboons During Perinatal Development. Front Cell Neurosci 2021; 15:648562. [PMID: 33897372 PMCID: PMC8062779 DOI: 10.3389/fncel.2021.648562] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2020] [Accepted: 03/09/2021] [Indexed: 01/22/2023] Open
Abstract
Children born prematurely suffer from learning disabilities and exhibit reading, speech, and cognitive difficulties, which are associated with an auditory processing disorder. However, it is unknown whether gestational age at delivery and the unnatural auditory environment in neonatal intensive care units (NICU) collectively affect proper auditory development and neuronal circuitry in premature newborns. We morphologically characterized fetal development of the medial superior olivary nucleus (MSO), an area important for binaural hearing and sound localization, in the auditory brainstem of baboon neonates at different gestational ages. Axonal and synaptic structures and the tonotopic differentiation of ion channels in the MSO underwent profound refinements after hearing onset in the uterus. These developmental refinements of the MSO were significantly altered in preterm baboon neonates in the NICU. Thus, the maternal environment in uterus is critical for auditory nervous system development during the last trimester of pregnancy and critically affects the anatomic and functional formation of synapses and neural circuitry in the preterm newborn brain.
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Affiliation(s)
- Eun Jung Kim
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center, San Antonio, TX, United States
| | - Kaila Nip
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center, San Antonio, TX, United States
| | - Cynthia Blanco
- Department of Pediatrics, University of Texas Health Science Center, San Antonio, TX, United States
| | - Jun Hee Kim
- Department of Cellular and Integrative Physiology, University of Texas Health Science Center, San Antonio, TX, United States
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Moore S, Meschkat M, Ruhwedel T, Trevisiol A, Tzvetanova ID, Battefeld A, Kusch K, Kole MHP, Strenzke N, Möbius W, de Hoz L, Nave KA. A role of oligodendrocytes in information processing. Nat Commun 2020; 11:5497. [PMID: 33127910 PMCID: PMC7599337 DOI: 10.1038/s41467-020-19152-7] [Citation(s) in RCA: 58] [Impact Index Per Article: 14.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/14/2019] [Accepted: 09/30/2020] [Indexed: 12/12/2022] Open
Abstract
Myelinating oligodendrocytes enable fast propagation of action potentials along the ensheathed axons. In addition, oligodendrocytes play diverse non-canonical roles including axonal metabolic support and activity-dependent myelination. An open question remains whether myelination also contributes to information processing in addition to speeding up conduction velocity. Here, we analyze the role of myelin in auditory information processing using paradigms that are also good predictors of speech understanding in humans. We compare mice with different degrees of dysmyelination using acute multiunit recordings in the auditory cortex, in combination with behavioral readouts. We find complex alterations of neuronal responses that reflect fatigue and temporal acuity deficits. We observe partially discriminable but similar deficits in well myelinated mice in which glial cells cannot fully support axons metabolically. We suggest a model in which myelination contributes to sustained stimulus perception in temporally complex paradigms, with a role of metabolically active oligodendrocytes in cortical information processing.
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Affiliation(s)
- Sharlen Moore
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- International Max Planck Research School for Neurosciences, Göttingen, Germany
- Göttingen Graduate Center for Neurosciences, Biophysics and Molecular Biosciences, Georg-August-Universität Göttingen, Göttingen, Germany
- Department of Psychological and Brain Sciences, Krieger School of Arts and Sciences, Johns Hopkins University, Baltimore, USA
| | - Martin Meschkat
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Torben Ruhwedel
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Andrea Trevisiol
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Sunnybrook Research Institute, Sunnybrook Health Sciences Centre, Toronto, Canada
| | - Iva D Tzvetanova
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Section of Pharmacology, School of Medicine, European University Cyprus, Nicosia, Cyprus
| | - Arne Battefeld
- Department of Axonal Signaling, Netherlands Institute for Neurosciences, Royal Netherlands Academy of Arts and Science, Amsterdam, The Netherlands
- Institut des Maladies Neurodégénératives, Université de Bordeaux, Bordeaux, France
| | - Kathrin Kusch
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
| | - Maarten H P Kole
- Department of Axonal Signaling, Netherlands Institute for Neurosciences, Royal Netherlands Academy of Arts and Science, Amsterdam, The Netherlands
- Cell Biology, Neurobiology and Biophysics, Department of Biology, Faculty of Science, University of Utrecht, Utrecht, The Netherlands
| | - Nicola Strenzke
- Institute for Auditory Neuroscience, University Medical Center, Göttingen, Germany
| | - Wiebke Möbius
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
| | - Livia de Hoz
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany.
- Charité Medical University, Neuroscience Research Center, Berlin, Germany.
| | - Klaus-Armin Nave
- Department of Neurogenetics, Max Planck Institute of Experimental Medicine, Göttingen, Germany
- Center for Nanoscale Microscopy and Molecular Physiology of the Brain, Göttingen, Germany
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Long P, Wan G, Roberts MT, Corfas G. Myelin development, plasticity, and pathology in the auditory system. Dev Neurobiol 2017; 78:80-92. [PMID: 28925106 DOI: 10.1002/dneu.22538] [Citation(s) in RCA: 46] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2017] [Revised: 08/23/2017] [Accepted: 09/14/2017] [Indexed: 11/11/2022]
Abstract
Myelin allows for the rapid and precise timing of action potential propagation along neuronal circuits and is essential for healthy auditory system function. In this article, we discuss what is currently known about myelin in the auditory system with a focus on the timing of myelination during auditory system development, the role of myelin in supporting peripheral and central auditory circuit function, and how various myelin pathologies compromise auditory information processing. Additionally, in keeping with the increasing recognition that myelin is dynamic and is influenced by experience throughout life, we review the growing evidence that auditory sensory deprivation alters myelin along specific segments of the brain's auditory circuit. © 2017 Wiley Periodicals, Inc. Develop Neurobiol 78: 80-92, 2018.
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Affiliation(s)
- Patrick Long
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan, 48109
| | - Guoqiang Wan
- MOE Key Laboratory of Model Animals for Disease Study, Model Animal Research Center of Nanjing University, Nanjing, Jiangsu Province, China
| | - Michael T Roberts
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan, 48109
| | - Gabriel Corfas
- Kresge Hearing Research Institute and Department of Otolaryngology - Head and Neck Surgery, University of Michigan, Ann Arbor, Michigan, 48109
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Chronic social defeat reduces myelination in the mouse medial prefrontal cortex. Sci Rep 2017; 7:46548. [PMID: 28418035 PMCID: PMC5394533 DOI: 10.1038/srep46548] [Citation(s) in RCA: 78] [Impact Index Per Article: 11.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2016] [Accepted: 03/17/2017] [Indexed: 11/12/2022] Open
Abstract
The medial prefrontal cortex (mPFC) plays a key role in top-down control of the brain’s stress axis, and its structure and function are particularly vulnerable to stress effects, which can lead to depression in humans and depressive-like states in animals. We tested whether chronic social defeat produces structural alterations in the mPFC in mice. We first performed a microarray analysis of mPFC gene expression changes induced by defeat, and biological pathway analysis revealed a dominant pattern of down-regulation of myelin-associated genes. Indeed, 69% of the most significantly down-regulated genes were myelin-related. The down regulation was confirmed by in situ hybridization histochemistry for two strongly down-regulated genes, myelin oligodendrocyte glycoprotein (Mog) and ermin (Ermn), and by immunohistochemistry for myelin basic protein. To test for stress-induced changes in myelin integrity, aurophosphate (Black Gold) myelin staining was performed on mPFC sections. Quantitative stereologic analysis showed reduced myelinated fiber length and density. Behavioral analysis confirmed that the 14-day social defeat sessions resulted in induction of depressive-like states measured in social interaction and light/dark tests. The combined data suggest that chronic social defeat induces molecular changes that reduce myelination of the prefrontal cortex, which may be an underlying basis for stress-induced depressive states.
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Herculano-Houzel S, von Bartheld CS, Miller DJ, Kaas JH. How to count cells: the advantages and disadvantages of the isotropic fractionator compared with stereology. Cell Tissue Res 2015; 360:29-42. [PMID: 25740200 DOI: 10.1007/s00441-015-2127-6] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2014] [Accepted: 01/15/2015] [Indexed: 01/12/2023]
Abstract
The number of cells comprising biological structures represents fundamental information in basic anatomy, development, aging, drug tests, pathology and genetic manipulations. Obtaining unbiased estimates of cell numbers, however, was until recently possible only through stereological techniques, which require specific training, equipment, histological processing and appropriate sampling strategies applied to structures with a homogeneous distribution of cell bodies. An alternative, the isotropic fractionator (IF), became available in 2005 as a fast and inexpensive method that requires little training, no specific software and only a few materials before it can be used to quantify total numbers of neuronal and non-neuronal cells in a whole organ such as the brain or any dissectible regions thereof. This method entails transforming a highly anisotropic tissue into a homogeneous suspension of free-floating nuclei that can then be counted under the microscope or by flow cytometry and identified morphologically and immunocytochemically as neuronal or non-neuronal. We compare the advantages and disadvantages of each method and provide researchers with guidelines for choosing the best method for their particular needs. IF is as accurate as unbiased stereology and faster than stereological techniques, as it requires no elaborate histological processing or sampling paradigms, providing reliable estimates in a few days rather than many weeks. Tissue shrinkage is also not an issue, since the estimates provided are independent of tissue volume. The main disadvantage of IF, however, is that it necessarily destroys the tissue analyzed and thus provides no spatial information on the cellular composition of biological regions of interest.
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Affiliation(s)
- Suzana Herculano-Houzel
- Instituto de Ciências Biomédicas, Universidade Federal do Rio de Janeiro, Rio de Janeiro, Brazil,
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Miller DJ, Balaram P, Young NA, Kaas JH. Three counting methods agree on cell and neuron number in chimpanzee primary visual cortex. Front Neuroanat 2014; 8:36. [PMID: 24904305 PMCID: PMC4032965 DOI: 10.3389/fnana.2014.00036] [Citation(s) in RCA: 55] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/28/2014] [Accepted: 04/29/2014] [Indexed: 11/18/2022] Open
Abstract
Determining the cellular composition of specific brain regions is crucial to our understanding of the function of neurobiological systems. It is therefore useful to identify the extent to which different methods agree when estimating the same properties of brain circuitry. In this study, we estimated the number of neuronal and non-neuronal cells in the primary visual cortex (area 17 or V1) of both hemispheres from a single chimpanzee. Specifically, we processed samples distributed across V1 of the right hemisphere after cortex was flattened into a sheet using two variations of the isotropic fractionator cell and neuron counting method. We processed the left hemisphere as serial brain slices for stereological investigation. The goal of this study was to evaluate the agreement between these methods in the most direct manner possible by comparing estimates of cell density across one brain region of interest in a single individual. In our hands, these methods produced similar estimates of the total cellular population (approximately 1 billion) as well as the number of neurons (approximately 675 million) in chimpanzee V1, providing evidence that both techniques estimate the same parameters of interest. In addition, our results indicate the strengths of each distinct tissue preparation procedure, highlighting the importance of attention to anatomical detail. In summary, we found that the isotropic fractionator and the stereological optical fractionator produced concordant estimates of the cellular composition of V1, and that this result supports the conclusion that chimpanzees conform to the primate pattern of exceptionally high packing density in V1. Ultimately, our data suggest that investigators can optimize their experimental approach by using any of these counting methods to obtain reliable cell and neuron counts.
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Affiliation(s)
- Daniel J. Miller
- Department of Psychology, Vanderbilt UniversityNashville, TN, USA
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Venkataraman Y, Bartlett EL. Postnatal development of auditory central evoked responses and thalamic cellular properties. Dev Neurobiol 2013; 74:541-55. [PMID: 24214269 DOI: 10.1002/dneu.22148] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/10/2013] [Revised: 10/23/2013] [Accepted: 11/04/2013] [Indexed: 01/04/2023]
Abstract
During development, the sense of hearing changes rapidly with age, especially around hearing onset. During this period, auditory structures are highly sensitive to alterations of the acoustic environment, such as hearing loss or background noise. This sensitivity includes auditory temporal processing, which is important for processing complex sounds, and for acquiring reading and language skills. Developmental changes can be observed at multiple levels of brain organization-from behavioral responses to cellular responses, and at every auditory nucleus. Neuronal properties and sound processing change dramatically in auditory cortex neurons after hearing onset. However, development of its primary source, the auditory thalamus, or medial geniculate body (MGB), has not been well studied over this critical time window. Furthermore, to understand how temporal processing develops, it is important to determine the relative maturation of temporal processing not only in the MGB, but also in its inputs. Cellular properties of rat MGB neurons were studied using in vitro whole-cell patch-clamp recordings, at ages postnatal day (P) 7-9; P15-17, and P22-32. Auditory evoked potentials were measured in P14-17 and P22-32 rats. MGB action potentials became about five times faster, and the ability to generate spike trains increased with age, particularly at frequencies of 50 Hz and higher. Evoked potential responses, including auditory brainstem responses (ABR), middle latency responses (MLR), and amplitude modulation following responses, showed increased amplitudes with age, and ABRs and MLRs additionally showed decreased latencies with age. Overall, temporal processing at subthalamic nuclei is concurrently maturing with MGB cellular properties.
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Affiliation(s)
- Yamini Venkataraman
- Weldon School of Biomedical Engineering, Purdue University, West Lafayette, Indiana
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