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Yao YG, Lu L, Ni RJ, Bi R, Chen C, Chen JQ, Fuchs E, Gorbatyuk M, Lei H, Li H, Liu C, Lv LB, Tsukiyama-Kohara K, Kohara M, Perez-Cruz C, Rainer G, Shan BC, Shen F, Tang AZ, Wang J, Xia W, Xia X, Xu L, Yu D, Zhang F, Zheng P, Zheng YT, Zhou J, Zhou JN. Study of tree shrew biology and models: A booming and prosperous field for biomedical research. Zool Res 2024; 45:877-909. [PMID: 39004865 PMCID: PMC11298672 DOI: 10.24272/j.issn.2095-8137.2024.199] [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: 06/17/2024] [Accepted: 07/03/2024] [Indexed: 07/16/2024] Open
Abstract
The tree shrew ( Tupaia belangeri) has long been proposed as a suitable alternative to non-human primates (NHPs) in biomedical and laboratory research due to its close evolutionary relationship with primates. In recent years, significant advances have facilitated tree shrew studies, including the determination of the tree shrew genome, genetic manipulation using spermatogonial stem cells, viral vector-mediated gene delivery, and mapping of the tree shrew brain atlas. However, the limited availability of tree shrews globally remains a substantial challenge in the field. Additionally, determining the key questions best answered using tree shrews constitutes another difficulty. Tree shrew models have historically been used to study hepatitis B virus (HBV) and hepatitis C virus (HCV) infection, myopia, and psychosocial stress-induced depression, with more recent studies focusing on developing animal models for infectious and neurodegenerative diseases. Despite these efforts, the impact of tree shrew models has not yet matched that of rodent or NHP models in biomedical research. This review summarizes the prominent advancements in tree shrew research and reflects on the key biological questions addressed using this model. We emphasize that intensive dedication and robust international collaboration are essential for achieving breakthroughs in tree shrew studies. The use of tree shrews as a unique resource is expected to gain considerable attention with the application of advanced techniques and the development of viable animal models, meeting the increasing demands of life science and biomedical research.
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Affiliation(s)
- Yong-Gang Yao
- Key Laboratory of Genetic Evolution and Animal Models, Yunnan Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), and National Resource Center for Non-Human Primates, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650107, China
- KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China. E-mail:
| | - Li Lu
- Key Laboratory of Genetic Evolution and Animal Models, Yunnan Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), and National Resource Center for Non-Human Primates, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650107, China
- KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Rong-Jun Ni
- Mental Health Center and Psychiatric Laboratory, West China Hospital, Sichuan University, Chengdu, Sichuan 610041, China
- Sichuan Clinical Medical Research Center for Mental Disorders, Chengdu, Sichuan 610044, China
| | - Rui Bi
- Key Laboratory of Genetic Evolution and Animal Models, Yunnan Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), and National Resource Center for Non-Human Primates, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650107, China
- KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Ceshi Chen
- Key Laboratory of Genetic Evolution and Animal Models, Yunnan Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Jia-Qi Chen
- National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), and National Resource Center for Non-Human Primates, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650107, China
| | - Eberhard Fuchs
- German Primate Center, Leibniz Institute of Primate Research, Göttingen 37077, Germany
| | - Marina Gorbatyuk
- Department of Optometry and Vision Science, School of Optometry, University of Alabama at Birmingham, Birmingham, AL 35294, USA
| | - Hao Lei
- State Key Laboratory of Magnetic Resonance and Atomic and Molecular Physics, Innovation Academy for Precision Measurement Science and Technology, Chinese Academy of Sciences, Wuhan, Hubei 430071, China
- Wuhan National Laboratory for Optoelectronics, Huazhong University of Science and Technology, Wuhan, Hubei 430074, China
| | - Hongli Li
- Key Laboratory of Genetic Evolution and Animal Models, Yunnan Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), and National Resource Center for Non-Human Primates, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650107, China
- KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Chunyu Liu
- Soong Ching Ling Institute of Maternity and Child Health, International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
| | - Long-Bao Lv
- National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), and National Resource Center for Non-Human Primates, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650107, China
| | - Kyoko Tsukiyama-Kohara
- Transboundary Animal Diseases Center, Joint Faculty of Veterinary Medicine, Kagoshima University, Kagoshima-city, Kagoshima 890-8580, Japan
| | - Michinori Kohara
- Department of Microbiology and Cell Biology, Tokyo Metropolitan Institute of Medical Science, Tokyo 156-8506, Japan
| | | | - Gregor Rainer
- Department of Medicine, University of Fribourg, Fribourg CH-1700, Switzerland
| | - Bao-Ci Shan
- Beijing Engineering Research Center of Radiographic Techniques and Equipment, Institute of High Energy Physics, Chinese Academy of Sciences, Beijing 100049, China
- School of Nuclear Science and Technology, University of Chinese Academy of Sciences, Beijing 100049, China
| | - Fang Shen
- CAS Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing 100101, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing 100101, China
| | - An-Zhou Tang
- Department of Otorhinolaryngology Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530000, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Nanning, Guangxi 530000, China
| | - Jing Wang
- Department of Neurobiology, School of Basic Medical Sciences, Nanjing Medical University, Nanjing, Jiangsu 211166, China
| | - Wei Xia
- Department of Otorhinolaryngology Head and Neck Surgery, First Affiliated Hospital of Guangxi Medical University, Nanning, Guangxi 530000, China
- Key Laboratory of Early Prevention and Treatment for Regional High Frequency Tumor (Guangxi Medical University), Ministry of Education, Nanning, Guangxi 530000, China
| | - Xueshan Xia
- School of Public Health, Kunming Medical University, Kunming, Yunnan 650500, China
| | - Ling Xu
- Key Laboratory of Genetic Evolution and Animal Models, Yunnan Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), and National Resource Center for Non-Human Primates, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650107, China
- KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Dandan Yu
- Key Laboratory of Genetic Evolution and Animal Models, Yunnan Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), and National Resource Center for Non-Human Primates, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650107, China
- KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Feng Zhang
- Soong Ching Ling Institute of Maternity and Child Health, International Peace Maternity and Child Health Hospital, Shanghai Jiao Tong University School of Medicine, Shanghai 200030, China
| | - Ping Zheng
- Key Laboratory of Genetic Evolution and Animal Models, Yunnan Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), and National Resource Center for Non-Human Primates, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650107, China
- KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Yong-Tang Zheng
- Key Laboratory of Genetic Evolution and Animal Models, Yunnan Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- National Research Facility for Phenotypic & Genetic Analysis of Model Animals (Primate Facility), and National Resource Center for Non-Human Primates, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650107, China
- KIZ-CUHK Joint Laboratory of Bioresources and Molecular Research in Common Diseases, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
- Kunming College of Life Science, University of Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Jumin Zhou
- Key Laboratory of Genetic Evolution and Animal Models, Yunnan Key Laboratory of Animal Models and Human Disease Mechanisms, Kunming Institute of Zoology, Chinese Academy of Sciences, Kunming, Yunnan 650204, China
| | - Jiang-Ning Zhou
- CAS Key Laboratory of Brain Function and Diseases, Division of Life Sciences and Medicine, University of Science and Technology of China, Hefei, Anhui 230027, China
- Institute of Brain Science, First Affiliated Hospital of Anhui Medical University, Hefei, Anhui 230022, China
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Bhagwandin A, Molnár Z, Bertelsen MF, Karlsson KÆ, Alagaili AN, Bennett NC, Hof PR, Kaswera-Kyamakya C, Gilissen E, Jayakumar J, Manger PR. Where Do Core Thalamocortical Axons Terminate in Mammalian Neocortex When There Is No Cytoarchitecturally Distinct Layer 4? J Comp Neurol 2024; 532:e25652. [PMID: 38962882 DOI: 10.1002/cne.25652] [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: 03/15/2024] [Revised: 05/20/2024] [Accepted: 06/07/2024] [Indexed: 07/05/2024]
Abstract
Although the mammalian cerebral cortex is most often described as a hexalaminar structure, there are cortical areas (primary motor cortex) and species (elephants, cetaceans, and hippopotami), where a cytoarchitecturally indistinct, or absent, layer 4 is noted. Thalamocortical projections from the core, or first order, thalamic system terminate primarily in layers 4/inner 3. We explored the termination sites of core thalamocortical projections in cortical areas and in species where there is no cytoarchitecturally distinct layer 4 using the immunolocalization of vesicular glutamate transporter 2, a known marker of core thalamocortical axon terminals, in 31 mammal species spanning the eutherian radiation. Several variations from the canonical cortical column outline of layer 4 and core thalamocortical inputs were noted. In shrews/microchiropterans, layer 4 was present, but many core thalamocortical projections terminated in layer 1 in addition to layers 4 and inner 3. In primate primary visual cortex, the sublaminated layer 4 was associated with a specialized core thalamocortical projection pattern. In primate primary motor cortex, no cytoarchitecturally distinct layer 4 was evident and the core thalamocortical projections terminated throughout layer 3. In the African elephant, cetaceans, and river hippopotamus, no cytoarchitecturally distinct layer 4 was observed and core thalamocortical projections terminated primarily in inner layer 3 and less densely in outer layer 3. These findings are contextualized in terms of cortical processing, perception, and the evolutionary trajectory leading to an indistinct or absent cortical layer 4.
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Affiliation(s)
- Adhil Bhagwandin
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
| | - Zoltán Molnár
- Department of Physiology, Anatomy and Genetics, Sherrington Building, University of Oxford, Oxford, UK
| | - Mads F Bertelsen
- Centre for Zoo and Wild Animal Health, Copenhagen Zoo, Frederiksberg, Denmark
| | - Karl Æ Karlsson
- Biomedical Engineering, Reykjavik University, Reykjavik, Iceland
| | | | - Nigel C Bennett
- South African Research Chair of Mammal Behavioural Ecology and Physiology, University of Pretoria, Pretoria, South Africa
| | - Patrick R Hof
- Nash Family Department of Neuroscience, Center for Discovery and Innovation, and Friedman Brain Institute, Icahn School of Medicine at Mount Sinai, New York, New York, USA
| | | | - Emmanuel Gilissen
- Department of African Zoology, Royal Museum for Central Africa, Tervuren, Belgium
- Laboratory of Histology and Neuropathology, Université Libre de Bruxelles, Brussels, Belgium
| | - Jaikishan Jayakumar
- Sudha Gopalakrishnan Brain Centre, Indian Institute of Technology Madras, Chennai, India
- Center for Computational Brain Research, Indian Institute of Technology Madras, Chennai, India
| | - Paul R Manger
- School of Anatomical Sciences, Faculty of Health Sciences, University of the Witwatersrand, Johannesburg, Republic of South Africa
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Cortes N, Ladret HJ, Abbas-Farishta R, Casanova C. The pulvinar as a hub of visual processing and cortical integration. Trends Neurosci 2024; 47:120-134. [PMID: 38143202 DOI: 10.1016/j.tins.2023.11.008] [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: 06/13/2023] [Revised: 10/26/2023] [Accepted: 11/26/2023] [Indexed: 12/26/2023]
Abstract
The pulvinar nucleus of the thalamus is a crucial component of the visual system and plays significant roles in sensory processing and cognitive integration. The pulvinar's extensive connectivity with cortical regions allows for bidirectional communication, contributing to the integration of sensory information across the visual hierarchy. Recent findings underscore the pulvinar's involvement in attentional modulation, feature binding, and predictive coding. In this review, we highlight recent advances in clarifying the pulvinar's circuitry and function. We discuss the contributions of the pulvinar to signal modulation across the global cortical network and place these findings within theoretical frameworks of cortical processing, particularly the global neuronal workspace (GNW) theory and predictive coding.
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Affiliation(s)
- Nelson Cortes
- Visual Neuroscience Laboratory, School of Optometry, Université de Montréal, Montreal, QC, Canada
| | - Hugo J Ladret
- Visual Neuroscience Laboratory, School of Optometry, Université de Montréal, Montreal, QC, Canada; Institut de Neurosciences de la Timone, UMR 7289, CNRS and Aix-Marseille Université, Marseille, 13005, France
| | - Reza Abbas-Farishta
- Visual Neuroscience Laboratory, School of Optometry, Université de Montréal, Montreal, QC, Canada
| | - Christian Casanova
- Visual Neuroscience Laboratory, School of Optometry, Université de Montréal, Montreal, QC, Canada.
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Maher EE, Briegel AC, Imtiaz S, Fox MA, Golino H, Erisir A. 3D electron microscopy and volume-based bouton sorting reveal the selectivity of inputs onto geniculate relay cell and interneuron dendrite segments. Front Neuroanat 2023; 17:1150747. [PMID: 37007643 PMCID: PMC10064015 DOI: 10.3389/fnana.2023.1150747] [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: 01/24/2023] [Accepted: 02/27/2023] [Indexed: 03/19/2023] Open
Abstract
Introduction The visual signals evoked at the retinal ganglion cells are modified and modulated by various synaptic inputs that impinge on lateral geniculate nucleus cells before they are sent to the cortex. The selectivity of geniculate inputs for clustering or forming microcircuits on discrete dendritic segments of geniculate cell types may provide the structural basis for network properties of the geniculate circuitry and differential signal processing through the parallel pathways of vision. In our study, we aimed to reveal the patterns of input selectivity on morphologically discernable relay cell types and interneurons in the mouse lateral geniculate nucleus. Methods We used two sets of Scanning Blockface Electron Microscopy (SBEM) image stacks and Reconstruct software to manually reconstruct of terminal boutons and dendrite segments. First, using an unbiased terminal sampling (UTS) approach and statistical modeling, we identified the criteria for volume-based sorting of geniculate boutons into their putative origins. Geniculate terminal boutons that were sorted in retinal and non-retinal categories based on previously described mitochondrial morphology, could further be sorted into multiple subpopulations based on their bouton volume distributions. Terminals deemed non-retinal based on the morphological criteria consisted of five distinct subpopulations, including small-sized putative corticothalamic and cholinergic boutons, two medium-sized putative GABAergic inputs, and a large-sized bouton type that contains dark mitochondria. Retinal terminals also consisted of four distinct subpopulations. The cutoff criteria for these subpopulations were then applied to datasets of terminals that synapse on reconstructed dendrite segments of relay cells or interneurons. Results Using a network analysis approach, we found an almost complete segregation of retinal and cortical terminals on putative X-type cell dendrite segments characterized by grape-like appendages and triads. On these cells, interneuron appendages intermingle with retinal and other medium size terminals to form triads within glomeruli. In contrast, a second, presumed Y-type cell displayed dendrodendritic puncta adherentia and received all terminal types without a selectivity for synapse location; these were not engaged in triads. Furthermore, the contribution of retinal and cortical synapses received by X-, Y- and interneuron dendrites differed such that over 60% of inputs to interneuron dendrites were from the retina, as opposed to 20% and 7% to X- and Y-type cells, respectively. Conclusion The results underlie differences in network properties of synaptic inputs from distinct origins on geniculate cell types.
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Affiliation(s)
- Erin E Maher
- Department of Psychology, University of Virginia, Charlottesville, VA, United States
| | - Alex C Briegel
- Department of Psychology, University of Virginia, Charlottesville, VA, United States
| | - Shahrozia Imtiaz
- Department of Psychology, University of Virginia, Charlottesville, VA, United States
| | - Michael A Fox
- School of Neuroscience, Virginia Tech, Blacksburg, VA, United States
- Fralin Biomedical Research Institute, Roanoke, VA, United States
| | - Hudson Golino
- Department of Psychology, University of Virginia, Charlottesville, VA, United States
| | - Alev Erisir
- Department of Psychology, University of Virginia, Charlottesville, VA, United States
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Abbas Farishta R, Zouahi H, Casanova C. Distributions of vesicular glutamate transporters 1 and 2 in the visual thalamus and associated areas of the cat. J Comp Neurol 2021; 530:1112-1125. [PMID: 34468980 DOI: 10.1002/cne.25239] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2021] [Revised: 07/20/2021] [Accepted: 08/25/2021] [Indexed: 12/20/2022]
Abstract
Glutamate is packaged in vesicles via two main vesicular transporter (VGLUT) proteins, VGLUT1 and VGLUT2, which regulate its storage and release from synapses of excitatory neurons. Studies in rodents, primates, ferrets, and tree shrews suggest that these transporters may identify distinct subsets of excitatory projections in visual structures, particularly in thalamocortical pathways where they tend to correlate with modulatory and driver projections, respectively. Despite being a well-studied model of thalamocortical connectivity, little is known about their expression pattern in the cat visual system. To expand current knowledge on their distribution and how they correlated with known driver and modulator projecting sites, we examined the protein expression patterns of VGLUT1 and VGLUT2 in the visual thalamus of the cat (lateral geniculate nucleus and the pulvinar complex). We also studied their expression pattern in relevant visual structures projecting to or receiving significant thalamic projections, such as the primary visual cortex and the superior colliculus. Our results indicate that both VGLUTs are consistently present throughout the cat visual system and show laminar or nuclei specificity in their distribution, which suggests, as in other species, that VGLUT1 and VGLUT2 represent distinct populations of glutamatergic projections.
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Affiliation(s)
- Reza Abbas Farishta
- Laboratoire des neurosciences de la vision, École d'optométrie, Université de Montréal, Montréal, Québec, Canada
| | - Hadjer Zouahi
- Laboratoire des neurosciences de la vision, École d'optométrie, Université de Montréal, Montréal, Québec, Canada
| | - Christian Casanova
- Laboratoire des neurosciences de la vision, École d'optométrie, Université de Montréal, Montréal, Québec, Canada
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Yao S, Zhou Q, Li S, Takahata T. Immunoreactivity of Vesicular Glutamate Transporter 2 Corresponds to Cytochrome Oxidase-Rich Subcompartments in the Visual Cortex of Squirrel Monkeys. Front Neuroanat 2021; 15:629473. [PMID: 33679337 PMCID: PMC7930324 DOI: 10.3389/fnana.2021.629473] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2020] [Accepted: 01/21/2021] [Indexed: 11/13/2022] Open
Abstract
Cytochrome oxidase (CO) histochemistry has been used to reveal the cytoarchitecture of the primate brain, including blobs/puffs/patches in the striate cortex (V1), and thick, thin and pale stripes in the middle layer of the secondary visual cortex (V2). It has been suggested that CO activity is coupled with the spiking activity of neurons, implying that neurons in these CO-rich subcompartments are more active than surrounding regions. However, we have discussed possibility that CO histochemistry represents the distribution of thalamo-cortical afferent terminals that generally use vesicular glutamate transporter 2 (VGLUT2) as their main glutamate transporter, and not the activity of cortical neurons. In this study, we systematically compared the labeling patterns observed between CO histochemistry and immunohistochemistry (IHC) for VGLUT2 from the system to microarchitecture levels in the visual cortex of squirrel monkeys. The two staining patterns bore striking similarities at all levels of the visual cortex, including the honeycomb structure of V1 layer 3Bβ (Brodmann's layer 4A), the patchy architecture in the deep layers of V1, the superficial blobs of V1, and the V2 stripes. The microarchitecture was more evident in VGLUT2 IHC, as expected. VGLUT2 protein expression that produced specific IHC labeling is thought to originate from the thalamus since the lateral geniculate nucleus (LGN) and the pulvinar complex both show high expression levels of VGLUT2 mRNA, but cortical neurons do not. These observations support our theory that the subcompartments revealed by CO histochemistry represent the distribution of thalamo-cortical afferent terminals in the primate visual cortex.
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Affiliation(s)
- Songping Yao
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China.,Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, Hangzhou, China
| | - Qiuying Zhou
- Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
| | - Shuiyu Li
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China.,Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, Hangzhou, China
| | - Toru Takahata
- Key Laboratory for Biomedical Engineering of Ministry of Education, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China.,Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University School of Medicine, Hangzhou, China.,Department of Neurology of the Second Affiliated Hospital, Zhejiang University School of Medicine, Hangzhou, China
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7
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Maher EE, Prillaman ME, Keskinoz EN, Petry HM, Erisir A. Immunocytochemical and ultrastructural organization of the taste thalamus of the tree shrew (Tupaia belangeri). J Comp Neurol 2021; 529:2558-2575. [PMID: 33458823 DOI: 10.1002/cne.25109] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2020] [Revised: 12/28/2020] [Accepted: 01/10/2021] [Indexed: 12/16/2022]
Abstract
Ventroposterior medialis parvocellularis (VPMP) nucleus of the primate thalamus receives direct input from the nucleus of the solitary tract, whereas the homologous thalamic structure in the rodent does not. To reveal whether the synaptic circuitries in these nuclei lend evidence for conservation of design principles in the taste thalamus across species or across sensory thalamus in general, we characterized the ultrastructural and molecular properties of the VPMP in a close relative of primates, the tree shrew (Tupaia belangeri), and compared these to known properties of the taste thalamus in rodent, and the visual thalamus in mammals. Electron microscopy analysis to categorize the synaptic inputs in the VPMP revealed that the largest-size terminals contained many vesicles and formed large synaptic zones with thick postsynaptic density on multiple, medium-caliber dendrite segments. Some formed triads within glomerular arrangements. Smaller-sized terminals contained dark mitochondria; most formed a single asymmetric or symmetric synapse on small-diameter dendrites. Immuno-EM experiments revealed that the large-size terminals contained VGLUT2, whereas the small-size terminal populations contained VGLUT1 or ChAT. These findings provide evidence that the morphological and molecular characteristics of synaptic circuitry in the tree shrew VPMP are similar to that in nonchemical sensory thalamic nuclei. Furthermore, the results indicate that all primary sensory nuclei of the thalamus in higher mammals share a structural template for processing thalamocortical sensory information. In contrast, substantial morphological and molecular differences in rodent versus tree shrew taste nuclei suggest a fundamental divergence in cellular processing mechanisms of taste input in these two species.
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Affiliation(s)
- Erin E Maher
- Department of Psychology, University of Virginia, Charlottesville, Virginia, USA
| | - McKenzie E Prillaman
- Department of Psychology, University of Virginia, Charlottesville, Virginia, USA
| | - Elif N Keskinoz
- Department of Psychology, University of Virginia, Charlottesville, Virginia, USA.,Department of Anatomy, School of Medicine, Acibadem Mehmet Ali Aydinlar University, Istanbul, Turkey
| | - Heywood M Petry
- Department of Psychological and Brain Sciences, University of Louisville, Louisville, Kentucky, USA
| | - Alev Erisir
- Department of Psychology, University of Virginia, Charlottesville, Virginia, USA
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Kaas JH, Baldwin MKL. The Evolution of the Pulvinar Complex in Primates and Its Role in the Dorsal and Ventral Streams of Cortical Processing. Vision (Basel) 2019; 4:E3. [PMID: 31905909 PMCID: PMC7157193 DOI: 10.3390/vision4010003] [Citation(s) in RCA: 29] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 11/26/2019] [Accepted: 12/19/2019] [Indexed: 01/05/2023] Open
Abstract
Current evidence supports the view that the visual pulvinar of primates consists of at least five nuclei, with two large nuclei, lateral pulvinar ventrolateral (PLvl) and central lateral nucleus of the inferior pulvinar (PIcl), contributing mainly to the ventral stream of cortical processing for perception, and three smaller nuclei, posterior nucleus of the inferior pulvinar (PIp), medial nucleus of the inferior pulvinar (PIm), and central medial nucleus of the inferior pulvinar (PIcm), projecting to dorsal stream visual areas for visually directed actions. In primates, both cortical streams are highly dependent on visual information distributed from primary visual cortex (V1). This area is so vital to vision that patients with V1 lesions are considered "cortically blind". When the V1 inputs to dorsal stream area middle temporal visual area (MT) are absent, other dorsal stream areas receive visual information relayed from the superior colliculus via PIp and PIcm, thereby preserving some dorsal stream functions, a phenomenon called "blind sight". Non-primate mammals do not have a dorsal stream area MT with V1 inputs, but superior colliculus inputs to temporal cortex can be more significant and more visual functions are preserved when V1 input is disrupted. The current review will discuss how the different visual streams, especially the dorsal stream, have changed during primate evolution and we propose which features are retained from the common ancestor of primates and their close relatives.
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Affiliation(s)
- Jon H. Kaas
- Department of Psychology, Vanderbilt University, Nashville, TN 37240, USA
| | - Mary K. L. Baldwin
- Center for Neuroscience, University of California at Davis, Davis, CA 95618, USA;
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9
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Takahata T, Patel NB, Balaram P, Chino YM, Kaas JH. Long-term histological changes in the macaque primary visual cortex and the lateral geniculate nucleus after monocular deprivation produced by early restricted retinal lesions and diffuser induced form deprivation. J Comp Neurol 2018; 526:2955-2972. [PMID: 30004587 DOI: 10.1002/cne.24494] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/08/2017] [Revised: 06/02/2018] [Accepted: 06/15/2018] [Indexed: 12/12/2022]
Abstract
Ocular dominance (OD) plasticity has been extensively studied in various mammalian species. While robust OD shifts are typically observed after monocular eyelid suture, relatively poor OD plasticity is observed for early eye removal or after tetrodotoxin (TTX) injections in mice. Hence, abnormal binocular signal interactions in the visual cortex may play a critical role in eliciting OD plasticity. Here, we examined the histochemical changes in the lateral geniculate nucleus (LGN) and the striate cortex (V1) in macaque monkeys that experienced two different monocular sensory deprivations in the same eye beginning at 3 weeks of age: restricted laser lesions in macular or peripheral retina and form deprivation induced by wearing a diffuser lens during the critical period. The monkeys were subsequently reared for 5 years under a normal visual environment. In the LGN, atrophy of neurons and a dramatic increase of GFAP expression were observed in the lesion projection zones (LPZs). In V1, although no obvious shift of the LPZ border was found, the ocular dominance columns (ODCs) for the lesioned eye shrunk and those for the intact eye expanded over the entirety of V1. This ODC size change was larger in the area outside the LPZ and in the region inside the LPZ near the border compared to that in the LPZ center. These developmental changes may reflect abnormal binocular interactions in V1 during early infancy. Our observations provide insights into the nature of degenerative and plastic changes in the LGN and V1 following early chronic monocular sensory deprivations.
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Affiliation(s)
- Toru Takahata
- Interdisciplinary Institute of Neuroscience and Technology, Qiushi Academy for Advanced Studies, Zhejiang University, Hangzhou, Zhejiang, People's Republic of China.,Department of Psychology, Vanderbilt University, Nashville, Tennessee
| | - Nimesh B Patel
- Department of Vision Sciences, College of Optometry, University of Houston, Houston, Texas
| | - Pooja Balaram
- Department of Psychology, Vanderbilt University, Nashville, Tennessee.,Department of Otolaryngology, Harvard Medical School, Boston, Massachusetts
| | - Yuzo M Chino
- Department of Vision Sciences, College of Optometry, University of Houston, Houston, Texas
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee
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10
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Baldwin MKL, Krubitzer L. Architectonic characteristics of the visual thalamus and superior colliculus in titi monkeys. J Comp Neurol 2018; 526:1760-1776. [PMID: 29658111 DOI: 10.1002/cne.24445] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/23/2017] [Revised: 03/21/2018] [Accepted: 03/22/2018] [Indexed: 12/27/2022]
Abstract
Titi monkeys are arboreal, diurnal New World monkeys whose ancestors were the first surviving branch of the New World radiation. In the current study, we use cytoarchitectonic and immunohistochemical characteristics to compare titi monkey subcortical structures associated with visual processing with those of other well-studied primates. Our goal was to appreciate features that are similar across all New World monkeys, and primates in general, versus those features that are unique to titi monkeys and other primate taxa. We examined tissue stained for Nissl substance, cytochrome oxidase (CO), acetylcholinesterase (AChE), calbindin (Cb), parvalbumin (Pv), and vesicular glutamate transporter 2 (VGLUT2) to characterize the superior colliculus, lateral geniculate nucleus, and visual pulvinar. This is the first study to characterize VGLUT2 in multiple subcortical structures of any New World monkey. Our results from tissue processed for VGLUT2, in combination with other histological stains, revealed distinct features of subcortical structures that are similar to other primates, but also some features that are slightly modified compared to other New World monkeys and other primates. These included subdivisions of the inferior pulvinar, sublamina within the stratum griseum superficiale (SGS) of the superior colliculus, and specific koniocellular layers within the lateral geniculate nucleus. Compared to other New World primates, many features of the subcortical structures that we examined in titi monkeys were most similar to those in owl monkeys and marmosets, with the lateral geniculate nucleus consisting of two main parvocellular layers and two magnocellular layers separated by interlaminar zones or koniocellular layers.
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Affiliation(s)
- Mary K L Baldwin
- Center for Neuroscience, University of California, 1544 Newton Court, Davis, California
| | - Leah Krubitzer
- Center for Neuroscience, University of California, 1544 Newton Court, Davis, California
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11
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Petry HM, Bickford ME. The Second Visual System of The Tree Shrew. J Comp Neurol 2018; 527:679-693. [PMID: 29446088 DOI: 10.1002/cne.24413] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2017] [Revised: 02/01/2018] [Accepted: 02/06/2018] [Indexed: 12/28/2022]
Abstract
This review provides a historical account of the discovery of secondary visual pathways (from retina to the superior colliculus to the dorsal thalamus and extrastriate cortex), and Vivien Casagrande's pioneering studies of this system using the tree shrew as a model. Subsequent studies of visual pathways in the tree shrew are also reviewed, beginning with a description of the organization and central projections of the tree shrew retina. The organization and connectivity of second visual system components that include the retino-recipient superior colliculus, tecto-recipient pulvinar nucleus and its projections, and the tecto-recipient dorsal lateral geniculate nucleus and its projections are detailed. Potential functions of the second visual system are discussed in the context of this work and in the context of the behavioral studies that initially inspired the secondary visual system concept.
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Affiliation(s)
- Heywood M Petry
- Department of Psychological and Brain Sciences, University of Louisville, Louisville, Kentucky
| | - Martha E Bickford
- Department of Anatomical Sciences and Neurobiology, University of Louisville, Louisville, Kentucky
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12
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Baldwin MKL, Balaram P, Kaas JH. The evolution and functions of nuclei of the visual pulvinar in primates. J Comp Neurol 2017; 525:3207-3226. [PMID: 28653446 DOI: 10.1002/cne.24272] [Citation(s) in RCA: 61] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/21/2017] [Revised: 05/31/2017] [Accepted: 06/14/2017] [Indexed: 11/06/2022]
Abstract
In this review, we outline the history of our current understanding of the organization of the pulvinar complex of mammals. We include more recent evidence from our own studies of both New and Old World monkeys, prosimian galagos, and close relatives of primates, including tree shrews and rodents. Based on cumulative evidence, we provide insights into the possible evolution of the visual pulvinar complex, as well as the possible co-evolution of the inferior pulvinar nuclei and temporal cortical visual areas within the MT complex.
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Affiliation(s)
- Mary K L Baldwin
- Department of Psychology, Vanderbilt University, Nashville, Tennessee.,Center for Neuroscience, University of California Davis, Davis, California
| | - Pooja Balaram
- Department of Psychology, Vanderbilt University, Nashville, Tennessee.,Massachusetts Eye and Ear Infirmary, Harvard Medical School, Cambridge, Massachusetts
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee
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13
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Turner EC, Sawyer EK, Kaas JH. Optic nerve, superior colliculus, visual thalamus, and primary visual cortex of the northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus). J Comp Neurol 2017; 525:2109-2132. [PMID: 28188622 DOI: 10.1002/cne.24188] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/05/2016] [Revised: 01/31/2017] [Accepted: 02/01/2017] [Indexed: 11/07/2022]
Abstract
The northern elephant seal (Mirounga angustirostris) and California sea lion (Zalophus californianus) are members of a diverse clade of carnivorous mammals known as pinnipeds. Pinnipeds are notable for their large, ape-sized brains, yet little is known about their central nervous system. Both the northern elephant seal and California sea lion spend most of their lives at sea, but each also spends time on land to breed and give birth. These unique coastal niches may be reflected in specific evolutionary adaptations to their sensory systems. Here, we report on components of the visual pathway in these two species. We found evidence for two classes of myelinated fibers within the pinniped optic nerve, those with thick myelin sheaths (elephant seal: 9%, sea lion: 7%) and thin myelin sheaths (elephant seal: 91%, sea lion: 93%). In order to investigate the architecture of the lateral geniculate nucleus, superior colliculus, and primary visual cortex, we processed brain sections from seal and sea lion pups for Nissl substance, cytochrome oxidase, and vesicular glutamate transporters. As in other carnivores, the dorsal lateral geniculate nucleus consisted of three main layers, A, A1, and C, while each superior colliculus similarly consisted of seven distinct layers. The sea lion visual cortex is located at the posterior side of cortex between the upper and lower banks of the postlateral sulcus, while the elephant seal visual cortex extends far more anteriorly along the dorsal surface and medial wall. These results are relevant to comparative studies related to the evolution of large brains.
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Affiliation(s)
- Emily C Turner
- Department of Psychology, Vanderbilt University, Nashville, Tennessee
| | - Eva K Sawyer
- Department of Psychology, Vanderbilt University, Nashville, Tennessee.,Department of Bioengineering, University of California, Berkeley, California
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee
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14
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Chen A, Hubbert KD, Foroudi PF, Lu VF, Janušonis S. Serotonin 5-HT 4 receptors modulate the development of glutamatergic input to the dorsal raphe nucleus. Neurosci Lett 2017; 640:111-116. [PMID: 28108396 DOI: 10.1016/j.neulet.2017.01.029] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/16/2016] [Revised: 12/19/2016] [Accepted: 01/11/2017] [Indexed: 11/20/2022]
Abstract
The dorsal raphe nucleus (DRN) is a major serotonin (5-hydroxytryptamine, 5-HT)-producing region in the central nervous system. It receives glutamatergic inputs from several brain regions, which are reciprocally modulated by serotonergic signals. We investigated whether serotonin 5-HT4 receptors (5-HT4Rs) play a role in the development of glutamatergic control of the DRN, with an emphasis on cortical inputs. Double-label immunohistochemistry and confocal microscopy were used to quantify vesicular glutamate transporter 1 (vGluT1)-immunoreactive terminals in the DRN of mice with a null-mutation in the 5-HT4R gene. We found no significant change in the overall density of vGluT1-positive terminals in homozygous and heterozygous mice, but heterozygous mice had a significantly higher density of vGluT1-positive terminals contacting serotonergic neurons. These results suggest that altered 5-HT4R expression may affect the development of cortical glutamatergic control of the DRN.
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Affiliation(s)
- Angela Chen
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA 93106-9660, USA
| | - Katherine D Hubbert
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA 93106-9660, USA
| | - Pasha F Foroudi
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA 93106-9660, USA
| | - Vivian F Lu
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA 93106-9660, USA
| | - Skirmantas Janušonis
- Department of Psychological and Brain Sciences, University of California, Santa Barbara, CA 93106-9660, USA.
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15
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Takahata T. What Does Cytochrome Oxidase Histochemistry Represent in the Visual Cortex? Front Neuroanat 2016; 10:79. [PMID: 27489537 PMCID: PMC4951485 DOI: 10.3389/fnana.2016.00079] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/05/2016] [Accepted: 07/06/2016] [Indexed: 11/13/2022] Open
Affiliation(s)
- Toru Takahata
- Laboratory of Comparative Molecular Neuroanatomy, Interdisciplinary Institute of Neuroscience and Technology, Zhejiang University Hangzhou, China
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16
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Takahata T, Kaas JH. c-FOS expression in the visual system of tree shrews after monocular inactivation. J Comp Neurol 2016; 525:151-165. [PMID: 27276555 DOI: 10.1002/cne.24053] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2016] [Revised: 05/26/2016] [Accepted: 05/27/2016] [Indexed: 01/30/2023]
Abstract
Tree shrews possess an unusual segregation of ocular inputs to sublayers rather than columns in the primary visual cortex (V1). In this study, the lateral geniculate nucleus (LGN), superior colliculus (SC), pulvinar, and V1 were examined for changes in c-FOS, an immediate-early gene, expression after 1 or 24 hours of monocular inactivation with tetrodotoxin (TTX) in tree shrews. Monocular inactivation greatly reduced gene expression in LGN layers related to the blocked eye, whereas normally high to moderate levels were maintained in the layers that receive inputs from the intact eye. The SC and caudal pulvinar contralateral to the blocked eye had greatly (SC) or moderately (pulvinar) reduced gene expressions reflective of dependence on the contralateral eye. c-FOS expression in V1 was greatly reduced contralateral to the blocked eye, with most of the expression that remained in upper layer 4a and lower 4b and lower layer 6 regions. In contrast, much of V1 contralateral to the active eye showed normal levels of c-FOS expression, including the inner parts of sublayers 4a and 4b and layers 2, 3, and 6. In some cases, upper layer 4a and lower 4b showed a reduction of gene expression. Layers 5 and sublayer 3c had normally low levels of gene expression. The results reveal the functional dominance of the contralateral eye in activating the SC, pulvinar, and V1, and the results from V1 suggest that the sublaminar organization of layer 4 is more complex than previously realized. J. Comp. Neurol. 525:151-165, 2017. © 2016 Wiley Periodicals, Inc.
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Affiliation(s)
- Toru Takahata
- Zhejiang University Interdisciplinary Institute of Neuroscience and Technology (ZIINT), Hangzhou, Zhejiang, China, 310016.,Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
| | - Jon H Kaas
- Department of Psychology, Vanderbilt University, Nashville, Tennessee, 37240
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17
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Heeringa AN, Stefanescu RA, Raphael Y, Shore SE. Altered vesicular glutamate transporter distributions in the mouse cochlear nucleus following cochlear insult. Neuroscience 2015; 315:114-24. [PMID: 26705736 DOI: 10.1016/j.neuroscience.2015.12.009] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2015] [Revised: 11/30/2015] [Accepted: 12/04/2015] [Indexed: 11/15/2022]
Abstract
Vesicular glutamate transporters 1 and 2 (VGLUT1 and VGLUT2) have distinct distributions in the cochlear nucleus that correspond to sources of the labeled terminals. VGLUT1 is mainly associated with terminals of auditory nerve fibers, whereas VGLUT2 is mainly associated with glutamatergic terminals deriving from other sources that project to the cochlear nucleus (CN), including somatosensory and vestibular terminals. Previous studies in guinea pig have shown that cochlear damage results in a decrease of VGLUT1-labeled puncta and an increase in VGLUT2-labeled puncta. This indicates cross-modal compensation that is of potential importance in somatic tinnitus. To examine whether this effect is consistent across species and to provide a background for future studies, using transgenesis, the current study examines VGLUT expression profiles upon cochlear insult by intracochlear kanamycin injections in the mouse. Intracochlear kanamycin injections abolished ipsilateral ABR responses in all animals and reduced ipsilateral spiral ganglion neuron densities in animals that were sacrificed after four weeks, but not in animals that were sacrificed after three weeks. In all unilaterally deafened animals, VGLUT1 density was decreased in CN regions that receive auditory nerve fiber terminals, i.e., in the deep layer of the dorsal cochlear nucleus (DCN), in the interstitial region where the auditory nerve enters the CN, and in the magnocellular region of the antero- and posteroventral CN. In contrast, density of VGLUT2 expression was upregulated in the fusiform cell layer of the DCN and in the granule cell lamina, which are known to receive somatosensory and vestibular terminals. These results show that a cochlear insult induces cross-modal compensation in the cochlear nucleus of the mouse, confirming previous findings in guinea pig, and that these changes are not dependent on the occurrence of spiral ganglion neuron degeneration.
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Affiliation(s)
- A N Heeringa
- Kresge Hearing Research Institute, Otolaryngology, University of Michigan, United States
| | - R A Stefanescu
- Kresge Hearing Research Institute, Otolaryngology, University of Michigan, United States
| | - Y Raphael
- Kresge Hearing Research Institute, Otolaryngology, University of Michigan, United States
| | - S E Shore
- Kresge Hearing Research Institute, Otolaryngology, University of Michigan, United States; Molecular and Integrative Physiology, University of Michigan, United States; Biomedical Engineering, University of Michigan, United States.
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18
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Vaughan SK, Kemp Z, Hatzipetros T, Vieira F, Valdez G. Degeneration of proprioceptive sensory nerve endings in mice harboring amyotrophic lateral sclerosis-causing mutations. J Comp Neurol 2015; 523:2477-94. [PMID: 26136049 DOI: 10.1002/cne.23848] [Citation(s) in RCA: 60] [Impact Index Per Article: 6.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/22/2015] [Revised: 06/29/2015] [Accepted: 06/29/2015] [Indexed: 12/13/2022]
Abstract
Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that primarily targets the motor system. Although much is known about the effects of ALS on motor neurons and glial cells, little is known about its effect on proprioceptive sensory neurons. This study examines proprioceptive sensory neurons in mice harboring mutations associated with ALS, in SOD1(G93A) and TDP43(A315T) transgenic mice. In both transgenic lines, we found fewer proprioceptive sensory neurons containing fluorescently tagged cholera toxin in their soma five days after injecting this retrograde tracer into the tibialis anterior muscle. We asked whether this is due to neuronal loss or selective degeneration of peripheral nerve endings. We found no difference in the total number and size of proprioceptive sensory neuron soma between symptomatic SOD1(G93A) and control mice. However, analysis of proprioceptive nerve endings in muscles revealed early and significant alterations at Ia/II proprioceptive nerve endings in muscle spindles before the symptomatic phase of the disease. Although these changes occur alongside those at α-motor axons in SOD1(G93A) mice, Ia/II sensory nerve endings degenerate in the absence of obvious alterations in α-motor axons in TDP43(A315T) transgenic mice. We next asked whether proprioceptive nerve endings are similarly affected in the spinal cord and found that nerve endings terminating on α-motor neurons are affected during the symptomatic phase and after peripheral nerve endings begin to degenerate. Overall, we show that Ia/II proprioceptive sensory neurons are affected by ALS-causing mutations, with pathological changes starting at their peripheral nerve endings.
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Affiliation(s)
- Sydney K Vaughan
- Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia, USA.,Graduate Program in Translational Biology, Medicine, and Health, Virginia Tech, Blacksburg, Virginia, USA
| | - Zachary Kemp
- Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia, USA
| | - Theo Hatzipetros
- ALS Therapy Development Institute, Cambridge, Massachusetts, 02139, USA
| | - Fernando Vieira
- ALS Therapy Development Institute, Cambridge, Massachusetts, 02139, USA
| | - Gregorio Valdez
- Virginia Tech Carilion Research Institute, Virginia Tech, Roanoke, Virginia, USA.,Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, 24061
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