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İşbilir F, Güzel BC, Gülaydin A, Choudhary OP. Osteometric and topographic measurement of the skull and mandible of Siirt colored Mohair goat with three-dimensional (3D) modeling technique. Folia Morphol (Warsz) 2023:VM/OJS/J/97504. [PMID: 37997456 DOI: 10.5603/fm.97504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/20/2023] [Revised: 11/07/2023] [Accepted: 11/09/2023] [Indexed: 11/25/2023]
Abstract
Siirt-colored Mohair goat is one of the breeds that contributed significantly to the existence of Mohair goats reared in Turkey. Morphological and morphometric characteristics of the Siirt-colored Mohair goat remained vague owing to a lack of studies. Recent advances in high-tech imaging have replaced conventional two-dimensional anatomical structures with three-dimensional (3D) models. In our study, morphometric features were determined by 3D modeling from computed tomography images obtained from the skull and mandibular bones of Siirt-colored Mohair goats. For this purpose, the skulls and mandibular bones of 20 Siirt-colored Mohair goats (10 females and 10 males) were used. The images were reconstructed with the help of a particular software program. The craniometric data were analyzed in terms of sexual dimorphism, and statistically significant difference was found in the A5, A18, and A31 measurement parameters (P<0.05) and Skull index (P<0.01) parameters. In the mandible measurements, there was a statistically significant difference between the sexes in C5, C10 measurement points (P<0.05), C2, C8, C12, C18, C21 measurement points (P<0.001) and surface area parameter (P<0.01). The morphometric data obtained is a resource in the fields of zoo archaeology, anatomy, forensics, anesthesia, surgery, and treatment.
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Affiliation(s)
- Fatma İşbilir
- Siirt University, Department of Anatomy, Faculty of Veterinary Medicine, Siirt, Turkey
| | - Barış Can Güzel
- Department of Veterinary Anatomy and Histology, College of Veterinary Sciences and Animal Husbandry, Central Agricultural University (I), Selesih, Aizawl, Mizoram, India
| | - Ali Gülaydin
- Siirt University, Department of Surgery, Faculty of Veterinary Medicine, Siirt, Turkey
| | - Om Prakash Choudhary
- Department of Veterinary Anatomy and Histology, College of Veterinary Sciences and Animal Husbandry, Central Agricultural University (I), Selesih, Aizawl, Mizoram, India.
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Mamiya A, Sustar A, Siwanowicz I, Qi Y, Lu TC, Gurung P, Chen C, Phelps JS, Kuan AT, Pacureanu A, Lee WCA, Li H, Mhatre N, Tuthill JC. Biomechanical origins of proprioceptor feature selectivity and topographic maps in the Drosophila leg. Neuron 2023; 111:3230-3243.e14. [PMID: 37562405 PMCID: PMC10644877 DOI: 10.1016/j.neuron.2023.07.009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/07/2022] [Revised: 04/28/2023] [Accepted: 07/12/2023] [Indexed: 08/12/2023]
Abstract
Our ability to sense and move our bodies relies on proprioceptors, sensory neurons that detect mechanical forces within the body. Different subtypes of proprioceptors detect different kinematic features, such as joint position, movement, and vibration, but the mechanisms that underlie proprioceptor feature selectivity remain poorly understood. Using single-nucleus RNA sequencing (RNA-seq), we found that proprioceptor subtypes in the Drosophila leg lack differential expression of mechanosensitive ion channels. However, anatomical reconstruction of the proprioceptors and connected tendons revealed major biomechanical differences between subtypes. We built a model of the proprioceptors and tendons that identified a biomechanical mechanism for joint angle selectivity and predicted the existence of a topographic map of joint angle, which we confirmed using calcium imaging. Our findings suggest that biomechanical specialization is a key determinant of proprioceptor feature selectivity in Drosophila. More broadly, the discovery of proprioceptive maps reveals common organizational principles between proprioception and other topographically organized sensory systems.
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Affiliation(s)
- Akira Mamiya
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Anne Sustar
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Igor Siwanowicz
- Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Yanyan Qi
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Tzu-Chiao Lu
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Pralaksha Gurung
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA
| | - Chenghao Chen
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA; Janelia Research Campus, Howard Hughes Medical Institute, Ashburn, VA, USA
| | - Jasper S Phelps
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | - Aaron T Kuan
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA
| | | | - Wei-Chung Allen Lee
- Department of Neurobiology, Harvard Medical School, Boston, MA, USA; F.M. Kirby Neurobiology Center, Boston Children's Hospital, Harvard Medical School, Boston, MA, USA
| | - Hongjie Li
- Huffington Center on Aging, Baylor College of Medicine, Houston, TX 77030, USA; Department of Molecular and Human Genetics, Baylor College of Medicine, Houston, TX 77030, USA
| | - Natasha Mhatre
- Department of Biology, University of Western Ontario, London, ON, Canada
| | - John C Tuthill
- Department of Physiology and Biophysics, University of Washington, Seattle, WA, USA.
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Liu X, Yang G, Que Q, Wang Q, Zhang Z, Huang L. How Do Landscape Heterogeneity, Community Structure, and Topographical Factors Contribute to the Plant Diversity of Urban Remnant Vegetation at Different Scales? Int J Environ Res Public Health 2022; 19:14302. [PMID: 36361180 PMCID: PMC9658405 DOI: 10.3390/ijerph192114302] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 09/02/2022] [Revised: 10/27/2022] [Accepted: 10/31/2022] [Indexed: 06/16/2023]
Abstract
In highly fragmented urban areas, plant diversity of remnant vegetation may depend not only on community structure and topographical factors, but also on landscape heterogeneity. Different buffer radius settings can affect the relative importance of these factors to plant diversity. The aim of this study was to examine the relative importance of landscape heterogeneity, community structure, and topographical factors on plant diversity under different buffer radii in biodiversity hotspots. We established 48 plots of remnant vegetation in Guangzhou city, one of the biodiversity hotspots. A buffer radius of 500 m, 1000 m, and 2000 m was established around the center of each sample plot, and 17 landscape heterogeneity indices in each buffer were calculated by FRAGSTATS 4.2 software. Combined with the community structure and topographical factors, the impact factors of plant diversity under different buffer radii were analyzed by multiple regression analysis. We found the following: (1) The combined explanatory power of the three factors accounted for 43% of the species diversity indices and 62% of the richness index at its peak. The three impact factors rarely act independently and usually create comprehensive cumulative effects. (2) Scale does matter in urban landscape studies. At a 500 m buffer radius, community structure combined with road disturbance indices was strongly related to diversity indices in herb and shrub layers. The stand age was negatively correlated with the tree-layer richness index. As the scale increased, the diversity indices and richness index in the three layers decreased or increased under the influence of comprehensive factors. (3) The richness index in the herb layer was more responsive to impact factors than other biodiversity indices. Except for the herb layer, the interpretation of landscape heterogeneity for each plant diversity index was more stable than that for the other two factors. Road disturbance indices, combined with the other six landscape pattern metrics, can well indicate species diversity and richness. We suggest that the vegetation area of remnant patches within a radius of 500-2000 m should be appropriately increased to protect plant diversity, and the negative effects of road disturbance should also be considered.
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Affiliation(s)
- Xingzhao Liu
- College of Landscape Architecture and Art, Fujian Agriculture and Forestry University, Fuzhou 350002, China
- Innovation Center of Engineering Technology for Monitoring and Restoration of Ecological Fragile Areas in Southeast China, Ministry of Natural Resources, Fuzhou 350013, China
| | - Guimei Yang
- College of Landscape Architecture and Art, Fujian Agriculture and Forestry University, Fuzhou 350002, China
| | - Qingmin Que
- College of Forestry and Landscape Architecture, South China Agriculture University, Guangzhou 510642, China
| | - Qi Wang
- School of Modern Agriculture and Environment, Weifang Institute of Technology, Weifang 262500, China
| | - Zengke Zhang
- School of Ecological and Environmental Sciences, East China Normal University, Shanghai 200241, China
| | - Liujing Huang
- College of Landscape Architecture and Art, Fujian Agriculture and Forestry University, Fuzhou 350002, China
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Bakry M, Bakry R. Changes in topographic electroencephalogram during deepening levels of propofol sedation based on alertness/sedation scale under bispectral index guidance. Anaesthesiol Intensive Ther 2019; 51:224-9. [PMID: 31434471 DOI: 10.5114/ait.2019.87361] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
BACKGROUND Sedation has been associated with numerous changes on electroencephalogram (EEG) but there is a need to clarify specific alterations in relation to deepening levels of sedation with different agents. We aimed to evaluate the effect of deepening levels of sedation induced by propofol and how they compare to natural sleep. METHODS Fifty consecutive neurologically normal patients who underwent upper gastrointestinal endoscopy while sedated with propofol were included. Topographic EEG spectral maps and the bispectral index (BIS) values were obtained at four time points: wakefulness, mild sedation, deep sedation and recovery. Observer's Assessment of Alertness and Sedation (OAA/S) score was used to assess sedation levels. RESULTS Propofol induced increased delta (0.5-3.5 Hz) and gamma (25-40 Hz) power throughout sedation. In addition, there was decreased alpha power (9-11.5 Hz) in the occipital area and increased global beta (12-25 Hz)/gamma (25-40 Hz) power during mild sedation. Deep sedation was associated with increased theta (4-7 Hz)/alpha (9-11.5 Hz)/beta (12-25 Hz) power, which was maximal frontally. CONCLUSION There are distinct changes associated with deepening levels of propofol induced sedation that distinguish it from natural sleep. This suggests that different mechanisms are involved in them and warrants further investigations to clarify the nature of these changes.
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Srinivasan S, Stevens CF. Scaling Principles of Distributed Circuits. Curr Biol 2019; 29:2533-2540.e7. [PMID: 31327712 DOI: 10.1016/j.cub.2019.06.046] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2018] [Revised: 03/21/2019] [Accepted: 06/17/2019] [Indexed: 12/17/2022]
Abstract
Identifying shared quantitative features of a neural circuit across species is important for 3 reasons. Often expressed in the form of power laws and called scaling relationships [1, 2], they reveal organizational principles of circuits, make insights gleaned from model systems widely applicable, and explain circuit performance and function, e.g., visual circuits [3, 4]. The visual circuit is topographic [5, 6], wherein retinal neurons target and activate predictable spatial loci in primary visual cortex. The brain, however, contains many circuits, where neuronal targets and activity are unpredictable and distributed throughout the circuit, e.g., olfactory circuits, in which glomeruli (or mitral cells) in the olfactory bulb synapse with neurons distributed throughout the piriform cortex [7-10]. It is unknown whether such circuits, which we term distributed circuits, are scalable. To determine whether distributed circuits scale, we obtained quantitative descriptions of the olfactory bulb and piriform cortex in six mammals using stereology techniques and light microscopy. Two conserved features provide evidence of scalability. First, the number of piriform neurons n and bulb glomeruli g scale as n∼g3/2. Second, the average number of synapses between a bulb glomerulus and piriform neuron is invariant at one. Using theory and modeling, we show that these two features preserve the discriminatory ability and precision of odor information across the olfactory circuit. As both abilities depend on circuit size, manipulating size provides evolution with a way to adapt a species to its niche without designing developmental programs de novo. These principles might apply to other distributed circuits like the hippocampus.
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Cimmino C, Rossano L, Netti PA, Ventre M. Spatio-Temporal Control of Cell Adhesion: Toward Programmable Platforms to Manipulate Cell Functions and Fate. Front Bioeng Biotechnol 2018; 6:190. [PMID: 30564573 PMCID: PMC6288377 DOI: 10.3389/fbioe.2018.00190] [Citation(s) in RCA: 31] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2018] [Accepted: 11/21/2018] [Indexed: 01/06/2023] Open
Abstract
Biophysical and biochemical signals of material surfaces potently regulate cell functions and fate. In particular, micro- and nano-scale patterns of adhesion signals can finely elicit and affect a plethora of signaling pathways ultimately affecting gene expression, in a process known as mechanotransduction. Our fundamental understanding of cell-material signals interaction and reaction is based on static culturing platforms, i.e., substrates exhibiting signals whose configuration is time-invariant. However, cells in-vivo are exposed to arrays of biophysical and biochemical signals that change in time and space and the way cells integrate these might eventually dictate their behavior. Advancements in fabrication technologies and materials engineering, have recently enabled the development of culturing platforms able to display patterns of biochemical and biophysical signals whose features change in time and space in response to external stimuli and according to selected programmes. These dynamic devices proved to be particularly helpful in shedding light on how cells adapt to a dynamic microenvironment or integrate spatio-temporal variations of signals. In this work, we present the most relevant findings in the context of dynamic platforms for controlling cell functions and fate in vitro. We place emphasis on the technological aspects concerning the fabrication of platforms displaying micro- and nano-scale dynamic signals and on the physical-chemical stimuli necessary to actuate the spatio-temporal changes of the signal patterns. In particular, we illustrate strategies to encode material surfaces with dynamic ligands and patterns thereof, topographic relieves and mechanical properties. Additionally, we present the most effective, yet cytocompatible methods to actuate the spatio-temporal changes of the signals. We focus on cell reaction and response to dynamic changes of signal presentation. Finally, potential applications of this new generation of culturing systems for in vitro and in vivo applications, including regenerative medicine and cell conditioning are presented.
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Affiliation(s)
- Chiara Cimmino
- Department of Chemical, Materials and Industrial Production Engineering, University of Naples Federico II, Naples, Italy
- Center for Advanced Biomaterials for Healthcare@CRIB, Fondazione Istituto Italiano di Tecnologia, Naples, Italy
| | - Lucia Rossano
- Department of Chemical, Materials and Industrial Production Engineering, University of Naples Federico II, Naples, Italy
- Center for Advanced Biomaterials for Healthcare@CRIB, Fondazione Istituto Italiano di Tecnologia, Naples, Italy
| | - Paolo Antonio Netti
- Department of Chemical, Materials and Industrial Production Engineering, University of Naples Federico II, Naples, Italy
- Center for Advanced Biomaterials for Healthcare@CRIB, Fondazione Istituto Italiano di Tecnologia, Naples, Italy
| | - Maurizio Ventre
- Department of Chemical, Materials and Industrial Production Engineering, University of Naples Federico II, Naples, Italy
- Center for Advanced Biomaterials for Healthcare@CRIB, Fondazione Istituto Italiano di Tecnologia, Naples, Italy
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Li Y, Jiao Q, Zhang TT, Liu AP, Huang LQ, Yang G, Zheng YG. [Research on topographic factors of ecology suitability regionalization of Bupleuri Radix in Hebei province]. Zhongguo Zhong Yao Za Zhi 2018; 42:4402-4407. [PMID: 29318842 DOI: 10.19540/j.cnki.cjcmm.2017.0191] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 04/26/2017] [Indexed: 11/18/2022]
Abstract
To study the correlation between the content of saikosaponins ingredient of Bupleuri Radix and topographic factors, we researched the ecology suitability regionalization of topographic of Bupleuri Radix from Hebei province to provide a scientific basis for selecting artificial planting. Based on 43 samples of Bupleuri Radix from Hebei province, the variation of the content of saikosaponins in different conditions of topographic factors and the influence of slope, altitude and aspect were comprehensively analyzed by SPSS 21.0. Then we studied topographic factors of ecology suitability regionalization of Bupleuri Radix on the basis of the relationship between the saikosaponins and topographic factors by ArcGIS. The most suitable conditions of topographic for cultivation of saikosaponins are as follows:altitude 600 m above, slope 4.00-5.50 degrees, aspect to the sun. In Hebei province, it is suitable for growth of Bupleuri Radix in the Taihang Mountains and the Yanshan Mountains where the content of saikosaponins is higher.
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Affiliation(s)
- Ying Li
- Hebei Medical University, Shijiazhuang 050091, China
| | - Qian Jiao
- Hebei Medical University, Shijiazhuang 050091, China
| | | | - Ai-Peng Liu
- Hebei University of Chinese Medicine, Shijiazhuang 050090, China
| | - Lu-Qi Huang
- State Laboratory of Dao-di Herbs, National Resources Center for Chinese Materia, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Guang Yang
- State Laboratory of Dao-di Herbs, National Resources Center for Chinese Materia, China Academy of Chinese Medical Sciences, Beijing 100700, China
| | - Yu-Guang Zheng
- Hebei Medical University, Shijiazhuang 050091, China.,Hebei University of Chinese Medicine, Shijiazhuang 050090, China
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Verstynen TD, Badre D, Jarbo K, Schneider W. Microstructural organizational patterns in the human corticostriatal system. J Neurophysiol 2012; 107:2984-95. [PMID: 22378170 PMCID: PMC4073961 DOI: 10.1152/jn.00995.2011] [Citation(s) in RCA: 73] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2011] [Accepted: 02/26/2012] [Indexed: 11/22/2022] Open
Abstract
The axons that project into the striatum are known to segregate according to macroscopic cortical systems; however, the within-region organization of these fibers has yet to be described in humans. We used in vivo fiber tractography, in neurologically healthy adults, to map white matter bundles that originate in different neocortical areas, navigate complex fiber crossings, and project into the striatum. As expected, these fibers were generally segregated according to cortical origin. Within a subset of pathways, a patched pattern of inputs was observed, consistent with previous ex vivo histological studies. In projections from the prefrontal cortex, we detected a topography in which fibers from rostral prefrontal areas projected mostly to rostral parts of the striatum and vice versa for inputs originating in caudal cortical areas. Importantly, within this prefrontal system there was also an asymmetry in the subset of divergent projections, with more fibers projecting in a posterior direction than anterior. This asymmetry of information projecting into the basal ganglia was predicted by previous network-level computational models. A rostral-caudal topography was also present at the local level in otherwise somatotopically organized fibers projecting from the motor cortex. This provides clear evidence that the longitudinal organization of input fields, observed at the macroscopic level across cortical systems, is also found at the microstructural scale at which information is segregated as it enters the human basal ganglia.
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Affiliation(s)
- Timothy D Verstynen
- Learning Research and Development Center, Univ. of Pittsburgh, Pittsburgh, PA 15260, USA.
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Abstract
The sleep electroencephalogram (EEG) changes across adolescence; however, there are conflicting data as to whether EEG changes are regionally specific, are evident in non-rapid eye movement (NREM) and rapid eye movement (REM) sleep, and whether there are sex differences. The present study seeks to resolve some of these issues in a combined cross-sectional and longitudinal analysis of sleep EEG in adolescents. Thirty-three healthy adolescents (18 boys, 15 girls; 11-14 years) were studied on two occasions 6-8 months apart. Cross-sectional analysis of data from the initial visit revealed significantly less slow-wave sleep, delta (0.3 to <4 Hz) and theta (4 to <8 Hz) power in both NREM and REM sleep with advancing age. The age-delta power relationship was significant at the occipital site, with age accounting for 26% of the variance. Longitudinal analysis revealed that NREM delta power declined significantly from the initial to follow-up visit, in association with declining delta amplitude and incidence (P < 0.01), with the effect being greatest at the occipital site. REM delta power also declined over time in association with reduced amplitude (P < 0.01). There were longitudinal reductions in theta, alpha and sigma power in NREM and REM sleep evident at the occipital site at follow-up (P < 0.01). No sex differences were apparent in the pattern of change with age for NREM or REM sleep. Declines in sleep EEG spectral power occur across adolescence in both boys and girls, particularly in the occipital derivation, and are not state-specific, occurring in both NREM and REM sleep.
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Affiliation(s)
- Fiona C Baker
- Human Sleep Research Program, SRI International, 333 Ravenswood Avenue, Menlo Park, CA 94043, USA.
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Rashid-Doubell F, McKinnell I, Aricescu AR, Sajnani G, Stoker A. Chick PTPsigma regulates the targeting of retinal axons within the optic tectum. J Neurosci 2002; 22:5024-33. [PMID: 12077198 PMCID: PMC6757722] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/25/2023] Open
Abstract
Chick PTPsigma (cPTPsigma), also known as CRYPalpha, is a receptor-like protein tyrosine phosphatase found on axons and growth cones. Putative ligands for cPTPsigma are distributed within basement membranes and on glial end feet of the retina, optic nerve, and optic tectum, suggesting that cPTPsigma signaling is occurring along the whole retinotectal pathway. We have shown previously that cPTPsigma plays a role in supporting the retinal phase of axon outgrowth. Here we have now addressed the role of cPTPsigma within retinal axons as they undergo growth and topographic targeting in the optic tectum. With the use of retroviruses, a secretable cPTPsigma ectodomain was ectopically expressed in ovo in the developing chick optic tectum, with the aim of directly disrupting the function of endogenous cPTPsigma. In ovo, the secreted ectodomains accumulated at tectal sites in which cPTPsigma ligands are also specifically found, suggesting that they are binding to these endogenous ligands. Anterograde labeling of retinal axons entering these optic tecta revealed abnormal axonal phenotypes. These included the premature stalling and arborization of fibers, excessive pretectal arbor formation, and diffuse termination zones. Most of the defects were rostral of the predicted termination zone, indicating that cPTPsigma function is necessary for sustaining the growth of retinal axons over the optic tectum and for directing axons to their correct sites of termination. This demonstrates that regulation of cPTPsigma signaling in retinal axons is required for their topographic mapping, the first evidence of this function for a receptor-like protein tyrosine phosphatase in the retinotectal projection.
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Affiliation(s)
- Fiza Rashid-Doubell
- Neural Development Unit, Institute of Child Health, London WC1N 1EH, United Kingdom
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Iyengar S, Bottjer SW. Development of individual axon arbors in a thalamocortical circuit necessary for song learning in zebra finches. J Neurosci 2002; 22:901-11. [PMID: 11826119 PMCID: PMC6758476] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/09/2001] [Revised: 10/10/2001] [Accepted: 10/25/2001] [Indexed: 02/23/2023] Open
Abstract
Individual axon arbors within developing neural circuits are remodeled during restricted sensitive periods, leading to the emergence of precise patterns of connectivity and specialized adaptive behaviors. In male zebra finches, the circuit connecting the medial dorsolateral nucleus of the thalamus (DLM) and its cortical target, the lateral magnocellular nucleus of the anterior neostriatum (lMAN), is crucial for the acquisition of a normal vocal pattern during the sensitive period for song learning. The shell subregion of lMAN as well as the entire terminal field of DLM axons within lMAN undergo a striking increase in overall volume during early stages of vocal learning followed by an equally substantial decrease by adulthood, by which time birds have acquired stable song patterns. Because the total number of DLM neurons remains stable throughout this period, the dramatic changes within the overall DLM-->lMAN circuit are presumably attributable to dynamic rearrangements at the level of individual DLM axon arbors over the course of vocal learning. To study such rearrangements directly, we reconstructed individual DLM axon arbors in three dimensions at different stages during vocal learning. Unlike axon arbors in other model systems, in which the number of branches increases during development, DLM arbors are unusual in that they have the greatest number of branches at the onset of vocal learning and undergo large-scale retraction during the sensitive period for song learning. Decreases in the degree of overlap between DLM arbors apparently contribute to the increased overall volume of the DLM-->lMAN circuit during vocal learning. These developmental changes in DLM axon arbors occur at the height of the sensitive period for vocal learning, and hence may represent either a morphological correlate of song learning or a necessary prerequisite for acquisition of song.
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Affiliation(s)
- Soumya Iyengar
- Department of Biology, University of Southern California, Los Angeles, California 90089-2520, USA
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