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Han Y, Yang H, Hua Z, Nie S, Xu S, Zhou C, Chen F, Li M, Yu Q, Sun Y, Wei Y, Wang X. Rotating Magnetic Field Mitigates Ankylosing Spondylitis Targeting Osteocytes and Chondrocytes via Ameliorating Immune Dysfunctions. Cells 2023; 12:cells12070972. [PMID: 37048045 PMCID: PMC10093245 DOI: 10.3390/cells12070972] [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: 01/06/2023] [Revised: 03/07/2023] [Accepted: 03/16/2023] [Indexed: 04/14/2023] Open
Abstract
Ankylosing spondylitis (AS) is clinically characterized by bone fusion that is induced by the pathological formation of extra bone. Unfortunately, the fundamental mechanism and related therapies remain unclear. The loss of SHP-2 (encoded by Ptpn11) in CD4-Cre;Ptpn11f/f mice resulted in the induction of AS-like pathological characteristics, including spontaneous cartilage and bone lesions, kyphosis, and arthritis. Hence, this mouse was utilized as an AS model in this study. As one of the basic physical fields, the magnetic field (MF) has been proven to be an effective treatment method for articular cartilage degeneration. In this study, the effects of a rotating magnetic field (RMF; 0.2 T, 4 Hz) on an AS-like mouse model were investigated. The RMF treatment (2 h/d, 0.2 T, 4 Hz) was performed on AS mice from two months after birth until the day before sampling. The murine specimens were subjected to transcriptomics, immunomics, and metabolomics analyses, combined with molecular and pathological experiments. The results demonstrated that the mitigation of inflammatory deterioration resulted in an increase in functional osteogenesis and a decrease in dysfunctional osteolysis due to the maintenance of bone homeostasis via the RANKL/RANK/OPG signaling pathway. Additionally, by regulating the ratio of CD4+ and CD8+ T-cells, RMF treatment rebalanced the immune microenvironment in skeletal tissue. It has been observed that RMF interventions have the potential to alleviate AS, including by decreasing pathogenicity and preventing disease initiation. Consequently, RMF, as a moderately physical therapeutic strategy, could be considered to alleviate the degradation of cartilage and bone tissue in AS and as a potential option to halt the progression of AS.
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Affiliation(s)
- Yu Han
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
| | - Hua Yang
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
| | - Zhongke Hua
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
| | - Shenglan Nie
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
| | - Shuling Xu
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
| | - Cai Zhou
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
| | - Fengyi Chen
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
| | - Mengqing Li
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
| | - Qinyao Yu
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
| | - Yang Sun
- State Key Laboratory of Pharmaceutical Biotechnology, Department of Biotechnology and Pharmaceutical Sciences, School of Life Sciences, Nanjing University, Nanjing 210023, China
| | - Yunpeng Wei
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
| | - Xiaomei Wang
- Magnetobiology Group, Department of Physiology, Shenzhen University Health Science Center, Xili Campus of Shenzhen University, Shenzhen 518055, China
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2
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Zhou Y, Tong T, Wei M, Zhang P, Fei F, Zhou X, Guo Z, Zhang J, Xu H, Zhang L, Wang S, Wang J, Cai T, Zhang X, Xie C. Towards magnetism in pigeon MagR: Iron- and iron-sulfur binding work indispensably and synergistically. Zool Res 2023; 44:142-152. [PMID: 36484226 PMCID: PMC9841195 DOI: 10.24272/j.issn.2095-8137.2022.423] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022] Open
Abstract
The ability to navigate long distances is essential for many animals to locate shelter, food, and breeding grounds. Magnetic sense has evolved in various migratory and homing species to orient them based on the geomagnetic field. A highly conserved iron-sulfur cluster assembly protein IscA is proposed as an animal magnetoreceptor (MagR). Iron-sulfur cluster binding is also suggested to play an essential role in MagR magnetism and is thus critical in animal magnetoreception. In the current study, we provide evidence for distinct iron binding and iron-sulfur cluster binding in MagR in pigeons, an avian species that relies on the geomagnetic field for navigation and homing. Pigeon MagR showed significantly higher total iron content from both iron- and iron-sulfur binding. Y65 in pigeon MagR was shown to directly mediate mononuclear iron binding, and its mutation abolished iron-binding capacity of the protein. Surprisingly, both iron binding and iron-sulfur binding demonstrated synergistic effects, and thus appear to be integral and indispensable to pigeon MagR magnetism. These results not only extend our current understanding of the origin and complexity of MagR magnetism, but also imply a possible molecular explanation for the huge diversity in animal magnetoreception.
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Affiliation(s)
- Yajie Zhou
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230039, China,High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China
| | - Tianyang Tong
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China,Department of Anatomy, Anhui Medical University, Hefei, Anhui 230032, China
| | - Mengke Wei
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230039, China,High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China
| | - Peng Zhang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui 230036, China
| | - Fan Fei
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui 230036, China
| | - Xiujuan Zhou
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui 230036, China
| | - Zhen Guo
- School of Life Sciences, Peking University, Beijing 100871, China
| | - Jing Zhang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui 230036, China
| | - Huangtao Xu
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China
| | - Lei Zhang
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui 230036, China
| | - Shun Wang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230039, China,High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui 230036, China
| | - Junfeng Wang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230039, China,High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui 230036, China,International Magnetobiology Frontier Research Center, Science Island, Hefei, Anhui 230031, China
| | - Tiantian Cai
- Department of Biological Chemistry and Molecular Pharmacology, Harvard Medical School, 250 Longwood Avenue, Boston, MA 02115, USA
| | - Xin Zhang
- Institutes of Physical Science and Information Technology, Anhui University, Hefei, Anhui 230039, China,High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui 230036, China,International Magnetobiology Frontier Research Center, Science Island, Hefei, Anhui 230031, China
| | - Can Xie
- High Magnetic Field Laboratory, Hefei Institutes of Physical Science, Chinese Academy of Sciences, Science Island, Hefei, Anhui 230031, China,Science Island Branch of Graduate School, University of Science and Technology of China, Hefei, Anhui 230036, China,International Magnetobiology Frontier Research Center, Science Island, Hefei, Anhui 230031, China,E-mail:
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Pophof B, Henschenmacher B, Kattnig DR, Kuhne J, Vian A, Ziegelberger G. Biological Effects of Electric, Magnetic, and Electromagnetic Fields from 0 to 100 MHz on Fauna and Flora: Workshop Report. HEALTH PHYSICS 2023; 124:39-52. [PMID: 36480584 PMCID: PMC9722389 DOI: 10.1097/hp.0000000000001624] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Subscribe] [Scholar Register] [Indexed: 06/17/2023]
Abstract
This report summarizes effects of anthropogenic electric, magnetic, and electromagnetic fields in the frequency range from 0 to 100 MHz on flora and fauna, as presented at an international workshop held on 5-7 November in 2019 in Munich, Germany. Such fields may originate from overhead powerlines, earth or sea cables, and from wireless charging systems. Animals and plants react differentially to anthropogenic fields; the mechanisms underlying these responses are still researched actively. Radical pairs and magnetite are discussed mechanisms of magnetoreception in insects, birds, and mammals. Moreover, several insects as well as marine species possess specialized electroreceptors, and behavioral reactions to anthropogenic fields have been reported. Plants react to experimental modifications of their magnetic environment by growth changes. Strong adverse effects of anthropogenic fields have not been described, but knowledge gaps were identified; further studies, aiming at the identification of the interaction mechanisms and the ecological consequences, are recommended.
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Affiliation(s)
- Blanka Pophof
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
| | - Bernd Henschenmacher
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
| | - Daniel R. Kattnig
- Department of Physics and Living Systems Institute, University of Exeter, Stocker Road, Exeter, EX4 4QD, United Kingdom
| | - Jens Kuhne
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
| | - Alain Vian
- Univ Angers, Institut Agro, INRAE, IRHS, SFR QUASAV, F-49000 Angers, France
| | - Gunde Ziegelberger
- Competence Centre for Electromagnetic Fields, Department of Effects and Risks of Ionizing and Non-Ionizing Radiation, Federal Office for Radiation Protection, 85764 Oberschleißheim, Germany
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4
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Morphology, biochemistry and connectivity of Cluster N and the hippocampal formation in a migratory bird. Brain Struct Funct 2022; 227:2731-2749. [DOI: 10.1007/s00429-022-02566-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/18/2022] [Accepted: 09/05/2022] [Indexed: 11/02/2022]
Abstract
AbstractThe exceptional navigational capabilities of migrating birds are based on the perception and integration of a variety of natural orientation cues. The “Wulst” in the forebrain of night-migratory songbirds contains a brain area named “Cluster N”, which is involved in processing directional navigational information derived from the Earth´s magnetic field. Cluster N is medially joined by the hippocampal formation, known to retrieve and utilise navigational information. To investigate the connectivity and neurochemical characteristics of Cluster N and the hippocampal formation of migratory birds, we performed morphological and histochemical analyses based on the expression of calbindin, calretinin, parvalbumin, glutamate receptor type 1 and early growth response protein-1 in the night-migratory Garden warbler (Sylvia borin) and mapped their mutual connections using neuronal tract tracing. The resulting expression patterns revealed regionally restricted neurochemical features, which mapped well onto the hippocampal and hyperpallial substructures known from other avian species. Magnetic field-induced neuronal activation covered caudal parts of the hyperpallium and the medially adjacent hippocampal dorsomedial/dorsolateral subdivisions. Neuronal tract tracings revealed connections between Cluster N and the hippocampal formation with the vast majority originating from the densocellular hyperpallium, either directly or indirectly via the area corticoidea dorsolateralis. Our data indicate that the densocellular hyperpallium could represent a central relay for the transmission of magnetic compass information to the hippocampal formation where it might be integrated with other navigational cues in night-migratory songbirds.
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5
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Kobylkov D, Musielak I, Haase K, Rook N, von Eugen K, Dedek K, Güntürkün O, Mouritsen H, Heyers D. Morphology of the "prefrontal" nidopallium caudolaterale in the long-distance night-migratory Eurasian blackcap (Sylvia atricapilla). Neurosci Lett 2022; 789:136869. [PMID: 36100042 DOI: 10.1016/j.neulet.2022.136869] [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: 06/08/2022] [Revised: 08/15/2022] [Accepted: 09/06/2022] [Indexed: 11/20/2022]
Abstract
Migrating birds have developed remarkable navigational capabilities to successfully master biannual journeys between their breeding and wintering grounds. To reach their intended destination, they need to calculate navigational goals from a large variety of natural directional and positional cues to set a meaningful motor output command. One brain area, which has been associated with such executive functions, is the nidopallium caudolaterale (NCL), which, due to its striking similarities in terms of neurochemistry, connectivity and function, is considered analogous to the mammalian prefrontal cortex. To establish a baseline for further analyses elucidating the neuronal correlates underlying avian navigation, we performed quantitative and qualitative analyses of dopaminergic fibres in the brains of long-distance night-migratory Eurasian blackcaps (Sylvia atricapilla). We identified four regions in the caudal telencephalon, each of which was characterized by its specific dopaminergic innervation pattern. At least three of them presumably constitute subareas of the NCL in Eurasian blackcaps and could thus be involved in integrating navigational input from different sensory systems. The observed heterogeneity and parcellation of the NCL subcompartments in this migratory species could be a consequence of the special demands related to navigation.
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Affiliation(s)
- Dmitry Kobylkov
- Center for Mind/Brain Science, University of Trento, Rovereto, TN, Italy; AG "Neurosensory Sciences", Carl-von-Ossietzky-Universität Oldenburg, Germany
| | - Isabelle Musielak
- AG "Neurosensory Sciences", Carl-von-Ossietzky-Universität Oldenburg, Germany
| | - Katrin Haase
- AG "Neurosensory Sciences", Carl-von-Ossietzky-Universität Oldenburg, Germany
| | - Noemi Rook
- Institute of Cognitive Neuroscience, Biopsychology, Ruhr-Universität, Bochum, Germany
| | - Kaya von Eugen
- Institute of Cognitive Neuroscience, Biopsychology, Ruhr-Universität, Bochum, Germany
| | - Karin Dedek
- AG "Neurosensory Sciences", Carl-von-Ossietzky-Universität Oldenburg, Germany; Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Germany
| | - Onur Güntürkün
- Institute of Cognitive Neuroscience, Biopsychology, Ruhr-Universität, Bochum, Germany
| | - Henrik Mouritsen
- AG "Neurosensory Sciences", Carl-von-Ossietzky-Universität Oldenburg, Germany; Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Germany
| | - Dominik Heyers
- AG "Neurosensory Sciences", Carl-von-Ossietzky-Universität Oldenburg, Germany; Research Centre for Neurosensory Sciences, Carl-von-Ossietzky-Universität Oldenburg, Germany.
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6
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Integration and evaluation of magnetic stimulation in physiology setups. PLoS One 2022; 17:e0271765. [PMID: 35867646 PMCID: PMC9307166 DOI: 10.1371/journal.pone.0271765] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 07/07/2022] [Indexed: 11/19/2022] Open
Abstract
A large number of behavioral experiments have demonstrated the existence of a magnetic sense in many animal species. Further, studies with immediate gene expression markers have identified putative brain regions involved in magnetic information processing. In contrast, very little is known about the physiology of the magnetic sense and how the magnetic field is neuronally encoded. In vivo electrophysiological studies reporting neuronal correlates of the magnetic sense either have turned out to be irreproducible for lack of appropriate artifact controls or still await independent replication. Thus far, the research field of magnetoreception has little exploited the power of ex vivo physiological studies, which hold great promise for enabling stringent controls. However, tight space constraints in a recording setup and the presence of magnetizable materials in setup components and microscope objectives make it demanding to generate well-defined magnetic stimuli at the location of the biological specimen. Here, we present a solution based on a miniature vector magnetometer, a coil driver, and a calibration routine for the coil system to compensate for magnetic distortions in the setup. The magnetometer fits in common physiology recording chambers and has a sufficiently small spatial integration area to allow for probing spatial inhomogeneities. The coil-driver allows for the generation of defined non-stationary fast changing magnetic stimuli. Our ex vivo multielectrode array recordings from avian retinal ganglion cells show that artifacts induced by rapid magnetic stimulus changes can mimic the waveform of biological spikes on single electrodes. However, induction artifacts can be separated clearly from biological responses if the spatio-temporal characteristics of the artifact on multiple electrodes is taken into account. We provide the complete hardware design data and software resources for the integrated magnetic stimulation system.
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Abstract
The ability to detect magnetic fields is a sensory modality that is used by many animals to navigate. While first postulated in the 1800s, for decades, it was considered a biological myth. A series of elegant behavioral experiments in the 1960s and 1970s showed conclusively that the sense is real; however, the underlying mechanism(s) remained unresolved. Consequently, this has given rise to a series of beliefs that are critically analyzed in this manuscript. We address six assertions: (1) Magnetoreception does not exist; (2) It has to be magnetite; (3) Birds have a conserved six loci magnetic sense system in their upper beak; (4) It has to be cryptochrome; (5) MagR is a protein biocompass; and (6) The electromagnetic induction hypothesis is dead. In advancing counter-arguments for these beliefs, we hope to stimulate debate, new ideas, and the design of well-controlled experiments that can aid our understanding of this fascinating biological phenomenon.
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Affiliation(s)
- Simon Nimpf
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, 82152 Munich, Germany
| | - David A Keays
- Division of Neurobiology, Faculty of Biology, Ludwig-Maximilians-University Munich, Planegg-Martinsried, 82152 Munich, Germany.,University of Cambridge, Department of Physiology, Development & Neuroscience, Downing Street, CB2 3EG Cambridge, UK.,Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus- Vienna-Biocenter 1, 1030 Vienna, Austria
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8
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Prussian blue technique is prone to yield false negative results in magnetoreception research. Sci Rep 2022; 12:8803. [PMID: 35614116 PMCID: PMC9132912 DOI: 10.1038/s41598-022-12398-9] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/03/2022] [Accepted: 05/04/2022] [Indexed: 12/13/2022] Open
Abstract
Perls’s Prussian blue staining technique has been used in magnetoreception research to screen tissues for iron-rich structures as proxies for putative magnetoreceptor structures based on magnetic particles. However, seemingly promising structural candidates in the upper beak of birds detected with Prussian blue turned out to be either irreproducible or located in non-neuronal cells, which has spurred a controversy that has not been settled yet. Here we identify possible pitfalls in the previous works and apply the Prussian blue technique to tissues implicated in magnetic-particle-based magnetoreception, in an effort to reassess its suitability for staining single-domain magnetite, i.e., the proposed magnetic substrate for the interaction with the external magnetic field. In the upper beak of night-migratory songbirds, we found staining products in great numbers, but not remotely associated with fiber terminals of the traced ophthalmic branch of the trigeminal nerve. Surprisingly, staining products were absent from the lamina propria in the olfactory rosette of rainbow trout where candidate magnetoreceptor structures were identified with different techniques earlier. Critically, magnetosome chains in whole cells of magnetotactic bacteria remained unstained. The failure to label single-domain magnetite in positive control samples is a serious limitation of the technique and suggests that two most influential but antipodal studies conducted previously stood little chances of obtaining correct positive results under the assumption that magnetosome-like particles were present in the tissues. Nonetheless, the staining technique appears suitable to identify tissue contamination with iron-rich fine dust trapped in epithelia already in vivo.
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Haase K, Musielak I, Warmuth-Moles L, Leberecht B, Zolotareva A, Mouritsen H, Heyers D. In Search for the Avian Trigeminal Magnetic Sensor: Distribution of Peripheral and Central Terminals of Ophthalmic Sensory Neurons in the Night-Migratory Eurasian Blackcap (Sylvia atricapilla). Front Neuroanat 2022; 16:853401. [PMID: 35321391 PMCID: PMC8936129 DOI: 10.3389/fnana.2022.853401] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 02/08/2022] [Indexed: 11/29/2022] Open
Abstract
In night-migratory songbirds, neurobiological and behavioral evidence suggest the existence of a magnetic sense associated with the ophthalmic branch of the trigeminal nerve (V1), possibly providing magnetic positional information. Curiously, neither the unequivocal existence, structural nature, nor the exact location of any sensory structure has been revealed to date. Here, we used neuronal tract tracing to map both the innervation fields in the upper beak and the detailed trigeminal brainstem terminations of the medial and lateral V1 subbranches in the night-migratory Eurasian Blackcap (Sylvia atricapilla). The medial V1 subbranch takes its course along the ventral part of the upper beak to innervate subepidermal layers and the mucosa of the nasal cavity, whereas the lateral V1 subbranch runs along dorsolateral levels until the nostrils to innervate mainly the skin of the upper beak. In the trigeminal brainstem, medial V1 terminals innervate both the dorsal part and the ventral, magnetically activated part of the principal sensory trigeminal brainstem nuclei (PrV). In contrast, the lateral V1 subbranch innervates only a small part of the ventral PrV. The spinal sensory trigeminal brainstem nuclei (SpV) receive topographically ordered projections. The medial V1 subbranch mainly innervates rostral and medial parts of SpV, whereas the lateral V1 subbranch mainly innervates the lateral and caudal parts of SpV. The present findings could provide valuable information for further analysis of the trigeminal magnetic sense of birds.
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Affiliation(s)
- Katrin Haase
- AG Neurosensorik, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Isabelle Musielak
- AG Neurosensorik, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Leonie Warmuth-Moles
- AG Neurosensorik, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Bo Leberecht
- AG Neurosensorik, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Anna Zolotareva
- Biological Station Rybachy, Zoological Institute of Russian Academy of Sciences, St Petersburg, Russia
| | - Henrik Mouritsen
- AG Neurosensorik, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Dominik Heyers
- AG Neurosensorik, Institute of Biology and Environmental Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
- *Correspondence: Dominik Heyers,
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Karwinkel T, Winklhofer M, Christoph P, Allenstein D, Hüppop O, Brust V, Bairlein F, Schmaljohann H. No apparent effect of a magnetic pulse on free-flight behaviour in northern wheatears ( Oenanthe oenanthe) at a stopover site. J R Soc Interface 2022; 19:20210805. [PMID: 35167773 PMCID: PMC8847002 DOI: 10.1098/rsif.2021.0805] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/23/2022] Open
Abstract
Naïve migrants reach their wintering grounds following a clock-and-compass strategy. During these inaugural migrations, birds internalise, among others, cues from the Earth's magnetic field to create a geomagnetic map, with which they navigate to destinations familiar to them on subsequent migrations. Geomagnetic map cues are thought to be sensed by a magnetic-particle-based receptor, which can be specifically affected by a magnetic pulse. Indeed, the orientation of experienced but not naïve birds was compromised after magnetic pulsing, indicating geomagnetic map use. Little is known about the importance of this putative magnetoreceptor for navigation and decision-making in free-flying migrants. Therefore, we studied in unprecedented detail how a magnetic pulse would affect departure probability, nocturnal departure timing, departure direction and consistency in flight direction over 50–100 km in experienced and naïve long-distant migrant songbirds using a large-scale radio-tracking system. Contrary to our expectations and despite a high sample size (ntotal = 137) for a free-flight study, we found no significant after-effect of the magnetic pulse on the migratory traits, suggesting the geomagnetic map is not essential for the intermediate autumn migration phase. These findings warrant re-thinking about perception and use of geomagnetic maps for migratory decisions within a sensory and ecological context.
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Affiliation(s)
- Thiemo Karwinkel
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.,Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Michael Winklhofer
- Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany.,Research Center for Neurosensory Sciences, Carl von Ossietzky University Oldenburg, 26111 Oldenburg, Germany
| | - Paula Christoph
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.,Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Dario Allenstein
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.,Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
| | - Ommo Hüppop
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
| | - Vera Brust
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany
| | - Franz Bairlein
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.,Max Planck Institute of Animal Behavior, Am Obstberg 1, 78315 Radolfzell, Germany
| | - Heiko Schmaljohann
- Institute of Avian Research 'Vogelwarte Helgoland', An der Vogelwarte 21, 26386 Wilhelmshaven, Germany.,Institute for Biology and Environmental Sciences (IBU), Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Straße 9-11, 26129 Oldenburg, Germany
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11
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Packmor F, Kishkinev D, Bittermann F, Kofler B, Machowetz C, Zechmeister T, Zawadzki LC, Guilford T, Holland RA. A magnet attached to the forehead disrupts magnetic compass orientation in a migratory songbird. J Exp Biol 2021; 224:jeb243337. [PMID: 34713887 PMCID: PMC8645232 DOI: 10.1242/jeb.243337] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2021] [Accepted: 10/25/2021] [Indexed: 11/20/2022]
Abstract
For studies on magnetic compass orientation and navigation performance in small bird species, controlled experiments with orientation cages inside an electromagnetic coil system are the most prominent methodological paradigm. These are, however, not applicable when studying larger bird species and/or orientation behaviour during free flight. For this, researchers have followed a very different approach, attaching small magnets to birds, with the intention of depriving them of access to meaningful magnetic information. Unfortunately, results from studies using this approach appear rather inconsistent. As these are based on experiments with birds under free-flight conditions, which usually do not allow exclusion of other potential orientation cues, an assessment of the overall efficacy of this approach is difficult to conduct. Here, we directly tested the efficacy of small magnets for temporarily disrupting magnetic compass orientation in small migratory songbirds using orientation cages under controlled experimental conditions. We found that birds which have access to the Earth's magnetic field as their sole orientation cue show a general orientation towards their seasonally appropriate migratory direction. When carrying magnets on their forehead under these conditions, the same birds become disoriented. However, under changed conditions that allow birds access to other (i.e. celestial) orientation cues, any disruptive effect of the magnets they carry appears obscured. Our results provide clear evidence for the efficacy of the magnet approach for temporarily disrupting magnetic compass orientation in birds, but also reveal its limitations for application in experiments under free-flight conditions.
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Affiliation(s)
- Florian Packmor
- School of Natural Sciences, Bangor University, Bangor LL57 2UW, UK
- Institute of Avian Research ‘Vogelwarte Helgoland’, Wilhelmshaven 26386, Germany
| | - Dmitry Kishkinev
- School of Life Sciences, Keele University, Newcastle-under-Lyme ST5 5BG, UK
| | - Flora Bittermann
- Biological Station Lake Neusiedl, Illmitz 7142, Austria
- Nationalpark Neusiedler See – Seewinkel, Apetlon 7143, Austria
- Austrian Ornithological Centre, Konrad-Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, 1160 Wien, Austria
| | | | - Clara Machowetz
- Biological Station Lake Neusiedl, Illmitz 7142, Austria
- Nationalpark Neusiedler See – Seewinkel, Apetlon 7143, Austria
- Austrian Ornithological Centre, Konrad-Lorenz Institute of Ethology, University of Veterinary Medicine Vienna, 1160 Wien, Austria
| | | | | | - Tim Guilford
- Department of Zoology, Oxford University, Oxford OX1 3SZ, UK
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12
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Electrophysiology and the magnetic sense: a guide to best practice. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:185-195. [PMID: 34713390 PMCID: PMC8918458 DOI: 10.1007/s00359-021-01517-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/22/2021] [Revised: 10/06/2021] [Accepted: 10/13/2021] [Indexed: 12/04/2022]
Abstract
Magnetoreception, sensing the Earth’s magnetic field, is used by many species in orientation and navigation. While this is established on the behavioural level, there is a severe lack in knowledge on the underlying neuronal mechanisms of this sense. A powerful technique to study the neuronal processing of magnetic cues is electrophysiology but, thus far, few studies have adopted this technique. Why is this the case? A fundamental problem is the introduction of electromagnetic noise (induction) caused by the magnetic stimuli, within electrophysiological recordings which, if too large, prevents feasible separation of neuronal signals from the induction artefacts. Here, we address the concerns surrounding the use of electromagnetic coils within electrophysiology experiments and assess whether these would prevent viable electrophysiological recordings within a generated magnetic field. We present calculations of the induced voltages in typical experimental situations and compare them against the neuronal signals measured with different electrophysiological techniques. Finally, we provide guidelines that should help limit and account for possible induction artefacts. In conclusion, if great care is taken, viable electrophysiological recordings from magnetoreceptive cells are achievable and promise to provide new insights on the neuronal basis of the magnetic sense.
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13
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Wiltschko R, Wiltschko W. The discovery of the use of magnetic navigational information. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2021; 208:9-18. [PMID: 34476571 PMCID: PMC8918449 DOI: 10.1007/s00359-021-01507-0] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Revised: 08/13/2021] [Accepted: 08/19/2021] [Indexed: 12/01/2022]
Abstract
The magnetic field of the Earth provides animals with various kinds of information. Its use as a compass was discovered in the mid-1960s in birds, when it was first met with considerable skepticism, because it initially proved difficult to obtain evidence for magnetic sensitivity by conditioning experiments. Meanwhile, a magnetic compass was found to be widespread. It has now been demonstrated in members of all vertebrate classes, in mollusks and several arthropod species, in crustaceans as well as in insects. The use of the geomagnetic field as a ‘map’ for determining position, although already considered in the nineteenth century, was demonstrated by magnetically simulating displacements only after 2000, namely when animals, tested in the magnetic field of a distant site, responded as if they were physically displaced to that site and compensated for the displacement. Another use of the magnetic field is that as a ‘sign post’ or trigger: specific magnetic conditions elicit spontaneous responses that are helpful when animals reach the regions where these magnetic characteristics occur. Altogether, the geomagnetic field is a widely used valuable source of navigational information for mobile animals.
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Affiliation(s)
- Roswitha Wiltschko
- Fachbereich Biowissenschaften, Goethe-Universität Frankfurt, Max-von-Laue-Straße 13, 60438, Frankfurt am Main, Germany.
| | - Wolfgang Wiltschko
- Fachbereich Biowissenschaften, Goethe-Universität Frankfurt, Max-von-Laue-Straße 13, 60438, Frankfurt am Main, Germany
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14
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Wan GJ, Jiang SL, Zhang M, Zhao JY, Zhang YC, Pan WD, Sword GA, Chen FJ. Geomagnetic field absence reduces adult body weight of a migratory insect by disrupting feeding behavior and appetite regulation. INSECT SCIENCE 2021; 28:251-260. [PMID: 32065478 DOI: 10.1111/1744-7917.12765] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2019] [Revised: 01/29/2020] [Accepted: 02/04/2020] [Indexed: 06/10/2023]
Abstract
The geomagnetic field (GMF) is well documented for its essential role as a cue used in animal orientation or navigation. Recent evidence indicates that the absence of GMF (mimicked by the near-zero magnetic field, NZMF) can trigger stress-like responses such as reduced body weight, as we have previously shown in the brown planthopper, Nilaparvata lugens. In this study, we found that consistent with the significantly decreased body weight of newly emerged female (-14.67%) and male (-13.17%) adult N. lugens, the duration of the phloem ingestion feeding waveform was significantly reduced by 32.02% in 5th instar nymphs reared under the NZMF versus GMF. Interestingly, 5th instar nymphs that exhibited reduced feeding had significantly higher glucose levels (+16.98% and +20.05%; 24 h and 48 h after molting), which are associated with food aversion, and expression patterns of their appetite-related neuropeptide genes (neuropeptide F, down-regulated overall; short neuropeptide F, down-regulated overall; adipokinetic hormone, up-regulated overall; and adipokinetic hormone receptor, down-regulated overall) were also altered under the absence of GMF in a manner consistent with diminishing appetite. Moreover, the expressions of the potential magnetosensor cryptochromes (Crys) were found significantly altered under the absence of GMF, indicating the likely upstream signaling of the Cry-mediated magnetoreception mechanisms. These findings support the hypothesis that strong changes in GMF intensity can reduce adult body weight through affecting insect feeding behavior and underlying regulatory processes including appetite regulation. Our results highlight that GMF could be necessary for the maintenance of energy homeostasis in insects.
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Affiliation(s)
- Gui-Jun Wan
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Shou-Lin Jiang
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Ming Zhang
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Jing-Yu Zhao
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
| | - Ying-Chao Zhang
- Beijing Key Laboratory of Bioelectromagetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Wei-Dong Pan
- Beijing Key Laboratory of Bioelectromagetics, Institute of Electrical Engineering, Chinese Academy of Sciences, Beijing, China
| | - Gregory A Sword
- Department of Entomology, Texas A&M University, College Station, TX, U.S.A
| | - Fa-Jun Chen
- Department of Entomology, Nanjing Agricultural University, Nanjing, China
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15
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Malkemper EP, Nimpf S, Nordmann GC, Keays DA. Neuronal circuits and the magnetic sense: central questions. ACTA ACUST UNITED AC 2020; 223:223/21/jeb232371. [PMID: 33168544 DOI: 10.1242/jeb.232371] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Magnetoreception is the ability to sense the Earth's magnetic field, which is used for orientation and navigation. Behavioural experiments have shown that it is employed by many species across all vertebrate classes; however, our understanding of how magnetic information is processed and integrated within the central nervous system is limited. In this Commentary, we review the progress in birds and rodents, highlighting the role of the vestibular and trigeminal systems as well as that of the hippocampus. We reflect on the strengths and weaknesses of the methodologies currently at our disposal, the utility of emerging technologies and identify questions that we feel are critical for the advancement of the field. We expect that magnetic circuits are likely to share anatomical motifs with other senses, which culminates in the formation of spatial maps in telencephalic areas of the brain. Specifically, we predict the existence of spatial cells that encode defined components of the Earth's magnetic field.
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Affiliation(s)
- E Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Center of Advanced European Studies and Research (caesar), Ludwig-Erhard-Allee 2, Bonn 53175, Germany
| | - Simon Nimpf
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, Vienna 1030, Austria
| | - Gregory C Nordmann
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, Vienna 1030, Austria
| | - David A Keays
- Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), Campus Vienna Biocenter 1, Vienna 1030, Austria .,Department of Anatomy and Neuroscience, University of Melbourne, Parkville, VIC 3010, Australia.,Division of Neurobiology, Department Biology II, Ludwig-Maximilians-University Munich, Planegg-Martinsried 82152, Germany
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16
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Caspar KR, Moldenhauer K, Moritz RE, Němec P, Malkemper EP, Begall S. Eyes are essential for magnetoreception in a mammal. J R Soc Interface 2020; 17:20200513. [PMID: 32993431 PMCID: PMC7536053 DOI: 10.1098/rsif.2020.0513] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2020] [Accepted: 09/02/2020] [Indexed: 11/12/2022] Open
Abstract
Several groups of mammals use the Earth's magnetic field for orientation, but their magnetosensory organ remains unknown. The Ansell's mole-rat (Fukomys anselli, Bathyergidae, Rodentia) is a microphthalmic subterranean rodent with innate magnetic orientation behaviour. Previous studies on this species proposed that its magnetoreceptors are located in the eye. To test this hypothesis, we assessed magnetic orientation in mole-rats after the surgical removal of their eyes compared to untreated controls. Initially, we demonstrate that this enucleation does not lead to changes in routine behaviours, including locomotion, feeding and socializing. We then studied magnetic compass orientation by employing a well-established nest-building assay under four magnetic field alignments. In line with previous studies, control animals exhibited a significant preference to build nests in magnetic southeast. By contrast, enucleated mole-rats built nests in random magnetic orientations, suggesting an impairment of their magnetic sense. The results provide robust support for the hypothesis that mole-rats perceive magnetic fields with their minute eyes, probably relying on magnetite-based receptors in the cornea.
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Affiliation(s)
- Kai R. Caspar
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstr. 5, 45117 Essen, Germany
| | - Katrin Moldenhauer
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstr. 5, 45117 Essen, Germany
| | - Regina E. Moritz
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstr. 5, 45117 Essen, Germany
- Department Vision, Visual Impairment & Blindness, Faculty 13, Technical University of Dortmund, Emil-Figge-Straße 50, 44227 Dortmund, Germany
| | - Pavel Němec
- Department of Zoology, Faculty of Science, Charles University, Vinicna 7, 12844 Prague, Czech Republic
| | - E. Pascal Malkemper
- Max Planck Research Group Neurobiology of Magnetoreception, Center of Advanced European Studies and Research (CAESAR), Ludwig-Erhard-Allee 2, 53175 Bonn, Germany
| | - Sabine Begall
- Department of General Zoology, University of Duisburg-Essen, Universitaetsstr. 5, 45117 Essen, Germany
- Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences, 16521 Prague 6, Czech Republic
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17
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Nordmann GC, Malkemper EP, Landler L, Ushakova L, Nimpf S, Heinen R, Schuechner S, Ogris E, Keays DA. A high sensitivity ZENK monoclonal antibody to map neuronal activity in Aves. Sci Rep 2020; 10:915. [PMID: 31969617 PMCID: PMC6976653 DOI: 10.1038/s41598-020-57757-6] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/07/2019] [Accepted: 12/20/2019] [Indexed: 01/04/2023] Open
Abstract
The transcription factor ZENK is an immediate early gene that has been employed as a surrogate marker to map neuronal activity in the brain. It has been used in a wide variety of species, however, commercially available antibodies have limited immunoreactivity in birds. To address this issue we generated a new mouse monoclonal antibody, 7B7-A3, raised against ZENK from the rock pigeon (Columba livia). We show that 7B7-A3 labels clZENK in both immunoblots and histological stainings with high sensitivity and selectivity for its target. Using a sound stimulation paradigm we demonstrate that 7B7-A3 can detect activity-dependent ZENK expression at key stations of the central auditory pathway of the pigeon. Finally, we compare staining efficiency across three avian species and confirm that 7B7-A3 is compatible with immunohistochemical detection of ZENK in the rock pigeon, zebra finch, and domestic chicken. Taken together, 7B7-A3 represents a useful tool for the avian neuroscience community to map functional activity in the brain.
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Affiliation(s)
- Gregory Charles Nordmann
- Research Institute of Molecular Pathology, Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Erich Pascal Malkemper
- Research Institute of Molecular Pathology, Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Lukas Landler
- Research Institute of Molecular Pathology, Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Lyubov Ushakova
- Research Institute of Molecular Pathology, Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Simon Nimpf
- Research Institute of Molecular Pathology, Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Robert Heinen
- Research Institute of Molecular Pathology, Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria
| | - Stefan Schuechner
- Monoclonal Antibody Facility, Max Perutz Labs, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - Egon Ogris
- Monoclonal Antibody Facility, Max Perutz Labs, Medical University of Vienna, Dr. Bohr-Gasse 9, 1030, Vienna, Austria
| | - David Anthony Keays
- Research Institute of Molecular Pathology, Vienna Biocenter (VBC), Campus-Vienna-Biocenter 1, 1030, Vienna, Austria.
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18
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Kobylkov D, Schwarze S, Michalik B, Winklhofer M, Mouritsen H, Heyers D. A newly identified trigeminal brain pathway in a night-migratory bird could be dedicated to transmitting magnetic map information. Proc Biol Sci 2020; 287:20192788. [PMID: 31964302 DOI: 10.1098/rspb.2019.2788] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Night-migratory songbirds can use geomagnetic information to navigate over thousands of kilometres with great precision. A crucial part of the magnetic 'map' information used by night-migratory songbirds is conveyed via the ophthalmic branches of the trigeminal nerves to the trigeminal brainstem complex, where magnetic-driven neuronal activation has been observed. However, it is not known how this information reaches the forebrain for further processing. Here, we show that the magnetically activated region in the trigeminal brainstem of migratory Eurasian blackcaps (Sylvia atricapilla) represents a morphologically distinctive neuronal population with an exclusive and previously undescribed projection to the telencephalic frontal nidopallium. This projection is clearly different from the known trigeminal somatosensory pathway that we also confirmed both by neuronal tracing and by a thorough morphometric analysis of projecting neurons. The new pathway we identified here represents part of a brain circuit that-based on the known nidopallial connectivities in birds-could potentially transmit magnetic 'map' information to key multisensory integration centres in the brain known to be critically involved in spatial memory formation, cognition and/or controlling executive behaviour, such as navigation, in birds.
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Affiliation(s)
- Dmitry Kobylkov
- AG 'Neurosensorik', University Oldenburg, Oldenburg 26111, Germany.,Research Centre for Neurosensory Sciences, University Oldenburg, Oldenburg 26111, Germany
| | - Susanne Schwarze
- Research Centre for Neurosensory Sciences, University Oldenburg, Oldenburg 26111, Germany.,AG 'Sensory Biology of Animals', University Oldenburg, Oldenburg 26111, Germany
| | - Bianca Michalik
- AG 'Neurosensorik', University Oldenburg, Oldenburg 26111, Germany.,Research Centre for Neurosensory Sciences, University Oldenburg, Oldenburg 26111, Germany
| | - Michael Winklhofer
- Research Centre for Neurosensory Sciences, University Oldenburg, Oldenburg 26111, Germany.,AG 'Sensory Biology of Animals', University Oldenburg, Oldenburg 26111, Germany
| | - Henrik Mouritsen
- AG 'Neurosensorik', University Oldenburg, Oldenburg 26111, Germany.,Research Centre for Neurosensory Sciences, University Oldenburg, Oldenburg 26111, Germany
| | - Dominik Heyers
- AG 'Neurosensorik', University Oldenburg, Oldenburg 26111, Germany.,Research Centre for Neurosensory Sciences, University Oldenburg, Oldenburg 26111, Germany
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19
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Abstract
Birds can use two kinds of information from the geomagnetic field for navigation: the direction of the field lines as a compass and probably magnetic intensity as a component of the navigational ‘map’. The direction of the magnetic field appears to be sensed via radical pair processes in the eyes, with the crucial radical pairs formed by cryptochrome. It is transmitted by the optic nerve to the brain, where parts of the visual system seem to process the respective information. Magnetic intensity appears to be perceived by magnetite-based receptors in the beak region; the information is transmitted by the ophthalmic branch of the trigeminal nerve to the trigeminal ganglion and the trigeminal brainstem nuclei. Yet in spite of considerable progress in recent years, many details are still unclear, among them details of the radical pair processes and their transformation into a nervous signal, the precise location of the magnetite-based receptors and the centres in the brain where magnetic information is combined with other navigational information for the navigational processes.
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Affiliation(s)
- Roswitha Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
| | - Wolfgang Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Frankfurt am Main, Germany
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20
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Nießner C, Denzau S, Peichl L, Wiltschko W, Wiltschko R. Magnetoreception: activation of avian cryptochrome 1a in various light conditions. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2018; 204:977-984. [DOI: 10.1007/s00359-018-1296-7] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2018] [Revised: 07/26/2018] [Accepted: 09/26/2018] [Indexed: 12/24/2022]
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21
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Magnetic map navigation in a migratory songbird requires trigeminal input. Sci Rep 2018; 8:11975. [PMID: 30097604 PMCID: PMC6086908 DOI: 10.1038/s41598-018-30477-8] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2017] [Accepted: 08/01/2018] [Indexed: 11/25/2022] Open
Abstract
Recently, virtual magnetic displacement experiments have shown that magnetic cues are indeed important for determining position in migratory birds; but which sensory system(s) do they use to detect the magnetic map cues? Here, we show that Eurasian reed warblers need trigeminal input to detect that they have been virtually magnetically displaced. Birds with bilaterally ablated ophthalmic branches of the trigeminal nerves were not able to re-orient towards their conspecific breeding grounds after a virtual magnetic displacement, exactly like they were not able to compensate for a real physical displacement. In contrast, sham-operated reed warblers re-oriented after the virtual displacement, like intact controls did in the past. Our results show that trigeminally mediated sensory information is necessary for the correct function of the reed warblers’ magnetic positioning system.
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22
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Engels S, Treiber CD, Salzer MC, Michalik A, Ushakova L, Keays DA, Mouritsen H, Heyers D. Lidocaine is a nocebo treatment for trigeminally mediated magnetic orientation in birds. J R Soc Interface 2018; 15:20180124. [PMID: 30089685 PMCID: PMC6127160 DOI: 10.1098/rsif.2018.0124] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/19/2018] [Accepted: 07/13/2018] [Indexed: 12/30/2022] Open
Abstract
Even though previously described iron-containing structures in the upper beak of pigeons were almost certainly macrophages, not magnetosensitive neurons, behavioural and neurobiological evidence still supports the involvement of the ophthalmic branch of the trigeminal nerve (V1) in magnetoreception. In previous behavioural studies, inactivation of putative V1-associated magnetoreceptors involved either application of the surface anaesthetic lidocaine to the upper beak or sectioning of V1. Here, we compared the effects of lidocaine treatment, V1 ablations and sham ablations on magnetic field-driven neuronal activation in V1-recipient brain regions in European robins. V1 sectioning led to significantly fewer Egr-1-expressing neurons in the trigeminal brainstem than in the sham-ablated birds, whereas lidocaine treatment had no effect on neuronal activation. Furthermore, Prussian blue staining showed that nearly all iron-containing cells in the subepidermal layer of the upper beak are nucleated and are thus not part of the trigeminal nerve, and iron-containing cells appeared in highly variable numbers at inconsistent locations between individual robins and showed no systematic colocalization with a neuronal marker. Our data suggest that lidocaine treatment has been a nocebo to the birds and a placebo for the experimenters. Currently, the nature and location of any V1-associated magnetosensor remains elusive.
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Affiliation(s)
- Svenja Engels
- AG Neurosensorics, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | | | | | - Andreas Michalik
- AG Neurosensorics, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | | | | | - Henrik Mouritsen
- AG Neurosensorics, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | - Dominik Heyers
- AG Neurosensorics, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
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23
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Long-distance navigation and magnetoreception in migratory animals. Nature 2018; 558:50-59. [PMID: 29875486 DOI: 10.1038/s41586-018-0176-1] [Citation(s) in RCA: 223] [Impact Index Per Article: 37.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/09/2017] [Accepted: 04/13/2018] [Indexed: 11/08/2022]
Abstract
For centuries, humans have been fascinated by how migratory animals find their way over thousands of kilometres. Here, I review the mechanisms used in animal orientation and navigation with a particular focus on long-distance migrants and magnetoreception. I contend that any long-distance navigational task consists of three phases and that no single cue or mechanism will enable animals to navigate with pinpoint accuracy over thousands of kilometres. Multiscale and multisensory cue integration in the brain is needed. I conclude by raising twenty important mechanistic questions related to long-distance animal navigation that should be solved over the next twenty years.
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24
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Slaby P, Bartos P, Karas J, Netusil R, Tomanova K, Vacha M. How Swift Is Cry-Mediated Magnetoreception? Conditioning in an American Cockroach Shows Sub-second Response. Front Behav Neurosci 2018; 12:107. [PMID: 29892217 PMCID: PMC5985609 DOI: 10.3389/fnbeh.2018.00107] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2017] [Accepted: 05/07/2018] [Indexed: 11/30/2022] Open
Abstract
Diverse animal species perceive Earth’s magnetism and use their magnetic sense to orientate and navigate. Even non-migrating insects such as fruit flies and cockroaches have been shown to exploit the flavoprotein Cryptochrome (Cry) as a likely magnetic direction sensor; however, the transduction mechanism remains unknown. In order to work as a system to steer insect flight or control locomotion, the magnetic sense must transmit the signal from the receptor cells to the brain at a similar speed to other sensory systems, presumably within hundreds of milliseconds or less. So far, no electrophysiological or behavioral study has tackled the problem of the transduction delay in case of Cry-mediated magnetoreception specifically. Here, using a novel aversive conditioning assay on an American cockroach, we show that magnetic transduction is executed within a sub-second time span. A series of inter-stimulus intervals between conditioned stimuli (magnetic North rotation) and unconditioned aversive stimuli (hot air flow) provides original evidence that Cry-mediated magnetic transduction is sufficiently rapid to mediate insect orientation.
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Affiliation(s)
- Pavel Slaby
- Faculty of Science, Institute of Experimental Biology, Masaryk University, Brno, Czechia
| | - Premysl Bartos
- Faculty of Science, Institute of Experimental Biology, Masaryk University, Brno, Czechia
| | - Jakub Karas
- Faculty of Science, Institute of Experimental Biology, Masaryk University, Brno, Czechia
| | - Radek Netusil
- Faculty of Science, Institute of Experimental Biology, Masaryk University, Brno, Czechia
| | - Kateřina Tomanova
- Faculty of Science, Institute of Experimental Biology, Masaryk University, Brno, Czechia
| | - Martin Vacha
- Faculty of Science, Institute of Experimental Biology, Masaryk University, Brno, Czechia
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Myklatun A, Lauri A, Eder SHK, Cappetta M, Shcherbakov D, Wurst W, Winklhofer M, Westmeyer GG. Zebrafish and medaka offer insights into the neurobehavioral correlates of vertebrate magnetoreception. Nat Commun 2018; 9:802. [PMID: 29476093 PMCID: PMC5824813 DOI: 10.1038/s41467-018-03090-6] [Citation(s) in RCA: 18] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2017] [Accepted: 01/18/2018] [Indexed: 11/12/2022] Open
Abstract
An impediment to a mechanistic understanding of how some species sense the geomagnetic field ("magnetoreception") is the lack of vertebrate genetic models that exhibit well-characterized magnetoreceptive behavior and are amenable to whole-brain analysis. We investigated the genetic model organisms zebrafish and medaka, whose young stages are transparent and optically accessible. In an unfamiliar environment, adult fish orient according to the directional change of a magnetic field even in darkness. To enable experiments also in juveniles, we applied slowly oscillating magnetic fields, aimed at generating conflicting sensory inputs during exploratory behavior. Medaka (but not zebrafish) increase their locomotor activity in this assay. Complementary brain activity mapping reveals neuronal activation in the lateral hindbrain during magnetic stimulation. These comparative data support magnetoreception in teleosts, provide evidence for a light-independent mechanism, and demonstrate the usefulness of zebrafish and medaka as genetic vertebrate models for studying the biophysical and neuronal mechanisms underlying magnetoreception.
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Affiliation(s)
- Ahne Myklatun
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
- Department of Nuclear Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
| | - Antonella Lauri
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
- Department of Nuclear Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
| | - Stephan H K Eder
- Department of Earth- and Environmental Sciences Section Geophysics, Ludwig Maximilian University of Munich, Theresienstrasse 41, 80333, Munich, Germany
| | - Michele Cappetta
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
- Department of Nuclear Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany
| | - Denis Shcherbakov
- Institute of Zoology 220, University of Hohenheim, 70593, Stuttgart, Germany
| | - Wolfgang Wurst
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany
| | - Michael Winklhofer
- Institute for Biology and Environmental Sciences IBU, Carl von Ossietzky University of Oldenburg, Carl-von-Ossietzky-Strasse 9-11, 26129, Oldenburg, Germany
- Research Center Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, D-26111, Germany
| | - Gil G Westmeyer
- Institute of Biological and Medical Imaging, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany.
- Institute of Developmental Genetics, Helmholtz Zentrum München, Ingolstädter Landstrasse 1, 85764, Neuherberg, Germany.
- Department of Nuclear Medicine, Technical University of Munich, Ismaninger Strasse 22, 81675, Munich, Germany.
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Krylov VV. Biological effects related to geomagnetic activity and possible mechanisms. Bioelectromagnetics 2017. [DOI: 10.1002/bem.22062] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022]
Affiliation(s)
- Viacheslav V. Krylov
- I.D. Papanin Institute for Biology of Inland Waters Russian Academy of Sciences; Borok Russian Federation
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Heyers D, Elbers D, Bulte M, Bairlein F, Mouritsen H. The magnetic map sense and its use in fine-tuning the migration programme of birds. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:491-497. [PMID: 28365788 DOI: 10.1007/s00359-017-1164-x] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/09/2016] [Revised: 03/06/2017] [Accepted: 03/07/2017] [Indexed: 10/19/2022]
Abstract
The Earth's magnetic field is one of several natural cues, which migratory birds can use to derive directional ("compass") information for orientation on their biannual migratory journeys. Moreover, magnetic field effects on prominent aspects of the migratory programme of birds, such as migratory restlessness behaviour, fuel deposition and directional orientation, implicate that geomagnetic information can also be used to derive positional ("map") information. While the magnetic "compass" in migratory birds is likely to be based on radical pair-forming molecules embedded in their visual system, the sensory correlates underlying a magnetic "map" sense currently remain elusive. Behavioural, physiological and neurobiological findings indicate that the sensor is most likely innervated by the ophthalmic branch of the trigeminal nerve and based on magnetic iron particles. Information from this unknown sensor is neither necessary nor sufficient for a functional magnetic compass, but instead could contribute important components of a multifactorial "map" for global positioning. Positional information could allow migratory birds to make vitally important dynamic adaptations of their migratory programme at any relevant point during their journeys.
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Affiliation(s)
- D Heyers
- AG Animal Navigation, Faculty of Biology/Environmental Sciences, University of Oldenburg, 26111, Oldenburg, Germany. .,Research Centre for Neurosensory Sciences, University of Oldenburg, 26111, Oldenburg, Germany.
| | - D Elbers
- AG Animal Navigation, Faculty of Biology/Environmental Sciences, University of Oldenburg, 26111, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, University of Oldenburg, 26111, Oldenburg, Germany.,AG Biochemistry, Faculty of Medicine/Health Sciences, University of Oldenburg, 26111, Oldenburg, Germany
| | - M Bulte
- , Schmidtkunzstraße 13, 86199, Augsburg, Germany.,Institute for Avian Research "Vogelwarte Helgoland", 26386, Wilhelmshaven, Germany
| | - F Bairlein
- Institute for Avian Research "Vogelwarte Helgoland", 26386, Wilhelmshaven, Germany
| | - H Mouritsen
- AG Animal Navigation, Faculty of Biology/Environmental Sciences, University of Oldenburg, 26111, Oldenburg, Germany.,Research Centre for Neurosensory Sciences, University of Oldenburg, 26111, Oldenburg, Germany
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28
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Magnetic activation in the brain of the migratory northern wheatear (Oenanthe oenanthe). J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2017; 203:591-600. [DOI: 10.1007/s00359-017-1167-7] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/01/2017] [Revised: 03/16/2017] [Accepted: 03/19/2017] [Indexed: 10/19/2022]
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Vincze O, Vágási CI, Pap PL, Osváth G, Møller AP. Brain regions associated with visual cues are important for bird migration. Biol Lett 2016; 11:rsbl.2015.0678. [PMID: 26538538 DOI: 10.1098/rsbl.2015.0678] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/25/2023] Open
Abstract
Long-distance migratory birds have relatively smaller brains than short-distance migrants or residents. Here, we test whether reduction in brain size with migration distance can be generalized across the different brain regions suggested to play key roles in orientation during migration. Based on 152 bird species, belonging to 61 avian families from six continents, we show that the sizes of both the telencephalon and the whole brain decrease, and the relative size of the optic lobe increases, while cerebellum size does not change with increasing migration distance. Body mass, whole brain size, optic lobe size and wing aspect ratio together account for a remarkable 46% of interspecific variation in average migration distance across bird species. These results indicate that visual acuity might be a primary neural adaptation to the ecological challenge of migration.
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Affiliation(s)
- Orsolya Vincze
- MTA-DE 'Lendület' Behavioural Ecology Research Group, Department of Evolutionary Zoology and Human Biology, University of Debrecen, Egytem tér 1, 4032, Debrecen, Hungary Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Babeş-Bolyai University, Clinicilor Street 5-7, 400006, Cluj-Napoca, Romania
| | - Csongor I Vágási
- MTA-DE 'Lendület' Behavioural Ecology Research Group, Department of Evolutionary Zoology and Human Biology, University of Debrecen, Egytem tér 1, 4032, Debrecen, Hungary Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Babeş-Bolyai University, Clinicilor Street 5-7, 400006, Cluj-Napoca, Romania
| | - Péter L Pap
- MTA-DE 'Lendület' Behavioural Ecology Research Group, Department of Evolutionary Zoology and Human Biology, University of Debrecen, Egytem tér 1, 4032, Debrecen, Hungary Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Babeş-Bolyai University, Clinicilor Street 5-7, 400006, Cluj-Napoca, Romania
| | - Gergely Osváth
- MTA-DE 'Lendület' Behavioural Ecology Research Group, Department of Evolutionary Zoology and Human Biology, University of Debrecen, Egytem tér 1, 4032, Debrecen, Hungary Evolutionary Ecology Group, Hungarian Department of Biology and Ecology, Babeş-Bolyai University, Clinicilor Street 5-7, 400006, Cluj-Napoca, Romania Museum of Zoology, Babeş-Bolyai University, Clinicilor Street 5-7, 400006, Cluj-Napoca, Romania
| | - Anders Pape Møller
- Laboratoire d'Ecologie, Systématique et Evolution, CNRS UMR 8079, Université Paris-Sud, Bâtiment 362, 91405 Orsay Cedex, France
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Kishkinev D, Heyers D, Woodworth BK, Mitchell GW, Hobson KA, Norris DR. Experienced migratory songbirds do not display goal-ward orientation after release following a cross-continental displacement: an automated telemetry study. Sci Rep 2016; 6:37326. [PMID: 27876843 PMCID: PMC5120330 DOI: 10.1038/srep37326] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2016] [Accepted: 10/20/2016] [Indexed: 11/09/2022] Open
Abstract
The ability to navigate implies that animals have the capability to compensate for geographical displacement and return to their initial goal or target. Although some species are capable of adjusting their direction after displacement, the environmental cues used to achieve this remain elusive. Two possible cues are geomagnetic parameters (magnetic map hypothesis) or atmospheric odour-forming gradients (olfactory map hypothesis). In this study, we examined both of these hypotheses by surgically deactivating either the magnetic or olfactory sensory systems in experienced white-throated sparrows (Zonotrichia albicollis) captured in southern Ontario, Canada, during spring migration. Treated, sham-treated, and intact birds were then displaced 2,200 km west to Saskatchewan, Canada. Tracking their initial post-displacement migration using an array of automated VHF receiving towers, we found no evidence in any of the groups for compensatory directional response towards their expected breeding grounds. Our results suggest that white-throated sparrows may fall back to a simple constant-vector orientation strategy instead of performing true navigation after they have been geographically displaced to an unfamiliar area during spring migration. Such a basic strategy may be more common than currently thought in experienced migratory birds and its occurrence could be determined by habitat preferences or range size.
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Affiliation(s)
- Dmitry Kishkinev
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, N1G 2W1 Guelph, Ontario, Canada
- School of Biological Sciences, Bangor University, Deiniol Road, LL57 2UW Bangor, Gwynedd, UK
| | - Dominik Heyers
- AG Neurosensorik / Animal Navigation, Institute of Biological and Environmental Sciences, University Oldenburg, D-26111 Oldenburg, Germany
| | - Bradley K. Woodworth
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, N1G 2W1 Guelph, Ontario, Canada
| | - Greg W. Mitchell
- Wildlife Research Division, Environment and Climate Change Canada, National Wildlife Research Centre, 1125 Colonel By Drive, K1H 0H3, Canada, Ottawa, Ontario, Canada
| | - Keith A. Hobson
- Wildlife Research Division, Environment and Climate Change Canada, 11 Innovation Boulevard, S7N 3H5 Saskatoon, Saskatchewan, Canada
- Department of Biology, University of Western Ontario, N6A 5B7, London, Ontario, Canada
| | - D. Ryan Norris
- Department of Integrative Biology, University of Guelph, 50 Stone Road East, N1G 2W1 Guelph, Ontario, Canada
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Migratory blackcaps can use their magnetic compass at 5 degrees inclination, but are completely random at 0 degrees inclination. Sci Rep 2016; 6:33805. [PMID: 27667569 PMCID: PMC5036058 DOI: 10.1038/srep33805] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/07/2016] [Accepted: 08/31/2016] [Indexed: 11/09/2022] Open
Abstract
It is known that night-migratory songbirds use a magnetic compass measuring the magnetic inclination angle, i.e. the angle between the Earth’s surface and the magnetic field lines, but how do such birds orient at the magnetic equator? A previous study reported that birds are completely randomly oriented in a horizontal north-south magnetic field with 0° inclination angle. This seems counter-intuitive, because birds using an inclination compass should be able to separate the north-south axis from the east-west axis, so that bimodal orientation might be expected in a horizontal field. Furthermore, little is known about how shallow inclination angles migratory birds can still use for orientation. In this study, we tested the magnetic compass orientation of night-migratory Eurasian blackcaps (Sylvia atricapilla) in magnetic fields with 5° and 0° inclination. At 5° inclination, the birds oriented as well as they did in the normal 67° inclined field in Oldenburg. In contrast, they were completely randomly oriented in the horizontal field, showing no sign of bimodality. Our results indicate that the inclination limit for the magnetic compass of the blackcap is below 5° and that these birds indeed seem completely unable to use their magnetic compass for orientation in a horizontal magnetic field.
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Mouloudakis K, Kominis IK. Revealing the properties of the radical-pair magnetoreceptor using pulsed photo-excitation timed with pulsed rf. Biosystems 2016; 147:35-9. [PMID: 27450635 DOI: 10.1016/j.biosystems.2016.07.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/03/2016] [Revised: 06/17/2016] [Accepted: 07/15/2016] [Indexed: 11/17/2022]
Abstract
The radical-pair mechanism is understood to underlie the magnetic navigation capability of birds and possibly other species. Experiments with birds have provided indirect and in cases conflicting evidence on the actual existence of this mechanism. We here propose a new experiment that can unambiguously identify the presence of the radical-pair magnetoreceptor in birds and unravel some of its basic properties. The proposed experiment is based on modulated light excitation with a pulsed laser, combined with delayed radio-frequency magnetic field pulses. We predict a resonance effect in the birds' magnetic orientation versus the rf-pulse delay time. The resonance's position reflects the singlet-triplet mixing time of the magnetoreceptor.
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Affiliation(s)
- K Mouloudakis
- Department of Physics, University of Crete, Heraklion 71003, Greece
| | - I K Kominis
- Department of Physics, University of Crete, Heraklion 71003, Greece.
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35
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Affiliation(s)
- P. J. Hore
- Department of Chemistry, University of Oxford, Oxford OX1 3QZ, United Kingdom;
| | - Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität Oldenburg, DE-26111 Oldenburg, Germany;
- Research Centre for Neurosensory Sciences, University of Oldenburg, DE-26111 Oldenburg, Germany
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36
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Malkemper EP, Painter MS, Landler L. Shifted magnetic alignment in vertebrates: Evidence for neural lateralization? J Theor Biol 2016; 399:141-7. [PMID: 27059891 DOI: 10.1016/j.jtbi.2016.03.040] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2016] [Revised: 03/13/2016] [Accepted: 03/28/2016] [Indexed: 11/15/2022]
Abstract
A wealth of evidence provides support for magnetic alignment (MA) behavior in a variety of disparate species within the animal kingdom, in which an animal, or a group of animals, show a tendency to align the body axis in a consistent orientation relative to the geomagnetic field lines. Interestingly, among vertebrates, MA typically coincides with the north-south magnetic axis, however, the mean directional preferences of an individual or group of organisms is often rotated clockwise from the north-south axis. We hypothesize that this shift is not a coincidence, and future studies of this subtle, yet consistent phenomenon may help to reveal some properties of the underlying sensory or processing mechanisms, that, to date, are not well understood. Furthermore, characterizing the fine structure exhibited in MA behaviors may provide key insights to the biophysical substrates mediating magnetoreception in vertebrates. Therefore, in order to determine if a consistent shift is exhibited in taxonomically diverse vertebrates, we performed a meta-analysis on published MA datasets from 23 vertebrate species that exhibited an axial north-south preference. This analysis revealed a significant clockwise shift from the north-south magnetic axis. We summarize and discuss possible competing hypotheses regarding the proximate mechanisms underlying the clockwise shifted MA and conclude that the most likely cause of such a shift would be a lateralization in central processing of magnetic information.
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Affiliation(s)
- E Pascal Malkemper
- Department of General Zoology, Faculty of Biology, University of Duisburg-Essen, Universitätsstrasse. 2, 45117 Essen, Germany; Department of Game Management and Wildlife Biology, Faculty of Forestry and Wood Sciences, Czech University of Life Sciences Prague, Kamýcká 129, 165 21 Prague 6, Czech Republic
| | - Michael S Painter
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America
| | - Lukas Landler
- Department of Biological Sciences, Virginia Tech, Blacksburg, Virginia, United States of America; Research Institute of Molecular Pathology (IMP), Vienna Biocenter (VBC), 1030 Vienna, Austria.
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Schwarze S, Schneider NL, Reichl T, Dreyer D, Lefeldt N, Engels S, Baker N, Hore PJ, Mouritsen H. Weak Broadband Electromagnetic Fields are More Disruptive to Magnetic Compass Orientation in a Night-Migratory Songbird (Erithacus rubecula) than Strong Narrow-Band Fields. Front Behav Neurosci 2016; 10:55. [PMID: 27047356 PMCID: PMC4801848 DOI: 10.3389/fnbeh.2016.00055] [Citation(s) in RCA: 63] [Impact Index Per Article: 7.9] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/26/2015] [Accepted: 03/07/2016] [Indexed: 11/13/2022] Open
Abstract
Magnetic compass orientation in night-migratory songbirds is embedded in the visual system and seems to be based on a light-dependent radical pair mechanism. Recent findings suggest that both broadband electromagnetic fields ranging from ~2 kHz to ~9 MHz and narrow-band fields at the so-called Larmor frequency for a free electron in the Earth's magnetic field can disrupt this mechanism. However, due to local magnetic fields generated by nuclear spins, effects specific to the Larmor frequency are difficult to understand considering that the primary sensory molecule should be organic and probably a protein. We therefore constructed a purpose-built laboratory and tested the orientation capabilities of European robins in an electromagnetically silent environment, under the specific influence of four different oscillating narrow-band electromagnetic fields, at the Larmor frequency, double the Larmor frequency, 1.315 MHz or 50 Hz, and in the presence of broadband electromagnetic noise covering the range from ~2 kHz to ~9 MHz. Our results indicated that the magnetic compass orientation of European robins could not be disrupted by any of the relatively strong narrow-band electromagnetic fields employed here, but that the weak broadband field very efficiently disrupted their orientation.
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Affiliation(s)
- Susanne Schwarze
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - Nils-Lasse Schneider
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - Thomas Reichl
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - David Dreyer
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - Nele Lefeldt
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - Svenja Engels
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
| | - Neville Baker
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry LaboratoryOxford, UK
| | - P. J. Hore
- Department of Chemistry, University of Oxford, Physical and Theoretical Chemistry LaboratoryOxford, UK
| | - Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl von Ossietzky Universität OldenburgOldenburg, Germany
- Research Centre for Neurosensory Sciences, University of OldenburgOldenburg, Germany
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Bolte P, Bleibaum F, Einwich A, Günther A, Liedvogel M, Heyers D, Depping A, Wöhlbrand L, Rabus R, Janssen‐Bienhold U, Mouritsen H. Localisation of the Putative Magnetoreceptive Protein Cryptochrome 1b in the Retinae of Migratory Birds and Homing Pigeons. PLoS One 2016; 11:e0147819. [PMID: 26953791 PMCID: PMC4783096 DOI: 10.1371/journal.pone.0147819] [Citation(s) in RCA: 51] [Impact Index Per Article: 6.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2015] [Accepted: 01/08/2016] [Indexed: 01/24/2023] Open
Abstract
Cryptochromes are ubiquitously expressed in various animal tissues including the retina. Some cryptochromes are involved in regulating circadian activity. Cryptochrome proteins have also been suggested to mediate the primary mechanism in light-dependent magnetic compass orientation in birds. Cryptochrome 1b (Cry1b) exhibits a unique carboxy terminus exclusively found in birds so far, which might be indicative for a specialised function. Cryptochrome 1a (Cry1a) is so far the only cryptochrome protein that has been localised to specific cell types within the retina of migratory birds. Here we show that Cry1b, an alternative splice variant of Cry1a, is also expressed in the retina of migratory birds, but it is primarily located in other cell types than Cry1a. This could suggest different functions for the two splice products. Using diagnostic bird-specific antibodies (that allow for a precise discrimination between both proteins), we show that Cry1b protein is found in the retinae of migratory European robins (Erithacus rubecula), migratory Northern Wheatears (Oenanthe oenanthe) and pigeons (Columba livia). In all three species, retinal Cry1b is localised in cell types which have been discussed as potentially well suited locations for magnetoreception: Cry1b is observed in the cytosol of ganglion cells, displaced ganglion cells, and in photoreceptor inner segments. The cytosolic rather than nucleic location of Cry1b in the retina reported here speaks against a circadian clock regulatory function of Cry1b and it allows for the possible involvement of Cry1b in a radical-pair-based magnetoreception mechanism.
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Affiliation(s)
- Petra Bolte
- Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | - Florian Bleibaum
- Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | - Angelika Einwich
- Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | - Anja Günther
- Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | | | - Dominik Heyers
- Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | - Anne Depping
- Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
| | - Lars Wöhlbrand
- Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky University, Oldenburg, Germany
| | - Ralf Rabus
- Institute for Chemistry and Biology of the Marine Environment, Carl-von-Ossietzky University, Oldenburg, Germany
| | | | - Henrik Mouritsen
- Institute for Biology and Environmental Sciences, University of Oldenburg, Oldenburg, Germany
- Research Centre for Neurosensory Sciences, University of Oldenburg, Oldenburg, Germany
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39
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Affiliation(s)
- Henrik Mouritsen
- Institut für Biologie und Umweltwissenschaften, Carl-von-Ossietzky-Universität Oldenburg, D-26111 Oldenburg, Germany; ,
- Research Center Neurosensory Sciences, University of Oldenburg, D-26111 Oldenburg, Germany
| | - Dominik Heyers
- Institut für Biologie und Umweltwissenschaften, Carl-von-Ossietzky-Universität Oldenburg, D-26111 Oldenburg, Germany; ,
- Research Center Neurosensory Sciences, University of Oldenburg, D-26111 Oldenburg, Germany
| | - Onur Güntürkün
- Department of Biopsychology, Institute of Cognitive Neuroscience, Faculty of Psychology, Ruhr-University Bochum, D-44780 Bochum, Germany;
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Beason RC, Wiltschko W. Cues indicating location in pigeon navigation. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2015; 201:961-7. [PMID: 26149606 DOI: 10.1007/s00359-015-1027-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/22/2015] [Revised: 06/06/2015] [Accepted: 06/19/2015] [Indexed: 11/24/2022]
Abstract
Domesticated Rock Pigeons (Columba livia f. domestica) have been selected for returning home after being displaced. They appear to use many of the physical cue sources available in the natural environment for Map-and-Compass navigation. Two compass mechanisms that have been well documented in pigeons are a time-compensated sun compass and a magnetic inclination compass. Location-finding, or map, mechanisms have been more elusive. Visual landmarks, magnetic fields, odors, gravity and now also infrasound have been proposed as sources of information on location. Even in highly familiar locations, pigeons appear to neither use nor need landmarks and can even return to the loft while wearing frosted lenses. Direct and indirect evidence indicates magnetic field information influences pigeon navigation in ways that are consistent with magnetic map components. The role of odors is unclear; it might be motivational in nature rather than navigational. The influence of gravity must be further analyzed. Experiments with infrasound have been interpreted in the sense that they provide information on the home direction, but this hypothesis is inconsistent with the Map-and-Compass Model. All these factors appear to be components of a multifactorial system, with the pigeons being opportunistic, preferring those cues that prove most suitable in their home region. This has made understanding the roles of individual cues challenging.
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Affiliation(s)
| | - Wolfgang Wiltschko
- FB Biowissenschaften, Goethe-Universität Frankfurt, Max-von-Laue-Straße 113, 60438, Frankfurt am Main, Germany.
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Lefeldt N, Heyers D, Schneider NL, Engels S, Elbers D, Mouritsen H. Magnetic field-driven induction of ZENK in the trigeminal system of pigeons (Columba livia). J R Soc Interface 2015; 11:20140777. [PMID: 25232052 DOI: 10.1098/rsif.2014.0777] [Citation(s) in RCA: 38] [Impact Index Per Article: 4.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Magnetoreception remains one of the few unsolved mysteries in sensory biology. The upper beak, which is innervated by the ophthalmic branch of the trigeminal nerve (V1), has been suggested to contain magnetic sensors based on ferromagnetic structures. Recently, its existence in pigeons has been seriously challenged by studies suggesting that the previously described iron-accumulations are macrophages, not magnetosensitive nerve endings. This raised the fundamental question of whether V1 is involved in magnetoreception in pigeons at all. We exposed pigeons to either a constantly changing magnetic field (CMF), to a zero magnetic field providing no magnetic information, or to CMF conditions after V1 was cut bilaterally. Using immediate early genes as a marker of neuronal responsiveness, we report that the trigeminal brainstem nuclei of pigeons, which receive V1 input, are activated under CMF conditions and that this neuronal activation disappears if the magnetic stimuli are removed or if V1 is cut. Our data suggest that the trigeminal system in pigeons is involved in processing magnetic field information and that V1 transmits this information from currently unknown, V1-associated magnetosensors to the brain.
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Affiliation(s)
- Nele Lefeldt
- AG Neurosensorik/Animal Navigation, Institute of Biological and Environmental Sciences, University Oldenburg, 26111 Oldenburg, Germany
| | - Dominik Heyers
- AG Neurosensorik/Animal Navigation, Institute of Biological and Environmental Sciences, University Oldenburg, 26111 Oldenburg, Germany
| | - Nils-Lasse Schneider
- AG Neurosensorik/Animal Navigation, Institute of Biological and Environmental Sciences, University Oldenburg, 26111 Oldenburg, Germany
| | - Svenja Engels
- AG Neurosensorik/Animal Navigation, Institute of Biological and Environmental Sciences, University Oldenburg, 26111 Oldenburg, Germany
| | - Dana Elbers
- AG Neurosensorik/Animal Navigation, Institute of Biological and Environmental Sciences, University Oldenburg, 26111 Oldenburg, Germany
| | - Henrik Mouritsen
- AG Neurosensorik/Animal Navigation, Institute of Biological and Environmental Sciences, University Oldenburg, 26111 Oldenburg, Germany
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Wang J, Du X, Pan W, Wang X, Wu W. Photoactivation of the cryptochrome/photolyase superfamily. JOURNAL OF PHOTOCHEMISTRY AND PHOTOBIOLOGY C-PHOTOCHEMISTRY REVIEWS 2015. [DOI: 10.1016/j.jphotochemrev.2014.12.001] [Citation(s) in RCA: 25] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
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Kishkinev DA, Chernetsov NS. Magnetoreception systems in birds: A review of current research. ACTA ACUST UNITED AC 2015. [DOI: 10.1134/s2079086415010041] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
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Wiltschko R, Wiltschko W. Avian Navigation: A Combination of Innate and Learned Mechanisms. ADVANCES IN THE STUDY OF BEHAVIOR 2015. [DOI: 10.1016/bs.asb.2014.12.002] [Citation(s) in RCA: 41] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/12/2022]
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Njus Z, Feldmann D, Brien R, Kong T, Kalwa U, Pandey S. Characterizing the Effect of Static Magnetic Fields on <i>C. elegans</i> Using Microfluidics. ACTA ACUST UNITED AC 2015. [DOI: 10.4236/abb.2015.69061] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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No evidence for intracellular magnetite in putative vertebrate magnetoreceptors identified by magnetic screening. Proc Natl Acad Sci U S A 2014; 112:262-7. [PMID: 25535350 DOI: 10.1073/pnas.1407915112] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
The cellular basis of the magnetic sense remains an unsolved scientific mystery. One theory that aims to explain how animals detect the magnetic field is the magnetite hypothesis. It argues that intracellular crystals of the iron oxide magnetite (Fe3O4) are coupled to mechanosensitive channels that elicit neuronal activity in specialized sensory cells. Attempts to find these primary sensors have largely relied on the Prussian Blue stain that labels cells rich in ferric iron. This method has proved problematic as it has led investigators to conflate iron-rich macrophages with magnetoreceptors. An alternative approach developed by Eder et al. [Eder SH, et al. (2012) Proc Natl Acad Sci USA 109(30):12022-12027] is to identify candidate magnetoreceptive cells based on their magnetic moment. Here, we explore the utility of this method by undertaking a screen for magnetic cells in the pigeon. We report the identification of a small number of cells (1 in 476,000) with large magnetic moments (8-106 fAm(2)) from various tissues. The development of single-cell correlative light and electron microscopy (CLEM) coupled with electron energy loss spectroscopy (EELS) and energy-filtered transmission electron microscopy (EFTEM) permitted subcellular analysis of magnetic cells. This revealed the presence of extracellular structures composed of iron, titanium, and chromium accounting for the magnetic properties of these cells. Application of single-cell CLEM to magnetic cells from the trout failed to identify any intracellular structures consistent with biogenically derived magnetite. Our work illustrates the need for new methods to test the magnetite hypothesis of magnetosensation.
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Ramírez E, Marín G, Mpodozis J, Letelier JC. Extracellular recordings reveal absence of magneto sensitive units in the avian optic tectum. J Comp Physiol A Neuroethol Sens Neural Behav Physiol 2014; 200:983-96. [PMID: 25281335 PMCID: PMC4237910 DOI: 10.1007/s00359-014-0947-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2014] [Revised: 09/13/2014] [Accepted: 09/15/2014] [Indexed: 11/25/2022]
Abstract
There is a consensus that birds detect the earth's magnetic field and use some of its features for orientation and homing purposes. Since the late 1960s, when the first solid behavioral evidence of magnetoreception was obtained, much research has been devoted to describing the ethological aspects of this behavior. The neurophysiological basis of magnetoreception has been much less studied, although a frequently cited 1986 report described a high prevalence (70 %) of magneto-sensitive neurons in the pigeon optic tectum with high signal-to-noise ratios (Semm and Demaine, J Comp Physiol A 159:619-625, 1986). Here, we repeated these neurophysiological experiments using anesthetized as well as awake pigeons and new recording techniques. Our data indicate that magneto-sensitive units do not exist in the avian tectum.
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Affiliation(s)
- Edgardo Ramírez
- Department of Biology, Facultad de Ciencias, Universidad de Chile, Santiago, Chile,
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Affiliation(s)
- R. A. Holland
- School of Biological Sciences; Queen's University of Belfast; Belfast UK
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Mora CV, Acerbi ML, Bingman VP. Conditioned discrimination of magnetic inclination in a spatial-orientation arena task by homing pigeons (Columba livia). J Exp Biol 2014; 217:4123-31. [PMID: 25278470 DOI: 10.1242/jeb.101113] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Abstract
It has been well established that homing pigeons are able to use the Earth’s magnetic field to obtain directional information when returning to their loft and that their magnetic compass is based, at least in part, on the perception of magnetic inclination. Magnetic inclination has also been hypothesized in pigeons and other long-distance navigators, such as sea turtles, to play a role providing positional information as part of a map. Here we developed a behavioural paradigm which allows us to condition homing pigeons to discriminate magnetic inclination cues in a spatial-orientation arena task. Six homing pigeons were required to discriminate in a circular arena between feeders located either in a zone with a close to 0º inclination cue or in a zone with a rapidly changing inclination cue (-3º to +85º when approaching the feeder and +85º to -3º when moving away from the feeder) to obtain a food reward. The pigeons consistently performed this task above chance level. Control experiments, during which the coils were turned off or the current was running anti-parallel through the double-wound coils system, confirmed that no alternative cues were used by the birds in the discrimination task. The results show that homing pigeons can be conditioned to discriminate differences in magnetic field inclination, enabling investigation into the peripheral and central neural processing of geomagnetic inclination under controlled laboratory conditions.
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