Clusters of iron-rich cells in the upper beak of pigeons are macrophages not magnetosensitive neurons

  title={Clusters of iron-rich cells in the upper beak of pigeons are macrophages not magnetosensitive neurons},
  author={Christoph Daniel Treiber and Marion Claudia Salzer and Johannes Riegler and Nathaniel B. Edelman and Cristina Sugar and Martin W. Breuss and Paul Pichler and Herv{\'e} Cadiou and Martin Saunders and Mark F. Lythgoe and Jeremy A. Shaw and David Anthony Keays},
Understanding the molecular and cellular mechanisms that mediate magnetosensation in vertebrates is a formidable scientific problem. One hypothesis is that magnetic information is transduced into neuronal impulses by using a magnetite-based magnetoreceptor. Previous studies claim to have identified a magnetic sense system in the pigeon, common to avian species, which consists of magnetite-containing trigeminal afferents located at six specific loci in the rostral subepidermis of the beak. These… 
High resolution anatomical mapping confirms the absence of a magnetic sense system in the rostral upper beak of pigeons
It is argued that it is important to critically assess conclusions that have been made in the past, while keeping an open mind as the search for the magnetoreceptor continues, and undertake high resolution anatomical mapping of iron-rich cells in the rostral upper beak of pigeons.
Magnetic field-driven induction of ZENK in the trigeminal system of pigeons (Columba livia)
It is reported 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.
No evidence for intracellular magnetite in putative vertebrate magnetoreceptors identified by magnetic screening
A “magnetoscope” coupled with single-cell correlative light and electron microscopy is used to identify candidate magnetoreceptors in the pigeon and trout, illustrating the need for new methods to test the magnetite hypothesis of magnetosensation.
Lidocaine is a nocebo treatment for trigeminally mediated magnetic orientation in birds
The data suggest that lidocaine treatment has been a nocebo to the birds and a placebo for the experimenters, and the nature and location of any V1-associated magnetosensor remains elusive.
Magnetic characterization of isolated candidate vertebrate magnetoreceptor cells
The results show that the magnetically identified cells clearly meet the physical requirements for a magnetoreceptor capable of rapidly detecting small changes in the external magnetic field, which would also explain interference of ac powerline magnetic fields with magnetoreception, as reported in cattle.
Magnetoreception systems in birds: A review of current research
It cannot be ruled out that iron-based magnetoreception takes place in lagena (a part of inner ear in fishes, amphibians, reptiles and birds), and the information perceived is processes in vestibular nuclei.
Eyes are essential for magnetoreception in a mammal
The results provide robust support for the hypothesis that mole-rats perceive magnetic fields with their minute eyes, and assesses magnetic orientation in enucleated mole- rats.
Magnetically induced behaviour of ferritin corpuscles in avian ears: can cuticulosomes function as magnetosomes?
Ferritin low-field paramagnetic susceptibility is determined to estimate its magnetically induced intracellular behaviour and an alternative hypothesis that ferritin corpuscle in avian ears may function as an intrACEllular electromagnetic oscillator is reached.
Prussian blue technique is prone to yield false negative results in magnetoreception research
The failure to label single-domain magnetite in positive control samples is a serious limitation of the Prussian blue staining 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.


Ultrastructural analysis of a putative magnetoreceptor in the beak of homing pigeons
The subcellular organization of afferent trigeminal terminals in the upper beak of the homing pigeon, Columba livia, which are about 5 μm in diameter and contain superparamagnetic magnetite (SPM) crystals was investigated.
Avian Magnetoreception: Elaborate Iron Mineral Containing Dendrites in the Upper Beak Seem to Be a Common Feature of Birds
The magnetic field sensors enabling birds to extract orientational information from the Earth's magnetic field have remained enigmatic. Our previously published results from homing pigeons have made
Avian magnetite-based magnetoreception: a physiologist's perspective
The aims of the present review are to review the evidence for a magnetite-based mechanism in birds and to introduce physiological concepts in order to refine the proposed models.
Magnetic field changes activate the trigeminal brainstem complex in a migratory bird
The results suggest that magnetic field changes activate neurons in and near the trigeminal brainstem complex and that V1 is necessary for this activation, and suggest that V 1 transmits magnetic information to the brain in this migratory passerine bird.
A novel concept of Fe-mineral-based magnetoreception: histological and physicochemical data from the upper beak of homing pigeons
Animals make use of the Earth’s magnetic field for navigation and regulation of vegetative functions; however, the anatomical and physiological basis for the magnetic sense has not been elucidated
Superparamagnetic Magnetite in the Upper Beak Tissue of Homing Pigeons
Neither electron-microscopic nor magnetic measurements revealed any single-domain magnetite in the upper-beak skin tissue of homing pigeons, but complementary low-temperature magnetic measurements confirm the microscopic observations of fine-grained superparamagnetic particles in the tissue.
Theoretical analysis of an iron mineral-based magnetoreceptor model in birds.
A theoretical model is developed to quantitatively and qualitatively describe the magnetic field effects among particles containing iron minerals in the avian beak skin and shows that it might indeed be a sensitive biological magnetometer providing an essential part of the magnetic map for navigation.
Visual but not trigeminal mediation of magnetic compass information in a migratory bird
The data strongly suggest that a vision-mediated mechanism underlies the magnetic compass in this migratory songbird, and that the putative iron-mineral-based receptors in the upper beak connected to the brain by the trigeminal nerve are neither necessary nor sufficient for magnetic compass orientation in European robins.
Magnetoreception and its trigeminal mediation in the homing pigeon
It is demonstrated that homing pigeons can discriminate between the presence and absence of a magnetic anomaly in a conditioned choice experiment, and results suggest that magnetoreception (probably magnetite-based) occurs in the upper beak area of the pigeon.