A magnetic sensor exists in our eyes

A compass needle made by a Magnetoreceptor and assisted by Cryptochromes



The Magnetoreceptor protein (MagR)

19 Nov 2015

Newly discovered 'biocompass' protein complex may explain how animals sense magnetic fields

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pigeonPicture from a related article



Here it is: In yellow, a polymer made of five molecules of the protein termed Magneto-Receptor (MagR) - five loops hosting iron. It is surrounded by cryptochrome proteins


Credit: S. Qin et al. Nature Mater. (2015).


"Together with Cry, it forms a nanoscale ‘needle’: a rod-like core of CG8198 (MagR) polymers with an outer layer of Cry proteins that twists around the core (see 'Protein biocompass')."


"Using an electron microscope, Xie’s team saw assemblies of these rods orienting themselves in a weak magnetic field in the same way as compass needles."




The Cryptochromes


Published 2011-June



"Many birds have a compass in their eyes. Their retinas are loaded with a protein called cryptochrome, which is sensitive to the Earth’s magnetic fields. It’s possible that the birds can literally see these fields, overlaid on top of their normal vision. This remarkable sense allows them to keep their bearings when no other landmarks are visible."


Following the experiments of Researcher Lauren Foley from the University of Massachusetts Medical School we can create artificial magnetic fields resembling the Earth's field and place for instance the fly food always in the south. Flies would learn to go to the south to find food. Transgenic flies that do not have cryptochromes in their retinas could not find the south. When the human gene was inserted in their genome, their capacity to find the pole with the food was restored.



Related Articles

Excerpts from an article by The Guardian


“The nanoscale biocompass has the tendency to align itself along geomagnetic field lines and to obtain navigation cues from a geomagnetic field,” said Xie. “We propose that any disturbance in this alignment may be captured by connected cellular machinery, which would channel information to the downstream neural system, forming the animal’s magnetic sense.”


“It has been well documented that cryptochromes, which are crucial to the compass proposed in this new paper, may harness significant quantum effects to convert the Earth’s weak magnetic field into a signal in the animal’s brain. This is a tantalising possibility since the new UK quantum technology hubs are focusing about a quarter of their £150M on sensor systems. It would be remarkable if we can learn some tricks from Mother Nature in this highly-advanced field of physics,” he added.


Related article:



Biological systems doing "quantum teleportation"

3 examples from The Guardian




Enzymes: "enzymes make use of a remarkable trick called quantum tunnelling to accelerate biochemical reactions. Essentially, the enzyme encourages electrons and protons to vanish from one position in a biomolecule and instantly rematerialise in another, without passing through the gap in between – a kind of quantum teleportation."


Photosynthesis: "Energy packet was not hopping haphazardly about, but performing a neat quantum trick. Instead of behaving like a localised particle travelling along a single route, it behaves quantum mechanically, like a spread-out wave, and samples all possible routes at once to find the quickest way."


European robin: "an internal chemical compass that utilises an astonishing quantum concept called entanglement, which Einstein dismissed as “spooky action at a distance”. This phenomenon describes how two separated particles can remain instantaneously connected via a weird quantum link. The current best guess is that this takes place inside a protein in the bird’s eye, where quantum entanglement makes a pair of electrons highly sensitive to the angle of orientation of the Earth’s magnetic field, allowing the bird to “see” which way it needs to fly."



Specialised/Mechanistic article Magnetoreception and the radical pair mechanism:



Crystals in our pineal gland similar to those in ear exhibit piezoelectric properties that would allow them to interact with the electrical component of the electromagnetic fields from 500MHz to 2.5GHz (including portable wireless frequencies)



  • Two biomineralization forms can be observed in the pineal gland. Concretions so called “brain sand”, a polycrystalline complex of few millimeters long, and microcrystals the length of which does not exceed 20 micrometers. While concretions have been extensively studied [5-9] no study has been published on the microcrystals.
  • The agreement of the peaks was excellent (Fig. 2), confirming the identification of the crystals as calcite (calcium carbonate).
  • This symmetry breaking would allow both SHG (Second Harmonic Generation) and piezoelectricity.
  • Calcite in otoconia, microcrystals found in the inner-ear otolith, has been shown to exhibit piezoelectricity [13, 14]. These crystals have a structure similar to that of the pineal microcrystals. By that very fact the piezoelectric property of the crystals would allow them to interact with the electrical component of electromagnetic fields.
  • A simplified formula applied to those crystals (f = v/2d) lets us think that these crystals could be sensitive to RF-EMF (radio frequency-modulated electromagnetic fields (RF-EMFs)) in the range of 500MHz to 2.5GHz depending on there size. This range contains portable wireless frequencies, GSM (872-960MHz), DCS (1710-1875MHz), UMTS (1900-1920MHz, 2010-2025MHz), or BlueTooth (2400-2483,5MHz).


  • We report here the presence of a new form of mineral deposits in the pineal gland. The calcite microcrystals would have piezoelectric properties with excitability in the frequency range of mobile communications.
  • A similar mechanism of magneto-transduction was revealed by Kirschvink in connection with magnetite crystals of the brain and their interaction with the magnetic component of RF-EMF [15]. Pinealocyte can "communicate" through their gap junction [16, 17]. The deformation caused by the crystal vibrations could thus by simple activation of one or two pinealocytes, activate a whole area of pineal cells and thereby act on the pineal physiology



"Calcite microcrystals in the pineal gland of the human brain: second harmonic generators and possible piezoelectric transducers"

IEEE link



Magnetite in the human brain

The discovery of magnetite (Fe3O4) in the human brain in 1992 by Dr. Joesph Kirschvink at CalTech

Using an ultrasensitive superconducting magnetometer in a clean-lab environment, we have detected the presence of ferromagnetic material in a variety of tissues from the human brain. These magnetic and high-resolution transmission electron microscopy measurements imply the presence of a minimum of 5 million single-domain crystals per gram for most tissues in the brain and greater than 100 million crystals per gram for pia and dura.


Biogenic magnetite in the human brain may account for high-field saturation effects observed in the T1 and T2 values of magnetic resonance imaging and, perhaps, for a variety of biological effects of low-frequency magnetic fields.


NYT on the discovery:



Another study by Dr. Joesph Kirschvink

Review study

Magnetite Minerals in the Human Brain: What Is Their Role?



Magnetite found in the ethmoid region (behind nose in humans) in different species

Production of single-domain magnetite throughout life by sockeye salmon, Oncorhynchus nerka.


Similar results in humans



Magnetite Biomineralization and Magnetoreception in Organisms

Google Book link