Did you know that we have magnetite crystals inside our brains? Magnetite is a mineral made up of iron oxide but it has equal amounts of iron (ii), which is ferrous oxide,  and iron (iii) which is ferric oxide. Ferric oxide has three electrons--represented by the number 3 and one of those came from ferrous oxide--represented by the number 2.
Both produce numerous types of materials such as plastics, heat-absorbing glass, ceramics and even rubber. Special high purity iron oxides are used in the production of ferrites, a type of ceramic magnet used in electronics such as speakers, TVs and computer memory cores.
Magnetite is found in all types of rocks--igneous, metamorphic and sedimentary and yes it is magnetic. And this stuff is in our bodies and more primarily, our brains.
Physics Today published an article back in 2018 titled 'Mapping magnetite in the human brain.' In 1992, researchers discovered the magnetic crystal in human brain tissue and it's thought to have formed biogenically with some possibly originating in ferritin which is an intracellular protein that is found in many organisms.
The article goes on to say that various studies have shown that brain cells respond to external magnetic fields. There's also a link between elevated levels of magnetite and neurodegenerative diseases. Researchers noted that there were elevated levels of magnetite in brain tissue from Alzheimer’s disease patients.
Two scientists from the Ludwig-Maximilians University of Munich, geophysicist Stuart Gilder and neuroscientist Christoph Schmitz, carried out the first systematic mapping of magnetite nanoparticles in the human brain.
They found magnetite concentrated in the same places in the seven brains they analyzed. They noted that the magnetite was mostly in the cerebellum and brain stem and that there was a striking asymmetry in the distribution of the magnetite particles between both hemispheres of the brain. In animals such as homing pigeons and honeybees, magnetites enable them to sense magnetic field lines. As for humans, we don't seem to sense those magnetic fields. Perhaps we are simply not in tune with our bodies anymore? Think of when a natural disaster is about to happen and animals start to flee. This is because they are able to sense a disturbance, but we are unable to.
For more information, explore the links in the podcast description.
LINKS
https://info.noahtech.com/blog/what-is-the-difference-between-ferrous-and-ferric-oxide
https://physicstoday.scitation.org/do/10.1063/PT.6.1.20180830a/full/
https://physicstoday.scitation.org/doi/10.1063/1.2897947
Photo in podcast cover from Arkenstone https://www.irocks.com/minerals/specimen/46980
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