A group of scientists, including a geophysical biologist, a cognitive neuroscientist and a neuroengineer, has found proof that the human brain is capable of detecting Earth's magnetic field despite previous conflicting results. The results of their research were published on the website Science Alert. The discovery shows that humans haven't entirely lost the mechanism of orienting themselves using the magnetic field, which many other animals enjoy.
The researchers placed the experiment subjects on a simple chair set up inside a Faraday cage that filters out all outside magnetic fields and then they used the coils installed inside to generate an artificially controlled magnetic field inside the cage. Although the subjects of the experiment failed to feel anything, their brains, connected to an electroencephalography (EEG) machine, clearly responded, when researchers shifted the direction of the artificial field.
What is even more intriguing, according to the scientists, is that the subjects' brains filtered out "irrelevant" information about the field. For example, when the field was configured in a way, unnatural for Earth's magnetosphere their brains didn't respond at all. The same happened when the field was configured to represent the southern hemisphere's magnetic field, while all the subjects lived in the northern one. The brain also ignores magnetic fields that are at least 25% stronger than the one generated by the Earth, meaning various electronic devices, generating such fields, can't affect the brain's functions.
The group of scientists suggests that the mechanism behind the ability to sense magnetic fields lies in cells' newly-discovered ability to form nanocrystals of the ferromagnetic mineral magnetite. Such crystals, found in many organisms, as well as in human brains, essentially work as micromagnets and although the nature of their functions in cells has been poorly studied so far, theoretically it can be used to keep track of the Earth's magnetosphere, the researchers pointed out.
The discovery comes amid the news that the focal point of the Earth's magnetic sphere — the magnetic pole is constantly shifting from the Canadian Arctic towards Russia's Siberia at a rate of around 55 kilometres per year. Despite the relatively slow pace, the scientists have to update the magnetosphere's maps each year, because all people and devices that still use compasses, heavily depend on them since a compass arrow always points in the direction of the pole.
Last time, they were forced to issue a new version of the map earlier than scheduled — in mid-February instead of late in 2019.