The brain in electromagnetic fields: the sixth sense of perception of the magnetic field is discovered

2024 Author: Seth Attwood | [email protected]. Last modified: 2023-12-16 15:55

Laboratory experiments have shown that our brains respond to changes in the Earth's magnetic field.

Many fish, insects and, of course, birds are able to navigate through magnetoreception - a special sense that allows you to sense the direction of the Earth's global magnetic field. It is believed that humans do not possess it, but experiments carried out with controlled magnetic fields in the laboratory have shown that magnetoreception is available to us to a certain extent. But if a specialized sensitive protein helps birds in this, then how the perception of magnetism in our body occurs is still a complete mystery.

A team of scientists from the United States and Japan talks about the new experiments in an article published in the journal eNeuro. Shinsuke Shimojo, Joseph Kirschvink and their colleagues selected 26 volunteers and placed them one at a time in a dark, soundproofed room. Inside, scientists created an artificial magnetic field of the same power as the geomagnetic field near the Earth's surface, but at the same time they could freely change the direction of its lines of force. While the magnetic field was spinning, the brain activity of each volunteer was recorded using an electroencephalograph (EEG).

According to the authors, such an experimental setup made it possible to simulate natural changes in the directions of the geomagnetic field during movement. At the same time, the body remained stationary, so that the level of sensorimotor signals was minimal, allowing you to better see the faint details of brain activity. These data were compared with the EEG data of people sitting in a dark room, in which the magnetic field did not change in any way. It was found that when the magnetic field rotates counterclockwise, the waves of the brain's alpha rhythm noticeably weaken - their amplitude drops by an average of a quarter.

Alpha waves have been associated with a state of relaxed wakefulness in which a person is not focused on vision or imagination. They weaken as soon as the brain begins to actively process sensory information. Such a drop was noted in volunteers when the magnetic field was changed indoors. In a fraction of a second, alpha waves could be attenuated by up to 60 percent, indicating that the brain is busy analyzing sensory data. How magnetic fields are perceived, and why large primates like us need this “extra” feeling at all, remains unclear.

It was also unexpected that the fall of the alpha waves caused only the rotation of the magnetic field counterclockwise (downward direction), as it happens in the northern hemisphere of the Earth. In the opposite direction (up), no changes in the EEG were observed - as if the brain ignored the knowingly false signal and did not concentrate on it. The ability to "turn off" magnetoreception is indeed shown by some animals when they encounter disturbed, "strange" magnetic fields - for example, during a thunderstorm. I wonder what results will show similar experiments with the inhabitants of the southern hemisphere.

“Aristotle described five senses, including sight, hearing, taste, smell and touch,” says Joseph Kirshvink, professor at the California Institute of Technology. “However, he did not consider the sensations of gravity, temperature, pain, balance and some internal stimuli, which, as we now understand, are a full part of our nervous system. The study of our animal ancestors shows that the perception of the geomagnetic field can also enter this series - as not the sixth, but the 10th, and maybe the 11th sense."