As one California study suggests, human brain activity changes depending on the direction of the magnetic field. If the results are confirmed, this will be a real discovery and will bring our brains closer to the brains of animals that are so sensitive to the magnetic field that they can use it for orientation in space. Le Monde talks about possible hypotheses.
A person has a real compass in their eyes. Well, or at least in the brain, according to a study by the California Institute of Technology, published March 18 in the magazine "eNeuro". Scientists were able to prove that the test subjects "feel" the Earth's magnetic field. "We prefer to say that their brains are responding to the movement of the magnetic field," notes first author Connie Wang.
If the results are confirmed, this will be a real discovery and will bring our brains closer to the brains of animals that are so sensitive to the magnetic field that they can use it for orientation in space: pigeons, fish, turtles, as well as some types of bacteria (even if they do not have brain).
Over the course of three years, this team of scientists, led by geophysicist Joseph Kirschvink, a renowned expert in his field, developed and tested an original protocol. For this, a cubic room with walls of 2 meters was created, in which wiring was installed to generate any weak magnetic field, including similar to the earth's (35 μT in California). In addition, there you can rotate the field from northeast to northwest or vice versa. Or, swap north and south, as if we had moved to another hemisphere. Similar cells have been used in the past, for example, to study the behavior of migratory birds.
Decreased activity of some waves
The participants in the experiment (in the published results there were no more than 30 of them) found themselves for an hour in complete darkness while the surrounding magnetic field changed in cycles of seven minutes. At the same time, an electroencephalogram was recorded to record their brain activity. An unexpected result was that when the field turned from northeast to northwest, a decrease in the activity of some waves in relation to the period of rest was noted in the brain of a third of the participants. For some, the decline reached 60%.
“We even found four particularly sensitive people and re-examined several weeks later to make sure it wasn't an accident,” says Connie Wong. “Brainwave patterns suggest that we are unconsciously responding to geomagnetic stimuli,” the scientists emphasize on their website. In the article, they note that the participants in the experiment could not tell when the magnetic field was turned on and when not.
To further improve the reliability of their protocol, they sought advice from illusionist James Randi, who became famous for exposing several supposedly paranormal phenomena. “The experiment was conducted very well, with an excellent engineering approach,” says Hervé Cadiou of the University of Strasbourg. “Be that as it may, other confirmation will be required.” “I got acquainted with the details, but have not yet decided what I think about this. The experience has a clear methodology, but it must be replicated by other independent teams,”says Oxford professor Peter Hore. He recalls that there has already been a lot of high-profile news in this area, which were later refuted.
One of these discoveries is noted in an article by the California Institute of Technology. In 1980, Robin Baker of the University of Manchester wrote that students who were blindfolded and taken by bus far from their base felt north. Be that as it may, similar experiments in 1981, 1986 and 1987 did not confirm this. In the 2000s, some experts claimed to have found iron oxide crystals in the beaks of pigeons that could trap a magnetic field. Be that as it may, in 2012 other experts denied this conclusion.
Finally, in 2016, several groups of scientists reported at once that they had found proteins sensitive to the magnetic field, but later another specialist proved that these substances did not have the necessary physical properties.
“In this area, repeatability is very important due to the range of potential interferences and the complexity of the experiments,” summarizes Peter Hoore.
The presented study also has some weak points. Thus, the number of participants is small, although the publication of results with electroencephalograms in such groups is not unusual. In addition, the differences in indicators from person to person are very large. The intensity of the magnetic field also did not change, in order to understand whether this would cause a reaction in those who did not react to it at the same level. Another worrying point is that the effect depends on the direction of rotation: it occurs when moving from northeast to northwest, but not vice versa. “This may be due to asymmetry in the human magnetic field sensor,” suggests Connie Wong. That is, among people there may be "magnetic" right-handers and left-handers. Finally, we don't know if this brain response is reflected in human behavior.
Scientists themselves say that they would like to conduct the experiment in other conditions, in particular with volunteers from the southern hemisphere. They also tried to understand how the brain picks up a magnetic field. To do this, they draw on one of the most famous works of Joseph Kirshvink, which was published in 1992 and concerns the discovery of iron oxide crystals in the brain. These particles behave like a compass needle and are sensitive to the absolute direction of the field. It is already known that they help bacteria navigate.
Experts also considered a hypothesis about the role of cryptochrome, which regulates the circadian rhythm in the human body, but is insensitive to the magnetic field. Californian experts have refuted it using tests, although there are many arguments about its reliability among other animals. "There is no reason for all animals to use the same systems," notes cryptochrome specialist Peter Hoore. “This work is going too fast in interpreting the results,” says Hervé Cadiou.
Plus, the study came out just a month after another experience that seems to completely refute it! South Korean experts published in February in PLoS One a similar study with an arbitrary change in the magnetic field, but its results, rather, play into the hands of the cryptochrome hypothesis. They showed that men (but not women) are sensitive to the direction of the magnetic field, but only in light and if they eat (after a hunger strike). Such data only further confuse experts.