A magnetic field surrounds our planet and protects against solar radiation. Our brain would be able to tune it.
For some creatures, the magnetic field that the stuffed animals of our planet serves as a compass for navigation or orientation.
Migratory birds, sea turtles and certain species of bacteria are counted among the species with these built-in navigation system. But what about the man? According to a new study, people can also sense the Earth’s magnetic field.
The new study, published today (18 March) in the journal, eNeuro, provides the first direct evidence, from brain scans that the human being can do that, probably by means of magnetic particles distributed about the brain.
The ability to detect the magnetic field, called magnetoreception, was first proposed to exist in the man back in the 1980s. But later studies of the brain, from the 1990s, not the proof of the ability. [Top 10 Mysteries of the Mind]
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But with the access to new data-analysis techniques, an international group of researchers decided to take another look.
The manipulation of the magnetic field
To study whether humans can sense the magnetic field, 34 adults were asked to sit in a dark chamber decorated with large, square coils. Electric currents traveled through these coils, the change of the magnetic field in the room.
The intensity of the magnetic field was approximately the same as that around our planet, said lead study author Connie Wang, a doctoral student at the California Institute of Technology. By way of comparison, is about 100,000 times weaker than those created by MRI machines, Wang noted.
The participants were told to relax and close their eyes while the researchers manipulated the magnetic field around them. During the experiment, the electroencephalogram (EEG) machines measured a type of brainwave called an alpha wave. Alpha waves are known to decrease in amplitude as the brain picks up a signal, or the image, the sound … or something magnetic.
The brain responds
Of the 34 participants, brain scans of four individuals showed strong responses to a change in the magnetic field : a shift from the northeast to the northwest. This shift would be the same as a person outside the room, move their head quickly from left to right, with the exception of the head moves through the static magnetic field than the field move. [Earth Quiz: Do You Really Know Your Planet?]
In the four individuals, the alpha brain waves decreased in amplitude by as much as 60 percent. But they responded only when the field shifted from north-east to north — west and not in the other direction.
“We were not really expected of an asymmetric response,” Wang told the Science. Although it is unclear why this happened, the researchers think that it could be something unique to humans, just as some people are right handed and some left-handed and right-handed.
A number of participants also had a strong reaction to a different set of experiments that shifted the slope of the field, and that is what would happen if you travelled between the Northern and Southern hemispheres.
To ensure the results were not a fluke, the study responders were re-tested a few weeks later and the results where. Stuart Gilder, a professor of geophysics at the Ludwig-Maximilians-University of Munich, which was not part of the new study, said that the repeated findings of the study convincing.
Gilder said that he didn’t view the finding that most people could not sense the magnetic field as a count against the study, because the power can be expressed differently in different brains. “Some people are really good at art and some people are really good at math,” Gilder told Live Science. Bodies do not “have to behave or react in the same way.”
Still, the research raises a number of additional questions, he noted. For example, how would the people out in the field as they had been lying, or the magnetic field had to move slower and slower?
It is unclear why some people seem to be capable of magnetoreception, but in theory, the skills can help with the orientation, or a remnant of an ability that is developed at an early stage to help beings — even old hunter-gatherers — navigate. “Many animals use the Earth’s magnetic field for navigation,” Wang told the Science. “For example, there is a wide range of beings, this sense that we think that man, at least only remains of this sentence, even if we don’t use it as much in our daily lives not more.”
And many questions remain about magnetoreception in general, such as how it works. Indeed, scientists have figured out how magnetoreception works in only one kind of being: a type of bacteria called magnetotactic bacteria. These bacteria migrate along the field lines of our planet’s magnetic field using magnetic particles, called magnetite (Fe3O4).
These magnetite particles are known to exist in the human brain for decades, and were first found by Joseph Kirschvink, professor of geobiology at Caltech, who is the senior author of the new study.
What’s more, a study published in August 2018 in the journal Scientific Reports van Gilder the group found that these magnetic particles are distributed by the human brain. The widespread presence in the brain suggested that the particles that probably served some kind of biological purpose, the authors of the study concluded.
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Editor’s note: This article was updated on 19 March to make it clear that magnetic particles are not limited to a “brain” in microbes. Bacteria are mostly made up of loose cells and so they do not have brains.
Originally published on Live Science.