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2019-04-05

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An artist's rendering of Earth's magnetic field  

Scientists have long known that turtles, birds, honeybees and even bacteria can sense the earth’s magnetic field and use them for navigation. But this magneto-reception has hardly been tested in humans and many studies have been inconclusive.

Now a team of researchers from California Institute of Technology, U.S. and the University of Tokyo has shown that humans do indeed unconsciously respond to the changes in the earth’s magnetic fields. But they are yet to decode what our brains may be using this information for. How did they find this?

They selected 34 volunteers, who sat with their eyes closed in a dark room. The room was wrapped with electrical coils, which helped simulate the earth’s natural magnetic field.

The participants were connected to an EEG set-up and their brain activity was monitored. In the one-hour session, for a few minutes, the magnetic field around the chamber was shifted. They noticed that during this period, the alpha power of the brain began to drop.

“When a human brain is unengaged, the alpha power is high. When something catches its attention, consciously or unconsciously, its alpha power drops.,” explains a release from Caltech.

The most interesting find was that the participants’ brain responded only to changes when the magnetic field pointed toward the floor. This may be due to the fact that the study participants were people who live in the Northern Hemisphere. In this region, the natural geomagnetic field points downwards to the North. “There are many studies needed. First and most important is independent replication. Second, the drop in alpha-wave power is only one expression of the brain’s receiving magnetic information... There may be many more magnetic fluctuations that trigger brain response, including variations in the total strength of the field,” Prof. Joseph Kirschvink, the corresponding author, said .

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