The study, led by geoscientist Joseph Kirschvink (BS, MS '75) and neuroscientist Shin Shimojo at Caltech as well as neuroengineer Ayu Matani at the University of Tokyo, offers experimental evidence that human brain waves respond to controlled changes in Earth-strength magnetic fields. Kirschvink and Shimojo say this is the first concrete evidence of a new human sense: magnetoreception.A beautiful example of REAL science. Quoting Carver: Look about you. "Many animals have magnetoreception, so why not us?" asks Connie Wang, Caltech graduate student and lead author of the eNeuro study. Take hold of the things that are here. To try to determine whether humans do sense magnetic fields, Kirschvink and Shimojo built an isolated radiofrequency-shielded chamber and had participants sit in silence and utter darkness for an hour. Talk to them. During that time, they shifted the magnetic field silently around the chamber.... Let them talk to you. ... and measured participants' brain waves via electrodes positioned at 64 locations on their heads. = = = = = Result: During a given session, the participants consciously experienced nothing more interesting than sitting alone in the dark. However, among many participants, changes in their brain waves correlated with changes in the magnetic field around them. Specifically, the researchers tracked the alpha rhythm in the brain, which occurs at between 8 and 13 Hertz and is a measure of whether the brain is being engaged or is in a resting or "autopilot" mode. When a human brain is unengaged, the alpha power is high. When something catches its attention, consciously or unconsciously, its alpha power drops. Several other sensory stimuli like vision, hearing, and touch are known to cause abrupt drops in the amplitude of alpha waves in the first few seconds after the stimulus. In other words, MAGNETISM IS A SENSE. Like other senses, it responds to DELTAS, which is probably why we don't feel it or think about it consciously. In pre-technological Nature, the earth's field is constant except before an earthquake. We experience a change in field when we turn while standing or walking, but all sorts of other DELTAS are happening at the same time. Our visual field changes, our binaural hearing changes phase, our semicircular canals experience the turn, our kinesthetic sense picks up the muscular twists involved in turning, the sun heats a different side of the body, the wind ruffles a different side. The subtle effect of the changed magnetic direction doesn't get a chance to reach awareness. Pre-tech hunters and nomads undoubtedly used their internal compass for navigation in the same way that bacteria and birds do, but without knowing what they were sensing. The only time a magnetic DELTA isn't completely overwhelmed by more familiar senses is before an earthquake, or during a geomagnetic storm (sunspot), when many people experience an unexplained mood shift. = = = = = Speculative: Previous research on the magnetic sense was focused on finding the sensor, which is reasonable because most senses do have an easily-defined locus. Eye, ear, nose, semicircular canal. Fish have a magnetosensor that closely resembles our semicircular canal. So far we haven't found any obvious deposits of ferromagnetic material in humans. If we're sensing the field dynamically via perturbations of constantly running waves in the brain, we don't need ferromagnetic otoliths. Even more speculative: You can imagine a literal compass on a literal map. When we turn CCW while walking, the wave patterns in the brain are pulled slightly CW, turning the 'needle' CW on a spatiotopic memory map in the hippocampus.
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