人类“第六感”首次被证实，大脑对磁场具有强烈感应
近日，加州理工学院（California Institute of Technology）的一项最新研究证实了人类“第六感”（sixth sense）——磁感（magnetic sense），表明人的大脑能感应到地球磁场（magnetic field），并会对磁场变化作出强烈反应。
Humans have a 'sixth sense' tuned to Earth's magnetic field, study reveals
Humans have a ‘sixth sense’ that's tuned to Earth's magnetic field, a new study has revealed.
Researchers from the California Institute of Technology have found this ‘magnetic sense’, which they claim is similar to that of animals.
This natural ‘compass’ is built into our brains, and may have helped our ancestors to navigate without getting lost.
compass
表示“罗盘；罗经；指南针；罗盘仪”，英文解释为“an instrument for finding direction, with a needle that always points to the north”，如：a map and compass 地图和指南针。
The researchers found the sixth sense through a series of experiments in which more than 30 volunteers were exposed to moving Earth-strength magnetic fields.
Electrical brain recordings showed a subtle response that appeared to be tuned to the magnetic field of the northern hemisphere, where the experiment was conducted.
subtle
表示“难以察觉，难以理解的；微妙的，细微的”，英文解释为“not easy to notice or understand unless you pay careful attention”举个🌰：
The pictures are similar, but there are subtle differences between them.
这些图片很相似，但它们之间有细微的差别。
hemisphere
1) 表示“（地球的）半球”，英文解释为“a half of the Earth, especially one of the halves above and below the equator”，如：the Northern hemisphere 北半球
2) 也可以表示“（大脑的）半球”，英文解释为“one of the two halves of your brain”。
Artificial geomagnetic stimulation caused a drop in alpha-wave brain activity known to signal sensory processing.
The implication is that the Earth's magnetic field can be sensed in humans just as it is in migrating birds and sea turtles.
However, none of the participants were able to tell when they were being subjected to changing magnetic fields.
alpha-wave
α波，四种基本脑波之一。通常所指的潜意识状态，即人的脑波处于α波时的状态。
Alpha waves are neural oscillations in the frequency range of 8–12 Hz[1] arising from the synchronous and coherent (in phase or constructive) electrical activity of thalamic pacemaker cells in humans.
The team led by Dr Joseph Kirschvink from the California Institute of Technology, US, wrote in the journal eNeuro: "Our results indicate that human brains are indeed collecting and selectively processing directional input from magnetic field receptors.
"These give rise to a brain response that is selective for field direction and rotation with a pattern of neural activity that is measurable at a group level and repeatable in strongly responding individuals."
receptor
表示“感受器；受体”，英文解释为“a nerve ending which receives information about changes in light, heat etc and causes the body to react in particular ways”。
For the experiment, each volunteer sat on a non-conducting wooden chair within a "Faraday cage" that blocked out interfering electromagnetic fields.
Inside the chamber, electric current was run through wire coils to mimic the Earth's magnetic field. The design allowed the direction of the field to be rotated.
non-conducting
conduct作动词，除了表示“实施，执行”，还可以表示“传导（热、电）”，英文解释为“if something conducts heat or electricity, it allows heat or electricity to pass through it or along it.”，举个🌰：
Water conducts heat faster than air.
水比空气导热快。
此处non-conducting即指不导电/热等的（not able to conduct heat or electricity or sound）。
Faraday Cage
法拉第笼（Faraday Cage）是一个由金属或者良导体形成的笼子。
chamber
1）表示“作特殊用途的房间”，英文解释为“a room used for a special purpose, especially an unpleasant one”。
2）表示“（人体内或某些机器中的）室，腔”，英文解释为“an enclosed space, especially in your body or inside a machine”。
Brain wave activity was measured by means of electroencephalogram (EEG) recordings using electrodes attached to the scalp.
How the magnetic sense works remains a mystery, but the scientists suspect it may involve tiny iron crystals in cells.
EEG
脑电波（Electroencephalogram, EEG）是一种使用电生理指标记录大脑活动得方法，大脑在活动时，大量神经元同步发生的突触后电位经总和后形成的。
scalp
表示“头皮”，英文解释为“the skin on the top of your head”。
The researchers concluded:
Given the known presence of highly-evolved geomagnetic navigation systems across the animal kingdom, it is perhaps not surprising that we might retain at least some functioning components, especially given the nomadic hunter-gatherer lifestyle of our not-too-distant ancestors.
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