University of Virginia scientists have demonstrated that neurons in the brain that have been supplemented with a synthetic gene can be remotely manipulated by a magnetic field. The finding has implications for possible future treatment of a range of neurological diseases, such as schizophrenia and Parkinson’s disease. 
 
 “We may have discovered a major step toward developing a ‘dream tool’ for remotely controlling neural circuits, by manipulating specific cells using engineered gene products that respond to magnets,” said Ali Deniz Güler, a UVA biology professor who led the study in his neuroscience lab. 
 
 The finding is published online this week in the journal Nature Neuroscience. 
 
 Güler and UVA neuroscience Ph.D. candidate Michael Wheeler engineered a gene that can make a cell sense the presence of a magnetic field. They coupled a gene that senses cellular stretch with another gene that functions as a nanomagnet. This synthetic combination turns on only when in the presence of a magnetic field, allowing them to control neuronal activity in the brain. 
 
 “We wanted to activate with magnetism a specific set of neurons in the brain responsible for pleasure,” Güler said. 
 
 Using gene therapy to insert the gene, they expressed the synthetic gene in adult mice or in zebrafish embryos, and witnessed remote activation of neurons the presence of a magnetic field through the altered behavior of the animals. 
 
 “We have validated that we can turn on cells in the brain with simple magnets, something that has not been achieved before,” Güler said. “We are actually magnetically evoking behavioral responses in animals by creating a cell that can sense magnetic fields. This could pave the way toward eventually treating neurological diseases through magnetism. It is precise and noninvasive.” 
 
 Güler and Wheeler call their synthetic gene “Magneto,” after a Marvel Comics cartoon character who can alter magnetic fields. 
 
 In a series of tests on mice that had the Magneto gene used to express comfort or pleasure, the mice voluntarily went to a chamber of their cage where the magnetic field was present, similar to going there as if food was present. Likewise, when the magnetic field was turned off, the mice did not display any particular preference for that area of the cage. But when the magnetic field was turned back on, they again moved to that area of the cage. 
 
 Mice without the Magneto gene did not display any behavioral changes in the presence of magnets. 
 
 “The mice were hanging out in the magnetic chamber because they were experiencing some pleasure there, since we were remotely turning on the neurons that signal reward,” Wheeler said. 
 
 In the team’s studies on zebrafish embryos, the embryos responded to a magnetic field by twirling, which they generally do in response to pressures in the water. When the magnetic field was removed, the embryos greatly reduced their twirling behavior. 
 
 “These response behaviors, in two separate species of animals, validate that the cells containing the synthetic gene turn on in a magnetic field,” Wheeler noted. “This field can penetrate the brain regardless of tissue density – like MRI – and can turn on specific circuits at a specific time, whenever the test subject is within the magnetic field.” 
 
 Güler added, “If we can use gene therapy to exert control over neurons, the potential exists to modify or eliminate the effects of certain neurological diseases by controlling ill-firing neural networks. Our method may be one possible approach.” 
 
 He emphasized, however, that at present the method is being used to better understand brain development, function and pathology. ||||| Photo: Getty Images 
 
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 Matching the brain’s machinery to behaviors and emotions was risky business throughout much of medical history. It was achievable, more or less, only through clumsy techniques such as lobotomies. Examiners who removed chunks of the brain could observe the surgery’s effects, but patients had to live with the results. 
 
 The rise of optogenetics, in which light in the form of lasers is used to manipulate individual neurons, has improved the situation slightly. But this technique still works only in regions of the brain where it’s easy to shine light. Neuroscientists must physically insert a fiber optic cable to study anything that isn’t easily accessible. 
 
 Now a team from the University of Virginia has shown that it’s possible to use a magnet to control neurons embedded deep in the brains of mice. This technique could offer a non-invasive alternative to optogenetics and aid researchers eager to understand the underpinnings of emotions or more clearly identify the origins of cognitive disorders. 
 
 By using this technique to flip genes on and off, researchers could trace neural circuits and determine which behaviors or feelings are affiliated with specific pathways in the brain. Ali Guler, a biochemist, led the group that published the results of this proof-of-concept research in the 7 March edition of Nature Neuroscience. 
 
 Guler, aware of the limits of other examination methods, wanted to find a way to remotely control neurons. His idea was to create a genetic analog to techniques used to alter cellular functions. If simple adjustments to calcium ion channels can change important processes such as muscle contraction and hormone secretion, he reasoned, why can’t we manipulate hard-to-reach areas of the brain, but with genetic switching as the trigger? 
 
 With this strategy in mind, he created a tool that linked the gene for a protein called TRPV4 (which serves as a gatekeeper for ion channels) with a gene for an iron-fixing protein called ferritin. Connecting the two genes in this way enabled his team to tug the ion channels open or push them closed simply by moving the nearby iron with a magnet. 
 
 "It's essentially a biological nanomagnet,” Guler says. He dubbed the creation “Magneto” for the Marvel comic book character capable of generating magnetic fields at will. 
 
 In one experiment, the Virginia researchers inserted the specially-designed Magneto genes in a virus, which acted as the transport medium to ferry the magnetic field–susceptible gene product to the striata of six mice. The aim: to see if they could switch ion channels open and closed in a way that might mimic the pleasurable effects of dopamine. The striatum, which processes rewards, is buried beneath the wrinkly bulk of the forebrain and has proven difficult to reach by other methods. If the technique worked, they figured, they could use Magneto in other parts of the brain to mimic different hormones and neurotransmitters. Six other mice formed the control group. 
 
 The researchers put all 12 mice into a chamber that was magnetized at one end. Their hypothesis: that the Magneto-carrying mice would scramble for the magnetized side because the open ion channels in their striata would give them a dopamine-like rush of pleasure. Indeed, they found that all six of the Magneto mice preferred to spend their time on the magnetized side of the chamber while all but one of the control mice kept to the non-magnetized end. 
 
 When Guler measured the rate at which the mice’s neurons fired, he found that the neurons in Magneto mice at the magnetized end fired more frequently than those in the untreated mice—an effect he would expect to see with true dopamine. 
 
 In the future, Guler says, this technique could be used to map neural pathways, tinker with behaviors, and compare neurons in different parts of the brain. “Similar to the optogenetic strategies, you can manipulate any group of neurons that you would like to control,” he says. 
 
 If that sounds eerie, rest assured that this power will stay confined to the lab for the time being. The synthetic genes that responded to Guler’s magnet were specially designed and built for this purpose. Magnets would not have the same effect on normal neurons in mice or people. ||||| Neurons in the brains of pigeons encode the direction of Earth's magnetic field, endowing the birds with an innate internal GPS system, according to a new study. Scientists have long known internal magnetic field receptors exist in many animals — from birds to foxes and possibly even people — but this is the first time someone has tried to explain the brain wiring that can actually use these receptors and provide a sense of direction. They did it by putting some pigeons in the dark and monitoring their brains. 
 
 Writing in Science, Le-Qing Wu and J. David Dickman at Baylor College of Medicine cite previous research identifying magnetic receptors in bird beaks, as well as in other areas in other vertebrates. They set out to find the neural network responsible for making sense of those signals. 
 
 Working with seven awake pigeons, the researchers used a Tesla coil to cancel out the effects of Earth's magnetic field and induce an artificial one. They put the pigeons in a completely dark room to cancel out any light-polarization effects, which have also been suggested as a mechanism for animals' magnetic navigation capabilities. They also stabilized the birds' heads so they couldn't rely on inner-ear cues to determine their directions. 
 
 Then Wu and Dickman turned up the magnetic field, adjusting its magnitude, elevation and other variables. They used a gene marker to identify when neurons were activated, focusing on neural areas that were already good candidates for this type of information processing. Ultimately, they pinpointed 53 neurons in the birds' brain stems that had greatly enhanced activity. What's more, those cells were most sensitive to the magnetic field ranges that correspond to Earth's real ones — 20 micro-Tesla (μT) at the magnetic equator to more than 60 μT at the magnetic poles. 
 
 The poles shift over time, however, so the researchers note that these neurons must be somewhat adaptable, either through evolution or brain plasticity. 
 
 As for the origin of the signals? Wu and Dickman believe the magnetic information is transmitted to the neurons via the inner ear, although it's also possible that beak and/or retinal receptors are involved. 
 
 "[The neurons] encode a geomagnetic vector that could be used by the neural population to computationally derive the bird's position and directional heading," they write. In other words: A neural global positioning system. 
 
 Exactly how these cells are used for orientation and navigation is still a mystery, however. 
 
 The research appears today at Science Express and will be published in the journal Science.
– Scientists at the University of Virginia were able to control the brains of living mice using magnetic fields, essentially harnessing the power of mind control, according to a study published this week in Nature Neuroscience. Researchers created a synthetic gene—dubbed Magneto, obviously—that is sensitive to magnetic fields and put it into a handful of mice, a university press release explains. Ars Technica reports scientists then created a magnetic field to simulate a dopamine-like response in the genetically altered mice—basically the mice felt as happy as if they had just been given a treat. “This is, to our knowledge, the first demonstration of bona fide magnetic control of the nervous system,” Ars Technica quotes the researchers as saying. Until this newfound power is hijacked by a super villain, scientists hope to use it to study how the brain works and test out "magneto-genetic" therapies for people with brain disorders. Ali Deniz Güler, the study's lead author, called their results a "dream tool." In the immediate future, researchers can use it to figure out what pathways in the brain do what in terms of feelings and behaviors, IEEE Spectrum reports. In the future, it could be used to control neural networks that aren't functioning properly, potentially treating conditions like schizophrenia and Parkinson's disease. (Dogs apparently mastered magnetic fields long ago, using the one created by Earth for pooping.)