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板凳
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发表于 2018-11-8 12:24:43
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Part I: Speaker
Ancient Human Migration Route Marked by Snail Shell "Bread Crumbs"
By Cynthia Graber | 6 June , 2015
Want to know the route humans took when they first migrated from Africa into Europe? Seems that they might have marked the path. Not like Hansel and Gretel, who consciously left bread crumbs. Ancient humans ate as they trekked. And they appear to have chucked aside the packaging for some of their slimy sustenance: snails.
Conventional wisdom has been that humans initially traveled from Africa to the Near East, then up around the Mediterranean through Lebanon before heading into Europe some 40[,000] to 50,000 years ago. But recently, some scientists have theorized that humans made it to Europe first and then headed east.
Now there’s more support for the old view that humans traveled through the Levant on the way to Europe–in the form of the shells of edible marine snails. The study is in the Proceedings of the National Academy of Sciences.
Researchers evaluated shells from an archaeological site dated to the Upper Paleolithic in Lebanon. The shells were mostly intact, except the tapered pointy tip had been removed—most likely for easier access to the meat inside.
The scientists calculated the age of the shells via a variety of methods. And they found that the snails dated back almost 46,000 years. The earliest evidence of modern human remains in Europe seem to be no more than 45,000 years old. The snail evidence thus adds weight to the hypothesis that ancient people passed through the Levant on their way to Europe. And not at a snail’s pace, either.
—Cynthia Graber
Source: Scientific American
http://www.scientificamerican.com/podcast/episode/ancient-human-migration-route-marked-by-snail-shell-bread-crumbs/
[Rephrase 1, 1:33]
Part II: Speed
Picture describe: This soft, conductive polymer mesh can be rolled up and injected into the brains of mice.
Injectable brain implant spies on individual neurons
Electronic mesh has potential to unravel workings of mammalian brain.
By Elizabeth Gibney | 8 June, 2015
[Time2]
A simple injection is now all it takes to wire up a brain. A diverse team of physicists, neuroscientists and chemists has implanted mouse brains with a rolled-up, silky mesh studded with tiny electronic devices, and shown that it unfurls to spy on and stimulate individual neurons.
The implant has the potential to unravel the workings of the mammalian brain in unprecedented detail. “I think it’s great, a very creative new approach to the problem of recording from large number of neurons in the brain,” says Rafael Yuste, director of the Neurotechnology Center at Columbia University in New York, who was not involved in the work.
If eventually shown to be safe, the soft mesh might even be used in humans to treat conditions such as Parkinson’s disease, says Charles Lieber, a chemist at Harvard University on Cambridge, Massachusetts, who led the team. The work was published in Nature Nanotechnology on 8 June.
Neuroscientists still do not understand how the activities of individual brain cells translate to higher cognitive powers such as perception and emotion. The problem has spurred a hunt for technologies that will allow scientists to study thousands, or ideally millions, of neurons at once, but the use of brain implants is currently limited by several disadvantages. So far, even the best technologies have been composed of relatively rigid electronics that act like sandpaper on delicate neurons. They also struggle to track the same neuron over a long period, because individual cells move when an animal breathes or its heart beats.
[261 words]
[Time 3]
The Harvard team solved these problems by using a mesh of conductive polymer threads with either nanoscale electrodes or transistors attached at their intersections. Each strand is as soft as silk and as flexible as brain tissue itself. Free space makes up 95% of the mesh, allowing cells to arrange themselves around it.
In 2012, the team showed that living cells grown in a dish can be coaxed to grow around these flexible scaffolds and meld with them, but this ‘cyborg’ tissue was created outside a living body. “The problem is, how do you get that into an existing brain?” says Lieber.
The team’s answer was to tightly roll up a 2D mesh a few centimetres wide and then use a needle just 100 micrometres in diameter to inject it directly into a target region through a hole in the top of the skull. The mesh unrolls to fill any small cavities and mingles with the tissue (see ‘Bugging the brain’). Nanowires that poke out can be connected to a computer to take recordings and stimulate cells.
So far, the researchers have implanted meshes consisting of 16 electrical elements into two brain regions of anaesthetized mice, where they were able to both monitor and stimulate individual neurons. The mesh integrates tightly with the neural cells, says Jia Liu, a member of the Harvard team, with no signs of an elevated immune response after five weeks. Neurons “look at this polymer network as friendly, like a scaffold”, he says.
[260 words]
[Time 4]
The next steps will be to implant larger meshes containing hundreds of devices, with different kinds of sensors, and to record activity in mice that are awake, either by fixing their heads in place, or by developing wireless technologies that would record from neurons as the animals moved freely. The team would also like to inject the device into the brains of newborn mice, where it would unfold further as the brain grew, and to add hairpin-shaped nanowire probes to the mesh to record electrical activity inside and outside cells.
When Lieber presented the work at a conference in 2014, it “left a few of us with our jaws dropping”, says Yuste.
There is huge potential for techniques that can study the activity of large numbers of neurons for a long period of time with only minimal damage, says Jens Schouenborg, head of the Neuronano Research Centre at Lund University in Sweden, who has developed a gelatin-based ‘needle’ for delivering electrodes to the brain. But he remains sceptical of this technique: “I would like to see more evidence of the implant’s long-term compatibility with the body,” he says. Rigorous testing would be needed before such a device could be implanted in people. But, says Lieber, it could potentially treat brain damage caused by a stroke, as well as Parkinson’s disease.
Lieber’s team is not funded by the US government’s US$4.5-billion Brain Research through Advancing Innovative Neurotechnologies (BRAIN) initiative, launched in 2013, but the work points to the power of that effort’s multidisciplinary approach, says Yuste, who was an early proponent of the BRAIN initiative. Bringing physical scientists into neuroscience, he says, could help to “break through the major experimental and theoretical challenges that we have to conquer in order to understand how the brain works”.
[317 words]
Source: Nature
http://www.nature.com/news/injectable-brain-implant-spies-on-individual-neurons-1.17713
Picture describe:The NIH report lays out seven research areas, such as the identification of all cell types in the brain.
Ambitious plans for BRAIN project unveiled
By Sara Reardon| 6 June, 2014
[Time 5]
A working group of the US National Institutes of Health (NIH) yesterday presented a ten-year plan for the agency's portion of a major neuroscience initiative announced last year by President Barack Obama. But the plan's recommended budget of US$4.5 billion over ten years, a more than ten-fold increase annually over its current 2014 budget, might be unrealistic.
The blueprint provides substantive specifics for the NIH's contribution to the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) initiative, which some criticized for its lack of a clear mission and agenda when it debuted last April. The working group presented the 146-page report to NIH director Francis Collins' advisory council meeting, at the NIH campus in Bethesda, Maryland.
The document lays out seven priority research areas and goals, including identifying all cell types in the brain, developing technologies to watch the brain in action and creating systems to make sense of the immense amount of data that will be generated. The programme will be overseen by a special council of external advisers, including bioethicists, as recommended by the Presidential Commission for the Study of Bioethical Issues.
Down to specifics
At the meeting, Collins hailed the working group's plan as “amazing”, and accepted it after a unanimous council vote. The council praised the report's focus on specific initiatives. “I’ve read a lot of reports, and this is the only one that brings me joy. It makes my heart go pitter-patter,” said council member Huda Akil, a neurobiologist at the University of Michigan in Ann Arbor.
“The report is broad but also scientifically very deep and sound,” adds neurobiologist Rafael Yuste of Columbia University in New York. Yuste was one of the initial proponents of the idea of a brain-activity mapping project, which grew into the BRAIN programme.
Partha Mitra, a neuroscientist at Cold Spring Harbor Laboratory in New York, notes that the report highlights many directions rather than working toward a single, defined endpoint. “There’s clearly recognition that this is not the [Human] Genome Project,” he says.
[346 words]
[Time 6]
Working group co-chair Cornelia Bargmann, a neuroscientist at Rockefeller University in New York, emphasizes that, rather than focusing on any particular diseases or research tools, the plan sticks to basic science at the level of neural circuits. So research areas such as stem cells or genetics will be funded only as they relate to brain circuits, she says. The project will also focus heavily on the development of technologies for observing and manipulating the brain.
That blueprint is unlikely to please everyone, Bargmann acknowledges. Yuste, for instance, says that he would have liked greater focus on creating 'brain observatories', where researchers could go to use high-tech equipment, as is done with large telescopes. The report does not rule out the possibility of setting up such observatories, but recommends waiting for further technological advances before committing to them.
The critical question, says Mitra, is whether the money will come from Congress rather than being redirected from other neuroscience research.
Money matters
For the first five years of the plan, which runs during fiscal years 2016–20, the NIH would invest $400 million annually. That money will be primarily devoted to developing technologies — for tasks such as recording groups of neurons as they fire in real time. Over the subsequent five years, the working group calls for $500 million per year, to capitalize on those new technologies through work on humans and animals.
Collins acknowledges that the report's $4.5-billion budget will be difficult to secure. The total 2014 budget for the BRAIN project is $110 million, of which the NIH received only $40 million, with the rest going to the National Science Foundation and the Defense Advanced Research Projects Agency. Without new money from Congress, Collins says, it will not be easy to find the report's requested amount in the NIH budget.
But those keen on the initiative insist that BRAIN will be funded, even if the full requested amount does not materialize. Thomas Insel, director of the National Institute of Mental Health, says that his institute might be willing to redirect funds from other neuroscience research to support BRAIN. “This is really important to us,” says Insel, who expects the initiative to accelerate the pace toward treatments by, for example, uncovering biomarkers and elucidating neural circuits.
[379 words]
Source: Nature
http://www.nature.com/news/ambitious-plans-for-brain-project-unveiled-1.15375
Part III: Obstacle
Overworking Your Brain Can Spark Ideas
Mental exhaustion can unleash creativity, research shows
By Madhuvanthi Kannan | 9 June , 2015
[Paraphrase 7]
If you walk down to the office gallery at Pearlfisher Inc., a design agency based in London, you are bound to hear the unmistakable cluck of plastic balls colliding. At first, you might dismiss it as the sound of employees chilling out on a ping pong game. But if you walk further, following signs for “Jump In!,” the sound will turn into a rattle like that of maracas. What you see next might take your breath away – a huge ball pit filled with 81,000 white plastic balls. But frolicking in the pit are not preschoolers or kindergartners. They are in fact corporate managers and associates, dressed in business suits, in an afternoon brainstorming session
Companies relying on innovation go to astonishing lengths to imbue creativity in their staff. Jump In!, the wacky brainchild of Pearlfisher’s creative strategist, is for instance, built on the premise that interleaving work and play can spark creativity in grown-ups, just like it did back in school days. Many companies including Google, Skype and Facebook similarly emphasize the power of play, while others, such as the news website The Huffington Post, insist on peace and quiet during the break hours. Their offices instead sport nap nooks, where employees can grab some z’s and feel refreshed before returning to write. In theory, both strategies can inspire creativity – one perhaps better than the other depending on whether, for instance, you design products or pen stories for a living. They essentially have the same effect on us: they help us relax and unwind, restoring some of our dulled senses.
But it turns out that mental exhaustion from overwork can itself unleash creativity. When we are tired, our mind can be too weary to control our thoughts, and eccentric ideas that might normally be filtered out as non-relevant can bubble up, suggests a recent study by Rémi Radel at the University of Nice Sophia-Antipolis, France. This means that perhaps creative ideas can be hatched at the workplace, right when we feel drained from a mental overload.
In their study, Radel and colleagues overtaxed the minds of a group of undergrads by having them perform a computerized task that demanded attention: finding the direction of a center arrow by ignoring the directions of surrounding arrows. The task was iterated across 2000 trials. In conflict trials, the center and surrounding arrows pointed in opposite directions whereas in non-conflict trials, all arrows pointed in the same direction. The controls and test subjects faced conflict in 10% and 50% of the trials, respectively. After the students finished the attention task, the scientists measured their creativity in verbal tests. First, they asked the students to enlist multiple, innovative uses for common objects, such as paperclip, newspaper, shoe. Next, they tested the students’ ability to connect unrelated words. They presented the students with a “priming word” followed by “target word” – for example, they flashed the word tiger followed by the word loni, jumbled from lion – and asked the students to vote whether the target word was a real or a non-existent word.
Radel found that students who took the rigorous attention task turned out to be more creative than others who had taken milder versions of the task. They came up with more numerous and quirkier ideas than the latter – one student, for instance, proposed to use a paperclip as a plectrum for guitar, and another saw its use as a compass when inserted into a piece of cork. These students were also more likely to connect unrelated words in the word association test. They identified more non-existent words as real words especially when the prime-target pairs were seemingly related, such as tiger and loni. They perceived loni as lion when it appeared after tiger and hence, called it a real word. Their ability to associate unrelated words, Radel suggests, came from a reduced filtering of irrelevant information – here, for instance, the priming word tiger – from the mind.
Radel’s attention task induced creativity in the students by exhausting their inhibition, which is the brain’s ability to sift out unwanted information from the conscious mind. Although inhibition is essential for day-to-day activities such as problem-solving and focusing on tasks, it stifles creative thinking by gating out eccentric thoughts and ideas. Uninhibited minds, on the other hand, can unleash our creative genius.
Low inhibition is in fact the basis of the paradoxical creativity seen in psychosis and the reason behind enviable accounts of sudden artistic output. For example, in a certain type of psychiatric disorder called fronto-temporal dementia, patients acquire artistic skills anew as their disease progresses. Bruce Miller, a neurologist at the University of California, San Francisco, is an expert in the field. He proposes that in these patients, the damage to parts of the prefrontal cortex – the brain’s seat of execution, in the area of the forehead – particularly in the analytical left hemisphere, releases the inhibition on the right side. As a result, their right prefrontal cortex – the region that fosters visual expression and metaphorical thinking – is liberated from control, and allows a flowering of creativity. The patients develop a sudden compulsive interest in painting. Of course, the sustained loss of inhibition has devastating problems on behavior including changes in social conduct and poor impulse control.
Creative, healthy minds on the other hand can control their inhibition more effectively. In an elegant experiment, back in 2008, neuroscientist Charles Limb at Johns Hopkins University captured brain activity in jazz pianists as they played a specially designed keyboard inside a functional MRI scanner. He saw that the pianists switched to an uninhibited state when they spontaneously improvised a musical piece but not when they played the C-major scale from memory. In the former case, which requires more creativity, Limb could observe a waning of activity in regions of the prefrontal cortex associated with planning, execution and self-assessment, unveiling newer activity in areas for self-expression and individuality. Of course, the inhibition was intact when the pianists played a learned order of notes from memory, a task requiring greater attention.
Being creative is not just about achieving a state of low inhibition, which is probably what we get from alcohol or drugs, but about tweaking inhibition for brief stints without losing control. Harvard psychologist Shelly Carson, author of Your Creative Brain, calls this process “flexing the brain.” She says that creative people can turn down the volume of inhibition to let novel ideas inspire them, and then, turn the volume back up to put their ideas to meaningful use.
Any strategy aimed at upping our creativity should do exactly this – help “manipulate” our inhibition. For beginners, Radel’s technique of overtaxing the brain, to find a sweet window for a creative spell, may be a good place to start. As we go through our day, juggling multiple tasks and deadlines, our mind works hard to stay focused on a single task. There is the added pressure to keep distractions at bay – meetings, e-mails, news updates, and so on. At the end of it all, we are left feeling exhausted. At such times, instead of shutting down and relaxing, we should perhaps learn to capitalize on the mental fatigue and try to kindle our creative genius.
[1230 words]
Source: Scientific American
http://www.scientificamerican.com/article/overworking-your-brain-can-spark-ideas/
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发表于 2018-11-8 10:50:00
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