In collaboration with Roozbeh Jafari, an assistant professor of electrical engineering at the University of Texas, Dallas, Samsung researchers are testing how people can use their thoughts to launch an application, select a contact, select a song from a playlist, or power up or down a Samsung Galaxy Note 10.1. While Samsung has no immediate plans to offer a brain-controlled phone, the early-stage research, which involves a cap studded with EEG-monitoring electrodes, shows how a brain-computer interface could help people with mobility issues complete tasks that would otherwise be impossible.

Brain-computer interfaces that monitor brainwaves through EEG have already made their way to the market. NeuroSky’s headset uses EEG readings as well as electromyography to pick up signals about a person’s level of concentration to control toys and games (see “Next-Generation Toys Read Brain Waves, May Help Kids Focus”). Emotiv Systems sells a headset that reads EEG and facial expression to enhance the experience of gaming (see “Mind-Reading Game Controller”).

To use EEG-detected brain signals to control a smartphone, the Samsung and UT Dallas researchers monitored well-known brain activity patterns that occur when people are shown repetitive visual patterns. In their demonstration, the researchers found that people could launch an application and make selections within it by concentrating on an icon that was blinking at a distinctive frequency.

Robert Jacob, a human-computer interaction researcher at Tufts University, says the project fits into a broader effort by researchers to find more ways for communicating with small devices like smartphones. “This is one of the ways to expand the type of input you can have and still stick the phone in the pocket,” he says.

Finding new ways to interact with mobile devices has driven the project, says Insoo Kim, Samsung’s lead researcher. “Several years ago, a small keypad was the only input modality to control the phone, but nowadays the user can use voice, touch, gesture, and eye movement to control and interact with mobile devices,” says Kim. “Adding more input modalities will provide us with more convenient and richer ways of interacting with mobile devices.”

Still, it will take considerable research for a brain-computer interface to become a new way of interacting with smartphones, says Kim. The initial focus for the team was to develop signal processing methods that could extract the right information to control a device from weak and noisy EEG signals, and to get those methods to work on a mobile device.

Jafari’s research is addressing another challenge—developing more convenient EEG sensors. Classic EEG systems have gel or wet contact electrodes, which means a bit of liquid material has to come between a person’s scalp and the sensor. “Depending on how many electrodes you have, this can take up to 45 minutes to set up, and the system is uncomfortable,” says Jafari. His sensors, however, do not require a liquid bridge and take about 10 seconds to set up, he says. But they still require the user to wear a cap covered with wires.

The concept of a dry EEG is not new, and it can carry the drawback of lower signal quality, but Jafari says his group is improving the system’s processing of brain signals. Ultimately, if reliable EEG contacts were convenient to use and slimmed down, a brain-controlled device could look like “a cap that people wear all day long,” says Jafari.

Kim says the speed with which a user of the EEG-control system can control the tablet depends on the user. In the team’s limited experiments, users could, on average, make a selection once every five seconds with an accuracy ranging from 80 to 95 percent.

“It is nearly impossible to accurately predict what the future might bring,” says Kim, “but given the broad support for initiatives such as the U.S. BRAIN initiative, improvements in man-machine interfaces seem inevitable” (see “Interview with BRAIN Project Pioneer: Miyoung Chun”).

The advance is the result of a 10-year odyssey in synthetic biology, the wholesale engineering of an organism’s genetic and metabolic system for practical purposes (see “Biology’s Master Programmers”). Amyris, the biotech startup that engineered the yeast strain, is also developing microbes to produce fragrances and other high-value chemicals.

“This is the first synthetic biology project that has been scaled up to industrial manufacturing and will have a real impact in the world,” says Jack Newman, chief scientific officer at Amyris. “There should never been a shortage of artemisinin ever again.”

Amyris had already engineered yeast capable of producing artemisinic acid, the precursor to the drug (see “Cheaper Malaria Drugs”). But the most recent advance, published today in Nature, dramatically improved the yield from 1.6 grams per liter to 25 grams per liter.

The improvement primarily comes from the discovery of three key enzymes in sweet wormwood, the plant that naturally produces artemisinin, which researchers then introduced to yeast.

Artemisinin is the primary ingredient in artemisinin combination therapies, the World Health Organization’s preferred malaria treatment. But because the drug is primarily derived from plants, its costs can vary from $350 to $1200 per kilogram of the active ingredient.

“The botanical supply is inconsistent for various reasons, including weather and incentives for farmers,” says Ponni Subbiah, global program leader for drug development at OneWorld Health, a nonprofit drug development organization that funded the research through a grant from the Gates Foundation.

The synthetic process can run year round and takes about three months, compared to 15 months for plant-based methods. “Our aim is to stabilize the supply independent of the plant supply,” says Chris Paddon, who leads the artemisinin project at Amyris.

OneWorldHealth has licensed the technology to Sanofi, which has already produced nearly 40 tons of the artemisinic acid. (The acid is then chemically converted into artemisinin.) Sanofi aims to produce 60 tons of the material next year —approximately 120 million courses of treatment — and has pledged to sell it without profit.

Some are concerned that introducing the synthetic version to the market too quickly might actually be disruptive, discouraging plant-based production. However, at a malaria conference in Nairobi in January, Sanofi said it will introduce its product at the lower end of the market range, with the goal of smoothing out price fluctuations rather than elbowing out other producers. Sixty tons of the drug would meet about a third of the world’s supply, says Subbiah.

Malaria sickens millions of people each year, killing at least 650,000 annually, mostly children.

The results demonstrate that the nanoparticles could be used to neutralize toxins produced by many bacteria, including some that are antibiotic-resistant, and could counteract the toxicity of venom from a snake or scorpion attack, says Liangfang Zhang, a professor of nanoengineering at the University of California, San Diego. Zhang led the research.

The “nanosponges” work by targeting so-called pore-forming toxins, which kill cells by poking holes in them. One of the most common classes of protein toxins in nature, pore-forming toxins are secreted by many types of bacteria, includingStaphylococcus aureus, of which antibiotic-resistant strains, called MRSA, are endemic in hospitals worldwide and cause tens of thousands of deaths annually. They are also present in many types of animal venom.

There are a range of existing therapies designed to target the molecular structure of pore-forming toxins and disable their cell-killing functions. But they must be customized for different diseases and conditions, and there are over 80 families of these harmful proteins, each with a different structure. Using the new nanosponge therapy, says Zhang, “we can neutralize every single one, regardless of their molecular structure.”

Zhang and his colleagues wrapped real red blood cell membranes around biocompatible polymeric nanoparticles. A single red blood cell supplies enough membrane material to produce over 3,000 nanosponges, each around 85 nanometers (a nanometer is a billionth of a meter) in diameter. Since red blood cells are a primary target of pore-forming toxins, the nanosponges act as decoys once in the bloodstream, absorbing the damaging proteins and neutralizing their toxicity. And because they are so small, the nanosponges will vastly outnumber the real red blood cells in the system, says Zhang. This means they have a much higher chance of interacting with and absorbing toxins, and thus can divert the toxins away from their natural targets.

In animal tests, the researchers showed that the new therapy greatly increased the survival rate of mice given a lethal dose of one of the most potent pore-forming toxins. Liver biopsies several days following the injection revealed no damage, indicating that the nanosponges, along with the sequestered toxins, were safely digested after accumulating in the liver.

If the drug can achieve regulatory approval, says Zhang, the major application would be the treatment of bacterial infections, especially those involving antibiotic-resistant bacteria. Neutralizing bacterially produced toxins not only protects the body, but can also weaken the bacteria against the immune system, since the bacteria can no longer rely on the toxins for protection, says Zhang. This is one of the ideas behind a relatively new approach to treating antibiotic-resistant bacterial infections, called anti-virulence therapy.

Zhang says his group hopes to pursue clinical trials of the nanosponge therapy soon, and he’s optimistic about its prospects. The polymer that makes up its core is already FDA-approved, and the red blood cell membrane is safe since it is taken from the body, he says. Compared to other types of drugs, says Zhang, “I envision much less hurdles for clinical trials and approval.”

Innovation in solar cell technology has slowed as startups struggle to get a foothold in a tough market and solar panel manufacturers delay purchasing the equipment they need to manufacture more efficient cells. But First Solar, one of the world’s largest solar companies, continues to invest in boosting the efficiency of its solar cells.

The company, which is based in Tempe, Arizona, announced this week that it had set a new world record in efficiency for thin-film cadmium telluride solar panels. The equipment it uses to produce the record-setting panels will eventually be installed on all its production lines. It also announced the acquisition of Tetrasun, a startup with high-efficiency silicon technology that First Solar hopes to bring to market next year. First Solar’s stock jumped from $29 to over $40 on Tuesday and is still above $35 a share.

First Solar is able to make these investments because it is in a much better position than other major solar manufacturers, most of which are either declaring bankruptcy or on the brink of it (see “Why We Need More Solar Companies to Fail” and “Solar Downturn Casts a Shadow over Innovation”). It’s doing better for at least two reasons. Its solar panels are cheaper to make than conventional silicon solar panels, which has given it better profit margins. And it was one of the first companies to expand beyond making solar panels to become a project developer, designing and installing complete solar power plants. These projects create a steady market for First Solar’s panels and help it drive down costs in areas besides the panels themselves, which account for less than a quarter of the expense of solar power. The company’s good balance sheet and project experience also help lower the risk to investors, helping it secure better financing rates. And financing is now the biggest single contributor to the cost of solar power, accounting for 36 percent of the total for large installations and even more for smaller ones.

The industry is “getting so good on the technology that finance costs and project development costs are becoming dominant,” says Raffi Garabedian, First Solar’s chief technology officer. “We’re entering an era—the next five years, I think—where a lot of effort is going to be applied to reducing the cost of financing these systems.”

By next year solar power could cost as little as 10 cents per kilowatt-hour without subsidies and thus become cheap enough to compete with fossil fuels in many markets around the world, First Solar says. It expects to lower costs to 7.5 cents per kilowatt-hour by 2016, bringing solar power close in price to one of the cheapest sources of power in the United States—a new natural-gas power plant, which the U.S. Energy Information Administration expects to average 6.5 cents per kilowatt-hour over its lifetime.

Thin-film solar panels are less efficient than conventional silicon panels, and efficiency not only determines the number of panels needed for a project but affects costs for installation and financing. However, First Solar has been closing the efficiency gap. By the end of last year, the company’s cadmium telluride panels were converting about 13 percent of the energy in sunlight into electricity, compared with roughly 15.5 percent for silicon. As it installs more of the new equipment that allowed it to make its record-setting panel, that figure should increase. By 2016, the company expects its average solar panels to reach nearly 17 percent efficiency, with much of the improvement coming from advances that have already been demonstrated it in its labs. Silicon panels will also improve over that time, but First Solar expects to have comparable efficiency at that point. Garabedian thinks it could be possible to reach 19 percent efficiency within five years.

Even with these advances, First Solar doesn’t expect to be able to compete in certain markets—especially in places like Japan. The solar market has been booming there since the Fukushima disaster caused nuclear power plants to be shut down, but most of the demand is for rooftop solar. With that technology, space is limited and costs for installation are relatively high, putting a premium on efficiency.

That’s why First Solar is turning to Tetrasun, which has developed a single-crystal silicon panel with an efficiency rate over 20 percent. First Solar says Tetrasun’s version of this high-efficiency technology will be cheaper to manufacture than similarly efficient—but expensive—silicon solar panels from SunPower and Panasonic.

The Tetrasun investment could be risky, says Shyam Mehta, a senior analyst at GTM Research. “Tetrasun’s technology is far from being proven as commercially viable—right now, it is a company of 14 people with little more than a pilot cell manufacturing plant,” he says. New solar technologies have been difficult to scale up, so a goal of mass-producing its panels by next year may be overly ambitious.

While improvements in efficiency may be the most powerful way to reduce the cost of solar power in the long term, most of the reductions in the next two years are expected to come in financing, which is far more expensive for solar than for many other capital projects, says Travis Bradford, a professor at Columbia University’s School of International and Public Affairs and president of the Prometheus Institute for Sustainable Development, a nonprofit research firm. He says First Solar is in a good position to lower these costs. “Suntech [the Chinese solar panel manufacturer] just went bankrupt, and most of the Chinese competitors have really bad balance sheets,” Bradford says. “But nobody thinks First Solar is going away.”

The company, which is based in Tempe, Arizona, announced this week that it had set a new world record in efficiency for thin-film cadmium telluride solar panels. The equipment it uses to produce the record-setting panels will eventually be installed on all its production lines. It also announced the acquisition of Tetrasun, a startup with high-efficiency silicon technology that First Solar hopes to bring to market next year. First Solar’s stock jumped from $29 to over $40 on Tuesday and is still above $35 a share.

First Solar is able to make these investments because it is in a much better position than other major solar manufacturers, most of which are either declaring bankruptcy or on the brink of it (see “Why We Need More Solar Companies to Fail” and “Solar Downturn Casts a Shadow over Innovation”). It’s doing better for at least two reasons. Its solar panels are cheaper to make than conventional silicon solar panels, which has given it better profit margins. And it was one of the first companies to expand beyond making solar panels to become a project developer, designing and installing complete solar power plants. These projects create a steady market for First Solar’s panels and help it drive down costs in areas besides the panels themselves, which account for less than a quarter of the expense of solar power. The company’s good balance sheet and project experience also help lower the risk to investors, helping it secure better financing rates. And financing is now the biggest single contributor to the cost of solar power, accounting for 36 percent of the total for large installations and even more for smaller ones.

The industry is “getting so good on the technology that finance costs and project development costs are becoming dominant,” says Raffi Garabedian, First Solar’s chief technology officer. “We’re entering an era—the next five years, I think—where a lot of effort is going to be applied to reducing the cost of financing these systems.”

By next year solar power could cost as little as 10 cents per kilowatt-hour without subsidies and thus become cheap enough to compete with fossil fuels in many markets around the world, First Solar says. It expects to lower costs to 7.5 cents per kilowatt-hour by 2016, bringing solar power close in price to one of the cheapest sources of power in the United States—a new natural-gas power plant, which the U.S. Energy Information Administration expects to average 6.5 cents per kilowatt-hour over its lifetime.

Thin-film solar panels are less efficient than conventional silicon panels, and efficiency not only determines the number of panels needed for a project but affects costs for installation and financing. However, First Solar has been closing the efficiency gap. By the end of last year, the company’s cadmium telluride panels were converting about 13 percent of the energy in sunlight into electricity, compared with roughly 15.5 percent for silicon. As it installs more of the new equipment that allowed it to make its record-setting panel, that figure should increase. By 2016, the company expects its average solar panels to reach nearly 17 percent efficiency, with much of the improvement coming from advances that have already been demonstrated it in its labs. Silicon panels will also improve over that time, but First Solar expects to have comparable efficiency at that point. Garabedian thinks it could be possible to reach 19 percent efficiency within five years.

Even with these advances, First Solar doesn’t expect to be able to compete in certain markets—especially in places like Japan. The solar market has been booming there since the Fukushima disaster caused nuclear power plants to be shut down, but most of the demand is for rooftop solar. With that technology, space is limited and costs for installation are relatively high, putting a premium on efficiency.

That’s why First Solar is turning to Tetrasun, which has developed a single-crystal silicon panel with an efficiency rate over 20 percent. First Solar says Tetrasun’s version of this high-efficiency technology will be cheaper to manufacture than similarly efficient—but expensive—silicon solar panels from SunPower and Panasonic.

The Tetrasun investment could be risky, says Shyam Mehta, a senior analyst at GTM Research. “Tetrasun’s technology is far from being proven as commercially viable—right now, it is a company of 14 people with little more than a pilot cell manufacturing plant,” he says. New solar technologies have been difficult to scale up, so a goal of mass-producing its panels by next year may be overly ambitious.

While improvements in efficiency may be the most powerful way to reduce the cost of solar power in the long term, most of the reductions in the next two years are expected to come in financing, which is far more expensive for solar than for many other capital projects, says Travis Bradford, a professor at Columbia University’s School of International and Public Affairs and president of the Prometheus Institute for Sustainable Development, a nonprofit research firm. He says First Solar is in a good position to lower these costs. “Suntech [the Chinese solar panel manufacturer] just went bankrupt, and most of the Chinese competitors have really bad balance sheets,” Bradford says. “But nobody thinks First Solar is going away.”

News today from OpenCoin, a startup that today launched its own digital currency called Ripple and tools for making transactions in other currencies, including Bitcoins, suggests that may change. The company says it has attracted early investments, of an undisclosed size, from established venture capital firms including Andreessen Horowitz, which reportedly made over $100 million when Microsoft bought Skype, and Lightspeed Ventures, one of the first investors in networking company Nicira, which sold to VMWare last year for $1.6 billion. OpenCoin has also received investment from the early-stage wing the Founder’s Fund, a venture firm owned by PayPal cofounder Peter Thiel.

Ripple, the currency developed by OpenCoin, is similar to Bitcoin in that it uses math to prevent counterfeiting and fraud. However, Ripple has features intended to make it more practical to use, and that enable Ripple to be used to make transactions with existing currencies. One major difference is that transfers made with Ripple can be confirmed in seconds; Bitcoin transfers take, on average, 10 minutes to be confirmed, and many sites that accept Bitcoins make users wait an hour for confirmation of their transaction.

“Bitcoin is focused more on the currency and less on the payments system,” says Chris Larsen, a cofounder and CEO of OpenCoin. “We’re trying to offer both.” Larsen previously founded the online lending and savings company e-loan, and founded OpenCoin with chief technology officer Jed McCaleb, who created the once-popular file sharing client eDonkey as well as the largest Bitcoin exchange, Mt Gox. OpenCoin currently has 14 employees.

The company’s website for Ripple is more polished and easy-to-use than most sites built for Bitcoin users. As well as sending Ripples to other people, users can also send and exchange U.S. dollars, Euros, Bitcoins, and other currencies using the site. Ripple’s design has those transactions automatically routed through exchange companies that are working with OpenCoin. Tools are also available to allow others to offer software or websites that make use of Ripple.

Transferring Ripples is free, while transactions that involve converting between currencies involve small transaction fees—typically 0.02 percent. That’s significantly less than the fees levied by existing financial companies, such as PayPal, credit card issuers, or banks, says Larsen, an advantage that he says will lead to online merchants experimenting with Ripple, and one that attracted OpenCoin’s investors.

“You can send e-mails for free, but not payments,” says Larsen. “Finally we might get finance to the place where e-mail or social networking has taken communication.”

“OpenCoin’s Ripple protocol, which enables free instant global payments in any currency, including Bitcoin, supports many of the advantages of a math-based currency like Bitcoin while also addressing some of the drawbacks,” says Jeremy Liew, managing director of Lightspeed Venture Partners. If math-backed currencies are made useful, as OpenCoin is trying to do, they will last, he says.

In recent years, technology investors have shown a lot of interest in payments companies such as Square and Dwolla, eyeing the lucrative transaction fees levied by credit-card companies. However, OpenCoin has a very different business model, since the company does not control Ripple even though it created it. OpenCoin plans to hand out some 50 billion Ripples in coming months, and more in the future, in an attempt to get the currency to function independently. Larsen says his company aims to turn a profit by retaining a chunk, likely 25 percent, of the total 100 billion Ripples that will ever exist, in the expectation that the currency gains value.

There are already signs that Ripple is finding favor with some devotees of Bitcoin, yet convincing people and companies outside that community to start using currency not issued by any government will be a tough sell.

Liew, of Lightspeed, notes that Bitcoin has already made significant progress. “While consumer usage is still largely confined to hobbyists, large Internet companies are starting to accept payments or donations in Bitcoin, including Expensify, WordPress, and Reddit.”

The ink is based on two advances from Lund University in Sweden. Professor Lars Samuelson demonstrated that nanowires can improve the efficiency of solar cells, and he developed a new way to manufacture nanowires that could make them practical to use.

Increasing solar cell efficiency is one of the most effective ways to reduce the cost of solar power, since it can lower the cost per watt of solar panels as well as reduce installation costs, because fewer solar panels would be needed (see “Alta Devices: Finding a Solar Solution”).

Lund, Sweden-based Sol Voltaics plans to develop equipment to produce nanowire ink, and then sell it to existing manufacturers.  The ink is expected to boost efficiency by helping solar cells absorb more sunlight.

Research in making nanowires for solar photovoltaics has been going on for years, but fabricating nanowires has never been done in an economical way (see “Nanowires Suck Up Light from Around Them” and “How to Double the Power of Solar Panels”). Nanowires are usually grown on a substrate in a batch process that is too expensive for large-scale production.

The Lund University team lead by Samuelson has developed an alternative method that does away with the substrate. It starts by vaporizing gold to produce aerosol nanoparticles, which flow into a tube-shaped furnace along with two other gases. The gold serves as a seed that catalyzes a reaction with the gases to form gallium arsenide nanowires. In a paper published in Nature last December, the Lund researchers said that the process, called aerotaxy, can grow gallium arsenide nanowires 20 to 1,000 faster than batch deposition methods. By controlling temperature and reaction time, they can control the dimensions of the nanowires, which is key to optimizing their performance for solar cells.

Brian Korgel, a professor of chemical engineering at the University of Texas, says aerotaxy “has the potential to be scaled to a continuous process.” Making large volumes would overcome one of the biggest technical challenges in scaling up gas-phase nanowire production, he says.

In a separate paper in Science earlier this year, the same researchers at Lund University showed that arrays of these nanowires made with the aerotaxy method improved the efficiency of indium phosphide solar cells by 13.8 percent by trapping more light.

The next step for Sol Voltaics is to demonstrate that the effect also works on silicon solar cells, the most common type, says CEO Dave Epstein. After it does that, it intends to develop equipment to manufacture the nanowires. He estimates that the ink would add one or two cents per watt to production costs—it currently costs less than 75 cents per watt to make solar panels. “It only takes one gram of nanowires to cover a square meter of a silicon solar panel, so they only need a very small amount of material,” he says.

 “Every indication is that even if there will be an additional cost, the increased efficiency will far outweigh the cost,” says Alf Bjørseth, the founder of REC Solar and an investor in Sol Voltaics.

If the nanowire-ink-on-silicon approach is effective, the company plans to begin small-scale production in 2015. It expects to need $50 million—much less than a full-scale solar factory—to produce at commercial scale, since it’s only selling an add-on product.

The Brain Research through Advancing Innovative Neurotechnologies, or BRAIN, as the project is now called, aims to reconstruct the activity of every single neuron as they fire simultaneously in different brain circuits, or perhaps even whole brains.

The “next great American project,” as Obama called it, could help neuroscientists understand the origins of cognition, perception, and other enigmatic brain activities, which may lead to new, more effective treatments for conditions like autism or mood disorders and could help veterans suffering from brain injuries.

Big brain science is also on the minds of Europeans; the European Union recently announced a nearly 1.2 billion Euro, 10-year proposal to computationally simulate the human brain from the level of molecules and neurons up through neuronal circuits.

Various tools—from genetics and molecular biology—have helped researchers understand how neurons behave as individuals. But neuroscientists are now able to study only the activity of a handful of these brain cells at a time using voltage-sensing electrode probes.

Other efforts to map the physical connections in the brain are already under way, but these projects either look at dead brains or provide only a rough, low-resolution view of how regions of the brain communicate. For example, the Allen Institute for Brain Science has developed several so-called Brain Atlases that map the physical connections between neurons in different species’ brains as well as the patterns of unique genetics in each neuron. While these static maps are great to learn about the architecture of the brain, they don’t provide information about how neuron activity leads to brain function.

It’s possible to get a rough view of whole-neural-circuit activity using tools like MRI and EEG, but only at a low resolution. And the behavior of the brain in between these two scales—how thousands or millions of neurons interact to control the behavior of discrete circuits in the brain—has been inaccessible. Scientists don’t yet understand how complex interactions among many neurons at once give rise to neural circuit function.

The BRAIN initiative proposes to develop new technologies that can record the activity from thousands, if not millions or billions, of neurons simultaneously at timescales matching behavior and mental activities. The initiative will likely tackle discrete brain circuits within different species of animals to understand how neurons work together to give rise to behaviors, moods, and other mental phenomena.

Developing novel technologies will be necessary to achieve the goals of BRAIN, and these will likely take advantage of recent advances in nanotechnology. Existing sensors can record the electrical activity of neurons, but can typically monitor fewer than 100 neurons at a time.

Emerging micro- and nanofabrication techniques could be used to create smaller chips bearing smaller electrical and even chemical probes that would be less invasive. Nanoprobes bearing several dozen electrodes, for instance, could be stacked to probe hundreds of thousands of recording sites and transmit data wirelessly.

Alternatively, nanoparticles carrying molecules that bring them to specific cell types could lodge in cell membranes so surgical placement wouldn’t be necessary. The nanoparticles could also carry molecules that can sense electrical activity, pressure, or even certain chemicals revealing brain activity.

Novel optical techniques could also aid the mapping project. When a neuron fires, the amount of calcium inside cells increases, so many research groups use calcium-sensitive fluorescent dyes to study neuron activity. But this measurement is once removed from the actual electrical activity of the neuron. A voltage-sensitive fluorescent molecule or other imaging agent could provide a more accurate view of activity.

Synthetic biology could be another useful tool. Enzymes that build strands of DNA are sensitive to ion concentration and will introduce more errors into their DNA production in the presence of calcium. As such, these enzymes could be used as sensors for neuron activity. A predetermined DNA sequence could be implanted into neurons and, as it is copied, the resulting strand of DNA would provide a record of the patterns of errors corresponding to patterns of neuron activity. Error-spotted strands from different neurons could later be sequenced.

Researchers sketched out a rough roadmap for the project in a 2012 proposal. The initiative will most likely start with the development of improved calcium-imaging methods for recording neuron firing, followed by voltage-imaging of neuron activity. Since these two methods would look only at surface structures (because light cannot travel far into brain tissue), the third step could be the development of large arrays of nanoprobes.

In the first five years, the initiative may start with small circuits, such as the whole nervous system of the nematode C. elegans (which has only 302 neurons and 7,000 connections) and discrete circuits of the fruit fly brain. Individual circuits in a mouse nervous system, such as that in the retina or olfaction center, could be tackled within 10 years, and within 15 years, scientists may be able to reconstruct the neuronal activity of the entire neocortex of a mouse.

Even without directly exploring the human brain, the resulting insights could have a profound impact on neuroscience and medicine—that is, if everything in this next great American project goes according to plan.