Let there be light: By seeding neurons with light-activated proteins and piping light through a fiber-optic cable into the brains of mice with Parkinson's disease (above), researchers reversed the mice's symptoms. The line on the left traces an untreated animal's path, which is restricted by the disorder's characteristic dysfunctional movement. The line on the right shows that when light was applied, the animal was able to move much more freely. Credit: Deisseroth lab, Stanford University

Parkinson's disease is often treated with deep brain stimulation (DBS), which delivers electrical pulses to a deep-seated cluster of neurons called the subthalamic nucleus. But while the technique is successful in many patients, scientists have struggled to understand its mechanism.

"What's been mysterious is we don't know how those stimulation treatments really work," says Karl Deisseroth, a bioengineer and psychiatrist at Stanford University and senior researcher on a new project that sheds light--literally--on how DBS affects the Parkinsonian brain.

Deisseroth and his colleagues engineered cells in the subthalamic nucleus of mice with Parkinson's to express proteins derived from light-sensing bacteria. One protein triggers cells to fire in response to blue light, while another quiets cells' electrical activity in response to yellow light. The researchers systematically marched through the circuit targeted by DBS, piping in light through a fiber-optic cable to probe each cell type in turn.

"What we found was quite surprising," says Deisseroth. None of the cell types in the subthalamic nucleus, when stimulated or calmed by light, had any effect on the mice's symptoms. But when light was used to activate the wire-like axons projecting to the subthalamic nucleus from other parts of the brain, the mice's symptoms were completely reversed. The results appeared online yesterday in the advance online edition of Science.

"That showed that a big feature of disease pathology may not always be misfiring of cells within a structure," says Deisseroth, "but more the flow of information between structures."

The researchers hope that by tracing the axons back to their source--nearer to the surface of the brain--they will uncover potential targets for less invasive treatment of the disease. Deisseroth also believes that a newer incarnation of his team's light-based approach, which activates cells biochemically rather than electrically, could reveal why some patients respond better than others to the electrical activation DBS produces. "For some symptoms or some disease states, biochemical modulation may be what should be the primary target," he says.

Algae growing in a heated pond at the University of Nevada test site. Credit: John Bebout

Green algae, or common pond scum, have been held up as a renewable energy panacea. Highly refined strains of the fast-growing biomass can absorb CO₂ straight from a power plant's smokestacks, thrive in brackish water, and have the potential to yield far more biofuel per acre than corn does. One promising method of algae production involves nurturing the green goo in decidedly low-tech, open-air ponds. But the approach is plagued by a number of issues, including a fivefold drop in yields in cold winter weather.

Now a team from the University of Nevada has shown that simply cranking up the heat can avoid much of the seasonal production decrease. In late November, John Cushman and his colleagues inoculated an outdoor pond with a "starter" culture of halophytic (salt-loving) algae cells. Since then, they have circulated water heated by natural gas through the pond to keep it at a constant 29 °C (85 °F), despite subzero winter temperatures--an approach that simulates the use of heat from geothermal vents. Three weeks later, they harvested approximately five pounds of algae by dry weight--just half the yield anticipated for summer.

"This will allow us to move from a seasonal crop to optimal production 365 days a year," says Cushman of the potential to combine algae production with geothermal heating. If the scheme proves a success, Nevada could be in a unique position to capitalize. The state is bathed in sunlight, has vast tracks of open desert, and sits on top of little-utilized saline aquifers and geothermal resources.

But even with the addition of geothermal heat, Al Darzins, head of the National Renewable Energy Laboratory's (NREL) recently reinstated algae biofuel research program, questions whether current production methods can be cost competitive. "The price range of algal oil that could currently be produced, from open ponds to closed bioreactors, may be $10 to $40 per gallon," Darzins says. "And that's even before you turn it into fuel."

While geothermal heat might increase production, Darzins says that the added investment could be significant. "You still have to put in pipes to transfer the heat to your algae ponds, and that comes at a cost."

The open-air facilities are also susceptible to contamination by lower-yield strains of algae and other organisms. Darzins says that the highly saline environment--the salinity of the University of Nevada test pond is roughly twice that of seawater--would help limit outside contamination, but he admits that the problem is likely to persist. "What's to say some protozoan that just loves to eat algae might take over the pond? There are ways of preventing their growth, but everything has a cost, and it has to be dirt, dirt cheap."

In January I was contacted by an editor from a major national news magazine to suggest a "dream Government-stimulus package" for President-elect Barack Obama. Before I tell you about my suggestion, I'd like to pause for a moment and direct your attention to the request itself - because I think it's an interesting example of how this country has already shifted its perspective since last November's elections.

This editor could have turned in any direction for eager respondents for this question, but she saw editorial value in the opinion of an engineer from MIT. For those of us who do scientific research - to say nothing of those who simply think science should be an important part of public-policy decisions - it seems we are headed in a direction where science and scientific credibility matter. MIT's reputation in engineering and science, and for their application to environmental sustainability, economics and public policy, has always made it a place from which the world expects great ideas. Apparently now, in this new context, we can also expect to be called in our collective efforts to forge a sense of new direction.

So here's what I suggested: Stimulate worker productivity and the economy at the same time while reducing our damage to the environment, by addressing the country's need for faster, more efficient, and more affordable high-speed railways. By connecting major metropolitan centers in the northeast, city centers and airports in the midwest, and large sprawling communities in the far west, we can create opportunities for enormous numbers of Americans to travel to and from work, and around the country and the world, more quickly and efficiently.

To address the challenges presented by the landscape, climates, and other issues unique to the continental US, the government cannot assume that current materials, transportation technologies, and manufacturing processes will generate the best results. They must invest in our research enterprise to ensure that the very latest technologies, novel infrastructure platforms, and materials are used to move people and goods more efficiently. (It's obvious, but worth noting, that the US has a great deal of catching up to do on the issue of rail transportation generally. Europeans have been using trains as part of more carefully considered national transportation systems for a long time. The Shanghai-Hangzhou Maglev Train in China is a marvel of modern engineering, capable of traveling at more than 300 miles per hour.)

Railroads and specific suggestions aside, the incoming administration needs a grand plan for our collective future--one that will galvanize the talents and enthusiasm of current and future scientists and engineers and support them in their quest to address the major issues of our time. Solutions to the challenges of energy, environmental sustainability, and transportation will not come easily. So, too, are the political challenges of reversing the last decade's decline in funding for scientific research. President Obama must bring a long-term, science-oriented perspective into government, and he must quickly and decisively reverse the more recent, opposing trends. The US's economic leadership has always depended on its ability to foster and maintain an ecosystem of scholarship and innovation in all fields. This system--our system--is perilously close to a tipping point. We need leadership that will invest in and help create a future as brilliant as our past.

Will my suggestion for a new railway system go anywhere? Will we soon travel from Cambridge to New York, or between the city centers of San Francisco and San Diego, more quickly by train than airplane? It's hard to say, but I'm glad they're asking. You can read the resulting article here.

Subra Suresh Dean of Engineering Ford Professor of Engineering, MIT Credit: Justin Knight