Robots are great at what they do — if the job is dull and predictable. Throw in the unexpected, and robots can do the unpredictable.

The task of programming a robot’s brain for the real world can be gnarly, says Josh Bongard, an assistant professor in the University of Vermont College of Engineering and Mathematical Sciences. “It turns out that building a robot, and programming it to do something interesting is a very non-intuitive process, and it’s a difficult one for humans to do well.”

The real world, he says, “is quite messy.”

Robots, in the jargon, need “adaptive behavior” to accommodate changing circumstances, says Bongard. When programming a free-roaming robot, “We are not likely to factor in a lighting change or people moving in and out of the field of view.”

It’s not clear how animals or people make adaptations, Bongard says, “and so it’s difficult to program a robot to do them.”

Robots: Are they alive?

Bongard, like a number of roboticists, is turning to biology for answers. But he does not want to emulate living structures. Instead, he wants to use evolution to craft robot control.

The process is akin to the “artificial selection” that helped lay the foundation for the science of evolution. Darwin, after all, wrote about how animal breeders had changed their livestock by repeatedly breeding the best animals and eating the rest.

In January, 2011, Bongard reported that he had taught four-legged, digital robots to stand and run toward a light source, by grading their control software on its ability to meet those goals.

Adaptive behavior was necessary, he says, because the light source could appear anywhere, or even take evasive action, “so the robot can’t just move its legs blindly every time.”

The robots had five seconds to do or die, and their first movements were grotesque because the control software initially moved their body parts at random. After every attempt, the control programs were graded by their ability to walk, stay upright and approach the light.

It’s brutal. More than 100 million failed programs went to the virtual graveyard in the name of science, Bongard says. The programs that showed some promise were retained, randomly varied and re-tested.

The same process is found in nature, where successful genes that face random mutation are re-tested by tomorrow’s environment.

Like the average biological mutation, the mutated robot software usually failed. But over a year of supercomputer time — equivalent to 1,000 years on a desktop computer — the winning programs evolved the ability to walk toward the light.

Weird winners

Considering the amount of trial and error, that was a satisfying but not necessarily surprising result. But here’s something to chew on. Bongard found that robots “born” with four legs had a handicap. During repeated simulations, the robots that started as snakes and developed legs during the five-second experiment were much quicker to learn the task.

You might guess — we would have — that the quick learning would have occurred in robots with full-time four-leg drive, given their longer experience with legged locomotion, but Bongard says the leg-free starters benefited by chunking the challenge: a) learn to approach the light, and b) learn to walk.

These robots “could evolve the ability to go from point A to point B while they still look like a snake, they don’t have to worry about balance, because they are already on the ground,” Bongard says. “Once evolution has figured out how to move toward the light, the ability to move on four legs could evolve.”

Meanwhile, the four-legged counterparts may still be flipping, flopping and floundering (Note to self: sell soul as political hit-man if science-writing gig crash-burns?) “The robots that had to stand upright would fall over, and it took evolution a long time to master balance,” Bongard says.

The approach — take the winners and vary them for a retest — resembles directed chemical evolution, which aims to create a better antibiotic by modifying and retesting molecules that show some ability to kill bacteria. “It’s basically the same idea,” says Bongard, “but instead of a candidate drug, we have virtual robots, and instead of selecting for … resistance to disease, they are selected for the ability to get to the light.”

Robots resemble rodents?

As a final exam for the digital robots, Bongard tested their balance with a blast of air. Although the leg-less robots “had evolved into legged robots that looked exactly like the other species, they were better able to run around under simulated windy conditions,” Bongard reports.

Bongard is first to acknowledge that he is “stealing from biology to help us build better robots,” but says, “the more interesting question is what this tells us about biological evolution. This recent work suggests that robots that change their bodies gain an adaptive advantage … and you see the same radical changes in body plan in nature: in insects, reptiles and in humans as they develop from infant to adult.”

If you’ve hung around a big-city park, you may think that pigeons are countless — or uncountable. But according to scientists from New Zealand, pigeons now join the short list of animals that can count — or at least, can places images containing two countable items in numerical order.

It’s blue news for those who think only humans deserve human capacities. From empathy and altruism to murder and war, animals seem to have caught on to some of our best — and worst — tricks.

Now Damian Scarf, a post-doctoral researcher at the University of Otago, with his colleagues, has taught three pigeons to order pairs of numbers in the range from one through nine.

This is not exactly counting, but it certainly is a sign of numerical awareness in birds.

More important, the researchers have taught these retired racing pigeons the concept of smaller-to-larger, Scarf says. “Previously, this number abstraction was only known in primates, and now we have shown that it is not unique to primates.”

Serious screen-time serves science

The experiment began with a year-long training period, during which the birds were shown pairs of images, each containing one, two or three countable items. If the birds pecked at both images, smaller number first, they were rewarded with some wheat. (Although the images never contained a numeral, we refer to the “number” they contain for brevity.)

To prevent the birds from focusing on color, shape or other non-numerical details, the images showed a range of items, so that the only correct answer would reflect their number rather than other distinctions.

“The training time reflects how difficult it is for them to abstract,” Scarf says. “It’s such a foreign situation, number is not the first port of call when presented with a stimulus to discriminate. That’s why we had so many shapes, colors, surface areas.”

Even if the birds originally made their judgments based on color, “we pushed them to use a different strategy, to break away from that. Number is not the default discrimination mechanism” for pigeons, says Scarf, who worked under advisor Michael Colombo of Otago.

A genius for abstraction?

This does not mean that the birds are counting, says Scarf. “It’s more a fuzzy representation in the brain of what ‘three’ is. We can apply this verbal label to three, but they cannot. Pigeons, and animals in general, don’t have a definite idea of a number, that’s why they don’t perform perfectly, and why we see the distance effect.”

When the numbers on the test pair are further apart, Scarf found, “the fuzziness overlaps a little less.”

A greater distance between the numbers produced a quicker response and greater accuracy. For adjacent numbers, like four and five, the birds scored about 66 percent accuracy, compared to more than 95 percent for numbers separated by at least six. Once the difference rose to at least three, the pigeons did as well as monkeys in a path-breaking 1998 study that opened the field of numerical “thinking” in animals.

Scarf stresses that the birds were not just regurgitating what they had learned, but were learning numerical rules. “The goal was to find out whether they could acquire an abstract rule. We were just training for one through three, but they learned some flexibility, an abstract, ascending rule for ordering numbers” that would apply to other numbers on the screen.

Rooted in evolution, but where?

Being able to recognize that one thing is more numerous than another could help an animal survive, Scarf says. “When food is available in multiple places, an animal has to develop an optimal strategy for figuring out where the most food is, and I think we have subverted that capacity for this task.”

Where this capacity arose is anybody’s guess at this point. The evolutionary lineage of mammals and birds divided about 300 million year ago, Scarf says. “If this derived from a common ancestor, it’s very old. It’s also possible that primates and birds have evolved this independently.”

“I do think it’s important, just as our study of mirror self-recognition in monkeys, from the fundamental standpoint of how these abilities come about,” says Luis Populin, a professor of anatomy at the University of Wisconsin-Madison, who has found that, under certain conditions, monkeys can recognize themselves in a mirror. “It’s very nice and is yet another step toward understanding how our cognitive functions develop.”

You have to hand it to these birds, which have set a new standard for avian aptitude. “The new part is the idea that this abstraction of numbers is not tied to training,” says Scarf. “Most numerical tests with animals involve training and testing with the same numbers, but we were training with a limited set of numbers and testing them with numbers outside the range. They learned an abstract rule, and that’s what makes this study unique.”

What causes your brain to switch from the quiet focus needed to read (or write) these words to the frantic, goggle-eyed arousal needed to confront a frothing dog or rabid boss?

That hyper condition, popularly called the fight-or-flight response, is a hormonally inflicted surge of stress that puts all systems on alert, raises the heart rate and blood pressure, and shifts blood from the gut to the muscles.

This is not when you want to be translating Latin or solving equations, but fight-or-flight certainly fulfills its evolutionary role of allowing the body and brain to survive threatening circumstances.

After the transition, the brain regulates attention differently: A person studying Japanese woodcuts is unlikely to notice someone prowling on the other side of the art library. A person cranked up on stress hormones is unlikely to miss the lurker.

Neuroscientists long ago fingered two “stress” hormones — cortisol and noradrenaline — as playing key roles in fight-or-flight and today, a study in Science helps confirm that noradrenaline, not cortisol, triggers the transition to a different level of attention. “Many people thought cortisol would have an effect on the attention process in the early phase, but our study shows cortisol probably is not as important” as noradrenaline, says first author Erno Hermans, of the Donders Institute for Brain, Cognition and Behaviour at Radboud University Nijmegen Medical Center in Holland.

Putting the stress on stress

Image: Irréversible

According to some film critics, Irréversible was one of the most disturbing films of 2002. No wonder it stressed-out the study subjects!

To study the mental effects of stress, Hermans and colleagues put 80 subjects in a magnetic resonance imager and tracked the usage of oxygen in the brain to show which structures were active at any moment. Then the subjects watched parts of a French movie containing what Hermans calls “particularly horrific” scenes of violence.

The scans revealed changes in what’s called the salience network, which “is active in a general state of hyper-arousal, vigilance,” Hermans says. “It scans the environment for things that might be important, and allows you to redirect your attention.” The result is not just a change of focus, “but a switch to a state where a change of your focus becomes more likely.”

To confirm that the violent movie clip was triggering the stress response, the researchers measured heart rate and chemicals in the saliva.

Counting on cortisol

Long-term stress can lead to many problems, including the disabling post-traumatic stress disorder, and cortisol, which makes memories more vivid and plays a major role in the constant arousal and intrusive memories of PTSD, has long been considered a major player in stress in general.

“Stress research in humans has been very focused on cortisol for very good reason,” says Hermans, “as it’s linked to a number of very important features of stress in the body and also in the brain.”

In a second phase of the experiment, Hermans and his colleagues used drugs to block either cortisol or noradrenaline. Blocking cortisol did not prevent the changes in brain networks, but blocking noradrenaline did. “Because blocking noradrenaline results in a reduction in the salience network, this shows that noradrenaline is important for this reorganization of the brain,” Hermans says.

Courtesy Erno Hermans

This animation shows which areas of the brain are switched on by a stressful situation.

Stress or distress?

The new study helps explain our world, says Christopher Coe, a professor of psychology at the University of Wisconsin-Madison and an expert in cortisol and stress. “As we all have subjectively experienced, a fearful stimulus can exert a galvanizing influence on us. It can reorient our attention and, when sufficiently provocative, make us feel more alert, energized and focused. This change in state is facilitated by the type of coordinated brain reaction described in this Science paper. We and our brains are mobilized in order to better analyze the situation, to quickly interpret and utilize incoming information … and to respond adaptively.”

Coe adds that although “it is reasonable to conclude” that cortisol is not initiating the change in salience, “nevertheless, because of cortisol’s widespread effects and potency, if its release into the blood stream is sustained, it may ultimately exert a more protracted effect on both the brain and other physiological functions.”

Changes in the mode of attention are a fact of life, Hermans says. “We are really selective about accepting information while doing a focused task,” but a threat “requires a switch so your brain can respond to significant things in the surroundings. The brain becomes more responsive to stimuli, the eyes are wide open, the pupils become larger, everything is focused on having more sensory intake.”

– David J. Tenenbaum

She asks if she’s overweight, and you wait half-a-second before responding, “Of course not, dear! I’ve just been noticing how slim you look these days.”

Any well-schooled husband knows the pitfalls of faltering in this “marital duet.”

Photo courtesy Eric Fortune and Melissa Coleman.
Video courtesy Science/AAAS

This image is an adult male plain-tailed wren.
Watch the video explaining how the bird-songs
study worked — with ultra-cool bird songs.

And now, we find a similar phenomenon among a singing duet by plain-tailed wrens, natives of the cloud forest in Ecuador.

Pairs of these wrens engage in a high-speed duet that relies on perfect timing: She utters a call, and if he chimes in on cue, she sings her part, and the duet continues.

If he’s late or silent, she is slow to resume the song.

This is cooperative behavior, but close examination also reveals a new mental phenomenon, says Eric Fortune, an associate professor of psychological and brain sciences at Johns Hopkins University. Fortune, first author of a study of the wrens that appears today, says his research “indicates that the full mental representation of the song exists in both birds, even though each one contributes only half of the song.”

The study looked at the interaction between the hearing and motor circuits in the brain via a concept called “mirror neurons.” Discovered in 1983 by Dan Margoliash of the University of Chicago, mirror neurons were “a key discovery that has profoundly shaped our thinking,” Fortune says. “He showed that an area of the brain used to control song responded only when the bird heard a playback of its own song, but not of any other bird’s song.”

Zina Deretsky,
National Science Foundation

Takes two to tango: The song of the plain-tailed
wren is a his-and-hers production.

These nerve cells, since seen in people, other primates and birds, are now called mirror neurons. In simple terms, mirror neurons allow a bird that hears its own song to “imagine” singing that song.

Brainiest birds?

In the new study, however, the mirror response occurs when an individual in a pair hears both birds singing — a sound that each bird cannot produce by itself.

In 2006, scientists identified the plain-tailed wren’s song as a two-part composition that required cues from both partners. “When we heard about these wrens, where one-half of the song is produced by the female, and the other half by the male, we thought, ‘This is amazing. Here’s a song this bird has learned completely in the sensory part of the brain, but it has only half of the motor program.’”

How could this work?

To unravel the sensory-motor linkage, Fortune, with Gregory Ball of Johns Hopkins and Melissa Coleman of Claremont McKenna College, recorded pairs of plain-tailed wrens, manipulated the songs in various ways, and then played them back.

They found that the birds not only sang in pairs, but sometimes also sang solo, making the same calls it would otherwise contribute to the duet, but with altered timing. They found that when a male flubbed his lines, the female might continue to sing, but with a measurable delay. “She’s waiting for him, then gives up and sings anyway,” Fortune says.

The birds were basing their behavior on what they heard — not very surprising. But the fascinating part emerged from the fact that they were engaged in a truly cooperative, back-and-forth behavior that was deeply embedded in the mirror neurons.

Both images courtesy Eric Fortune and Melissa Coleman

Like many field worker, Fortune had to make do with local material, as
shown in this laboratory. Rollover for a look at their solar and
hydro-powered neurophysiological rig, featuring a home-made version
of a $7,000 vibration damper.

Such cooperation, also evinced by dancers and musical ensembles, requires each party to know its own part, but the brain studies showed that they knew much more than that, says Fortune, who is also a visiting professor at Catholic University in Quito, Ecuador. “Both birds had very similar patterns of activity. The neurons responded most strongly to the combined song, not to their own part. The brain knows that they were trying to do this together.”

Got my eye (and ear) on you, mister!

Although Fortune says the songs are probably used to defend territory, he suspects she is also checking him out, gauging his evolutionary fitness, much as female birds rate a fellow’s feathers. “The female is testing the male’s ability to cooperate,” Fortune says. “She produces a long song, and the male has to work hard to insert his syllables at exactly the right time.”

Louis Vest

People also learn cooperatively. Do these
tango dancers hold a representation of the
complete dance in their heads, or is this just
another example of sexual selection at work?

These wrens, he says, “are wired to cooperate. There is a set of rules and the male’s job is to respond rapidly and accurately to the female’s challenge.”

It’s not just feathery guys that fail to respond on cue, and the evolutionary significance could extend far beyond birds. “This happens a lot in people,” Fortune speculates. “Why do women get annoyed when you forget their birthday? They are challenging your neural circuitry. It’s not like flexing your muscles; they are probing your brain. That’s a stronger cue for sexual selection.”

Bringing it back to birds, Fortune says, “It’s most surprising that these animals have a memory of their cooperative behavior in the brain, which includes the performance of another animal; this had not been shown before on a neurological basis. You can take their own half of the song, and play it back, and the motor neurons fire,” but the response is much more powerful when the bird hears the full, two-part song.

— David J. Tenenbaum

It’s an old, grim axiom of neuroscience: After an injury, the nerves in your hand, arm or leg may grow back, but neurons in the brain and the spinal cord will not.

Part of the reason is a molecule called proteoglycan — a biological insulation that separates tissues. During gestation, for example, proteoglycans prevent the placenta from growing too deeply into the uterus. “The proteoglycan molecule has been known as nature’s own barrier molecule,” says Jerry Silver, a professor of neuroscience at Case Western Reserve University.

Proteoglycan strongly inhibits the growth and movement of cells, and explains why cartilage has neither nerves nor a blood supply.

In the spinal cord, proteoglycan serves to lock the nerves into position, preventing unwanted growth. Unfortunately, when the spinal cord is injured, a new burst of proteoglycan “walls off the injury site, but also blocks nerve regeneration,” says Silver.

A bacterial balm?

Now, using an enzyme made by a deadly bacterium, Silver and his colleagues have learned to restore normal breathing in rats with a damaged spinal cord. The study, published in Nature yesterday, shows that a combination of grafting and a proteoglycan-eating enzyme called chondroitinase may sidestep the proteoglycan’s growth-deadening effect – and open a path to the holy Grail of partial repair to the spinal cord.

As scientists continue trying to rebuild the spinal cord with stem cells, the new study shows an alternative route to healing.

The technique is rooted in evolution, Silver says. “Proteoglycans are boundary molecules that have evolved over millennia. One bacterium, proteus vulgaris knows that, and has figured out how to release this enzyme to eat through our defenses.”

That ability allows the bacterium to cause deadly septic shock.

What they did

To demonstrate that grafts plus chondroitinase enzyme could restore function, Warren Alilain, the paper’s first author:

It’s important to realize that when the graft was first connected to the spinal cord, it no longer contained neurons. The graft serves as a tunnel lined with cells that supply growth factors and nutrients to nerves that are growing from the upper part of the spinal cord.

The wait for recovery seemed interminable, Silver admits. “Warren Alilain, my genius post-doc, had given up, he saw no substantial return of function at two months … but at 10 weeks, he ran into my office, he saw some activity coming back.”

After another two weeks, the disconnected nerves had regained at least 80 percent of their normal electrical output in 9 of the 11 animals that got grafts and enzyme.

Spinal cord: A brainy organ?

Just getting neurons to grow in the central nervous system is not enough: the nerves must connect to the motor nerves that activate the diaphragm. After all, the spinal cord contains more than ten thousand nerve cells, and neurosurgeons cannot hope to connect them individually; and instead want to coax a process of self-connection.

The coaxing worked: among about 3,000 spinal-cord neurons that grew through the graft tube, 400 to 500 linked to the neurons that used to control the diaphragm. In other words, the growing neurons seem to be “looking” for precisely those nerve cells that must be reconnected so the diaphragm can return to work. The spinal cord, Silver says, is “smart, and that’s encouraging news. I am more optimistic than I have ever been: The gain in function is really high.”

Yet despite the crying need for better treatments for spinal cord injury, at best this technique will not be available for some years.

The technique seems unlikely to restore the complicated connections needed for walking or typing, but severe paralysis would be eased just by activating a single muscle, Silver says. Bladder control is a major issue after a lower spinal injury, and many quadriplegics require a ventilator, which can fail or cause deadly infection. Learning to reactivate the diaphragm – and to breathe — could produce huge gains in quality of life.

Courtesy Jerry Silver, Case Western Reserve University

Enzyme and graft treatment each restored nerve function in most of the rats, but the best response came from a combined treatment.

“This is an interesting study,” says Daniel Resnick, associate professor of neurosurgery at University of Wisconsin-Madison. “It’s a fairly vigorous model, measuring the diaphragm motion is a fairly clean measure.” Not only did the grafting process restore fairly normal breathing, but when the researchers cut the nerve graft at the end of the experiment, that removed the improvement in breathing. “That’s pretty convincing evidence that you have got neurons growing through the graft.”

The repair was not a true replacement for the spinal cord, Resnick adds. “They are not regenerating across the injury itself, but are by-passing it, going directly to the muscle. It’s not a cure for a spinal cord injury, but is a means to promote focal re-enervation, but for a high spinal cord injury, if you could get them off a ventilator, that is a big deal.”

Silver says the data also suggest that the bacterial enzyme may in some cases be effective enough to avoid grafting. “I am enthusiastic about using just the enzyme, in spinal cord injury and stroke rehabilitation,” Silver says. “Given the success to date – in our lab and others — it’s simple to do and seems to carry almost no risk — it’s just putting in a shot of enzyme as a way of stimulating neural plasticity.”

– David J. Tenenbaum

As deadly American drones work the skies over Afghanistan and Pakistan, we got to wondering how similar remote-control approaches are contributing to science. In science, as in war, leaving the staff behind can slash costs and allow sustained exploration of no-go zones.

Part of the story is propulsion: New science vehicles can travel long distances through the ocean and atmosphere with minimum energy. Brains-on-board also matter: Computers enable these super-sensors to make decisions and work long stretches with little or no back-seat driving.

The result is a lot of science per gallon.

Although the vehicles we’ll look at have scientific purposes, they get major financial and technical support from the Department of Defense, proving that military and peaceful pursuits are inextricably linked in extreme environments.

If you dig the deep ocean, WHOI — the Woods Hole Oceanographic Institution on Cape Cod — is a good place to be. The renowned saltwater scientific outfit has a new, deep-water explorer that works without a lifeline.

Meet Sentry, which can take photos and make chemical and geophysical measurements down to 4,500 meters depth, and has worked two high-profile environmental issues: global warming through methane release, and BP’s Deepwater disaster.

Sentry has been used to look for “cold seeps,” regions of the seafloor that release large amounts of methane, says Chris German, WHOI’s chief scientist for deep submergence. “Cold seeps are like the overlooked younger sisters of hydrothermal vents,” the “black smokers” that release superheated fluids and anchor unique ecosystems at the sea floor, usually in mid-ocean.

Cold seeps are located closer to the continents, and “are not as spectacular thermally or geologically, but they do have some of the same chemistry,” says German, “and a lot of the same kinds of animals, even the exact same species.” Cold seeps may explain the distribution of deep-sea organisms around the ocean, he adds. “We want to understand … whether animals are using these locations as stepping stones.”

Most cold seeps were found by accident, but German thought Sentry could detect subtle chemical clues, and last October, he got to test that idea at an underwater landslide off the coast of Norway. The landslide had released pressure on a material called methane hydrate, and a large amount of methane was bubbling from the seafloor mud, creating a “mud volcano.”

Methane is a much more powerful greenhouse gas than carbon dioxide, and given the staggering amount of methane held in methane hydrates, such releases could create a nightmare feedback: warming releases methane, which traps more heat, causing more warming that releases more methane.

Getting engulfed

By prowling around the known cold seep near Norway, German confirmed the detection hypothesis.

Then, the day after Sentry returned to Woods Hole, a real-world opportunity appeared for the new technique.

Biologist Charles Fisher at Penn State was about to embark on a mission into the aftermath of BP’s blowout in the Gulf of Mexico, and he wanted help locating a coral patch to compare to another he’d already located 1,200 meters deep, 11 kilometers southwest of the blowout.

That coral was coated with a brown goop that looked suspiciously like crude oil. Could Sentry locate, for long-term comparison purposes, a similar coral outside the oil plume?

Fisher was part of a National Science Foundation-sponsored “rapid response” cruise to the Gulf, but German was still unpacking. “We’d have two weeks to turn around and get going, and I went to our guys Monday morning and asked, ‘Can you do this?’”

The maintenance crew figured out who would miss what weekend, and they agreed to do it, German says.

Cold seeps and deepwater coral in the Gulf of Mexico are linked, German explains, because the coral live on bare rock, which is often carbonate, and carbonate rock forms at cold seeps when methane is oxidized into carbon dioxide. “So beneath every healthy deep coral, is an active or historic cold seep.”

Suddenly, a theoretically interesting search technique became relevant to the biggest American oil spill in a century.

“Flying” with a map

Based on oil-industry data about the sea bottom, Sentry visited one location southeast of the Macondo well and found no coral. But at the second location, German says, “We hit pay dirt. We flew backward and forward, and found an active cold seep and evidence for tube worms, mussels and coral.”

Ocean-floor research seldom moves so fast, German says, and within hours, he was one of three people to visit the spot in Alvin. “In 36 hours, we went from nothing other than a hunch, to having a topographic map and photos,” German says. “We dove to the sea floor, and there was no mysterious driving around in the dark. Within 15 minutes, we drove to the site because we had a perfect map of where to go.”

In fact, German was holding a fresh, glossy photo of the target, taken less than two days previously.

Sub-terra cognita? Not!

And so is the ocean bottom, as people often say, still less familiar than the far side of the moon? German insists that it still is, despite years of research and an increasingly capable flotilla of deep-sea ships. “In December, in the Gulf, I could see at least 10 to 20 oil rigs… but I’m pretty sure, driving across that seafloor a couple of hours offshore from the United States, that nobody ever laid eyes on it before.”

A recent survey of marine biodiversity shows a chain of ignorance stretching across the Pacific, located near regions of extremely high biodiversity near the Philippines and Australia, German says. “In many of those locations, they’re 300 miles square, there have been fewer than 50 biological measurements in the history of the ocean. This is a chain across the South Pacific ocean, the single biggest contiguous ecosystem on the planet, and it has not been studied.”

And that’s the rule, not the exception, German says. “Close to one-half of the planet is at least 3,000 meters deep, and it’s much further away [and deeper] than the Gulf. From satellite altimetry we have an idea where the bumps are on the seabed, but we don’t know what’s going on; we have a vanishingly small idea.”

Deep water may be the sexiest place in oceanography, but long-term studies are also difficult and expensive in shallow waters, especially if they are remote, icy, stormy, or all three. Propellers, the standard way of moving through water, require a lot of energy and quickly drain batteries on artificial fish.

Gliding — think of soaring like a hawk as opposed to flapping like a sparrow — is a much more conservative approach.

And gliding is the MO of Seaglider, a project built by the University of Washington with money from the Office of Naval Research and the National Science Foundation. Using battery power, the glider alters its buoyancy, causing it to rise or fall through the water. By altering its center of gravity and adjusting its fins, the metal fish moves horizontally with minimal amounts of electric current.

How minimal? In 2009, a Seaglider traveled a record 3,050 miles through the North Pacific during a 9-month journey, without the caress of a human hand or an electric transfusion.

Costing “only” about $100,000 apiece, about 60 gliders are working around the globe, says Craig Lee, a principal oceanographer at UW’s Applied Physics Laboratory, recording basics like temperature, salinity, dissolved oxygen and optical characteristics of its surroundings.

In 2008, south of Iceland, gliders and floats studied carbon uptake by phytoplankton — floating plants that bloom in spring and play a major role in the global carbon cycle. The goal was to follow “parcels” of water during the entire bloom — which ends after some weeks when plankton are eaten or sink in the water. Both processes can remove carbon dioxide from the atmosphere for long-term storage, and therefore have implications for global warming.

“We were trying to learn what drives the carbon flow,” says Lee. “Nobody had done this before: the Seagliders and the buoys had the persistence, the ability to be there for the entire duration of the bloom. You would have to schedule a ship one year ahead, and … if you got there on time, it would be too expensive to keep the ship out there for the whole bloom.”

If ice is nice, under ice is nicer!

In 2009, a Seaglider spent 51 days in Davis Strait, the frigid water separating Greenland and Baffin Island, traveling more than 450 miles under the ice. The Strait is a chief source of melt-water from the frozen Arctic Ocean.

Climatologists worry that a rush of cold, fresh water through the Strait could alter the warm Gulf Stream and freeze Northern Europe.

Getting measurements from Davis Strait is expensive and dangerous, especially considering how much of it is under ice. But the Seaglider did just fine, says Lee. “This was very exciting, that ability to stay out there for a long time, and the ability to get to places that otherwise would be difficult. In winter in the North Atlantic, nobody wants to be there…”

The fish navigated under the ice using five anchored sonar beacons that created an undersea version of GPS, Lee says. Ten times, using its software, the glider found holes in the ice, poked its nose through them, and phoned home via satellite telephone. “It tries to sense ice by looking at the temperature of the water,” says Lee. “It emits a ping and tries determine whether ice is overhead, and it has a climate map that tells it, for a given position at a given time, is ice likely to be overhead? Using all that information, it decides whether to surface.”

During those famous North Atlantic storms, “It just keeps working, it does just fine, continues to navigate, continues to report. We’ve been in 40-foot seas, with 60- to 80-knot winds, and everybody’s happy, although it takes a little longer to get a phone call through.”

The glider carries a quarter for the phone call, but no Dramamine…

A fruit of the military’s desire to see everything from a safe vantage, Global Hawk is a secretive, high-flying, pilot-free jet that can fly at 60,000 feet for 30 hours, non-stop.

For its occasional forays into peaceful work, Global Hawk carries a large cargo of scientific instruments that can monitor light, pollution, ozone, water vapor, weather, clouds, incoming and outgoing radiation, even particles smaller than 1 millionth of a meter across.

The Hawk, which flew scientific missions from NASA’s Dryden Flight Research Center in California in April, 2010, can also be used for earth observation, such as tracking algal blooms in the ocean, vegetation on land, and various resource issues.

Hawk has tracked pollution from Asia above the North Pacific as it moves toward North America and looked at large-scale atmospheric circulation, which influences weather and the distribution of radiation-blocking high-altitude ozone.

We could not get through to a source at the National Oceanic and Atmospheric Administration, which plays a role in Hawk’s science, but we grabbed a press release issued after Hawk’s first environmental flight.

According to Paul Newman, an atmospheric scientist from NASA, “The Global Hawk is a revolutionary aircraft for science because of its enormous range and endurance. No other science platform provides this much range and time to sample rapidly evolving atmospheric phenomena. This mission is our first opportunity to demonstrate the unique capabilities of this plane, while gathering atmospheric data in a region that is poorly sampled.”

In their quest for data on the deep, scientists have gotten a trickle of info from sensors attached to deep-diving marine mammals. In November, 2009, the Scripps Institution of Oceanography launched SOLO TREC (Sounding Oceanographic Lagrangrian Observer Thermal RECharging vehicles; glad you asked?), a bobber that can sink 500 meters into the ocean, then return to the surface to report via satellite to scientists who may prefer sipping lattes at a Java Joint to crowding the rail on a topsy-turvy research ship.

Let’s call this Solo, and let’s agree that it’s a strange vessel. Solo can adjust its buoyancy, but lacks propellers and cannot drive laterally, so its location is at the mercy of the currents.

Solo records basic ocean conditions, but the real accomplishment is proving that its power system needs no recharging and could, theoretically, operate more or less forever – or at least until it breaks or barnacles or plants foul the fish up and slow it down.

Solo had already completed 300 dives by March, 2010, and although it sounds like a perpetual motion machine, it actually sucks its energy from the ocean as it rises toward the surface:

According to Yi Chao of the Jet Propulsion Lab, a Solo principal investigator, “This technology to harvest energy from the ocean will have huge implications for how we can measure and monitor the ocean and its influence on climate.”

Funded by NASA and the U.S. Navy, Solo’s technology is also obviously useful for monitoring animals and the movement of ships and submarines.

It’s been a bad month for brains, and particularly for traumatic brain injury:

In national security, the national sport, and on the national highways, brains are getting banged. Some estimates say 5 million Americans have some permanent damage from a traumatic brain injury which is due to impact rather than bleeding or loss of blood flow — the causes of stroke.

2006, Centers for Disease Control

The causes of brain injuries in the United States during six years.

Eighty two years after dementia pugilistica was diagnosed in boxers, we should not be surprised that impacts in war, car accidents and high-intensity sports are taking a toll on the thinking organ, says Robert John Dempsey, chair of neurological surgery at the University of Wisconsin-Madison. “As we have improved our ability to image brains, and to diagnose dysfunction to include cognition, we have discovered deficits that may have been obvious to family members and physicians.”

Dempsey says autopsies of people who have had multiple concussions, “suggest there was a permanent injury, a disruption of axons and loss of brain substance.”

The brain shrinkage seen in autopsies of former football players after multiple concussions is called chronic traumatic encephalopathy. This disturbing shrinkage of the brain is linked to severe, deadly brain abnormalities, including memory loss, confusion, paranoia, depression, dementia and Parkinsonism.

Images: WBUR, Boston’s NPR Station

Chronic traumatic encephalopathy is marked by concentrations of tau protein, shown here as brown spots. More tau equals more damage. Left: a normal, 65-year-old brain. Right: The brain of former NFL linebacker John Grimsley, who died of a gunshot at age 45 after nine concussions.

Striking younger

After the growing concern about traumatic brain injury among middle-aged football veterans who were paid to endure thousands of blows to the head, the discovery of such damage in the 21-year-old Penn player raised questions for young athletes and their parents, as Robert Stern, a professor of neurology at Boston University, explained to the New York Times. “We don’t know if it’s a specific age, we don’t know if it’s a cumulative number of years of exposure to head trauma, we don’t know what combination of hits to the head set this disease in motion. These are critical issues that need to be answered in order to help guide any dramatic policy changes and individual decisions down the road.”

Photo: Jayme Pastoric/U.S. Navy

A 2007 study by University of North Carolina scientists suggests that concussions can follow almost any type of head impact in football, regardless of its strength and location.

A changed picture of brain injury

Until recently, impact was considered less serious than contusions — brain injuries with obvious damage like bleeding and swelling, says Dempsey. “It was considered possible you would not make a full recovery [of movement, speech and vision] from a contusion.”

Until a decade or two ago, Dempsey says, “concussion without a structural disruption was considered a source of transient loss of function, consciousness, confusion, but one where recovery was felt to be complete.”

But when the brains of former pro football players were examined after death, massive damage was blamed for serious problems like depression, confusion and movement disorders.

Today, concussion and contusion seem less like distinct things and more like stages of a continuum of brain injury, Dempsey says. “There is a wave of increasing realization that any injury to the brain should be taken seriously, and that repeated minor injury is cumulative.”

Searching for succor

What can be done in the face of a wave of traumatic brain injuries? The obvious measure, protection and prevention, seems, well, obvious. But ironically, better protection is part of the reason why so many soldiers are returning with brain injuries — body and vehicle armor keeps them alive without always protecting the head.

So what is medicine learning about treating traumatic brain injury? Nobody has a recipe for repairing damage once it’s complete — but traumatic brain injury is not always sudden, and researchers are hot on the trail of techniques that can interrupt the damage process and preserve brain tissue and function.

Photo: 2008, Kamryn Jaroszewski/U.S. Navy

Hospital corpsman Anthony Thompson gets a medal while being treated for a traumatic brain injury caused by an improvised bomb in Iraq.

What do some promising recent studies say about halting or treating traumatic brain injury in animals or people?

Glucose — a sweet solution?

Doctors have long worried that an injured brain often contains too much energy in the form of blood sugar, says David Hovda, a professor of neurosurgery and director of Brain Injury Research Center at the University of California at Los Angeles. In stroke victims, a high level glucose in the blood is known to be “really bad because it promotes more damage, and we thought the same thing was true in traumatic brain injuries, so the standard of care became to reduce plasma glucose down to normal.”

Photo: biblicone

Car accidents account for 20 percent of traumatic brain injuries.

But Hovda questions the wisdom of reducing fuel to the brain after trauma. “In animal studies, we began to manipulate serum glucose and found that if we dropped it, brain cells began to show all the signs of being killed by not having enough fuel. When we began to use the same sort of measures in human patients, we discovered the same thing: If we deprive the brain of more glucose, brain cells start to die.”

Hovda says his studies in rodents suggest the brain has complicated fuel needs during recovery. “We believe, but don’t know, that the fuel characteristics are also going to be different, given age, gender, stage of recovery and perhaps the type of injury.”

Photo: U.S. Air Force Tech. Sgt. Cecilio M. Ricardo Jr.

With improved safety gear, more U.S. soldiers are surviving attacks, but then must live with brain injuries.

Hovda says UCLA is in the second year of a five-year project to test the optimum level of plasma glucose after a traumatic brain injury in 20 to 25 patients. Beyond glucose, he will also test other fuels that might support recovery while reducing harm in other parts of the brain. “We’re going to see if we can change their outcome; it’s an efficacy trial, and it’s funded by National Institutes of Health for $5 million.”

If the new approach has promise, Hovda hopes to start a larger trial that would treat traumatic brain injury patients with a variety of intravenous fuels.

Supreme supplements?

Brain injuries can affect small structures like the hippocampus, which is critical to memory and other higher thought processes. In a mouse model of brain injury, Akiva Cohen, an associate professor of pediatrics and neurology at the University of Pennsylvania School of Medicine, has found that dietary supplements may help the hippocampus work after injury.

“We have shown in an animal model that dietary intervention can restore a proper balance of neurochemicals in the injured part of the brain, and simultaneously improves cognitive performance,” says Cohen, who is also a neuroscientist at Children’s Hospital of Philadelphia.

Photo: Buckeye Surgeon

A 2007 study found that football impacts could reach more than 100 Gs (100 times the acceleration of gravity). That’s equivalent to slamming against a brick wall at 25 mph.

Like many biological processes, the transmission of nerve impulses is tightly controlled. One major neurotransmitter, glutamate, excites neurons, while another, GABA, calms them. An imbalance in these compounds can cause the hippocampus to malfunction, Cohen says.

The imbalance has been concealed because the hippocampus has two pools of the neurotransmitters, and only the smaller pools at synapses (where two brain cells make contact) appear to be altered after injury.

If you study the hippocampus as a whole, Cohen says, “you can’t see the change in smaller, synaptic pool because it’s concealed by a larger pool of the neurotransmitters used for other cellular functions.”

In a study with mice, Cohen found that feeding the mice with branched chain amino acids that are precursors — raw materials — for the two transmitters returned their level at the synapses to normal.

“Once we saw that through feeding, we could bring the concentration back to the level of the control animal, we asked if we could bring back memory, and memory did come back to normal,” Cohen told us. “Memory is a hippocampus-dependent task, and it was only restored because we restored precursors to those two neurotransmitters.”

The team performed electrical tests on brain slices and got normal results if the amino-acid supplements were present.

Even though the supplements “are not really fixing the problem — there are still things wrong in the pathway — we are synthesizing enough new glutamate, and subsequently enough GABA, to restore the synaptic pools, allowing the hippocampus function to return to normal,” Cohen says.

As Cohen searches for funding for a human trial, he notes that the mice received leucine, isoleucine and valine. “These are essential amino acids, you have to eat them, but if you don’t need them, you will just get rid of them. There are athletes who take these supplements for strength training.”

A visionary idea

It sounds too good to be true, but a Michigan research group has published a study showing that simple corrective lenses can reduce headache, neck ache, and dizziness — common symptoms of traumatic brain injury. “We came into this backward,” says Mark Rosner, an adjunct clinical instructor in emergency medicine at the University of Michigan, who worked with optometrists who were treating the same symptoms in people without brain injury.

Image: Jmh649

A CT scan of the head after a traumatic brain injury. Arrow shows a damaged, empty space.

“We found that the post-concussion visual symptoms pretty much crossed over with the symptoms we were already treating in headachy, dizzy people,” Rosner says.

The problem seems to be rooted in a brain malfunction that prevents the eyes from converging, so one eye aims slightly above or below the other. The misalignment can cause words to bounce around on the page.

The working hypothesis, Rosner says, is that “There’s a faulty signal from the brain that is trying to vertically diverge the eyes, and that makes them double the image, but other parts of the brain say ‘You can’t do that! You are giving us double imagery!’”

The resulting tug of war between the muscles that raises and lower the eyes causes tension and headaches, Rosner says.

The divergence is subtle, but detectable, and in many cases, it can be cured with prismatic eyeglasses, Rosner contends. Many patients even notice their headache and neck ache start to subside during a 20-minute trial period in the office.

Like regular eyeglasses, the lenses are used continually; the goal is not to retrain the brain but to correct the misalignment.

A published study of 43 patients¹, for whom Rosner and his colleagues had complete records, found a 72 percent reduction in several symptoms of traumatic brain injury, based on a subjective scale.

The majority of the patients had had a motor vehicle accident, Rosner says, but falls, strokes or and blast injuries to veterans were also represented.

As Rosner and colleagues struggle to get the word out on their simple treatment, he says prism glasses are helpful, but not a panacea. “These people do have other injuries. I would love to tell you this would fix all traumatic brain injuries. It cannot do that, but it does do a lot.”

Learning is about connections: when the pathways between neurons get stronger, information flow is faster and smoother. We get better at triple toe-loops on the ice, or crooning a romantic ballad for “American Idyll.”

Nice notion, but what, exactly, is changing? Here, we get help from a singing bird that may never get beyond YouTube: the zebra finch.

In a study in Nature, Richard Mooney, a professor of neurobiology at Duke University, used a laser-powered microscope to peer into the brains of male zebra finches 60 days after hatching. Mooney and colleagues studied the birds’ first exposure to the song of their species, and correlated the amount of learning with changes in tiny spines on the dendrites of nerve cells, or neurons, in a motor circuit for singing in the bird’s brain.

Dendrites are branch-like structures on neurons that detect chemical signals, known as neurotransmitters, released from other neurons. When a neurotransmitter diffuses across a tiny gap, called a synapse, it is often received on tiny “dendritic spines” that, in their billions, define the neural wiring and thus the computational properties of the brain.

More and larger dendritic spines make stronger synapses, and that makes stronger and more reliable brain circuits.

Learning: All a matter of spines

In the study, Mooney, Todd Roberts, Katherine Tschida and Marguerita Klein labeled certain neurons so they would glow when viewed under a microscope; they then watched these neurons in living finches and measured what percentage of the dendritic spines appeared or disappeared over a two-hour interval.

The next day, these juvenile birds were allowed to hear the song of an adult male “tutor” of their species. Afterwards, the researchers looked at the spines again, noting that some had appeared, disappeared or changed size. In the following weeks, these birds never again heard their characteristic song, although some went on to learn it.

The birds with the highest spine turnover before hearing the tutor had a significant increase in spine size and stability immediately after tutoring. Eventually, these birds also did the best job of copying the tutor’s song.

Image: Todd Roberts

These tiny structures, called dendritic spines, receive inputs from neighboring neurons, and are an essential part of the brain’s wiring. A new study showed that these spines got stronger and larger as a bird learned to sing.

“We made an average measure of the turnover rate, and found some juveniles with high turnover and others with low turnover, and asked what their learning outcomes were, many weeks later,” says Mooney. “Those with high turnover before hearing a tutor song eventually learned more, and those with low turnover essentially learned nothing from their tutor. Apparently, if you have more dynamic spines, you are better equipped to encode and learn from experience. That’s a pretty important message, and this is the first time that relationship has been established in the context of learning a new behavior.”

Spinal tapestry

The pre-test differences in spines proved to have long-lasting influence, Mooney told us. “We are seeing changes in the brain that occur really quickly, within hours, even though the process of learning that is unfolding will take many weeks to complete. It’s not like the animal hears the tutor, and has mastered the song by the time we see the change.”

Image: Todd Roberts

After this zebra finch was “tutored” in singing by an adult finch, dendritic spines (the tiny white branches) emerged from the dendrite (green arrows) or enlarged (blue arrow). Both changes helped the birds remember the song.

And what makes a dumb bird? A fixity in the number of dendritic spines, Mooney says. The fact that spines tend to become fixed in mature birds could explain why birds cannot learn to sing if they wait too long to hear another bird’s song.

The same phenomenon could explain why it’s difficult or impossible for adult people to become fluent in a new language.

The study not only provides support for the notion that certain neural pathways grow stronger during learning, but it also explains how this could happen. A better distribution of dendritic spines eases the flow of nerve signals across synapses, which helps the bird remember how to sing like another zebra finch.

In essence, the mechanism that Mooney was watching comes down to a neural hybrid of use-it-or-lose-it and trial and error. “The spines are asking, ‘Am I needed? If no, I go. If yes, I stay,’” says Mooney. “They are waiting for a signal, and when it comes through, they are almost like a piece of photographic film. They respond and the synapse is permanently altered.”

Watching – and learning

Humans have many forms of learning, Mooney admits, “But bird song is imitative learning, and imitation is not only the sincerest form of flattery; it’s also basis of much of our culture,” such as speech, art and music. “Finding an animal model in which you can study cultural transmission of behavior is a really powerful way to explore how the brain responds to modeling of behavior by another animal.”

Smart brains are flexible brains, Mooney found. “We were able to see differences in juvenile brains in animals that were the same age, but some could learn and some could not. This suggests that if the brain is in a highly stable condition, you can get stuck.”

David J. Tenenbaum

Test touches truth: Tiny fingers tout terrific tactile talents!

On average, blind people have a better sense of touch than sighted people. But as Daniel Goldreich, an associate professor of neuroscience at McMaster University in Ontario, looked into the matter, he stumbled on something else: Blind women have a finer sense of touch than blind men. Ditto for sighted women.

Why?

In a study reported this week, Goldreich and colleagues reached a disarmingly simple answer: One type of sensory neuron is closer together in smaller fingers, which makes them more able to detect slight differences in object shapes.

The researchers looked at static touch, the ability to sense shape while the fingertip is not moving. Such sensation might be called into play when we attach a button or feel the “hand” of a piece of leather, although in reality, we are more likely to move our fingers in these situations, which recruits inputs from other types of sensory neurons as well.

The smooth, hairless skin on the fingertips has several types of touch detectors:

• Merkel corpuscles: light, static touch, as tested in the Goldreich study.
• Ruffini corpuscles: stretch.
• Meissner corpuscles: low-frequency vibration.
• Pacinian corpuscles: deep pressure and high-frequency vibration.
• Free nerve endings (axons): pain and temperature.

For the study, Goldreich and colleagues carved grooves in plastic plates, reducing the dimensions until the ridges left behind became undetectable. Then the researchers asked 100 undergraduates to sit in a “tactometer.” (We’re sure it’s got a snazzy “scientific” name, but you get the idea).

Groovy, man

As the tactometer uniformly pressed a succession of plates against a fingertip, the subjects were asked if the ridges were running parallel or perpendicular to the finger.

 

Courtesy Daniel Goldreich

a) Scans of woman’s (left) and man’s (right) index finger. Yellow line shows area that was measured to determine finger size.

b) The boxed area was finger painted and put into a high-res scanner. Sweat pores are closer together in the smaller finger.

The subject’s tactile talent was gauged by the narrowest detectable grooves.

The study confirmed what Goldreich had found with the blind: The average woman could detect ridges that were about 10 percent (0.18 millimeter) finer than what the average man could detect.

But what really mattered was finger size, not sex. “People with the smallest fingers could feel grooves that were 0.7 millimeters thinner than people with the largest fingers,” Goldreich adds, “and since the average person can feel grooves of about 1.5 millimeter, that’s a big percentage difference.”

Once finger size was considered, sex played no role in explaining touch skills, Goldreich says.

The average difference is too small to confer much real-world advantage, Goldreich says. “Most likely these effects would be a little too subtle to influence our occupational abilities, except in the most extreme situations. But you could imagine that tasks involving very fine tactile acuity, like needlepoint, might be more accessible to people with smaller fingers.”

Poring over the results

The key suspects in explaining the difference are Merkel corpuscles, a specialized type of sensory nerve cell that is, unfortunately, hard to see by microscope, but is often located near sweat pores. By examining the location of sweat pores (located by dabbing the finger with, yes, finger-paint), Goldreich concluded that the Merkel corpuscles are further apart in bigger fingers, and thus finger size is inversely related to sensitivity.

Owen's masterpiece! Courtesy Stacy Forster Benedict.

“Neuroscientists have long known that some people have a better sense of touch than others, but the reasons for this difference have been mysterious,” said Goldreich. “Our discovery reveals that one important factor in the sense of touch is finger size.”

“Gender differences have been examined for nearly every motor task imaginable, however, the question of whether differences in performance between men and women are truly gender related (i.e. hormonal or cortical) or whether they are correlated with body-size remains an important (and unanswered) question,” says Andrea Mason, an assistant professor of kinesiology at the University of Wisconsin-Madison. “The fact that gender per se can be eliminated as a contributing factor to tactile acuity is an important and impactful finding. These results may ultimately influence the methods we use when training and rehabilitating tasks that depend on accurately interpreting tactile feedback.”

The study has limits, Goldreich cautions. First, it was not possible to directly locate the Merkel corpuscles, and so their location had to be inferred. Second, we seldom hold the finger stationary to feel an object. “Our experiment is an artificial situation,” says Goldreich. “It’s good to start with a test like that, it’s well-controlled, but in real life, we move our fingers across an object to feel its structure, and that sets up a vibration that activates the Meissner cells, and may activate the Ruffini [stretch-detecting] cells as well.”

In follow-up study, “We are really interested in looking at small children, to see whether the sense of touch is better in young kids,” Goldreich says.

For example, what can we learn about touch from expert finger painters?