Brain Images Reveal the Secret to Higher IQ

Pixilated brain: At the bottom, an MRI image shows a slice of the human brain. At the top is shown a magnified portion of this section, created using diffusion imaging. To create the image, scientists measured the direction of the water diffusion in brain tissue. The "flower petals" at each point show the directions of fastest diffusion. These are aligned along the neural pathways of the brain, because water diffuses directionally along the well-insulated neural wires that carry electrical signals. The different directions of diffusion are color-coded red, green, and blue. In this example, the bright red areas reveal the thick fiber tract, called the corpus callosum, which transfers information between the left and right sides of the brain.
Credit: David Shattuck, Arthur Toga, Paul Thompson/UCLA
New research suggests that the layer of insulation coating neural wiring in the brain plays a critical role in determining intelligence. In addition, the quality of this insulation appears to be largely genetically determined, providing further support for the idea that IQ is partly inherited. 

The findings, which result from a detailed study of twins' brains, hint at how ever-improving brain-imaging technology could shed light on some of our most basic characteristics. 

"The study answers some very fundamental questions about how the brain expresses intelligence," says Philip Shaw, a child psychiatrist at the National Institute of Mental Health, in Bethesda, MD, who was not involved in the research.

The neural wires that transmit electrical messages from cell to cell in the brain are coated with a fatty layer called myelin. Much like the insulation on an electrical wire, myelin stops current from leaking out of the wire and boosts the speed with which messages travel through the brain--the higher quality the myelin, the faster the messages travel. These myelin-coated tracts make up the brain's white matter, while the bodies of neural cells are called grey matter.

White matter is invisible on most brain scans, but a recently developed variation of magnetic resonance imaging, called diffusion-tensor imaging (DTI), allows scientists to map the complex neural wiring in our brains by measuring the diffusion of water molecules through tissue. Thanks to the fatty myelin coating, water diffuses along the length of neural wires, while in other types of brain tissue it moves in all different directions. Researchers can calculate the direction of fastest diffusion at each point in the brain and then construct a picture of the brain's fiber tracts. A well-organized brain has well-functioning myelin, in which water can be seen clearly moving along specific paths. "Diffusion imaging gives a picture of how intact your brain connections are," says Paul Thompson, a neuroscientist at the University of California, Los Angeles, who lead the study. 

Thompson and his colleagues took DTI scans of 92 pairs of fraternal and identical twins. They found a strong correlation between the integrity of the white matter and performance on a standard IQ test. "Going forward, we are certainly going to think of white matter structure as an important contributor of intelligence," says Van Wedeen, a neuroscientist at Massachusetts General Hospital in Boston, who was also not involved in the research. "It also changes how you think about what IQ is measuring," says Wedeen. The research was published last month in the Journal of Neuroscience.
IQ inheritance: By comparing the brain scans of twins, scientists discovered that the quality of the fatty tissue that insulates neural wires is largely inherited. The parietal lobe, which is involved in logic and mathematics, is 85 percent genetically determined, whereas the visual cortex is about 76 percent, and the temporal lobe, which is involved in learning and memory, is only 45 percent genetically determined. 
Credit: David Shattuck, Arthur Toga, Paul Thompson/UCLA
If white matter is linked to both processing speed and IQ, this raises the question: is intelligence merely a function of how fast your brain works? Previous research has linked processing speed to IQ, but the tests used in the study are measures of general intelligence, including verbal skills, math, and logic. "Processing speed plays a big part in how intelligent you are, but it's not the only factor," says Shaw.

The new study is among the first to link a specific neural architecture to IQ in healthy individuals. "Most people have focused on grey matter," says Shaw. "This is good evidence we should be looking at white matter as well." Previous studies using DTI have linked white matter damage to Alzheimer's disease, chronic alcoholism, and traumatic brain injury. 

The UCLA researchers took the study a step further by comparing the white matter architecture of identical twins, who share almost all their DNA, and fraternal twins, who share only half. Results showed that the quality of the white matter is highly genetically determined, although the influence of genetics varies by brain area. According to the findings, about 85 percent of the variation in white matter in the parietal lobe, which is involved in mathematics, logic, and visual-spatial skills, can be attributed to genetics. But only about 45 percent of the variation in the temporal lobe, which plays a central role in learning and memory, appears to be inherited.

Thompson and his collaborators also analyzed the twins' DNA, and they are now looking for specific genetic variations that are linked to the quality of the brain's white matter. The researchers have already found a candidate--the gene for a protein called BDNF, which promotes cell growth. "People with one variation have more intact fibers," says Thompson. 

The search for the genetic and neuroanatomical basis of intelligence has been controversial, largely because opponents fear it will spawn a deterministic view of abilities and education. "People worry that if something is genetic, they have no power to influence it," says Thompson. "But that's not true at all." For example, both an average runner and a genetically gifted one can benefit from training. 

But the debate may be moot since, as Wedeen points out, it is unlikely that an individual brain scan could predict a person's IQ. "The report described aggregate data over number of individuals," he says. "That's not the same as saying we can do a scan and determine a person's intelligence. That may be in the offing, but we don't know that yet."

Brown sets targets for science

Prime Minister Gordon Brown has set targets to increase the number of pupils in secondary school in England taking science subjects. 

In the next five years, Mr Brown wants to double the number of pupils taking "triple science", which includes biology, chemistry and physics. 

He also wants to have access to science as single subjects in 90% of schools. 

Mr Brown, speaking at Oxford University, says he wants to "ring-fence" science during the recession. 

The prime minister emphasised the economic importance of protecting the investment in science. 

Teacher training 

"Some say that now is not the time to invest, but the bottom line is that the downturn is no time to slow down our investment in science. We will not allow science to become a victim of the recession," said Mr Brown.  
There were promises to help redundant workers re-train as teachers


There were also promises to offer "personalised support from education consultants" for graduates made redundant from science and technology companies who are considering re-training as maths or science teachers. 

Mr Brown set out targets to increase the number of pupils taking the triple science option, at present taken by 8.5% of students. By 2014, he said he wanted to double this figure, representing an extra 100,000 pupils. 

There was also a target to increase the number of pupils taking A-level maths, from 56,000 to 80,000 in the next five years. 

The Conservatives' Schools Secretary, Michael Gove, rejected the promises. 

"The government's latest promises are completely meaningless given Labour's appalling record on science. 

"The reality is that thanks to their reforms the number of children taking only one science GCSE has doubled in the last year alone, and there are whole areas of the country where not a single child sits three sciences at GCSE." 

Specialist teachers 

Mike Harris of the Institute of Directors said there was an important economic need to provide specialist science and maths teachers in schools to help nurture the subject and to protect the supply of graduates in these fields. 

"The uncomfortable reality is that despite reservoirs of good will, considerable industry engagement and positive government intervention, the number of graduates in the key Stem [science, technology, engineering and maths] disciplines has at best remained pretty flat in recent years. This must be turned around, and quickly." 

There have been warnings about the difficulty in recruiting specialist science teachers. 

Last summer, a report from the University of Buckingham found that almost one in four secondary schools in England no longer has any specialist physics teachers. 

On the wider issues associated with the "knowledge economy", Mr Brown stressed that he would maintain the increased momentum in expenditure he outlined as Chancellor in the 2004, in his 10-year Science and Innovation Investment Framework. 

This should see public spend in the science base of the UK rise to £6.3bn by 2010/2011.

UNNATURAL ROBOTS

LIVING creatures took millions of years to evolve from amphibians to four-legged mammals - with larger, more complex brains to match. Now an evolving robot has performed a similar trick in hours, thanks to a software "brain" that automatically grows in size and complexity as its physical body develops.

Existing robots cannot usually cope with physical changes - the addition of a sensor or new type of limb, say - without a complete redesign of their control software, which can be time-consuming and expensive.

So artificial intelligence engineer Christopher MacLeod and his colleagues at the Robert Gordon University in Aberdeen, UK, created a robot that adapts to such changes by mimicking biological evolution. "If we want to make really complex humanoid robots with ever more sensors and more complex behaviours, it is critical that they are able to grow in complexity over time - just like biological creatures did," he says.

As animals evolved, additions of small groups of neurons on top of existing neural structures are thought to have allowed their brain complexity to increase steadily, he says, keeping pace with the development of new limbs and senses. In the same way, Macleod's robot's brain assigns new clusters of "neurons" to adapt to new additions to its body.

The robot is controlled by a neural network - software that mimics the brain's learning process. This comprises a set of interconnected processing nodes which can be trained to produce desired actions. For example, if the goal is to remain balanced and the robot receives inputs from sensors that it is tipping over, it will move its limbs in an attempt to right itself. Such actions are shaped by adjusting the importance, or weighting, of the input signals to each node. Certain combinations of these sensor inputs cause the node to fire a signal - to drive a motor, for example. If this action works, the combination is kept. If it fails, and the robot falls over, the robot will make adjustments and try something different next time.

Finding the best combinations is not easy - so roboticists often use an evolutionary algorithm to "evolve" the optimal control system. The EA randomly creates large numbers of control "genomes" for the robot. These behaviour patterns are tested in training sessions, and the most successful genomes are "bred" together to create still better versions - until the best control system is arrived at.

MacLeod's team took this idea a step further, however, and developed an incremental evolutionary algorithm (IEA) capable of adding new parts to its robot brain over time.

The team started with a simple robot the size of a paperback book, with two rotatable pegs for legs that could be turned by motors through 180 degrees. They then gave the robot's six-neuron control system its primary command - to travel as far as possible in 1000 seconds. The software then set to work evolving the fastest form of locomotion to fulfil this task.

"It fell over mostly, in a puppyish kind of way," says MacLeod. "But then it started moving forward and not falling over straight away - and then it got better and better until it could eventually hop along the bench like a mudskipper."

When the IEA realises that its evolutions are no longer improving the robot's speed it freezes the neural network it has evolved, denying it the ability to evolve further. That network knows how to work the peg legs - and it will continue to do so.

At this point, it is just like any other evolved robot: it would be unable to cope with the addition of knee-like joints, say, or more legs. But unlike conventional EAs, the IEA is sensitive to a sudden inability to live up to its primary command. So when the team fixed jointed legs to their robot's pegs, the software "realises" that it has to learn how to walk all over again. To do this, it automatically assigns itself fresh neurons to learn how to control its new legs.
When the team fixed jointed legs onto the robot, it 'realised' it had to learn how to walk all over again 

As the IEA runs again, the leg below the "knee" is initially wobbly, but the existing peg-leg "hip" is already trained. "So it flops about, but with more purpose to it," says MacLeod. "Eventually the knee joint works and the robot evolves a salamander-like motion."

Wireless Detectors for Dementia

 Researchers hope that radio transmitters can warn of cognitive decline earlier.The RFID transponder shown here weighs 40 grams. It sends information about the walking patterns of residents at an assisted-living center in Florida, which may reveal early signs of dementia.Researchers at the University of South Florida (USF) have developed a wireless network that evaluates walking patterns in an attempt to detect early signs of dementia. 

Currently, doctors ask patients to answer a series of questions to determine whether they may be suffering from Alzheimer's or another form of dementia. But by the time a patient is diagnosed, she may have already begun to experience symptoms such as memory loss. Drugs that are currently available can only slow the progression of related diseases, so the earlier dementia is caught, the better a patient's treatment will be.

Researchers are exploring ways to identify the condition earlier--for example, by detecting biomarkers, conducting new brain scans, or monitoring movements such as walking. The USF researchers have developed an RFID system that allows walking patterns to be monitored in a natural setting.

"We're looking at a device that may help us perform early detection [of dementia] as a way of ensuring that [older] people get the best remaining years they can," says William Kearns, an assistant professor of experimental psychology at USF. In particular, dementia increases the risk of injury caused by a fall. "That's a huge problem for assisted-living facilities," he says.

To test the approach, the USF researchers put RFID tags on the wrists of residents at two assisted-living homes in Florida. These tags transmitted signals that were picked up by receivers placed around each building, revealing the wearer's movements in all three spatial dimensions to within 10 inches of accuracy.

The researchers analyzed participants' movements for telltale signs of cognitive decline: a tendency to wander, veer suddenly, or repeatedly pause. In a study involving 20 residents the researchers found a statistical relationship between those who showed abnormal walking patterns and those whose mental test scores indicated dementia. In the future, the USF team plans to develop software that will automatically detect these warning signs.

Others are exploring RFID technology as a low-cost way to improve elder care. In 2004, Intel launched a project that used passive RFID tags attached to objects to monitor individuals' everyday activities. This approach can warn a caregiver to check, for example, that a patient has taken his medicine that day. Other systems, such as Accutech's ResidentGuard, send an alarm when users wearing an RFID bracelet venture beyond a designated zone, in order to prevent those with dementia from wandering.

GENETIC TEST FOR HEART DISEASE AND CANCER RISK

Customers who order DecodeMe’s genetic tests receive the kit pictured above. The black wand is scraped against the inside of the cheek to collect cells for DNA analysis.From car makers to cosmetic surgeons, everyone is scrambling to develop and market more economical products--and the consumer-genetics industry is no exception. DecodeMe, a division of Iceland-based Decode Genetics, launched two new services this week: a test that detects genetic variations associated with different cardiovascular diseases, and a screen that detects genetic variations linked to the risk of developing various cancers. At $195 and $225, respectively, the new tests are cheaper than Decode's genome-wide screen, which for $985 assesses genetic risk for 34 diseases and traits ranging from diabetes to male-pattern baldness. "We wanted to give people an opportunity to buy a test that would only address their needs," says Kari Stefansson, Decode's president and cofounder.

But the same question that has plagued direct-to-consumer genetic testing since its inception remains: the clinical utility of such screens. "We have not sorted out what the best approach is for dealing with prostate-cancer risk in the normal population, much less in those who are at some increased risk," says James Evans, a physician and geneticist at the University of North Carolina at Chapel Hill. He says that the same is true for other types of cancer.

The first test--deCODEme Cardio--detects eight genetic variations, known as single-nucleotide polymorphisms (SNPs), associated with the risk of heart attack, intracranical and abdominal aortic aneurysm, stroke and atrial fibrillation, peripherial arterial disease, and venous thromboempolism (clots in blood vessels). The second test--deCODEme Cancer--measures 29 SNPs associated with the risk of prostate, lung, bladder, colorectal, and breast cancers, as well as basal cell carcinoma.

The variations detected by the Decode tests clearly do increase risk of these diseases--in most cases, the link has been replicated numerous times. But they each boost risk of disease by a modest amount: typically 20 percent or less. In contrast, mutations in the BRCA1 gene, which physicians often screen for in women with a family history of breast cancer, boost a woman's risk of developing breast cancer to between three and seven times that of someone who lacks the mutation. While the latter can help physicians recommend preventative measures, such as a mastectomy, it's not yet clear how common variations of moderate effect can help shape an individual's plan for prevention or treatment of disease.

VIRUS REBUILDS DAMAGED NERVES

Genetically engineered viruses could form a scaffold for nerve cells.This fiber is made of billions of viruses and is being studied as a tissue-engineering scaffold. The fiber helps progenitor cells grow into neurons.Viruses that mimic supportive nerve tissue may someday help regenerate injured spinal cords. While other tissue-engineering materials must be synthesized and shaped in the lab, genetically engineered viruses have the advantage of being self-replicating and self-assembling. They can be designed to express cell-friendly proteins on their surfaces and, with a little coaxing, be made into complex tissuelike structures. Preliminary studies show that scaffolds made using a type of virus called a bacteriophage (or phage) that infects bacteria but cannot invade animal cells can support the growth and organization of nerve cells.

Researchers working on tissue engineering hope to eventually be able to use a patient's own cells to grow replacement tissue for damaged hearts, livers, and nerves. But mimicking the structure and function of the body's tissue has proved difficult. Matrices of supportive, fibrous proteins sustain the cells of the heart, lungs, and other tissues in the body. These scaffolds provide both structural support and chemical signals that enable an organ or nerve tissue to function properly.

Some biological engineers are using scaffolds made of polymers to try to mimic the supportive matrix of real tissue. Seung-Wuk Lee, a bioengineer at the University of California, Berkeley, has turned to viruses instead. "Viruses are smart materials," he says. "Once you construct the genome, you can make billions of phages, and they're self-replicating materials." The phage that Lee is working with, called M13, is long and thin like the protein fibers that make up the cellular matrices inside the body.

First, Lee and his colleague Anna Merzlyak genetically engineered M13 to display nerve-friendly proteins on their outer coats. These proteins are known to help nerve cells proliferate, adhere, and extend into long fiberlike shapes. Next, the researchers grew large numbers of the viruses in bacterial-cell hosts and dropped them into a solution containing neural-progenitor cells. These cells are more fully developed than stem cells but are still young and need coaxing to form new tissues. In the solution, the viruses align themselves like a liquid crystal, says Lee. He and Merzlyak used pipettes to inject the solution into agar, a Jell-O-like cell-culture medium, creating long, nerve-like fibers of the virus interspersed with cells. The progenitor cells then multiplied and grew the long branches characteristic of neurons. Lee says that the phage are well suited to making long, fiberlike structures such as nerve tissue but can also be made into more complex structures by varying their concentration or manipulating their position with a magnetic field.

Lee is not the first to use a virus as an engineering material. Other researchers have used the same virus to build battery electrodes. Using the virus in this way was pioneered by Angela Belcher, now a professor of materials science and engineering and of biological engineering at MIT, and was the basis of Lee's graduate work while he was in her lab. Genetically engineered phages have already been approved as an antibacterial food preservative by the U.S. Food and Drug Administration, for use in lunch meats like bologna, for example. Phages are also under study as a potential treatment for chronic bacterial infections.

MIT Institute Professor Robert Langer says that Lee's work is interesting from a materials perspective, but he cautions that its practicality must be established through in vivo studies.

Lee says that his group plans to establish the safety of phage scaffolds in live animals next. M13 has a good safety record and is not capable of infecting people. Still, the Berkeley researchers will need to investigate how an animal's immune system responds to the viral scaffolds and prove that they encourage nerve regeneration once inside the body. Lee hopes that the viral system will eventually be used to regenerate neurons in patients with spinal-cord injuries.

ROBOTICS FOR PERSONAL ASSISTANCE,MEDICAL

Biomedical robots performed less invasive and more complex experimental surgeries, winged robots copied each other to perform potential military maneuvers, and researchers began work on robots that may even be able to travel through the blood to zap a tumor. Some highlights:

Grab and Grasp:

Robotic grasping and learning is becoming sophisticated enough that people may soon be able to simply gesture to any object that they want and, without needing to program specifics, rely on a robot to retrieve it. A robot demonstrated this year at Georgia Tech, El-E (pronounced "Ellie"), a wheeled, one-armed robot, follows a green laser pointer to retrieve objects.  Later in the year, the group gave El-E new abilities based on how dogs respond to humans.  Another grasper, the UMass Mobile Manipulator--UMan, for short--demonstrated that it could learn how to use new objects.  Just as humans learn by testing an object, UMan is able to experiment and learn by playing with objects, including scissors, shears, and wooden toys.

Stomach Explorers:

While doctors have used capsule cameras for the past few years to image the insides of patients, they hope for ways to control such a camera so that it pauses at areas of interest. A group in Germany uses a magnetic device outside the body to control the movement of a pill camera  while researchers at Carnegie Mellon University created a robot capsule that can anchor on delicate internal tissue without damaging it.