Brain's 'atlas' of words revealed

Their "semantic atlas" shows how, for example, one region of the brain activates in response to words about clothing and appearance.

The researchers found that these maps were quite similar across the small number of individuals in the study, even down to minor details.

The work, by a team at the University of California, Berkeley, is published in the journal Nature.

It had previously been proposed that information about words' meaning was represented in a group of brain regions known as the semantic system.

But the new work uncovers the fine detail of this network, which is spread right across the outer layer of the human brain.

The results could eventually help those who are unable to speak, such as victims of stroke or brain damage, or motor neuron diseases.

Volunteers - including lead author Alex Huth - listened to more than two hours of stories from a US radio programme while remaining still inside a functional Magnetic Resonance Imaging (MRI) scanner.

'Higher' functions

The team collected data on changes in blood flow and oxygenation - indicators of activity - in different areas of the cerebral cortex.

The cerebral cortex is the brain's outer layer of tissue, playing a key role in higher functions such as language and consciousness.

The brain imaging data were matched against time-coded transcriptions of the stories. The researchers then used a computer algorithm that scored words according to how closely they are related in terms of meaning.

The results were converted into a thesaurus-like map where the words were arranged on the left and right hemispheres of the brain.

They show that the semantic system is distributed broadly in more than 100 distinct areas across both halves - hemispheres - of the cortex and in intricate patterns that were consistent across individuals in the study.

The maps show that many areas of the human brain represent language describing people and social relations rather than abstract concepts.

But the same word could be repeated several times on different parts of the brain map. For example, the word "top" was represented in a part of the brain that responds to words about clothing and appearance, and also in a region that deals with numbers and measurements.

"Our semantic models are good at predicting responses to language in several big swaths of cortex," said Dr Huth.

"But we also get the fine-grained information that tells us what kind of information is represented in each brain area. That's why these maps are so exciting and hold so much potential."

Scientists could track the brain activity of patients who have difficulty communicating and then match that data to language maps to determine what their patients are trying to express.

"Although the maps are broadly consistent across individuals, there are also substantial individual differences," said the study's senior author Jack Gallant.

"We will need to conduct further studies across a larger, more diverse sample of people before we will be able to map these individual differences in detail."

Source: BBC

'Superhero DNA' keeps diseases at bay

The study of nearly 600,000 people found 13 who should have developed debilitating diseases, but did not.

The hope is discovering what, against the odds, keeps them healthy and if that could lead to new therapies.

Experts said the approach, published in Nature Biotechnology, was "fascinating" but that it was still early days.

Errors in our code of life - our DNA - can cause disease.

Large numbers of studies have tried to understand these mutations by looking at people who become ill.

But the international team of researchers tried the opposite approach - searching for people harbouring damaging mutations but who remain healthy.

"Millions of years of evolution have produced far more protective mechanisms than we currently understand," said Dr Eric Schadt from the Icahn School of Medicine at Mount Sinai Hospital in New York.
He added: "Most genomic studies focus on finding the cause of a disease, but we see tremendous opportunity in figuring out what keeps people healthy."

The researchers scoured DNA databases containing information on 589,306 people.

They found 13 healthy people who should have developed one of eight genetic diseases: cystic fibrosis, Smith-Lemli-Opitz syndrome, familial dysautonomia, epidermolysis bullosa simplex, Pfeiffer syndrome, autoimmune polyendocrinopathy syndrome, acampomelic campomelic dysplasia and atelosteogenesis.

The report said the diseases were so severe that it was "highly unlikely that such an individual would have manifested the disease without it being clearly annotated in their health records".

Prof Stephen Friend, from the Icahn School of Medicine, said: "Finding these individuals is a starting point to searching for the other changes, eg in the genome, that might give us clues to develop therapies.

"Study the healthy, don't just study the sick."

However, this is where the tantalising story ends. The scientists were unable to go out and find the lucky 13 because of the consent rules signed when their DNA sample was taken.

It means they do not know what is protecting them against disease.

It also leaves the team unable to prove that errors in testing, bad record keeping or mosaicism - in which the genetic defect affects only some cells in the body - are not behind their findings.

"Because of the inability to confirm the source or validity of the variants and the inability to recontact the individuals, this paper does not constitute a proof of principle," Dr Ada Hamosh, from Johns Hopkins University, argued.

And while Dr Scott Hebbring, from the University of Wisconsin, described the study as "fascinating" he also cautioned that diseases can present very differently even between patients that have same mutations.
Some may have few symptoms at all.

Superheroes

The research group is aiming to do a new study from scratch where patients can be traced. It also argues that other forms of protection - from infections to dementia - could be detected through this approach.

Dr Daniel MacArthur, from the Massachusetts General Hospital, said: "Finding genetic superheroes will require other kinds of heroism - a willingness of participants to donate their genomic and clinical data and a commitment by researchers and regulators to overcome the daunting obstacles to data sharing on a global scale."
Dr Matthew Hurles, from the Wellcome Trust Sanger Institute, said the study "exemplifies the often unforeseen benefits that can be achieved from responsible sharing of anonymised genetic and clinical data".

However, he added: "The full benefits of such altruistic data sharing is only fully realised when it becomes possible to go back to the resilient individual to try to understand how their resilience is achieved.

"This poses research and ethical questions. Personally, if I were that individual, I'd happily share my genome if it could help someone else who had been dealt a less favourable genetic hand."

Source: BBC

'Stunning' operation regenerates eye's lens

More than half of all cases of blindness are caused by cataracts - the clouding of the eye's lens.

An implanted lens is normally needed to restore sight, but the operation described in Nature activated stem cells in the eye to grow a new one.

Experts describe the breakthrough as one of the finest achievements in regenerative medicine.

The lens sits just behind the pupil and focuses light on to the retina.

About 20 million people are blind because of cataracts, which become more common with age - although some children are born with them.

Conventional treatment uses ultrasound to soften and break up the lens, which is then flushed out.

An artificial intraocular lens must then be implanted back into the eye, but this can result in complications, particularly in children.

The technique developed by scientists at the Sun Yat-sen University and the University of California, San Diego removes the cloudy cataract from inside the lens via a tiny incision.

Crucially it leaves the outer surface - called the lens capsule - intact.

This structure is lined with lens epithelial stem cells, which normally repair damage.

The scientists hoped that preserving them would regenerate the lens.

The team reported that tests on rabbits and monkeys were successful, so the approach was trialled in 12 children.

Within eight months the regenerated lens was back to the same size as normal.

"The study is one of the finest achievements in the field of regenerative medicine until now"
Dr Dusko Ilic, King's College London

Dr Kang Zhang, one of the researchers, told the BBC News website: "This is the first time an entire lens has been regenerated. The children were operated on in China and they continue to be doing very well with normal vision."

It also showed a dramatically lower complication rate "by almost every measure, supporting the superiority of the treatment".

However, he says larger trials are needed before it should become the standard treatment for patients.

Source: BBC

Doctors 3D-print 'living' body parts

The sections of bone, muscle and cartilage all functioned normally when implanted into animals.

The breakthrough, published in Nature Biotechnology, raises the hope of using living tissues to repair the body.

Experts described the technology, developed in the US, as a "goose that really does lay golden eggs".

The idea of placing individual human cells in a precise pattern to replace a damaged jaw, missing ear or scarred heart muscle holds much promise.

But the field has been limited by the huge challenge of keeping the cells alive - they become starved of oxygen and nutrients in tissues thicker than 0.2 millimetres.

Sponge

The team at Wake Forest Baptist Medical Centre developed a new technique that 3D-prints a tissue riddled with micro-channels, rather like a sponge, to allow nutrients to penetrate the tissue.

The Integrated Tissue and Organ Printing System - or Itop - combines a bio-degradeable plastic which gives the structure and a water-based gel which contains the cells and encourages them to grow.

When the structures were implanted into animals, the plastic broke down as it was replaced by a natural, structural "matrix" of proteins produced by the cells.

Meanwhile, blood vessels and nerves grew into the implants.

Prof Anthony Atala, the lead researcher, said tissues could now be printed on a human scale.

While the implants have the same strength as human tissues, the researchers are now waiting to see how durable they are.

But Prof Atala said 3D printing was opening new doors for medicine.

He told the BBC News website: "Let's say a patient presented with an injury to their jaw bone and there's a segment missing.
"We'd bring the patient in, do the imaging and then we would take the imaging data and transfer it through our software to drive the printer to create a piece of jawbone that would fit precisely in the patient."


Similar techniques in which the biodegradable scaffolding is built first and then soaked in cells are already being used in patients.

Women were given lab-grown vaginas at the Wake Forest centre two years ago, but the range of treatments is again limited by keeping the cells alive.

Prof Atala added: "In this study we printed a wide range of tissue strengths - from muscles as a soft tissue to cartilage and bone as a hard tissue showing a whole range of tissue strengths is possible.
"The hope is to continue work on these technologies to target other humans tissues as well."

And ultimately they aim to print directly into a patient.

'Golden goose'

Prof Martin Birchall, a surgeon at University College London, said the results were "striking".

He told the BBC: "The prospect of printing human tissues and organs for implantation has been a real one for some time, but I confess I did not expect to see such rapid progress.

"They have managed to create what appears to be the goose that really does lay golden eggs!"
He cautioned there was still more research to be done before the printer could be used in patients.

But he concluded: "Given the scale of this breakthrough, progress in other fields, the resources available to the researchers at Wake Forest and the imperatives for human health, I think it will be less than a decade before surgeons like me are trialling customised printed organs and tissues. I can't wait!"

Source: BBC