Chapter 7. Life-Span Development of the Brain and Behavior
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Ann Robinson Neuroscience research got a huge boost last week with news of Professor John O’Keefe’s Nobel prize for work on the “brain’s internal GPS system”. It is an exciting new part of the giant jigsaw puzzle of our brain and how it functions. But how does cutting-edge neuroscience research translate into practical advice about how to pass exams, remember names, tot up household bills and find where the hell you left the car in a crowded car park? O’Keefe’s prize was awarded jointly with Swedish husband and wife team Edvard and May-Britt Moser for their discovery of “place and grid cells” that allow rats to chart where they are. When rats run through a new environment, these cells show increased activity. The same activity happens much faster while the rats are asleep, as they replay the new route. We already knew that the part of the brain known as the hippocampus was involved in spatial awareness in birds and mammals, and this latest work on place cells sheds more light on how we know where we are and where we’re going. In 2000, researchers at University College London led by Dr Eleanor Maguire showed that London taxi drivers develop a pumped-up hippocampus after years of doing the knowledge and navigating the backstreets of the city. MRI scans showed that cabbies start off with bigger hippocampuses than average, and that the area gets bigger the longer they do the job. As driver David Cohen said at the time to BBC News: “I never noticed part of my brain growing – it makes you wonder what happened to the rest of it!” © 2014 Guardian News and Media Limited
For decades, scientists thought that neurons in the brain were born only during the early development period and could not be replenished. More recently, however, they discovered cells with the ability to divide and turn into new neurons in specific brain regions. The function of these neuroprogenitor cells remains an intense area of research. Scientists at the National Institutes of Health (NIH) report that newly formed brain cells in the mouse olfactory system — the area that processes smells — play a critical role in maintaining proper connections. The results were published in the October 8 issue of the Journal of Neuroscience. “This is a surprising new role for brain stem cells and changes the way we view them,” said Leonardo Belluscio, Ph.D., a scientist at NIH’s National Institute of Neurological Disorders and Stroke (NINDS) and lead author of the study. The olfactory bulb is located in the front of the brain and receives information directly from the nose about odors in the environment. Neurons in the olfactory bulb sort that information and relay the signals to the rest of the brain, at which point we become aware of the smells we are experiencing. Olfactory loss is often an early symptom in a variety of neurological disorders, including Alzheimer’s and Parkinson’s diseases. In a process known as neurogenesis, adult-born neuroprogenitor cells are generated in the subventricular zone deep in the brain and migrate to the olfactory bulb where they assume their final positions. Once in place, they form connections with existing cells and are incorporated into the circuitry.
by Andy Coghlan Ten years after the death of everyone's favourite Superman, Christopher Reeve, his son Matthew Reeve is pushing ahead with a spine-tingling clinical trial You're planning a large study of a paralysis treatment that has already helped four young men. What will it entail? This study will include 36 people with spinal cord injuries who will be treated with epidural stimulation – a technique in which a device is used to apply electrical current to the spinal cord. If we see the same results as we did in the first four, this therapy could have a profound impact on thousands of people living with paralysis. It has the potential to become as commonplace as the pacemaker is for cardiac patients. How well has the treatment worked for the four men who have already received it? Prior to epidural stimulation, they had all suffered chronic injuries caused by completely severed spinal cords. All four have seen dramatic improvements, including the ability to voluntarily move their toes, feet, ankles and legs, and even stand at times, when the device is on. One unexpected bonus has been the return of autonomic function, such as bladder and bowel control and sexual function. From a quality-of-life point of view, this is the biggest improvement. Also unexpectedly, these autonomic functions continue in all four men even when the device is switched off, although they still need it to stand, move their legs and do exercises. © Copyright Reed Business Information Ltd.
By Sarah C. P. Williams If you sailed through school with high grades and perfect test scores, you probably did it with traits beyond sheer smarts. A new study of more than 6000 pairs of twins finds that academic achievement is influenced by genes affecting motivation, personality, confidence, and dozens of other traits, in addition to those that shape intelligence. The results may lead to new ways to improve childhood education. “I think this is going to end up being a really classic paper in the literature,” says psychologist Lee Thompson of Case Western Reserve University in Cleveland, Ohio, who has studied the genetics of cognitive skills and who was not involved in the work. “It’s a really firm foundation from which we can build on.” Researchers have previously shown that a person’s IQ is highly influenced by genetic factors, and have even identified certain genes that play a role. They’ve also shown that performance in school has genetic factors. But it’s been unclear whether the same genes that influence IQ also influence grades and test scores. In the new study, researchers at King’s College London turned to a cohort of more than 11,000 pairs of both identical and nonidentical twins born in the United Kingdom between 1994 and 1996. Rather than focus solely on IQ, as many previous studies had, the scientists analyzed 83 different traits, which had been reported on questionnaires that the twins, at age 16, and their parents filled out. The traits ranged from measures of health and overall happiness to ratings of how much each teen liked school and how hard they worked. © 2014 American Association for the Advancement of Science
by Michael Marshall When we search for the seat of humanity, are we looking at the wrong part of the brain? Most neuroscientists assume that the neocortex, the brain's distinctive folded outer layer, is the thing that makes us uniquely human. But a new study suggests that another part of the brain, the cerebellum, grew much faster in our ape ancestors. "Contrary to traditional wisdom, in the human lineage the cerebellum was the part of the brain that accelerated its expansion most rapidly, rather than the neocortex," says Rob Barton of Durham University in the UK. With Chris Venditti of the University of Reading in the UK, Barton examined how the relative sizes of different parts of the brain changed as primates evolved. During the evolution of monkeys, the neocortex and cerebellum grew in tandem, a change in one being swiftly followed by a change in the other. But starting with the first apes around 25 million years ago through to chimpanzees and humans, the cerebellum grew much faster. As a result, the cerebellums of apes and humans contain far more neurons than the cerebellum of a monkey, even if that monkey were scaled up to the size of an ape. "The difference in ape cerebellar volume, relative to a scaled monkey brain, is equal to 16 billion extra neurons," says Barton. "That's the number of neurons in the entire human neocortex." © Copyright Reed Business Information Ltd.
By Fredrick Kunkle Years ago, many scientists assumed that a woman’s heart worked pretty much the same as a man’s. But as more women entered the male-dominated field of cardiology, many such assumptions vanished, opening the way for new approaches to research and treatment. A similar shift is underway in the study of Alzheimer’s disease. It has long been known that more women than men get the deadly neurodegenerative disease, and an emerging body of research is challenging the common wisdom as to why. Although the question is by no means settled, recent findings suggest that biological, genetic and even cultural influences may play heavy roles. Of the more than 5 million people in the United States who have been diagnosed with Alzheimer’s, the leading cause of dementia, two-thirds are women. Because advancing age is considered the biggest risk factor for the disease, researchers largely have attributed that disparity to women’s longer life spans. The average life expectancy for women is 81 years, compared with 76 for men. Yet “even after taking age into account, women are more at risk,” said Richard Lipton, a physician who heads the Einstein Aging Study at Albert Einstein College of Medicine in New York. With the number of Alzheimer’s cases in the United States expected to more than triple by 2050, some researchers are urging a greater focus on understanding the underlying reasons women are more prone to the disease and on developing gender-specific treatments. .
By Smitha Mundasad Health reporter, BBC News Measuring people's sense of smell in later life could help doctors predict how likely they are to be alive in five years' time, a PLOS One study suggests. A survey of 3,000 adults found 39% with the poorest sense of smell were dead within five years - compared to just 10% who identified odours correctly. Scientists say the loss of smell sense does not cause death directly, but may be an early warning sign. They say anyone with long-lasting changes should seek medical advice. Researchers from the University of Chicago asked a representative sample of adults between the ages of 57-85 to take part in a quick smell test. The assessment involved identifying distinct odours encased on the tips of felt-tip pens. The smells included peppermint, fish, orange, rose and leather. Five years later some 39% of adults who had the lowest scores (4-5 errors) had passed away, compared with 19% with moderate smell loss and just 10% with a healthy sense of smell (0-1 errors). And despite taking issues such as age, nutrition, smoking habits, poverty and overall health into account, researchers found those with the poorest sense of smell were still at greatest risk. Lead scientist, Prof Jayant Pinto, said: "We think loss of the sense of smell is like the canary in the coal mine. BBC © 2014
By Fredrick Kunkle Here’s something to worry about: A recent study suggests that middle-age women whose personalities tend toward the neurotic run a higher risk of developing Alzheimer’s disease later in life. The study by researchers at the University of Gothenburg in Sweden followed a group of women in their 40s, whose disposition made them prone to anxiety, moodiness and psychological distress, to see how many developed dementia over the next 38 years. In line with other research, the study suggested that women who were the most easily upset by stress — as determined by a commonly used personality test — were two times more likely to develop Alzheimer’s disease than women who were least prone to neuroticism. In other words, personality really is — in some ways — destiny. “Most Alzheimer’s research has been devoted to factors such as education, heart and blood risk factors, head trauma, family history and genetics,” study author Lena Johansson said in a written statement. “Personality may influence the individual’s risk for dementia through its effect on behavior, lifestyle or reactions to stress.” The researchers cautioned that the results cannot be extrapolated to men because they were not included in the study and that further work is needed to determine possible causes for the link. The study, which appeared Wednesday in the American Academy of Neurology’s journal, Neurology, examined 800 women whose average age in 1968 was 46 years to see whether neuroticism — which involves being easily distressed and subject to excessive worry, jealousy or moodiness — might have a bearing on the risk of dementia.
|By Brian Bienkowski and Environmental Health News Babies born to mothers with high levels of perchlorate during their first trimester are more likely to have lower IQs later in life, according to a new study. The research is the first to link pregnant women's perchlorate levels to their babies’ brain development. It adds to evidence that the drinking water contaminant may disrupt thyroid hormones that are crucial for proper brain development. Perchlorate, which is both naturally occurring and manmade, is used in rocket fuel, fireworks and fertilizers. It has been found in 4 percent of U.S. public water systems serving an estimated 5 to 17 million people, largely near military bases and defense contractors in the U.S. West, particularly around Las Vegas and in Southern California. “We would not recommend action on perchlorate levels from this study alone, although our report highlights a pressing need for larger studies of perchlorate levels from the general pregnant population and those with undetected hypothyroidism,” the authors from the United Kingdom, Italy and Boston wrote in the study published in The Journal of Clinical Endocrinology & Metabolism. The Environmental Protection Agency for decades has debated setting a national drinking water standard for perchlorate. The agency in 2011 announced it would start developing a standard, reversing an earlier decision. In the meantime, two states, California and Massachusetts, have set their own standards. © 2014 Scientific American
By Gary Stix If it’s good for the heart, it could also be good for the neurons, astrocytes and oligodendrocytes, cells that make up the main items on the brain’s parts list. The heart-brain adage comes from epidemiological studies that show that people with cardiovascular risk factors such as high-blood pressure and elevated cholesterol levels, may be more at risk for Alzheimer’s and other dementias. This connection between heart and brain has also led to some disappointments: clinical trials of lipid-lowering statins have not helped patients diagnosed with Alzheimer’s, although epidemiological studies suggest that long-term use of the drugs may help prevent Alzheimer’s and other dementias. The link between head and heart is still being pursued because new Alzheimer’s drugs have failed time and again. One approach that is now drawing some interest looks at the set of proteins that carry around fats in the brain. These lipoproteins could potentially act as molecular sponges that mop up the amyloid-beta peptide that clogs up connections among brain cells in Alzheimer’s. One of these proteins—Apolipoprotein J, also known as clusterin—intrigues researchers because of the way it interacts with amyloid-beta and the status of its gene as a risk factor for Alzheimer’s. A researcher from the University of Minnesota, Ling Li, recently presented preliminary work at the Alzheimer’s Disease Drug Discovery Foundation annual meeting that showed that, at least in a lab dish, a molecule made up of a group of amino acids from APOJ is capable of protecting against the toxicity of the amyloid-beta peptide. It also quelled inflammation and promoted the health of synapses—the junctions where one brain cell encounters another. Earlier work by another group showed that the peptide prevented the development of lesions in the blood vessels of animals.
Link ID: 20135 - Posted: 09.30.2014
By Smitha Mundasad Health reporter, BBC News A spice commonly found in curries may boost the brain's ability to heal itself, according to a report in the journal Stem Cell Research and Therapy. The German study suggests a compound found in turmeric could encourage the growth of nerve cells thought to be part of the brain's repair kit. Scientists say this work, based in rats, may pave the way for future drugs for strokes and Alzheimer's disease. But they say more trials are needed to see whether this applies to humans. Researchers from the Institute of Neuroscience and Medicine in Julich, Germany, studied the effects of aromatic-turmerone - a compound found naturally in turmeric. Rats were injected with the compound and their brains were then scanned. Particular parts of the brain, known to be involved in nerve cell growth, were seen to be more active after the aromatic-turmerone infusion. Scientists say the compound may encourage a proliferation of brain cells. In a separate part of the trial, researchers bathed rodent neural stem cells (NSCs) in different concentrations of aromatic-tumerone extract. NSCs have the ability to transform into any type of brain cell and scientists suggest they could have a role in repair after damage or disease. Dr Maria Adele Rueger, who was part of the research team, said: "In humans and higher developed animals their abilities do not seem to be sufficient to repair the brain but in fish and smaller animals they seem to work well." Picture of the spice turmeric Turmeric belongs to the same plant family as ginger BBC © 2014
by Sarah Zielinski Chimps may be cute and have mannerisms similar to humans, but they are wild animals. A new study finds that chimps raised as pets or entertainers have behavioral problems as adults. There are plenty of good reasons why chimpanzees should not be pets or performers, no matter how cute or humanlike they appear: They are wild animals. They can be violent with each other. And they can be violent toward humans — even humans that have a long history with the chimp. Plus, there’s evidence that seeing an adorable chimp dressed up like a miniature human actually makes us care less about the plight of their species. Now comes evidence that the way that chimps are raised to become pets or entertainers — taking them away from other chimps at a young age and putting them in the care of humans, who may or may not feed and care for them properly — has long-term, negative effects on their behavior. “We now add empirical evidence of the potentially negative welfare effects on the chimpanzees themselves as important considerations in the discussion of privately owned chimpanzees,” Hani Freeman and Stephen Ross of the Lincoln Park Zoo in Chicago write September 23 in PeerJ. Freeman and Ross compiled life history and behavioral data on 60 captive chimps living in zoos. Some of the animals had always lived in zoos and grew up in groups of chimpanzees. Six were raised solely by humans and were later placed in zoos after they became too big or too old for their owners to care for them. Others had a more mixed background. © Society for Science & the Public 2000 - 2014
Jia You In the future, a nurse could determine whether a baby is likely to develop a reading disorder simply by attaching a few electrodes to its scalp and watching its brain waves respond to human speech. Such is the scenario suggested by a new study, which finds a potential biological indicator of how well preschool children perceive rhythm, an ability linked to language development. “It’s really impressive to work with children this young, who are not often looked at,” says Aniruddh Patel, a cognitive neuroscientist at Tufts University in Medford, Massachusetts, who was not involved with the research. Spoken language consists of sound waves occurring over multiple timescales. A syllable, for example, takes place over a quarter of a second, while a sentence unfolds over a few seconds. To make sense of this complex auditory information, humans use rhythmic cues such as stress and pause to discern words and syllables. Adults and school-aged children with reading disorders, however, struggle to pick up on these rhythmic patterns. Scientists estimate that dyslexia and other reading disabilities plague about 5% to 10% of the population. Detecting such impairments early could lead to more effective intervention, but observing telltale signs in younger children who have not learned to read has proven a challenge. So biologist Nina Kraus of Northwestern University in Evanston, Illinois, and her colleagues looked for automatic brain responses that can track language development in preschoolers, who have not learned to read. © 2014 American Association for the Advancement of Science
|By Melinda Wenner Moyer Autism is primarily a disorder of the brain, but research suggests that as many as nine out of 10 individuals with the condition also suffer from gastrointestinal problems such as inflammatory bowel disease and “leaky gut.” The latter condition occurs when the intestines become excessively permeable and leak their contents into the bloodstream. Scientists have long wondered whether the composition of bacteria in the intestines, known as the gut microbiome, might be abnormal in people with autism and drive some of these symptoms. Now a spate of new studies supports this notion and suggests that restoring proper microbial balance could alleviate some of the disorder's behavioral symptoms. At the annual meeting of the American Society for Microbiology held in May in Boston, researchers at Arizona State University reported the results of an experiment in which they measured the levels of various microbial by-products in the feces of children with autism and compared them with those found in healthy children. The levels of 50 of these substances, they found, significantly differed between the two groups. And in a 2013 study published in PLOS ONE, Italian researchers reported that, compared with healthy kids, those with autism had altered levels of several intestinal bacterial species, including fewer Bifidobacterium, a group known to promote good intestinal health. One open question is whether these microbial differences drive the development of the condition or are instead a consequence of it. A study published in December 2013 in Cell supports the former idea. When researchers at the California Institute of Technology incited autismlike symptoms in mice using an established paradigm that involved infecting their mothers with a viruslike molecule during pregnancy, they found that after birth, the mice had altered gut bacteria compared with healthy mice. © 2014 Scientific American,
Link ID: 20104 - Posted: 09.23.2014
By Filipa Ioannou Per the Associated Press, the Food and Drug Administration is considering a ban on electric-shock devices that are used to punish unwanted behavior by patients with autism and other developmental disabilities. If it comes as a surprise to you that any involuntary electric shocks are administered to autism patients in the United States, that's because the devices are only used at one facility in the country—the Judge Rotenberg Educational Center in Canton, Mass. The school has been a target of media attention in the past; in 2012, video leaked of 18-year-old patient Andre McCollins being restrained face-down and shocked 31 times. McCollins’ mother sued the center, and the lawsuit was settled outside of court. Rotenberg must get a court’s approval to begin administering skin shocks to a student. The center uses a graduated electronic decelerator, or GED, that is attached to the arms or legs. If the student acts aggressively – head-banging, throwing furniture, attacking someone – then a center worker can press a button to activate the electrode, delivering a two-second shock to the skin. The amount of pain generated by the device is a contentious subject. The Rotenberg Center's Glenda Crookes compared the sensation to “a bee sting” in comments to CBS News, and some Rotenberg parents are strong proponents of the device. But a U.N. official in 2010 said the shocks constituted “torture." An FDA report also addresses the widely held belief that autistic individuals have a high pain threshold, pointing out the possibility that “not all children with ASD express their pain in the same way as a ‘neurotypical child’ would (e.g., cry, moan, seek comfort, etc.), which may lead to misinterpretation by caregivers and medical professionals that patients are insensitive or to an incorrect belief that the child is not in pain.” © 2014 The Slate Group LLC.
By Megan Allison Diagnoses of Attention Hyperactivity Disorder are on the rise. The Centers for Disease Control and Prevention calculated that by 2011, 11 percent of children had been diagnosed with ADHD, and 6.1 percent of all US children were taking an ADHD medication. But could a solution be as simple as exercise? A study published this month in the Journal of Abnormal Child Psychology found that aerobic activity sessions before school helped children with ADHD with their moods and attention spans. The study involved a group of just over 200 students in kindergarten through second grade at schools in Indiana and Vermont. For 12 weeks, the students did 31 minutes of physical activity. The control group participated in classroom activities during this time. Although the results showed that all students showed improvement, authors noted that the exercise especially helped kids with ADHD. “It benefits all the kids, but I definitely see where it helps the kids with ADHD a lot,” said Jill Fritz, a fourth-grade teacher in Jacksonville, Fla. in an interview with The Wall Street Journal. “It really helps them get back on track and get focused.” In the Boston area, Dr. Sarah Sparrow Benes, Program Director of Physical and Health Education Programs at Boston University, teaches elementary and special educators how to use movement as a strategy in their classroom for learning. She finds that all students can benefit from exercise.
By Linda Searing THE QUESTION Benzodiazepines such as Valium, Xanax and Ativan, widely prescribed to relieve anxiety and alleviate insomnia, are known to affect memory and cognition in the short term. Might they also have a more serious, longer-term effect on the brain? THIS STUDY analyzed data on 8,990 adults older than 66, including 1,796 with Alzheimer’s disease. In a five-to-10-year span before the start of the study, 3,767 of the participants (52 percent) had taken benzodiazepines. Overall, those who had taken the drugs were 51 percent more likely to have Alzheimer’s than were those who had never taken benzodiazepines. The longer people took the drugs, the greater their risk for Alzheimer’s. Those who took the drugs for less than 90 days had essentially the same risk as those who never took them. But risk nearly doubled for people who took them for longer than six months. Risk also was greater for longer-acting vs. shorter-acting benzodiazepines. WHO MAY BE AFFECTED? Adults, especially older people, who take benzodiazepines. The drugs have a calming effect on the body and work quickly, unlike antidepressants, which can take weeks to have an effect. The American Geriatrics Society lists benzodiazepines as inappropriate for treating older people for insomnia or agitation because of their negative effect on cognition seen in that age group and an increased likelihood of falls and accidents. However, some recent estimates note that roughly half of older adults take benzodiazepines. CAVEATS Some study participants may have been prescribed benzodiazepines to treat early symptoms of unrecognized dementia, which can include depression, anxiety and sleep disorders; the study authors noted that use of the drugs “might be an early marker of a condition associated with an increased risk of dementia and not the cause.”
By ANDREW POLLACK New York State’s attorney general filed an antitrust lawsuit on Monday seeking to stop a pharmaceutical company from forcing patients with Alzheimer’s disease to switch to a new version of a widely used drug. The lawsuit contends that the switch is designed to blunt competition from low-priced generic versions of the medication. Forest Laboratories, now owned by Actavis, announced in February that it would stop selling the existing tablet form of the drug, Namenda, in favor of new extended-release capsules called Namenda XR that can be taken once a day instead of twice. While the company said that patients preferred the newer drug, it has made little secret of its desire to switch all patients to the newer form, which has a longer patent life, before the old tablets face generic competition in July. The strategy would make it much harder for the generics to gain traction. The lawsuit, filed in Federal District Court in Manhattan, says the step is an illegal attempt by Forest to maintain its monopoly even after its patent expires. “A drug company manipulating vulnerable patients and forcing physicians to alter treatment plans unnecessarily, simply to protect corporate profits, is unethical and illegal,” the attorney general, Eric T. Schneiderman, said in a statement. A spokesman for Actavis said the company did not comment on pending litigation as a matter of policy. The company said that the once-a-day drug had “significant advantages” for patients and their caregivers. The lawsuit argues that the benefit of switching is not very great. It says the company decided to force the switch because it feared that not enough patients would switch voluntarily. © 2014 The New York Times Company
Link ID: 20078 - Posted: 09.16.2014
by Michael Slezak It's one of the biggest mysteries of Alzheimer's. The disease is associated with the formation of protein plaques in the brain, but why is it that some people with plaques seem not to have the disease? Research suggests that some people's brains are able to reorganise during the early stages of Alzheimer's, delaying the appearance of initial symptoms. The plaques in question are small mounds of a protein called beta-amyloid, and are found in the brains of people with Alzheimer's disease. Whether these plaques are a cause of the disease has been hotly debated. One reason for doubt is the appearance of plaques in many older people who have no symptoms Movie Cameraof dementia at all. Using fMRI to measure changes in blood flow around the brain, William Jagust from the University of California in Berkley and colleagues compared brain function in three groups of people without symptoms of dementia: 22 young people, 16 older people with beta-amyloid plaques and 33 older people without the plaques. He asked each of them to memorise a photographed scene while inside the machine. Jagust found that older people with plaques had increased blood flow – which means stronger activation of that brain area – in the regions of the brain that are usually activated during memory formation, compared with the older people who did not have plaques. The team then analysed whether this extra brain activation might be helping to compensate for the plaques. © Copyright Reed Business Information Ltd.
David Cyranoski A Japanese patient with a debilitating eye disease is about to become the first person to be treated with induced pluripotent stem cells, which have generated enthusiastic expectations and earned their inventor a Nobel Prize. A health-ministry committee has vetted researchers' safety tests and cleared the team to begin the experimental procedure. Masayo Takahashi, an ophthalmologist at the RIKEN Center for Developmental Biology (CDB) in Kobe, has been using induced pluripotent stem (iPS) cells to prepare a treatment for age-related macular degeneration. Unlike embryonic stem cells, iPS cells are produced from adult cells, so they can be genetically tailored to each recipient. They are capable of becoming any cell type in the body, and have the potential to treat a wide range of diseases. The CDB trial will be the first opportunity for the technology to prove its clinical value. In age-related macular degeneration, extra blood vessels form in the eye, destabilizing a supportive base layer of the retina known as the retinal pigment epithelium. This results in the loss of the light-sensitive photoreceptors that are anchored in the epithelium, and often leads to blindness. Takahashi took skin cells from people with the disease and converted them to iPS cells. She then coaxed these cells to become retinal pigment epithelium cells, and then to grow into thin sheets that can be transplanted to the damaged retina. Takahashi and her collaborators have shown in monkey studies1 that iPS cells generated from the recipients' own cells do not provoke an immune reaction that causes them to be rejected. There have been concerns that iPS cells could cause tumours, but Takahashi's team has found that to be unlikely in mice2 and monkeys1. © 2014 Nature Publishing Group