Chapter 2. Functional Neuroanatomy: The Nervous System and Behavior
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By Neuroskeptic Nothing that modern neuroscience can detect, anyway. This is the message of a provocative article by Pace University psychologist Terence Hines, just published in Brain and Cognition: Neuromythology of Einstein’s brain As Hines notes, the story of how Einstein’s brain was preserved is well known. When the physicist died in 1955, his wish was to be cremated, but the pathologist who performed the autopsy decided to save his brain for science. Einstein’s son Hans later gave his blessing to this fait accompli. Samples and photos of the brain were then made available to neuroscientists around the world, who hoped to discover the secret of the great man’s genius. Many have claimed to have found it. But Hines isn’t convinced. Some researchers, for instance, have used microscopy to examine Einstein’s brain tissue on a histological (cellular) level. Most famous amongst these studies is Diamond et al, who in 1985 reported that Einstein’s brain had a significantly higher proportion of glial cells than those of matched, normal control brains. However, Hines points out that this ‘finding’ may have been a textbook example of the multiple-comparisons problem: Diamond et al. (1985) reported four different t-tests, each comparing Einstein’s brain to the brains of the controls. Only one of the four tests performed was significant at the .05 level. Although only the results of the neuron to glial cell ratios were reported by Diamond et al. (1985), the paper makes it clear that at least six other dependent measures were examined: (1) number of neurons, (2) total number of glial cells, (3) number of astrocytes, (4) number of oligodendrocytes, (5) neuron to astrocyte ratio and (6) neuron to oligodendrocyte ratio. Thus a total of seven different dependent measures were examined in four different brain areas for a total of 28 comparisons… one p less than 0.05 result out of 28 is not surprising. Other histological studies followed from other researchers, but Hines says that they do not present a coherent picture of clear differences:
The Presidential Commission for the Study of Bioethical Issues today released its first set of recommendations for integrating ethics into neuroscience research in the Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative. Last July, President Barack Obama charged the commission with identifying key ethical questions that may arise through the BRAIN Initiative and wider neuroscience research. The report is “a dream come true,” says Judy Illes, a neuroethicist at the University of British Columbia in Vancouver, Canada, who was a guest presenter to the commission. Brain research raises unique ethical issues because it “strikes at the very core of who we are,” said political scientist and philosopher Amy Gutmann of the University of Pennsylvania, who chairs the commission, in a call with reporters yesterday. Specific areas of concern identified in the report include questions of brain privacy raised by advances in neuroimaging research; whether research participants and patients with dementia can give informed consent to participate in experimental trials; and research into cognitive enhancement, which raises “issues of distributive justice and fairness,” Gutmann says. Parsing hope from hype is key to ethical neuroscience research and its application, Gutmann notes. Citing the troubled ethical history of psychosurgery in the United States, in which more than 40,000 people were lobotomized based on shaky evidence that the procedure could treat psychiatric illnesses such as schizophrenia and depression, Gutmann cautions that a similar ethical derailment is possible in contemporary neuroscience research. A misstep with invasive experimental treatments such as deep brain stimulation surgery would not only be tragic for patients, but have “devastating consequences” for scientific progress, she says. © 2014 American Association for the Advancement of Science
By Melissa Hogenboom Science reporter, BBC Radio Science Neuroscience is a fast growing and popular field, but despite advances, when an area of the brain 'lights up" it does not tell us as much as we'd like about the inner workings of the mind. Many of us have seen the pictures and read the stories. A beautiful picture of the brain where an area is highlighted and found to be fundamental for processes like fear, disgust or impaired social ability. There are so many stories it can be easy to be swayed into thinking that much more of the brain's mystery has been solved than is the case. The technology is impressive but one of the most popular scanning methods - functional magnetic resonance imaging (fMRI) actually measures regional regional changes of blood flow to areas of the brain, not our neurons directly. Researchers use it when they want to understand what part of the brain is involved in a particular task. They can place a person in a brain scanner and see which areas become active. The areas that light up are then inferred to be important for that task, but the resulting images and phrase "lighting up the brain" can lead to over interpretation. Neuroscientist Molly Crocket from University College London explains that while fMRI is extremely useful, we are still very far from being able to read an individual's mind from a scan. "There's a misconception that's still rather common that you can look at someone's brain imaging data and be able to read off what they're thinking and feeling. This is certainly not the case," Dr Crocket told the BBC's Inside Science programme. 19th Century brain "A study will have been done which tells us something about the brain, but what [the public] really want to do is make the leap and understand the mind." She cites an article with the headline, "You love your iPhone, literally". In this case a team saw an area previously associated with love - the insula - was active when participants watched videos of a ringing iPhone. BBC © 2014
By Gabriella Rosen Kellerman By 1664, the year he published his most famous book of neuroanatomy, Cerebri Anatome, Dr. Thomas Willis was already renowned in Britain for saving lives. Fourteen years earlier, the corpse of executed murderer Anne Green had been delivered to Willis and some of his colleagues for autopsy. Upon opening the coffin—the story goes—the doctors heard a gasp. Ms. Green, they discovered, had been hanged but not executed. Thanks to the resuscitation efforts of Willis and his colleagues, Green survived, and was given a stay of execution. She died fifteen years later. The episode supposedly drew jealousy from Willis’s contemporaries, who could have had no idea just how many lives Willis’s work would one day save. Among the important discoveries included in Cerebri Anatome, considered the founding text of neurology, is the Circle of Willis, a map of the interconnecting arteries at the base of the brain. Such circular connections among arteries are called anastomoses. They enable blood to reach vital tissue along multiple routes so that when one is blocked, the blood has an alternative outlet. The Circle of Willis is perhaps most important because of its implications for stroke. Stroke, which is the third leading cause of death in this country, occurs when blood flow to the brain is disrupted. This can occur when an artery gets blocked with plaque or a clot (called an ischemic stroke) or when at artery bursts (called hemorrhagic stroke). Many of these problems, particularly the latter kind of stroke, occur in the Circle of Willis. © 2014 Scientific American
Link ID: 19564 - Posted: 05.03.2014
By Greg Miller As a journalist who writes about neuroscience, I’ve gotten a lot of super enthusiastic press releases touting a new breakthrough in using brain scans to read people’s minds. They usually come from a major university or a prestigious journal. They make it sound like a brave new future has suddenly arrived, a future in which brain scans advance the cause of truth and justice and help doctors communicate with patients whose minds are still active despite their paralyzed bodies. Amazing, right? Drop everything and write a story! Well, not so fast. Whenever I read these papers and talk to the scientists, I end up feeling conflicted. What they’ve done–so far, anyway–really doesn’t live up to what most people have in mind when they think about mind reading. Then again, the stuff they actually can do is pretty amazing. And they’re getting better at it, little by little. In pop culture, mind reading usually looks something like this: Somebody wears a goofy-looking cap with lots of wires and blinking lights while guys in white lab coats huddle around a monitor in another room to watch the movie that’s playing out in the person’s head, complete with cringe-inducing internal monologue. We are not there yet. “We can decode mental states to a degree,” said John-Dylan Haynes, a cognitive neuroscientist at Charité-Universitätsmedizin Berlin. “But we are far from a universal mind reading machine. For that you would need to be able to (a) take an arbitrary person, (b) decode arbitrary mental states and (c) do so without long calibration.” © 2014 Condé Nast.
By JAMES GORMAN SAN DIEGO — Dr. Karl Deisseroth is having a very early breakfast before the day gets going at the annual meeting of the Society for Neuroscience. Thirty thousand people who study the brain are here at the Convention Center, a small city’s worth of badge-wearing, networking, lecture-attending scientists. For Dr. Deisseroth, though, this crowd is a bit like the gang at Cheers — everybody knows his name. He is a Stanford psychiatrist and a neuroscientist, and one of the people most responsible for the development of optogenetics, a technique that allows researchers to turn brain cells on and off with a combination of genetic manipulation and pulses of light. He is also one of the developers of a new way to turn brains transparent, though he was away when some new twists on the technique were presented by his lab a day or two earlier. “I had to fly home to take care of the kids,” he explained. He went home to Palo Alto to be with his four children, while his wife, Michelle Monje, a neurologist at Stanford, flew to the conference for a presentation from her lab. Now she was home and, here he was, back at the conference, looking a bit weary, eating eggs, sunny side up, and talking about the development of new technologies in science. A year ago, President Obama announced an initiative to invest in new research to map brain activity, allocating $100 million for the first year. The money is a drop in the bucket compared with the $4.5 billion the National Institutes of Health spends annually on neuroscience, but it is intended to push the development of new techniques to investigate the brain and map its pathways, starting with the brains of small creatures like flies. Cori Bargmann of Rockefeller University, who is a leader of a committee at the National Institutes of Health setting priorities for its piece of the brain initiative, said optogenetics was a great example of how technology could foster scientific progress. © 2014 The New York Times Company
Keyword: Brain imaging
Link ID: 19520 - Posted: 04.22.2014
By JAMES GORMAN As the Brain Initiative announced by President Obama a year ago continues to set priorities and gear up for what researchers hope will be a decade-long program to understand how the brain works, two projects independent of that effort reached milestones in their brain mapping work. Both projects, one public and one private, are examples of the widespread effort in neuroscience to create databases and maps of brain structure and function that can serve as a foundation for research. While the Obama initiative is concentrating on the development of new tools, that research will build on and use the data being acquired in projects like these. One group of 80 researchers, working as part of a consortium of institutions funded by the National Institute of Mental Health, reported that it had mapped the genetic activity of the human fetal brain. Among other initial findings, the map, the first installment of an atlas of the developing human brain called BrainSpan, confirmed the significance of areas thought to be important in the development of autism. A group of 33 researchers, all but one at the Allen Institute for Brain Science, announced an atlas of the mouse brain showing the connections among 295 different regions. Ed Lein, an investigator at Allen, was the senior author on the fetal brain paper. He said the research required making sections only 20 microns thick, up to 3,500 for each of four brains, two from fetuses at 15 weeks of development and two from about 21 weeks. The researchers measured the activity of 20,000 genes in 300 different brain structures. One interesting finding, Dr. Lein said, was that “95 percent of the genome was used,” meaning almost all of the genes were active during brain development, significantly more than in adult brains. The team also found many differences from the mouse brain, underscoring the findings that, despite the many similarities in all mammalian brains, only so much can be extrapolated to humans from other animals. © 2014 The New York Times Company
by Ashley Yeager A nerve cell's long, slender tentacle isn’t evenly coated with an insulating sheath as scientists had thought. Instead, many nerve cells in the brains of mice have stretches of these tentacles, called axons, that are naked, researchers report April 18 in Science. The unsheathed feeler can be as long as 80 micrometers. Nerve cells can also have specific patterns in the gaps of the insulating layer, called myelin. The differences in the thickness of that coating may control how fast signals travel between nerve cells, the scientists suggest. The finding could have implications for understanding nerve-based diseases, such as multiple sclerosis, and improve scientists’ understanding of how signals are transmitted in the brain. © Society for Science & the Public 2000 - 2013.
By Melissa Hogenboom Artists have structurally different brains compared with non-artists, a study has found. Participants' brain scans revealed that artists had increased neural matter in areas relating to fine motor movements and visual imagery. The research, published in NeuroImage, suggests that an artist's talent could be innate. But training and environmental upbringing also play crucial roles in their ability, the authors report. As in many areas of science, the exact interplay of nature and nurture remains unclear. Lead author Rebecca Chamberlain from KU Leuven University, Belgium, said she was interested in finding out how artists saw the world differently. "The people who are better at drawing really seem to have more developed structures in regions of the brain that control for fine motor performance and what we call procedural memory," she explained. In their small study, researchers peered into the brains of 21 art students and compared them to 23 non-artists using a scanning method called voxel-based morphometry. Detail of 'Giant Lobster' from NHM specimen collection One artist who has practised for many years is Alice Shirley - here is a detail of her Giant Lobster These detailed scans revealed that the artist group had significantly more grey matter in an area of the brain called the precuneus in the parietal lobe. "This region is involved in a range of functions but potentially in things that could be linked to creativity, like visual imagery - being able to manipulate visual images in your brain, combine them and deconstruct them," Dr Chamberlain told the BBC's Inside Science programme. BBC © 2014
By DENISE GRADY People with severe brain injuries sometimes emerge from a coma awake but unresponsive, leaving families with painful questions. Are they aware? Can they think and feel? Do they have any chance of recovery? A new study has found that PET scans may help answer these wrenching questions. It found that a significant number of people labeled vegetative had received an incorrect diagnosis and actually had some degree of consciousness and the potential to improve. Previous studies using electroencephalogram machines and M.R.I. scanners have also found signs of consciousness in supposedly vegetative patients. “I think these patients are kind of neglected by both medicine and society,” said Dr. Steven Laureys, an author of the new study and the director of the Coma Science Group at the University of Liège in Belgium. “Many of them don’t even see a medical doctor or a specialist for years. So I think it’s very important to ask the question, are they unconscious?” In the United States, 100,000 to 300,000 people are thought to be minimally conscious, and an additional 25,000 are vegetative. In Belgium, the combined incidence of the two conditions is about 150 new cases per year, Dr. Laureys said. An article about the new research was published on Tuesday in The Lancet. Dr. Laureys and his colleagues studied 122 patients with brain injuries, including 41 who had been declared vegetative — awake but with no behavioral signs of awareness. People who are vegetative for a year are thought to have little or no chance of recovering, and the condition can become grounds for withdrawing medical treatment. Terri Schiavo, in a vegetative state for 15 years, died in 2005 in Florida after courts allowed the removal of her feeding tube. © 2014 The New York Times Company
Associated Press NEW YORK -- A small study of casual marijuana smokers has turned up evidence of changes in the brain, a possible sign of trouble ahead, researchers say. The young adults who volunteered for the study were not dependent on pot, nor did they show any marijuana-related problems. "What we think we are seeing here is a very early indication of what becomes a problem later on with prolonged use," things like lack of focus and impaired judgment, said Dr. Hans Breiter, a study author. Longer-term studies will be needed to see if such brain changes cause any symptoms over time, said Breiter, of the Northwestern University Feinberg School of Medicine and Massachusetts General Hospital. Previous studies have shown mixed results in looking for brain changes from marijuana use, perhaps because of differences in the techniques used, he and others noted in Wednesday's issue of the Journal of Neurosciences. The study is among the first to focus on possible brain effects in recreational pot smokers, said Dr. Nora Volkow, director of the National Institute on Drug Abuse. The federal agency helped pay for the work. She called the work important but preliminary. The 20 pot users in the study, ages 18 to 25, said they smoked marijuana an average of about four days a week, for an average total of about 11 joints. Half of them smoked fewer than six joints a week. Researchers scanned their brains and compared the results with those of 20 nonusers who were matched for age, sex and other traits. The results showed differences in two brain areas associated with emotion and motivation - the amygdala and the nucleus accumbens. Users showed higher density than nonusers, as well as differences in shape of those areas. Both differences were more pronounced in those who reported smoking more marijuana. © 2014 Hearst Communications, Inc.
A high-resolution map of the human brain in utero is providing hints about the origins of brain disorders including schizophrenia and autism. The map shows where genes are turned on and off throughout the entire brain at about the midpoint of pregnancy, a time when critical structures are taking shape, researchers Wednesday in the journal Nature. "It's a pretty big leap," says , an investigator at the in Seattle who played a central role in creating the map. "Basically, there was no information of this sort prior to this project." Having a map like this is important because many psychiatric and behavioral problems appear to begin before birth, "even though they may not manifest until teenage years or even the early 20s," says , director of the . The human brain is often called the most complex object in the universe. Yet its basic architecture is created in just nine months, when it grows from a single cell to more than 80 billion cells organized in a way that will eventually let us think and feel and remember. "We're talking about a remarkable process," a process controlled by our genes, Lein says. So he and a large team of researchers decided to use genetic techniques to create a map that would help reveal this process. Funding came from the 2009 federal stimulus package. The massive effort required tens of thousands of brain tissue samples so small that they had to be cut out with a laser. Researchers used brain tissue from aborted fetuses, which the Obama administration has authorized over the objections of abortion opponents. ©2014 NPR
A new study has raised new questions about how MRI scanners work in the quest to understand the brain. The research, led by Professor Brian Trecox and a team of international researchers, used a brand new technique to assess fluctuations in the performance of brain scanners as they were being used during a series of basic experiments. The results are due to appear in the Journal of Knowledge in Neuroscience: General later today. “Most people think that we know a lot about how MRI scanners actually work. The truth is, we don’t,” says Trecox. “We’ve even been misleading the public about the name – we made up functional Magnetic Resonance Imaging in 1983 because it sounded scientific and technical. fMRI really stands for flashy, Magically Rendered Images. So we thought: why not put an MRI scanner in an MRI scanner, and figure out what’s going on inside?” To do this, Trecox and his team built a giant imaging machine – thought to be the world’s largest – using funds from a Kickstarter campaign and a local bake sale. They then took a series of scans of standard-sized MRI scanners while they were repeatedly switched on and off, in one of the largest and most robust neuroscience studies of its type. “We tested six different MRI scanners,” says Eric Salmon, a PhD student involved in the project. “We found activation in an area called insular cortex in four of the six machines when they were switched on,” he added. In humans, the insular cortex has previously been implicated in a wide range of functions, including consciousness and self-awareness. According to Trecox and his team, activation in this area has never been found in imaging machines before. While Salmon acknowledged that the results should be treated with caution – research assistants were found asleep in at least two of the machines – the results nevertheless provide a potentially huge step in our understanding of the tools we use to research the brain. © 2014 Guardian News and Media Limited
Keyword: Brain imaging
Link ID: 19435 - Posted: 04.01.2014
Matt Wall Given the media coverage brain imaging studies get, you might think that they are constantly revealing important secrets about this mysterious organ. Catherine Loveday thinks otherwise. She makes the point that using brain-scanning technology to understand what a diseased brain is doing is only of academic interest. It is the study of the mind through behaviour and other cognitive functions, she argues, that leads to useful insights about disorders and treatments. There is some truth here, but as a scientist who uses brain scans every day, I would argue that they contribute a lot more than Loveday gives them credit for. The main problem is that, when it comes to the brain, all analogies are hopelessly crude. The distinction between hardware and software – or the brain and the mind – only has limited practical usefulness. Since all mental processes arise as a result of brain processes, it follows that all mental problems are also a result of dysfunctions in the physical brain. This will be seen by many as an extreme and reductionist position, but a specific example should help to show that it has some value. Parkinson’s disease is a degenerative disorder that causes a variety of symptoms including motor problems, sleep disturbance, various cognitive issues, and often depression. This variety of symptoms might suggest that the underlying problem in Parkinson’s is quite broad and complex, affecting several brain systems. However, it turns out the cause of all these symptoms is quite specific: a loss of neurons in a region of the brain called the substantia nigra. © 2014 Guardian News and Media Limited
Keyword: Brain imaging
Link ID: 19414 - Posted: 03.27.2014
Sara Reardon The US brain-research programme aims to create tools to image and control brain activity, while its European counterpart hopes to create a working computational model of the organ. It seems a natural pairing, almost like the hemispheres of a human brain: two controversial and ambitious projects that seek to decipher the body's control center are poised to join forces. The European Union’s €1-billion (US$1.3-billion) Human Brain Project (HBP) and the United States’ $1-billion Brain Research through Advancing Innovative Neurotechnologies (BRAIN) Initiative will launch a collaboration later this year, according to government officials involved in both projects. Representative Chaka Fattah (Democrat, Pennslyvania) hinted at the plan in a speech on 12 March. The brain, he says, ”is something that has defied understanding. You can't imagine a more important scientific cooperation”, says Fattah, the highest-ranking Democratic member of a House of Representatives panel that oversees funding for several US science agencies. Details about how closely the US and European programmes will coordinate are still nebulous, but US government officials say that the effort will include all of the BRAIN Initiative's government partners — the US National Institutes of Health (NIH), the National Science Foundation and Defense Advanced Research Projects Agency. Henry Markram, a neuroscientist at the Swiss Federal Institute of Technology in Lausanne (EPFL), who directs the HBP, says that Israel's brain initiative will also be involved. © 2014 Nature Publishing Group
Keyword: Brain imaging
Link ID: 19384 - Posted: 03.19.2014
By Klint Finley Today’s neuroscientists need expertise in more than just the human brain. They must also be accomplished hardware engineers, capable of building new tools for analyzing the brain and collecting data from it. There are many off-the-shelf commercial instruments that help you do such things, but they’re usually expensive and hard to customize, says Josh Siegle, a doctoral student at the Wilson Lab at MIT. “Neuroscience tends to have a pretty hacker-oriented culture,” he says. “A lot of people have a very specific idea of how an experiment needs to be done, so they build their own tools.” The problem, Siegle says, is that few neuroscientists share the tools they build. And because they’re so focused on creating tools for their specific experiments, he says, researchers don’t often consider design principles like modularity, which would allow them to reuse tools in other experiments. That can mean too much redundant work as researchers spend time solving problems others already have solved, and building things from scratch instead of repurposing old tools. ‘We just want to build awareness of how open source eliminates redundancy, reduces costs, and increases productivity’ That’s why Siegle and Jakob Voigts of the Moore Lab at Brown University founded Open Ephys, a project for sharing open source neuroscience hardware designs. They started by posting designs for the tools they use to record electrical signals in the brain. They hope to kick start an open source movement within neuroscience by making their designs public, and encouraging others to do the same. “We don’t necessarily want people to use our tools specifically,” Siegle says. “We just want to build awareness of how open source eliminates redundancy, reduces costs, and increase productivity.” © 2014 Condé Nast.
Link ID: 19353 - Posted: 03.12.2014
Penis envy. Repression. Libido. Ego. Few have left a legacy as enduring and pervasive as Sigmund Freud. Despite being dismissed long ago as pseudoscientific, Freudian concepts such as these not only permeate many aspects of popular culture, but also had an overarching influence on, and played an important role in the development of, modern psychology, leading Time magazine to name him as one of the most important thinkers of the 20th century. Before his rise to fame as the founding father of psychoanalysis, however, Freud trained and worked as a neurologist. He carried out pioneering neurobiological research, which was cited by Santiago Ramóny Cajal, the father of modern neuroscience, and helped to establish neuroscience as a discipline. The eldest of eight children, Freud was born on 6 May, 1856, in the Moravian town of Příbor, in what is now the Czech Republic. Four years later, Freud's father Jakob, a wool merchant, moved the family to Austria in search of new business opportunities. Freud subsequently entered the university there, aged just 17, to study medicine and, in the second year of his degree, became preoccupied with scientific research. His early work was a harbinger of things to come – it focused on the sexual organs of the eel. The work was, by all accounts, satisfactory, but Freud was disappointed with his results and, perhaps dismayed by the prospect of dissecting more eels, moved to Ernst Brücke's laboratory in 1877. There, he switched to studying the biology of nervous tissue, an endeavour that would last for 10 years. © 2014 Guardian News and Media Limited
Link ID: 19350 - Posted: 03.12.2014
By BENEDICT CAREY Jack Belliveau, a Harvard scientist whose quest to capture the quicksilver flare of thought inside a living brain led to the first magnetic resonance image of human brain function, died on Feb. 14 in San Mateo, Calif. He was 55. The cause was complications of a gastrointestinal disorder, said his wife, Brigitte Poncelet-Belliveau, a researcher who worked with him at the Athinoula A. Martinos Center for Biomedical Imaging at Massachusetts General Hospital. He lived in Boston. His wife said he died suddenly while visiting an uncle at his childhood home, which he owned. Dr. Belliveau was a 30-year-old graduate student at the Martinos Center when he hatched a scheme to “see” the neural trace of brain activity. Doctors had for decades been taking X-rays and other images of the brain to look for tumors and other lesions and to assess damage from brain injuries. Researchers had also mapped blood flow using positron emission tomography scans, but that required making and handling radioactive trace chemicals, whose signature vanished within minutes. Very few research centers had the technical knowledge or the machinery to pull it off. Dr. Belliveau tried a different approach. He had developed a technique to track blood flow, called dynamic susceptibility contrast, using an M.R.I. scanner that took split-second images, faster than was usual at the time. This would become a standard technique for assessing blood perfusion in stroke patients and others, but Dr. Belliveau thought he would try it to spy on a normal brain in the act of thinking or perceiving. “He went out to RadioShack and bought a strobe light, like you’d see in a disco,” said Dr. Bruce Rosen, director of the Martinos Center and one of Dr. Belliveau’s advisers at the time. “He thought the strobe would help image the visual areas of the brain, where there was a lot of interest.” © 2014 The New York Times Company
Keyword: Brain imaging
Link ID: 19337 - Posted: 03.10.2014
Sara Reardon A flipped mental switch is all it takes to make a fly fall in love — even if its object of desire is a ball of wax. A technique called thermogenetics allows researchers to control fly behaviour by activating specific neurons with heat. Combining the system with techniques that use light to trigger neurons could help to elucidate how different neural circuits work together to control complex behaviours such as courtship. Optogenetics — triggering neurons with light — has been successful in mice but has not been pursued much in flies, says Barry Dickson, a neuroscientist at the Howard Hughes Medical Institute's Janelia Farm Research Campus in Ashburn, Virginia. A fibre-optic cable embedded in a mouse’s brain can deliver light to cells genetically engineered to make light-activated proteins, but flies are too small for these fibre optics. Neither will these cells be activated when the flies are put into an illuminated box, because most wavelengths of visible light cannot penetrate a fly’s exoskeleton. Heat can penetrate the exoskeleton, however. Researchers have already studied fly behaviour by adding a heat-activated protein called TRPA1 to neural circuits that control behaviours such as mating and decision-making. When these flies are placed in a hot box, the TRPA1 neurons begin to fire within minutes and drive the fly’s actions1. But it would be better to trigger the behaviours more quickly. So Dickson’s lab has developed a system called the Fly Mind-Altering Device (FlyMAD), which uses a video camera to track the fly as it moves around in a box. The device then shines an infrared laser at the fly to deliver heat directly to the head. Dickson’s group presented the system last October at the Neurobiology of Drosophila conference at Cold Spring Harbor Laboratory in New York, and he is now submitting the work to a peer-reviewed journal. © 2014 Nature Publishing Group
Brendan Borrell Scientists can now take snapshots of where and how thousands of genes are expressed in intact tissue samples, ranging from a slice of a human brain to the embryo of a fly. The technique, reported today in Science1, can turn a microscope slide into a tool for creating data-rich, three-dimensional maps of how cells interact with one another — a key to understanding the origins of diseases such as cancer. The methodology also has broader applications, enabling researchers to create, for instance, unique molecular ‘barcodes’ to trace connections between cells in the brain, a stated goal of the US National Institutes of Health's Human Connectome Project. Previously, molecular biologists had a limited spatial view of gene expression, the process by which a stretch of double-stranded DNA is turned into single-stranded RNAs, which can in turn be translated into protein products. Researchers could either grind up a hunk of tissue and catalogue all the RNAs they found there, or use fluorescent markers to track the expression of up to 30 RNAs inside each cell of a tissue sample. The latest technique maps up to thousands of RNAs. Mapping the matrix In a proof-of-principle study, molecular biologist George Church of Harvard Medical School in Boston, Massachusetts, and his colleagues scratched a layer of cultured connective-tissue cells and sequenced the RNA of cells that migrated to the wound during the healing process. Out of 6,880 genes sequenced, the researchers identified 12 that showed changes in gene expression, including eight that were known to be involved in cell migration but had not been studied in wound healing, the researchers say. “This verifies that the technique could be used to do rapidly what has taken scientists years of looking at gene products one by one,” says Robert Singer, a molecular cell biologist at Albert Einstein College of Medicine in New York, who was not involved in the study. © 2014 Nature Publishing Group,