By Scicurious They are Captain Planet! Ok, not quite. But, strangely, antidepressants on top of stress hormones may be stronger than they are alone. Why is this? And what’s going on? Well, we’re not quite sure. The most commonly prescribed antidepressant (and antianxiety) medications out there are the SSRI, selective serotonin reuptake inhibitors. These include drugs like fluoxetine (Prozac), citalopram (Celexa), or sertraline (Zoloft). How these drugs work, however, is still up for debate. At first, everyone thought that, because these drugs increase levels of the neurotransmitter serotonin in the brain, that depression must be caused by low levels of serotonin, and the increase would make you feel better. We have since learned that this is not the case. Headaches don’t result from lack of aspirin, and depression doesn’t result from lack of serotonin. The next theory for how depression, and antidepressants, might work was the neurogenesis theory. We used to believe that you were born with all the neurons you’d ever have, but we now know that neurogenesis, the birth of new neurons, occurs throughout life in areas of the brain like the hippocampus, an area usually associated with learning and memory. Antidepressants can increase neurogenesis, on a time course which matches the clinical efficacy of antidepressants. © 2012 Scientific American

Keyword: Depression; Stress
Link ID: 16851 - Posted: 05.29.2012

By NICHOLAS BAKALAR Babies delivered by Caesarean section may have an increased risk of obesity by age 3, a new study has found. Among 1,255 women recruited in early pregnancy for the study, 284 gave birth by Caesarean section. By age 3, 15.7 percent of those children were obese (with a body mass index in the 95th percentile or greater), compared with 7.5 percent of those delivered vaginally. Mothers who delivered by Caesarean were on average heavier than those who delivered vaginally, and they breast-fed less. But after controlling for these and other maternal health and socioeconomic factors, the scientists found that Caesarean delivery was associated with a doubling of the odds of obesity in these children. Whether the Caesarean was planned or an emergency delivery made no difference. “Those mothers who are considering C-section in the absence of a medical indication should be counseled about this potential risk,” said the lead author, Dr. Susanna Y. Huh, an assistant professor of pediatrics at Harvard. Babies born by Caesarean develop different intestinal flora from those born vaginally, and the authors suggest this could be a factor. Or, the mode of delivery might have long-term effects on immune or endocrine function. The report was published online Wednesday in The Archives of Disease in Childhood. Copyright 2012 The New York Times Company

Keyword: Obesity; Development of the Brain
Link ID: 16850 - Posted: 05.29.2012

By Meehan Crist For decades researchers have known that our ability to remember everyday experiences depends on a slender belt of brain tissue called the hippocampus. Basic memory functions, such as forming new memories and recalling old ones, were thought to be performed along this belt by different sets of neurons. Now findings suggest that the same neurons in fact perform both these very different functions, changing from one role to another as they age. The vast majority of these hippocampal neurons, called granule cells, develop when we are very young and remain in place throughout our lives. But about 5 percent develop in adulthood through the birth of new neurons, a process known as neurogenesis. Young granule cells help form new memories, but as they get older they switch roles to helping recall the past. Newer granule cells pick up the slack, taking on the role of helping to form new memories. Susumu Tonegawa of the Massachusetts Institute of Technology and his colleagues published the findings on March 30 in the journal Cell. Tonegawa’s team tested the role of these adult-born cells by genetically engineering mice in which the old cells could be selectively turned off. They then put the mice through a series of mazes and fear-conditioning tests, which demonstrated that young granule cells are essential to forming separate memories of similar events, whereas old granule cells are essential to recalling past events based on small cues. This discovery suggests that memory impairments common in aging and in post-traumatic stress disorder may be connected to an imbalance of old and new cells. “If you don’t have a normal amount of young cells, you may have a problem distinguishing between two events that would be seen as different by healthy people,” Tonegawa says. At the same time, the presence of too many old cells would make it easier to recall traumatic past experiences based on current cues. © 2012 Scientific American,

Keyword: Learning & Memory; Neurogenesis
Link ID: 16849 - Posted: 05.29.2012

By Morgen E. Peck Tracking eye movements lets scientists figure out what we pay attention to in a scene. When people blink during such experiments, those few milliseconds are usually discarded as junk data. A new study finds that blinking might reveal important information, too. It turns out that the more we blink, the less focused is our attention. In kids with autism, blink patterns appear to offer clues about how they engage with the world around them. During eye-tracking experiments with toddlers, Warren Jones, a pedia­trician at the Emory University School of Medicine, found that the children were strategic about when they blinked. While watching a recorded scene, the toddlers seemed to inhibit their blink­ing during the moments that sucked them in. “The timing of when we don’t blink seems to relate to how engaged we are with what we’re looking at,” Jones says. He now uses this discovery as a tool to study attention in autistic children. In a paper published last December in the Proceedings of the National Academy of Sciences USA, Jones observed differences in the blinking patterns of autistic and develop­mentally normal children. Both groups watched a video that included moments of human emotion and sudden action. Developmentally normal children inhibited their blinking before emo­tional climaxes, as though they were following the narrative and predicting an outcome. Autistic children blinked right through those moments, sug­gesting they were not following the emotional arc of the story, but they responded sharply when an object suddenly moved. © 2012 Scientific American,

Keyword: Autism; Attention
Link ID: 16848 - Posted: 05.29.2012

By Keith Seinfeld If you came face to face with a great whale, you might find a few surprises in its chin: Like whiskers, if you look closely at the surface. And, hidden inside the chin, lies a mysterious sensory organ, unknown to centuries of whalers and biologists. You just need the right tools to find it: a high-tech, oversized x-ray machine, and the right saws to slice it into thin pieces that fit in a microscope. A group of scientists based at the University of British Columbia, in Vancouver, BC, have done all that looking—and they discovered an organ that serves a crucial purpose and answers a longstanding mystery. Here is a graphic from the science study, published in Nature (expand the graphic to full screen to for best browsing of the information and images): How do great whales, such as humpbacks and blues, drive their jaws so wide open and then snap them shut, while swimming at full speed? “These heads are five meters long and weigh close to ten tons,” says Nick Pyenson, first author of the new study, published in the journal Nature. He’s now the curator of fossil marine mammals at the Smithsonian Institution. “What we found in the course of our investigation into the jaw and skull anatomy was this surprising structure in the chin. We had no idea what it was.” KPLU is a service of Pacific Lutheran University | ©2012

Keyword: Pain & Touch; Evolution
Link ID: 16847 - Posted: 05.29.2012

by Jeff Hecht After overindulging in berries, flocks of cedar waxwings flew drunkenly to their doom. That's the conclusion of a new report in the Journal of Ornithology. Cedar waxwings have evolved to live on a diet that averages 84 per cent fruit. But those evolutionary innovations backfired on several occasions between 2005 and 2007 when flocks of them died after crashing into windows and fences in broad daylight in the Los Angeles area. Residents puzzled by the deaths sent the bodies to the California Animal Health and Food Safety Laboratory in San Bernardino. Necropsies performed by Hailu Kinde and colleagues at the lab showed the birds had been healthy when they gorged on berries from the Brazilian pepper tree, then died from ruptured livers or other traumas caused by the collisions. Flocking hell Cedar waxwings have the most fruit-rich diet of all North American birds, and dining on overripe berries can leave them visibly tipsy. Their short intestines can process large volumes of fruit, and their large livers – about 5 per cent of body mass – can break down toxic ethanol before it causes serious damage. Yet although earlier studies had found isolated birds that had died from collisions when flying drunk, no one had seen whole flocks careen to their doom. © Copyright Reed Business Information Ltd.

Keyword: Drug Abuse; Evolution
Link ID: 16846 - Posted: 05.26.2012

by Linda Geddes SECOND by second changes in the brain's pH can be visualised for the first time. This ability may provide fresh insights into learning, memory and disease. Oxygen deprivation can alter the brain's pH, and even normal brain signals from acidic neurotransmitters or metabolic by-products such as lactic acid may lead to local changes in pH. Studies in mice have also uncovered pH-sensitive receptors in brain areas involved in emotion and memory - although their function is something of a mystery. "If these receptors are activated by pH change, it's possible that abnormalities in this system could lead to changes in learning, memory and mood," says Vincent Magnotta at the University of Iowa in Iowa City. A common way of studying the brain is with an MRI scanner, which detects differences in the spin of protons in tissues according to water content. Although brain pH can be measured using a form of MRI called MR spectroscopy, it only detects changes that occur over minutes - not fast enough to keep up with the rapid pace of the brain. T1ρ MRI analyses the interaction between spinning protons and other ions in a solution, which changes under different pHs. By tweaking the technique so that multiple measurements could be taken simultaneously, Magnotta and his colleagues have found that T1ρ MRI can detect changes in brain acidity happening over seconds. © Copyright Reed Business Information Ltd.

Keyword: Brain imaging
Link ID: 16845 - Posted: 05.26.2012

by Elizabeth Norton Do our brains continue to produce neurons throughout our lifetimes? That's been one of the most hotly debated questions in the annals of science. Since the 1950s, studies have hinted at the possibility, but not until the late 1990s did research prove that the birth of new neurons, called neurogenesis, goes on in the brains of adult primates and humans. Now a surprising new study in humans shows that in the olfactory bulb-the interface between the nose and the brain and an area long—known to be a hot spot of neurogenesis—new neurons may be born but not survive. The finding may rule out neurogenesis in this area, or it might show only that some people don't stimulate their brains enough through the sense of smell, some researchers say. Previous studies have found evidence of neurogenesis in the olfactory bulb of adult humans. But those studies measured only proteins produced by immature neurons, leaving open the question of whether these youngsters ever grew up to connect with other cells to form functional networks, says neuroscientist Jonas Frisén of the Karolinska Institute in Stockholm. If new olfactory neurons really reached adulthood throughout a person's life, researchers should find neurons of a variety of ages in this region. That's not what Frisén and his team saw. The discovery is based on a technique he and his colleague Kirsty Spalding hit upon in 2005, in which they found a clever way to deduce the age of neurons. The method relies on atomic testing carried out in the 1950s and 1960s, which released massive amounts of carbon-14 into the atmosphere; the atmospheric 14C has been steadily declining ever since. Thus, the later a cell is born after this testing, the less 14C it contains. © 2010 American Association for the Advancement of Science.

Keyword: Chemical Senses (Smell & Taste); Neurogenesis
Link ID: 16844 - Posted: 05.26.2012

By Jason G. Goldman Getting around is complicated business. Every year, animals traverse miles of sky and sea (and land), chasing warmth or food or mates as the planet rotates and the seasons change. And with such precision! Some animals rely on visual landmarks, others on subtle changes in magnetic fields, and yet others match their internal clocks with the movement of the sun and stars across the sky. One researcher, Jennifer A. Mather, wondered: how do octopuses navigate? Do they rely on chemotactile sensory information, or do they orient towards visual landmarks? Octopuses occupy “homes” for several days or in some instances for several weeks, and when they go out looking for food, they are sometimes gone for several hours at a time. Therefore, they must use some sort of memory to find their way back home. Many molluscs use trail-following, and follow their own mucus trails, or the trails of others. You might expect that octopuses use trail-following as well, since they forage by using chemotactile exploration – at least four different types of receptors on their suckers gather chemical and tactile information as they move along the rocky seafloor. However, many other species use visual scene recognition to aid in navigation: ants, bees, gerbils, hamsters, pigeons, and even humans, use visual landmarks to navigate around their environments. Since octopuses use visual information to distinguish among different objects, they could use visual landmarks to get home as well. © 2012 Scientific American

Keyword: Animal Migration; Chemical Senses (Smell & Taste)
Link ID: 16843 - Posted: 05.26.2012

Sandrine Ceurstemont, editor, New Scientist TV It's the closest any of us are likely to get to telekinesis. New animations created by Stuart Anstis from the University of California, San Diego, are showing how changing your gaze can alter the direction in which objects are moving. If you watch this video normally, the moving circles in the first animation rotate while the shifting dots in the second clip follow a horizontal path. But if you look away and watch the movie out of the corner of your eye, the direction of motion will appear to change. In both cases, the moving objects seem to follow the direction of the background stripes. The illusion proves that we perceive motion very differently when it's in the periphery compared with when it's picked up by the fovea, a tiny area at the back of the eye responsible for central vision. Looking at a scene directly results in the sharpest vision, whereas our peripheral vision is good at picking up motion but poor at making out the details of shapes. "That's why when you wave at someone in a crowded airport, your peripheral motion detectors pick up the motion and an eye movement steers the target onto the fovea for more detailed analysis," says Anstis. The animation was a finalist in the 2012 Best Illusion of the Year Contest and was presented earlier this month at the event gala in Naples, Florida. © Copyright Reed Business Information Ltd

Keyword: Vision
Link ID: 16842 - Posted: 05.26.2012

Why do those first hot days of the year feel so bad? Because our bodies' best methods of coping with heat haven’t been tested in three seasons. But if you’re slogging though your work or workout now, you are already starting the process of acclimatization, which will make you better able to withstand heat all summer. These changes can happen in as little as two weeks, according to Lawrence Armstrong, a bioenergetics expert who has studied heat’s effect on the body since 1982. © 1996-2012 The Washington Post

Keyword: Miscellaneous
Link ID: 16841 - Posted: 05.26.2012

By Susan Milius New high-speed video of the tropical bats swooping toward various frogs and toads shows that the predators deploy a sequence of senses to update their judgment of prey during an attack to avoid eating a toxic amphibian, says behavioral ecologist Rachel Page of the Smithsonian Tropical Research Institute in Gamboa, Panama. The bats proved hard to fool even when researchers played the call of a favorite edible frog while offering up another species, Page and her colleagues report in an upcoming Naturwissenschaften. In the tropics, various bats will nab a frog if given half a chance, but only the fringe-lipped species (Trachops cirrhosus) is known to follow frog calls, such as the “tuuun chuck” call of the túngara frog (Engystomops pustulosus). In tests in Panama, Page and her colleagues found that fringe-lipped bats turned aside in mid-air if researchers broadcast enticing túngara calls but offered up a cane toad (Rhinella marina), which is way too big for a bat to carry off. The possibility that incoming bats might use echolocation to avoid overweight prey intrigues bat specialist Brock Fenton at the University of Western Ontario in Canada. Early studies of these bats largely ignored possible last-minute echolocation, he says. The new tests also revealed that playing túngara calls while offering a right-sized but toxic leaf litter toad (Rhinella alata) led bats to catch and then drop the unpleasant prey. (Both bats and toads survived.) © Society for Science & the Public 2000 - 2012

Keyword: Hearing
Link ID: 16840 - Posted: 05.26.2012

By Ferris Jabr Lia Kvavilashvili sat in her office at the University of Hertfordshire, mentally reviewing a study she had recently published. She knew that there was a particular statistical measure that might have been useful in the study, but she could not remember its name. Frustrated, she got up to make a cup of tea. Suddenly the word "hurdle" popped into her mind, unannounced, uninvited. Kvavilashvili—who grew up in Georgia speaking Georgian, Russian and Estonian, and only started to learn English at age 13—had no idea what "hurdle" meant. She looked it up in her dictionary. The second definition was underlined. Although she had no conscious recollection of it, Kvavilashvili had evidently looked up the meaning of "hurdle" before. Somehow, she concluded, her subconscious knew that the word was relevant to her difficulty remembering the name of the useful statistical measure. She had just experienced what she and a few other psychologists call "mind-pops"—fragments of knowledge, such as words, images or melodies that drop suddenly and unexpectedly into consciousness. In most cases, mind-pops seem completely irrelevant to the moments in time and thought into which they intrude. But Kvavilashvili is discovering that mind-pops are not truly random—they are linked to our experiences and knowledge of the world, albeit with hidden threads. Research on mind-pops is preliminary, but so far studies suggest that the phenomenon is genuine and common. Some people notice their mind-pops far more often than others and frequent mind-popping could quicken problem solving and boost creativity. However, in some people's minds—such as those with schizophrenia—mind-pops might evolve from benign phenomena into unsettling hallucinations. © 2012 Scientific American

Keyword: Learning & Memory; Attention
Link ID: 16839 - Posted: 05.24.2012

By Tina Hesman Saey People may be born with all the smell-sensing brain cells they will ever have, a new study concludes. That makes human brains different from those of rodents, nonhuman primates and other mammals, which constantly make new nerve cells, or neurons, in the odor-processing olfactory bulb. Humans don’t rely on the sense of smell as much as other animals do, so maybe it isn’t surprising that people don’t make new odor-sensing cells, says study author Jonas Frisén, a neuroscientist at the Karolinska Institute in Stockholm. Neurons are born in two areas: a memory-and-learning center called the hippocampus and the subventricular zone, which surrounds the two vacant spaces in the middle of the brain. In mice, neurons from the subventricular zone migrate to the olfactory bulb and wire into neural circuits, helping the animals learn new smells. Some evidence exists already that humans also repopulate their hippocampus with new neurons, but data have been less clear for olfactory neurons. Now, Frisén and colleagues have used the steady decline of radiocarbon produced in 20th century nuclear tests to determine the birth dates of brain cells. The results, published in the May 24 Neuron, show that few if any olfactory neurons are created after a person’s birth. A very small number of neurons may still be born and incorporated in the olfactory bulb, but may not be enough to matter. The researchers calculate that olfactory neurons are replaced at a rate of less than 1 percent per century in humans, compared with about 50 percent annually in rodents. © Society for Science & the Public 2000 - 2012

Keyword: Chemical Senses (Smell & Taste); Neurogenesis
Link ID: 16838 - Posted: 05.24.2012

Researchers have shown in mice how immune cells in the brain target and remove unused connections between brain cells during normal development. This research, supported by the National Institutes of Health, sheds light on how brain activity influences brain development, and highlights the newly found importance of the immune system in how the brain is wired, as well as how the brain forms new connections throughout life in response to change. Disease-fighting cells in the brain, known as microglia, can prune the billions of tiny connections (or synapses) between neurons, the brain cells that transmit information through electric and chemical signals. This new research demonstrates that microglia respond to neuronal activity to select synapses to prune, and shows how this pruning relies on an immune response pathway — the complement system — to eliminate synapses in the way that bacterial cells or other pathogenic debris are eliminated. The study was led by Beth Stevens, Ph.D., assistant professor of neurology at Boston Children's Hospital and Harvard Medical School. The brain is created with many more synapses than it retains into adulthood. As the brain develops, it goes through dynamic changes to refine its circuitry, trimming away the synaptic connections that do not have a lot of activity, and preserving the stronger, more active synapses. This period, known as synaptic pruning, is a key part of normal brain development. Scientists do not have a clear understanding of how these synapses are selected, targeted and then pruned. However, precise elimination of unused synapses and strengthening those that are most needed is essential for normal brain function. Many childhood disorders, such as amblyopia (a loss of vision in one eye that can occur when the eyes are misaligned), various forms of mental retardation, epilepsy and autism are thought to be due to abnormal brain development.

Keyword: Development of the Brain; Glia
Link ID: 16837 - Posted: 05.24.2012

By Stephani Sutherland Amputees who experience phantom limb pain can sometimes get relief from an optical illusion. This trick involves looking in a mirror at the reflection of a healthy limb from a certain angle, which causes it to appear where the missing limb should be. Seeing the limb move freely fools the brain into relieving the pain. Now a study suggests this technique might also work for arthritis pain. Cognitive scientist Laura Case, working in the lab of Vilayanur S. Ramachandran (a member of Scientific American Mind’s board of advisers) at the University of California, San Diego, used a modified version of the mirror technique to superimpose a researcher’s healthy hand over a subject’s arthritic hand, which was painfully constricted or contorted. Subjects mimicked the slow, purposeful movements of the researcher’s hand with their own unseen hand. After experiencing the illusion of their hand moving smoothly, subjects rated their arthritis pain slightly lower than before and had an increased range of motion. The result suggests that the toxic soup of inflammatory molecules bathing an arthritic joint is not the only source of painful sensations. “The brain has learned to associate movement with pain,” says Case, who presented her results at the Society for Neuroscience meeting last November in Washington, D.C. The illusion provides the brain with a way to disconnect the sight from the sensation. Next, the group will investigate whether this type of mirror therapy might provide long-term benefits for arthritis, a condition that affects about 50 million Americans. © 2012 Scientific American,

Keyword: Pain & Touch; Vision
Link ID: 16836 - Posted: 05.24.2012

Meredith Wadman Of the top ten leading causes of death in the United States, Alzheimer’s disease — which ranks sixth — is particularly devastating in that there is no cure, no way to prevent it and no proven way to slow its progression. And with at least 11 million Americans expected to have the disease by the middle of the century (see ‘Degeneration generation’) — boosting the annual costs of health care to more than US$1 trillion — the US government is anxiously looking to researchers to improve the prognosis. Last week, the government set out how it planned to spend a $50-million top-up to this year’s funding for the National Institutes of Health (NIH) in Bethesda, Maryland, announced in February as part of a bid to “prevent and effectively treat Alzheimer’s disease by 2025”. The money adds to the $448 million that the NIH was allocated to spend on the disease this year, and roughly half of it is already being used by scientists funded by the National Human Genome Research Institute and the National Institute on Aging. They are preparing to conduct whole-genome and whole-exome studies to discover mutations that may predispose someone to the disease or protect against it. The scientists are assembling a bank of thousands of DNA samples from patients and other people whose DNA could be informative — such as elderly individuals who carry predisposing mutations but show no sign of the disease. The first results from the effort are expected as early the end of this year. © 2012 Nature Publishing Group,

Keyword: Alzheimers
Link ID: 16835 - Posted: 05.23.2012

By Fergus Walsh Medical correspondent Many patients with advanced cancer and other debilitating conditions are being "under-treated" for their pain, new guidance from the health watchdog says. NICE wants doctors in England and Wales to make more use of morphine and other strong opioids - the only adequate pain relief source for many patients. The guidelines recommend doctors discuss patients' concerns. These may include addiction, tolerance, side-effects and fears that treatment implies the final stage of life. The guidance deals with five opioids: morphine, diamorphine (heroin), buprenorphine, fentanyl and oxycodone. They come either from the opium poppy or are synthetically produced versions. NICE - the National Institute for Clinical Excellence - says "misinterpretations and misunderstanding" have surrounded the use of strong opioids for decades, which has resulted in errors "causing under-dosing and avoidable pain, or overdosing and distressing adverse effects". There is also the legacy of Dr Harold Shipman who used diamorphine to murder his victims. It has made many doctors wary of prescribing strong opioids. NICE says the aim is to improve both pain management and patient safety. BBC © 2012

Keyword: Pain & Touch
Link ID: 16834 - Posted: 05.23.2012

by Peter Aldhous If ever we develop a DeLorean-based time machine, it would be handy to send information into the past revealing what kind of medical research to focus on. For years, actor Michael J. Fox was on the front line of the US's "stem cell wars", arguing that embryonic stem cells could cure conditions like his own – Parkinson's disease. Last week Fox revealed he now believes that other lines of research hold more promise. "There have been some issues with stem cells, some problems along the way," Fox told ABC News. "An answer may come from stem cell research but it's more than likely to come from another area." Complicated business The Michael J. Fox Foundation, based in New York City, is still backing stem cell research, says its chief scientific adviser, Gene Johnson of Washington University in St Louis, but has shifted its emphasis in recent years. "Using stem cells as therapeutic agents is a very complicated business," Johnson says. Obstacles include working out how to get transplanted cells to integrate into the brain, and developing "off-the-shelf" cell lines that can be used for any recipient. Meanwhile, other avenues are speeding towards clinical trials. These include neurotrophic factors – proteins that promote the survival of nerve cells – as well as antibodies that target the alpha-synuclein protein, which may be a cause of the brain damage seen in Parkinson's. © Copyright Reed Business Information Ltd.

Keyword: Parkinsons; Stem Cells
Link ID: 16833 - Posted: 05.23.2012

By Partha Mitra Frontiers are in short supply. No explorer will again catch that first glimpse of the Pacific Ocean with “wild surmise,” take the first steps on the moon, or arrive first at the Challenger deep – the remotest corners of the earth are now tourist attractions. Even in science, great mysteries have fallen – life itself has gone from being the subject of metaphysical speculation about vital substances to the biophysical understanding of cellular processes. Uncharted territories, both physical and metaphorical, are hard to find. Yet there is one largely unmapped continent, perhaps the most intriguing of them all, because it is the instrument of discovery itself: the human brain. It is the presumptive seat of our thoughts, and feelings, and consciousness. Even the clinical criteria for death feature the brain prominently, so it arbitrates human life as well. One would think, that after a century of intensive research, its outlines would be well known to us: after all, colorful pictures of brain activity have been making regular appearances in the news media for some time. However, if one scratches the surface, our knowledge of how the human brain is put together remains limited: not in some esoteric, complicated manner, but in the straightforward sense that we have simply no means to visualize entire neurons in the brain (and the brain, being a collection of neurons, therefore remains a shut book in important ways). We can’t see them in their full glory, even with all our advanced technology. The problem is that compared to other cells visualized under a microscope, neurons are at the same time very small, and very big. While their soma (cell bodies) are like other cells, neurons can send out branches (axons) that travel very long distances, sometimes several feet, which don’t fit into the sections of tissue that we do histology on. © 2012 Scientific American,

Keyword: Brain imaging
Link ID: 16832 - Posted: 05.23.2012