Chapter 13. Memory and Learning

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Links 1 - 20 of 1926

By Laura Sanders It’s a bit like seeing a world in a grain of sand. Except the view, in this case, is the exquisite detail inside a bit of human brain about half the size of a grain of rice. Held in that minuscule object is a complex collective of cells, blood vessels, intricate patterns and biological puzzles. Scientists had hints of these mysteries in earlier peeks at this bit of brain (SN: 6/29/21). But now, those details have been brought into new focus by mapping the full landscape of some 57,000 cells, 150 million synapses and their accompanying 23 centimeters of blood vessels, researchers report in the May 10 Science. The full results, the scientists hope, may lead to greater insights into how the human brain works. “We’re going in and looking at every individual connection attached to every cell — a very high level of detail,” says Viren Jain, a computational neuroscientist at Google Research in Mountain View, Calif. The big-picture goal of brain mapping efforts, he says, is “to understand how human brains work and what goes wrong in various kinds of brain diseases.” The newly mapped brain sample was removed during a woman’s surgery for epilepsy, so that doctors could reach a deeper part of the brain. The bit, donated with the woman’s consent, was from the temporal lobe of the cortex, the outer part of the brain involved in complex mental feats like thinking, remembering and perceiving. This digital drawing of a person's head shows the brain inside. An arrow points to the bottom left side of the brain. After being fixed in a preservative, the brain bit was sliced into almost impossibly thin wisps, and then each slice was imaged with a high-powered microscope. Once these views were collected, researchers used computers to digitally reconstruct the three-dimensional objects embedded in the piece of brain. © Society for Science & the Public 2000–2024

Keyword: Brain imaging; Development of the Brain
Link ID: 29324 - Posted: 05.25.2024

By Yasemin Saplakoglu György Buzsáki first started tinkering with waves when he was in high school. In his childhood home in Hungary, he built a radio receiver, tuned it to various electromagnetic frequencies and used a radio transmitter to chat with strangers from the Faroe Islands to Jordan. He remembers some of these conversations from his “ham radio” days better than others, just as you remember only some experiences from your past. Now, as a professor of neuroscience at New York University, Buzsáki has moved on from radio waves to brain waves to ask: How does the brain decide what to remember? By studying electrical patterns in the brain, Buzsáki seeks to understand how our experiences are represented and saved as memories. New studies from his lab and others have suggested that the brain tags experiences worth remembering by repeatedly sending out sudden and powerful high-frequency brain waves. Known as “sharp wave ripples,” these waves, kicked up by the firing of many thousands of neurons within milliseconds of each other, are “like a fireworks show in the brain,” said Wannan Yang, a doctoral student in Buzsáki’s lab who led the new work, which was published in Science in March. They fire when the mammalian brain is at rest, whether during a break between tasks or during sleep. Sharp wave ripples were already known to be involved in consolidating memories or storing them. The new research shows that they’re also involved in selecting them — pointing to the importance of these waves throughout the process of long-term memory formation. It also provides neurological reasons why rest and sleep are important for retaining information. Resting and waking brains seem to run different programs: If you sleep all the time, you won’t form memories. If you’re awake all the time, you won’t form them either. “If you just run one algorithm, you will never learn anything,” Buzsáki said. “You have to have interruptions.” © 2024 the Simons Foundation.

Keyword: Learning & Memory
Link ID: 29322 - Posted: 05.23.2024

By Angie Voyles Askham Some questions about neurons, such as how they give rise to behavior, are tricky to answer when those cells are embedded within their natural milieu. “Is residence in a nervous system sufficient to allow synapses to form?” says Kristin Baldwin, professor of genetics and development at Columbia University. “Are synapses that we can see sufficient to allow communication? And is synaptic communication sufficient to actually endow an animal with a set of behaviors that would be appropriate for it?” The best way to answer those questions is to put the cells in a new environment where their extrinsic and intrinsic influences can be teased apart, says Xin Jin, assistant professor of neuroscience at the Scripps Research Institute. For a long time, Jin says, that new environment was the unnatural setting of a petri dish. But two new studies that make use of chimeric mice—animals with both mouse and rat cells in their brain—point to another option: One demonstrates how rat stem cells can restore a mouse’s ability to smell, whereas the other shows how rat stem cells can give rise to a forebrain in mice that would otherwise lack one. The studies were published last month in Cell. Because rat brains are larger than mouse brains and develop at a different rate, the chimeras enable researchers to probe the competing forces of a cell’s intrinsic programming and its external environment. The work opens up doors for new research and the ability to explore the origins of species-specific cellular behaviors, says Jin, who was not involved in either study. “It’s sort of a fundamental ‘nature versus nurture,’” says Baldwin, who led one of the new studies. © 2024 Simons Foundation

Keyword: Development of the Brain
Link ID: 29312 - Posted: 05.18.2024

By Lee Alan Dugatkin 1 The complexity of animal social behavior is astonishing I have studied animal behavior for more than 35 years, so I’m rarely surprised at just how nuanced, subtle, and complex the social behavior of nonhuman animals can be. But, every once in a while, that “my goodness, how astonishing!” feeling—which I felt so often in graduate school—returns. That’s how I felt when I read Kevin Oh and Alexander Badyaev’s work on sexual selection and social networks in house finches (Haemorhous mexicanus). The house finches in question, I learned while researching my book, live on the campus of the University of Arizona, where, in 2003, Oh was doing his graduate work and Badyaev was a young assistant professor. Using data on thousands of finches they banded over six years, these two researchers were able to map the social network the birds relied on during breeding season. This network was composed of 25 “neighborhoods” with an average of 30 finches per group. Females rarely left their neighborhoods to interact with birds in other neighborhoods. But how much males moved around from one neighborhood to the next depended on their coloring. Those with plenty of red coloration—which females tend to prefer as mating partners—generally remained put, just like females. But drabber colored males were more likely to socialize across many neighborhoods. The question was why? The answer was what rekindled my own sense of awe in the power of natural selection to shape animal social behavior. When Oh and Bedyaev mapped reproductive success in their house finches, they found that the most colorful males did well no matter what neighborhood they were in. Drab males, however, had greater reproductive success if they tried their luck all around town—essentially, this allowed them to find just the spot where their relative coloration was greatest and therefore most likely to score them a mate. In other words, they learned to play the field, restructuring social networks in a way that served their purposes best. 2 Technology is radically changing how scientists study the behavior of animals © 2024 NautilusNext Inc.,

Keyword: Learning & Memory; Evolution
Link ID: 29305 - Posted: 05.14.2024

By Carissa Wong Researchers have mapped a tiny piece of the human brain in astonishing detail. The resulting cell atlas, which was described today in Science1 and is available online, reveals new patterns of connections between brain cells called neurons, as well as cells that wrap around themselves to form knots, and pairs of neurons that are almost mirror images of each other. The 3D map covers a volume of about one cubic millimetre, one-millionth of a whole brain, and contains roughly 57,000 cells and 150 million synapses — the connections between neurons. It incorporates a colossal 1.4 petabytes of data. “It’s a little bit humbling,” says Viren Jain, a neuroscientist at Google in Mountain View, California, and a co-author of the paper. “How are we ever going to really come to terms with all this complexity?” The brain fragment was taken from a 45-year-old woman when she underwent surgery to treat her epilepsy. It came from the cortex, a part of the brain involved in learning, problem-solving and processing sensory signals. The sample was immersed in preservatives and stained with heavy metals to make the cells easier to see. Neuroscientist Jeff Lichtman at Harvard University in Cambridge, Massachusetts, and his colleagues then cut the sample into around 5,000 slices — each just 34 nanometres thick — that could be imaged using electron microscopes. Jain’s team then built artificial-intelligence models that were able to stitch the microscope images together to reconstruct the whole sample in 3D. “I remember this moment, going into the map and looking at one individual synapse from this woman’s brain, and then zooming out into these other millions of pixels,” says Jain. “It felt sort of spiritual.” When examining the model in detail, the researchers discovered unconventional neurons, including some that made up to 50 connections with each other. “In general, you would find a couple of connections at most between two neurons,” says Jain. Elsewhere, the model showed neurons with tendrils that formed knots around themselves. “Nobody had seen anything like this before,” Jain adds. © 2024 Springer Nature Limited

Keyword: Brain imaging; Development of the Brain
Link ID: 29304 - Posted: 05.14.2024

Nicola Davis Science correspondent Having two copies of a gene variant known to predispose people to Alzheimer’s could in fact represent a distinct genetic form of the disease, researchers have said. The variant, known as ApoE4, has long been known to increase the risk of developing Alzheimer’s, with two copies conferring greater risk than one. Now research has revealed almost everyone with two copies of the variant goes on to develop Alzheimer’s disease (AD), suggesting it is not only a risk factor but a cause. “Over 95% of the individuals [with two copies of ApoE4], have AD pathology either in the brain or in the biomarkers that we analysed,” said Dr Juan Fortea, the co-author of the research from the Sant Pau hospital in Barcelona. The video player is currently playing an ad. His team said the predicability of the age at which symptoms began was similar to other genetic forms of the disease such as autosomal-dominant Alzheimer’s disease (ADAD) and Alzheimer’s disease in Down syndrome (DSAD). Dr Victor Montal, a co-author from Barcelona Supercomputing Center, said the research had catalysed a paradigm shift in the understanding of the disease. “Whereas previously, the etiology of dementia was known in less than 1% of cases, our work has now enabled the identification of causative factors in over 15% of instances,” he said. However, the study did not shed light on the risk of developing dementia itself for people with two copies of ApoE4. © 2024 Guardian News & Media Limited

Keyword: Alzheimers; Genes & Behavior
Link ID: 29292 - Posted: 05.07.2024

By Gayathri Vaidyanathan An orangutan in Sumatra surprised scientists when he was seen treating an open wound on his cheek with a poultice made from a medicinal plant. It’s the first scientific record of a wild animal healing a wound using a plant with known medicinal properties. The findings were published this week in Scientific Reports1. “It shows that orangutans and humans share knowledge. Since they live in the same habitat, I would say that’s quite obvious, but still intriguing to realize,” says Caroline Schuppli, a primatologist at the Max Planck Institute of Animal Behavior in Konstanz, Germany, and a co-author of the study. In 2009, Schuppli’s team was observing Sumatran orangutans (Pongo abelii) in the Gunung Leuser National Park in South Aceh, Indonesia, when a young male moved into the forest. He did not have a mature male’s big cheek pads, called flanges, and was probably around 20 years old, Schuppli says. He was named Rakus, or ‘greedy’ in Indonesian, after he ate all the flowers off a gardenia bush in one sitting. In 2021, Rakus underwent a growth spurt and became a mature flanged male. The researchers observed Rakus fighting with other flanged males to establish dominance and, in June 2022, a field assistant noted an open wound on his face, possibly made by the canines of another male, Schuppli says. Days later, Rakus was observed eating the stems and leaves of the creeper akar kuning (Fibraurea tinctoria), which local people use to treat diabetes, dysentery and malaria, among other conditions. Orangutans in the area rarely eat this plant. In addition to eating the leaves, Rakus chewed them without swallowing and used his fingers to smear the juice on his facial wound over seven minutes. Some flies settled on the wound, whereupon Rakus spread a poultice of leaf-mash on the wound. He ate the plant again the next day. Eight days after his injury, his wound was fully closed. © 2024 Springer Nature Limited

Keyword: Learning & Memory; Evolution
Link ID: 29290 - Posted: 05.03.2024

By Dana G. Smith When it comes to aging, we tend to assume that cognition gets worse as we get older. Our thoughts may slow down or become confused, or we may start to forget things, like the name of our high school English teacher or what we meant to buy at the grocery store. But that’s not the case for everyone. For a little over a decade, scientists have been studying a subset of people they call “super-agers.” These individuals are age 80 and up, but they have the memory ability of a person 20 to 30 years younger. Most research on aging and memory focuses on the other side of the equation — people who develop dementia in their later years. But, “if we’re constantly talking about what’s going wrong in aging, it’s not capturing the full spectrum of what’s happening in the older adult population,” said Emily Rogalski, a professor of neurology at the University of Chicago, who published one of the first studies on super-agers in 2012. A paper published Monday in the Journal of Neuroscience helps shed light on what’s so special about the brains of super-agers. The biggest takeaway, in combination with a companion study that came out last year on the same group of individuals, is that their brains have less atrophy than their peers’ do. The research was conducted on 119 octogenarians from Spain: 64 super-agers and 55 older adults with normal memory abilities for their age. The participants completed multiple tests assessing their memory, motor and verbal skills; underwent brain scans and blood draws; and answered questions about their lifestyle and behaviors. The scientists found that the super-agers had more volume in areas of the brain important for memory, most notably the hippocampus and entorhinal cortex. They also had better preserved connectivity between regions in the front of the brain that are involved in cognition. Both the super-agers and the control group showed minimal signs of Alzheimer’s disease in their brains. © 2024 The New York Times Company

Keyword: Learning & Memory; Development of the Brain
Link ID: 29280 - Posted: 04.30.2024

Jon Hamilton Scientists have found a way to restore brain cells impaired by a rare and life-threatening genetic disorder called Timothy syndrome. A type of drug known as an antisense oligonucleotide allowed clusters of human neurons to develop normally even though they carried the mutation responsible for Timothy syndrome, a team reports in the journal Nature. The approach may help researchers develop treatments for other genetic conditions, including some that cause schizophrenia, epilepsy, ADHD, and autism spectrum disorder. "It's immensely exciting because we now have the tools," says Dr. Sergiu Pasca, a professor of psychiatry and behavioral sciences at Stanford University and the study's senior author. "It's the beginning of a new era for many of these diseases that we first thought were untreatable," says Dr. Huda Zoghbi, a professor at Baylor College of Medicine who was not involved in the research. But most of these conditions involve multiple genes, not just one — and scientists don't yet know enough about these multiple gene disorders to effectively treat them with antisense oligonucleotides, Zoghbi says. Timothy Syndrome has been diagnosed in fewer than 100 people worldwide. Children born with it often have heart problems, autism, epilepsy, developmental delay, and intellectual disability. But because Timothy syndrome is caused by a mutation in a single gene, it offers scientists a way to study changes that affect brain development. "Rare syndromes that are very clearly defined genetically are sort of like windows, or Rosetta Stones, into understanding other, more common conditions," Pasca says. © 2024 npr

Keyword: Autism; Genes & Behavior
Link ID: 29277 - Posted: 04.30.2024

By Laura Sanders What does it feel like to be a rat? We will never know, but some very unusual mice may now have an inkling. In a series of new experiments, bits of rat brain grew inside the brains of mice. Donor stem cells from rats formed elaborate — and functional — neural structures in mice’s brains, despite being from a completely different species, researchers report in two papers published April 25 in Cell. The findings are “remarkable,” says Afsaneh Gaillard, a neuroscientist at INSERM and the University of Poitiers in France. “The ability to generate specific neuronal cells that can successfully integrate into the brain may provide a solution for treating a variety of brain diseases associated with neuronal loss.” These chimeric mice are helping to reveal just how flexible brain development can be (SN: 3/29/23). And while no one is suggesting that human brains could be grown in another animal, the results may help clarify biological details relevant to interspecies organ transplants, the researchers say. The success of these rat-mouse hybrids depended on timing: The rat and mouse cells had to grow into brains together from a very young stage. Stem cells from rats that had the potential to mature into several different cell types were injected into mouse embryos. From there, these rat cells developed alongside mice cells in the growing brain, though researchers couldn’t control exactly where the rat cells ended up. In one set of experiments, researchers first cleared the way for these rat cells to develop in the young mouse brains. Stem cell biologist Jun Wu and colleagues used a form of the genetic tool CRISPR to inactivate a mouse gene that instructs their brain cells to build a forebrain, a large region involved in learning, remembering and sensing the world. This left the mice without forebrains — normally, a lethal problem. © Society for Science & the Public 2000–2024.

Keyword: Development of the Brain; Neurogenesis
Link ID: 29274 - Posted: 04.26.2024

Sofia Quaglia Noise pollution from traffic stunts growth in baby birds, even while inside the egg, research has found. Unhatched birds and hatchlings that are exposed to noise from city traffic experience long-term negative effects on their health, growth and reproduction, the study found. “Sound has a much stronger and more direct impact on bird development than we knew before,” said Dr Mylene Mariette, a bird communication expert at Deakin University in Australia and a co-author of the study, published in the journal Science. “It would be wise to work more to reduce noise pollution.” A growing body of research has suggested that noise pollution causes stress to birds and makes communication harder for them. But whether birds are already distressed at a young age because they are affected by noise, or by how noise disrupts their environment and parental care, was still unclear. Mariette’s team routinely exposed zebra finch eggs for five days to either silence, soothing playbacks of zebra finch songs, or recordings of city traffic noises such as revving motors and cars driving past. They did the same with newborn chicks for about four hours a night for up to 13 nights, without exposing the birds’ parents to the sounds. They noticed that the bird eggs were almost 20% less likely to hatch if exposed to traffic noise. The chicks that did hatch were more than 10% smaller and almost 15% lighter than the other hatchlings. When the team ran analyses on their red blood cells and their telomeres – a piece of DNA that shortens with stress and age – they were more eroded and shorter than their counterparts’. The effects continued even after the chicks were no longer exposed to noise pollution, and carried over into their reproductive age four years later. The birds disturbed by noise during the early stages of their lives produced fewer than half as many offspring as their counterparts. © 2024 Guardian News & Media Limited

Keyword: Hearing; Development of the Brain
Link ID: 29273 - Posted: 04.26.2024

By Sara Reardon Researchers have hailed organoids — 3D clusters of cells that mimic aspects of human organs — as a potential way to test drugs and even eliminate some forms of animal experimentation. Now, in two studies published on 24 April in Nature1,2, biologists have developed gut and brain organoids that could improve understanding of colon cancer and help to develop treatments for a rare neurological disorder. “In the last ten years, people spent a lot of time to develop and understand how to make organoids,” says Shuibing Chen, a chemical biologist at Weill Cornell Medical College in New York City. “But this is the time now to think more about how to use” the models. Organoids — particularly those made from human stem cells — sometimes reveal things that animal models can’t, says Sergiu Pașca, a neuroscientist at Stanford University in California and a co-author of one of the studies1. Pașca’s group studies Timothy syndrome: a genetic disorder involving autism, neurological problems and heart conditions that affects only a few dozen people in the world. Timothy syndrome is caused by a single mutation in a gene called CACNA1C, which encodes a channel through which calcium ions enter cells including neurons. Pașca says that there are no good animal models for Timothy syndrome because the underlying mutation doesn’t always cause the same symptoms in rodents. “It became very clear to us we’d need to find a way of testing in vivo,” he says. © 2024 Springer Nature Limited

Keyword: Development of the Brain
Link ID: 29271 - Posted: 04.26.2024

By Diana Kwon Overall, people in U.S. live longer than they did a hundred years ago. The growing number of people reaching old age has meant an increased proportion are at risk of developing dementia or Alzheimer’s disease, illnesses that typically strike later in life. However, researchers have found that, in the U.S. and elsewhere, dementia risk may actually be decreasing, at least in a subset of the population. A new study provides a potential explanation for this trend: Human brains may be getting larger—and thus more resilient to degeneration—over time. Several large population studies in countries including the U.S. and Great Britain have found that, in recent decades, the number of new cases, or incidence, of dementia has declined. Among these is the Framingham Heart Study, which has been collecting data from individuals living in Framingham, Massachusetts since 1948. Now accommodating a third generation of participants, the study includes data from more than 15,000 people. In 2016, Sudha Seshadri, a neurologist at UT Health San Antonio and her colleagues published findings revealing that while the prevalence—the total number of people with dementia—had increased, the incidence had declined since the late 1970s. “That was a piece of hopeful news,” Seshadri says. “It suggested that over 30 years, the average age at which somebody became symptomatic had gone up.” These findings left the team wondering: What was the cause of this reduced dementia risk? While the cardiovascular health of the Framingham residents and their descendants—which can influence the chances of developing dementia—had also improved over the decades, this alone could not fully explain the decline. On top of that, the effect only appeared in people who had obtained a high school diploma, which, according to Seshadri, pointed to the possibility that greater resilience against dementia may result from changes that occur in early life. © 2024 SCIENTIFIC AMERICAN,

Keyword: Development of the Brain; Learning & Memory
Link ID: 29265 - Posted: 04.20.2024

By Saima S. Iqbal Before becoming a researcher, Aimee Grant worked as a caregiver for six years in Cornwall, England, supporting autistic adults in group homes. But only more than a decade later, after befriending an autistic colleague at a sociology conference, did she realize she was autistic herself. The stereotypical view of autism as a brain impairment more commonly found in men made it difficult for Grant to make sense of her internal world. From an early age, she struggled to pick up on important social cues and found the sounds and scents in her environment distractingly painful. But like many children in her generation, she says, she grew accustomed to either dismissing or disguising her discomfort. It was by listening to some of the stories of her female peers that Grant saw that the label could fit. Receiving a diagnosis in 2019 prompted her to “reframe [my] entire life,” she says. She began working with her mind rather than against it. She no longer felt the same pressure to seem as nonautistic as possible with friends and family members, and she began to make use of accommodations at work, such as a light filter for her computer monitor. Today, as a public health researcher at Swansea University in Wales, Grant aims to uncover the lived experience of autistic people. Many scientists and clinicians see autism as a developmental disorder that hinders a person’s ability to understand and communicate with others. Grant believes that their work often obscures the heterogeneity of autism. And because many studies view autism as a disease, they overlook the reality that autistic people can feel more disabled by widespread misunderstanding and a lack of accommodations than by autistic traits themselves. © Society for Science & the Public 2000–2024.

Keyword: Autism
Link ID: 29261 - Posted: 04.20.2024

By Bob Holmes Like many of the researchers who study how people find their way from place to place, David Uttal is a poor navigator. “When I was 13 years old, I got lost on a Boy Scout hike, and I was lost for two and a half days,” recalls the Northwestern University cognitive scientist. And he’s still bad at finding his way around. The world is full of people like Uttal — and their opposites, the folks who always seem to know exactly where they are and how to get where they want to go. Scientists sometimes measure navigational ability by asking someone to point toward an out-of-sight location — or, more challenging, to imagine they are someplace else and point in the direction of a third location — and it’s immediately obvious that some people are better at it than others. “People are never perfect, but they can be as accurate as single-digit degrees off, which is incredibly accurate,” says Nora Newcombe, a cognitive psychologist at Temple University who coauthored a look at how navigational ability develops in the 2022 Annual Review of Developmental Psychology. But others, when asked to indicate the target’s direction, seem to point at random. “They have literally no idea where it is.” While it’s easy to show that people differ in navigational ability, it has proved much harder for scientists to explain why. There’s new excitement brewing in the navigation research world, though. By leveraging technologies such as virtual reality and GPS tracking, scientists have been able to watch hundreds, sometimes even millions, of people trying to find their way through complex spaces, and to measure how well they do. Though there’s still much to learn, the research suggests that to some extent, navigation skills are shaped by upbringing. Nurturing navigation skills

Keyword: Learning & Memory
Link ID: 29255 - Posted: 04.13.2024

By Joanne Silberner In March, the sons of Gabriel García Márquez, the Nobel Prize-winning Colombian writer, published a posthumous novel against the specific wishes their father expressed before he died in 2014 at the age of 87. García Márquez had struggled through several versions of the book as dementia set in, and, perhaps stung by uncharacteristic negative reviews from his previous novel, didn’t want the new one published. “Until August,” the story of a woman who travels to her mother’s grave once a year and takes a new lover on each visit, got mixed reviews. Some were outright harsh. In The New York Times, Michael Greenberg wrote “It would be hard to imagine a more unsatisfying goodbye.” García Márquez’s decline, he continued, “seems to have been steep enough to prevent him from holding together the kind of imagined world that the writing of fiction demands.” Wendy Mitchell, who was an administrator with England’s National Health Service until her diagnosis of early-onset Alzheimer’s disease in 2014, recalled the moment she learned of the publication plans last year. “I type every day for fear of dementia snatching away that creative skill, which I see as my escape from dementia,” she wrote last October in The Guardian. “Maybe Márquez thought the same?” The novel’s publication raises some vital questions about living with an aging and perhaps ailing brain. What do mild cognitive impairment and dementia do to our creativity? How do these conditions affect our ability to use words, formulate sentences, and craft stories? Neuroscientists have been exploring these questions for several decades. First, a few definitions. People with mild cognitive impairment have lost more of their cognitive functioning than others their age, and often struggle to remember things. But they’re capable of managing daily activities like dressing, eating, bathing, and finding their way around. In dementia, cognitive difficulties have increased enough to interfere with daily life, and personality changes are more likely.

Keyword: Alzheimers
Link ID: 29254 - Posted: 04.13.2024

By Nicole Rust We readily (and reasonably) accept that the causes of memory dysfunction, including Alzheimer’s disease, reside in the brain. The same is true for many problems with seeing, hearing and motor control. We acknowledge that understanding how the brain supports these functions is important for developing treatments for their corresponding dysfunctions, including blindness, deafness and Parkinson’s disease. Applying the analogous assertion to mood—that understanding how the brain supports mood is crucial for developing more effective treatments for mood disorders, such as depression—is more controversial. For brain researchers unfamiliar with the controversy, it can be befuddling. You might hear, “Mental disorders are psychological, not biological,” and wonder, what does that mean, exactly? Experts have diverse opinions on the matter, with paper titles ranging from “Brain disorders? Not really,” to “Brain disorders? Precisely.” Even though a remarkable 21 percent of adults in the United States will experience a mood disorder at some point in their lives, we do not fully understand what causes them, and existing treatments do not work for everyone. How can we best move toward an impactful understanding of mood and mood disorders, with the longer-term goal of helping these people? What, if anything, makes mood fundamentally different from, say, memory? The answer turns out to be complex and nuanced—here, I hope to unpack it. I also ask brain and mind researchers with diverse perspectives to chime in. Among contemporary brain and mind researchers, I have yet to find any whose position is driven by the notion that some force in the universe beyond the brain, like a nonmaterial soul, gives rise to mood. Rather, the researchers generally agree that our brains mediate all mental function. If everyone agrees that both memory and mood disorders follow from things that happen in the brain, why would the former but not the latter qualify as “brain disorders”? © 2024 Simons Foundation

Keyword: Depression; Learning & Memory
Link ID: 29251 - Posted: 04.11.2024

By Helen Bradshaw Walk into a gas station in the United States, and you may see more than just boxes of cigarettes lining the back wall. Colorful containers containing delta-8, a form of the substance THC, are sold in gas stations and shops across the country, and teens are buying them. A recent survey of more than 2,000 U.S. high school seniors found that more than 11 percent of them had used delta-8 in the past year, researchers report March 12 in JAMA. This is the first year the Monitoring the Future study, one of the leading nationally representative surveys of drug use trends among adolescents in the United States, looked at delta-8 use. Because more than 1 in 10 senior students said they used the drug, the survey team plans to monitor delta-8 use every year going forward. “We don’t really want to see any kids being exposed to cannabis, because it potentially increases their risk for developmental harms … and some psychiatric reactions” such as suicidal thoughts, says Alyssa Harlow, a researcher on the survey and an epidemiologist at the University of Southern California Keck School of Medicine in Los Angeles. Despite its prevalence, especially in the South and the Midwest, delta-8 is still new to consumers and research. Science News talked with Harlow and addiction researcher Jessica Kruger of the University of Buffalo in New York to help explain the delta-8 craze and its effects on kids. What is delta-8-THC? Cannabis plants contain over 100 compounds known as cannabinoids. Delta-8 is one of them. The most well-known is delta-9-tetrahydrocannabinol, or delta-9-THC. © Society for Science & the Public 2000–2024.

Keyword: Drug Abuse
Link ID: 29248 - Posted: 04.11.2024

Jon Hamilton Sam and John Fetters, 19, are identical twins at opposite ends of the autism spectrum. Sam is a sophomore at Amherst College who plans to double major in history and political science. In his free time, he runs marathons. John attends a special school, struggles to form sentences, and likes to watch "Teletubbies" and "Sesame Street." Two brothers. Same genes. Different flavors of autism. To scientists, twins like Sam and John pose an important question: How can a disorder that is known to be highly genetic look so different in siblings who share the same genome? "That is one of the greatest mysteries right now in research on autism," says Dr. Stephanie Morris, a pediatric neurologist at the Kennedy Krieger Institute in Baltimore. Solving that mystery could help explain autism's odd mix of nature and nurture, Morris says. It also might help "modify the trajectory" of autistic children experiencing speech and language delays, or difficulty with social communication. Identical twins on separate paths Sam and John are spending the weekend with their mom, Kim Leaird, at the family's apartment in West Tisbury, a small town on Martha's Vineyard. The twins are crowded together on a couch. Even seated, they look tall. Standing, Sam is 6 feet five inches, his brother just an inch shorter. John lets Sam do most of the talking. He frequently touches his brother, who sometimes takes his hand. John has "a truly tremendous amount of empathy," Sam says. "He's able to be very supportive." © 2024 npr

Keyword: Autism; Genes & Behavior
Link ID: 29239 - Posted: 04.04.2024

by Alex Blasdel Patient One was 24 years old and pregnant with her third child when she was taken off life support. It was 2014. A couple of years earlier, she had been diagnosed with a disorder that caused an irregular heartbeat, and during her two previous pregnancies she had suffered seizures and faintings. Four weeks into her third pregnancy, she collapsed on the floor of her home. Her mother, who was with her, called 911. By the time an ambulance arrived, Patient One had been unconscious for more than 10 minutes. Paramedics found that her heart had stopped. After being driven to a hospital where she couldn’t be treated, Patient One was taken to the emergency department at the University of Michigan. There, medical staff had to shock her chest three times with a defibrillator before they could restart her heart. She was placed on an external ventilator and pacemaker, and transferred to the neurointensive care unit, where doctors monitored her brain activity. She was unresponsive to external stimuli, and had a massive swelling in her brain. After she lay in a deep coma for three days, her family decided it was best to take her off life support. It was at that point – after her oxygen was turned off and nurses pulled the breathing tube from her throat – that Patient One became one of the most intriguing scientific subjects in recent history. For several years, Jimo Borjigin, a professor of neurology at the University of Michigan, had been troubled by the question of what happens to us when we die. She had read about the near-death experiences of certain cardiac-arrest survivors who had undergone extraordinary psychic journeys before being resuscitated. Sometimes, these people reported travelling outside of their bodies towards overwhelming sources of light where they were greeted by dead relatives. Others spoke of coming to a new understanding of their lives, or encountering beings of profound goodness. Borjigin didn’t believe the content of those stories was true – she didn’t think the souls of dying people actually travelled to an afterworld – but she suspected something very real was happening in those patients’ brains. In her own laboratory, she had discovered that rats undergo a dramatic storm of many neurotransmitters, including serotonin and dopamine, after their hearts stop and their brains lose oxygen. She wondered if humans’ near-death experiences might spring from a similar phenomenon, and if it was occurring even in people who couldn’t be revived. © 2024 Guardian News & Media Limited

Keyword: Consciousness; Attention
Link ID: 29236 - Posted: 04.02.2024