By Daniela Hirschfeld Peter Mombaerts is a man of strong preferences. He likes Belgian beer — partly, but not entirely, for patriotic reasons. He likes classical music and observing the Earth from above while flying small planes with his amateur pilot’s license. He loves the feel of alpaca clothing during winter. But Mombaerts, who leads the Max Planck Research Unit for Neurogenetics in Frankfurt, Germany, says he has no favorite odor — even though he has been studying smells for more than 30 years. Mombaerts’s research has focused on how the brain processes odors, and on the impressive group of genes encoding odorant receptors in mammals. Humans have about 400 of these genes, which means that 2 percent of our roughly 20,000 genes help us to smell — the largest gene family known to date, as Mombaerts noted back in 2001 in the Annual Review of Genomics and Human Genetics. More than two decades later, it remains the record holder, and Mombaerts continues to delve into the genetics and neuroscience of how we smell the world around us. He spoke with Knowable Magazine about what’s been learned about the genes, receptors and neurons involved in sensing odors — and the mysteries that remain. This interview has been edited for length and clarity. Why did you start working on smell? When studying medicine in my native Belgium in the 1980s, I learned that I don’t really like to work so much with patients. But research interested me. I wanted to do neurobiology. I did my PhD in immunology with mice and genetics, and then moved to neuroscience. It was what I always wanted to do, but I had to find the right topic, the right lab and the right mentor — and all that came together when Linda Buck and Richard Axel published their paper about their discovery of the genes for odorant receptors. This paper came out in the journal Cell on April 5, 1991, and when I read the first few sentences I thought, “That’s what I want to work on.” Axel became my postdoc mentor. When Buck and Axel won the Nobel Prize in Physiology or Medicine in 2004, I wrote a Perspective piece for the New England Journal of Medicine  that I titled “Love at First Smell.” © 2024 Annual Reviews

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29469 - Posted: 09.07.2024

Nicola Davis Science correspondent Researchers have gained new insight into how and why some people experience depression after finding a particular brain network is far bigger in people living with the condition. The surface of the brain is a communication junction box at which different areas talk to each other to carry out particular processes. But there is a finite amount of space for these networks to share. Now researchers say that in people with depression, a larger part of the brain is involved in the network that controls attention to rewards and threats than in those without depression. “It’s taking up more real estate on the brain surface than we see is typical in healthy controls,” said Dr Charles Lynch, a co-author of the research, from Weill Cornell Medicine in New York. He added that expansion meant the size of other – often neighbouring – brain networks were smaller. Writing in the journal Nature, Lynch and colleagues report how they used precision functional mapping, a new approach to brain imaging that analyses a host of fMRI (functional MRI) scans from each individual. The team applied this method to 141 people with depression and 37 people without it, enabling them to measure accurately the size of each participant’s brain networks. They then took the average size for each group. They found that a part of the brain called the frontostriatal salience network was expanded by 73% on average in participants with depression compared with healthy controls. © 2024 Guardian News & Media Limited

Keyword: Depression; Brain imaging
Link ID: 29468 - Posted: 09.07.2024

By Christina Jewett The number of teenagers who reported using e-cigarettes in 2024 has tumbled from a worrisome peak reached five years ago, raising hopes among public health officials for a sustained reversal in vaping trends among adolescents. In an annual survey conducted from January through May in schools across the nation, fewer than 8 percent of high school students reported using e-cigarettes in the past month, the lowest level in a decade. That’s far lower than the apex, in 2019, when more than 27 percent of high school students who took the survey reported that they vaped — and an estimated 500,000 fewer adolescents than last year. The data is from the National Youth Tobacco Survey, a questionnaire filled out by thousands of middle and high school students that is administered each year by the Food and Drug Administration and the Centers for Disease Control and Prevention. Overall, it found that just under 6 percent of middle and high school students reported vaping in the last month, down from nearly 8 percent among those surveyed last year. Use among high school students largely accounted for this year’s decline; middle school use stayed fairly steady with 3.5 percent reporting they had vaped compared to 4.6 percent the year before. “I want to be unequivocally clear that this continued decline in e-cigarette use among our nation’s youth is a monumental public health win,” Brian King, the director of the F.D.A.’s tobacco division, said during a news briefing on Wednesday. Public health experts said several factors may have contributed to the decline in teenage vaping, including city and state flavored tobacco bans, a blitz of enforcement against sellers of flavored vapes and three public messaging campaigns aimed at young people about the dangers of vaping. © 2024 The New York Times Company

Keyword: Drug Abuse
Link ID: 29467 - Posted: 09.07.2024

Does a whiff of pollen trigger a sneeze or a cough? Scientists have discovered nerve cells that cause one response versus another: ‘sneeze neurons’ in the nasal passages relay sneeze signals to the brain, and separate neurons send cough messages, according to a study1 performed in mice. The findings could lead to new and improved treatments for conditions such as allergies and chronic coughs. That’s welcome news because these conditions can be “incredibly frustrating” and the side effects of current treatments can be “incredibly problematic”, says pulmonologist Matthew Drake at Oregon Health & Science University in Portland, who was not involved in the work. The study was published today in Cell. Previous work2 categorized neurons in the mouse airway on the basis of the proteins complexes, called ion channels, that are carried on the cell surfaces. To work out which nose neurons cause sneezing, researchers exposed mice to various compounds, each known to activate specific types of ion channel. They struck gold when a substance called BAM 8-22 left the mice sneezing. The compound is known to activate an ion channel called MrgprC11, leading the researchers to suspect that neurons carrying MrgprC11 cause sneezing. Indeed, when the researchers deleted MrgprC11 from the suspected sneeze neurons and then gave mice the flu, they found themselves with sick, but sneezeless, mice. Even with the sneeze neurons out of the picture, the sick mice continued to have cough-like reactions to influenza infection. Using methods similar to those that homed in on the sneeze neurons, the researchers tracked the cough response to a set of neurons in the trachea that express a signalling chemical called somatostatin. Viruses “evolve very quickly”, says neuroscientist and study co-author Qin Liu at Washington University in St. Louis, Missouri. That could explain why there are two separate systems capable of detecting and clearing them from the airways. © 2024 Springer Nature Limited

Keyword: Neuroimmunology
Link ID: 29466 - Posted: 09.07.2024

By Rodrigo Pérez Ortega Names can be deceiving. One might think “cerebrospinal fluid” only lives in the brain and spinal cord. Indeed, that’s what scientists and doctors have largely believed for centuries. But the clear liquid—which cleans, feeds, and protects the organs it surrounds—also bathes the body’s nerves, researchers report today in Science Advances. “This is one of the [most] important papers in this area,” says Karl Bechter, a clinical neurologist at Ulm University who was not involved in the study. In the past, he and others have suggested instances in which cerebrospinal fluid (CSF) permeates nerves, but he says this is the first study that shows it can travel far throughout the body. The finding could open new ways to deliver drugs to some of the most inaccessible parts of the body. The human body is a bundle of nerves. Besides the head honchos that make up the central nervous system—the brain and spinal cord—kilometers of spindly fibers snake their way throughout our anatomy. Here, they form a peripheral nervous system that fires the signals that allow us to do everything from walking to feeling pain. Yet even though the two systems interface, previous anatomy studies indicated CSF was restricted to the central nervous system. Things changed 2.5 years ago when Edward Scott, a stem cell biologist at the University of Florida, and his surgeon colleague Joe Pessa noticed something strange during a plastic surgery study. Pessa was researching ways to avoid damaging CSF-containing structures and nerves during surgical procedures. When the scientists injected saline into the brain chambers of human cadavers that contained CSF, a peripheral nerve in the wrist swelled up. They then decided to explore further, injecting a fluorescent liquid in live mice’s brain chambers to track where the liquid went. The dye somehow made its way to the sciatic nerve, which runs throughout the back of the leg. Intrigued, the team decided to repeat the experiment in mice using a much finer tracer: nanoparticles of gold. These tiny particles can be detected through both light and electron microscopy and can be tailored to specific sizes.

Keyword: Brain imaging; Biomechanics
Link ID: 29465 - Posted: 09.07.2024

By Jessica Silver-Greenberg and Katie Thomas Acadia Healthcare is one of America’s largest chains of psychiatric hospitals. Since the pandemic exacerbated a national mental health crisis, the company’s revenue has soared. Its stock price has more than doubled. But a New York Times investigation found that some of that success was built on a disturbing practice: Acadia has lured patients into its facilities and held them against their will, even when detaining them was not medically necessary. In at least 12 of the 19 states where Acadia operates psychiatric hospitals, dozens of patients, employees and police officers have alerted the authorities that the company was detaining people in ways that violated the law, according to records reviewed by The Times. In some cases, judges have intervened to force Acadia to release patients. Some patients arrived at emergency rooms seeking routine mental health care, only to find themselves sent to Acadia facilities and locked in. A social worker spent six days inside an Acadia hospital in Florida after she tried to get her bipolar medications adjusted. A woman who works at a children’s hospital was held for seven days after she showed up at an Acadia facility in Indiana looking for therapy. And after police officers raided an Acadia hospital in Georgia, 16 patients told investigators that they had been kept there “with no excuses or valid reason,” according to a police report. Acadia held all of them under laws meant for people who pose an imminent threat to themselves or others. But none of the patients appeared to have met that legal standard, according to records and interviews. Most doctors agree that people in the throes of a psychological crisis must sometimes be detained against their will to stabilize them and prevent harm. These can be tough calls, balancing patients’ safety with their civil rights. But at Acadia, patients were often held for financial reasons rather than medical ones, according to more than 50 current and former executives and staff members. © 2024 The New York Times Company

Keyword: Schizophrenia; Depression
Link ID: 29464 - Posted: 09.04.2024

By Kerri Smith The smell in the laboratory was new. It was, in the language of the business, tenacious: for more than a week, the odour clung to the paper on which it had been blotted. To researcher Alex Wiltschko, it was the smell of summertime in Texas: watermelon, but more precisely, the boundary where the red flesh transitions into white rind. “It was a molecule that nobody had ever seen before,” says Wiltschko, who runs a company called Osmo, based in Cambridge, Massachusetts. His team created the compound, called 533, as part of its mission to understand and digitize smell. His goal — to develop a system that can detect, predict or create odours — is a tall order, as molecule 533 shows. “If you looked at the structure, you would never have guessed that it smelled this way.” That’s one of the problems with understanding smell: the chemical structure of a molecule tells you almost nothing about its odour. Two chemicals with very similar structures can smell wildly different; and two wildly different chemical structures can produce an almost identical odour. And most smells — coffee, Camembert, ripe tomatoes — are mixtures of many tens or hundreds of aroma molecules, intensifying the challenge of understanding how chemistry gives rise to olfactory experience. Another problem is working out how smells relate to each other. With vision, the spectrum is a simple colour palette: red, green, blue and all their swirling intermediates. Sounds have a frequency and a volume, but for smell there are no obvious parameters. Where does an odour identifiable as ‘frost’ sit in relation to ‘sauna’? It’s a real challenge to make predictions about smell, says Joel Mainland, a neuroscientist at the Monell Chemical Senses Center, an independent research institute in Philadelphia, Pennsylvania. © 2024 Springer Nature Limited

Keyword: Chemical Senses (Smell & Taste)
Link ID: 29463 - Posted: 09.04.2024

Jon Hamilton Aging and Alzheimer's leave the brain starved of energy. Now scientists think they've found a way to aid the brain's metabolism — in mice. PM Images/Getty Images The brain needs a lot of energy — far more than any other organ in the body — to work properly. And aging and Alzheimer’s disease both seem to leave the brain underpowered. But an experimental cancer drug appeared to re-energize the brains of mice that had a form of Alzheimer’s — and even restore their ability to learn and remember. The finding, published in the journal Science, suggests that it may eventually be possible to reverse some symptoms of Alzheimer’s in people, using drugs that boost brain metabolism. The results also offer an approach to treatment that’s unlike anything on the market today. Current drugs for treating Alzheimer’s, such as lecanemab and donanemab, target the sticky amyloid plaques that build up in a patient’s brain. These drugs can remove plaques and slow the disease process, but do not improve memory or thinking. The result should help “change how we think about targeting this disease,” says Shannon Macauley, an associate professor at the University of Kentucky who was not involved in the study. The new research was prompted by a lab experiment that didn’t go as planned. A team at Stanford was studying an enzyme called IDO1 that plays a key role in keeping a cell’s metabolism running properly. They suspected that in Alzheimer’s disease, IDO1 was malfunctioning in a way that limited the brain’s ability to turn nutrients into energy. © 2024 npr

Keyword: Alzheimers; Learning & Memory
Link ID: 29462 - Posted: 09.04.2024

By Jan Hoffman The message emblazoned on a walkway window at the airport in Burlington, Vt., is a startling departure from the usual tourism posters and welcome banners: “Addiction is not a choice. It’s a disease that can happen to anyone.” The statement is part of a public service campaign in yet another community assailed by drug use, intended to reduce stigma and encourage treatment. For decades, medical science has classified addiction as a chronic brain disease, but the concept has always been something of a hard sell to a skeptical public. That is because, unlike diseases such as Alzheimer’s or bone cancer or Covid, personal choice does play a role, both in starting and ending drug use. The idea that those who use drugs are themselves at fault has recently been gaining fresh traction, driving efforts to toughen criminal penalties for drug possession and to cut funding for syringe-exchange programs. But now, even some in the treatment and scientific communities have been rethinking the label of chronic brain disease. In July, behavior researchers published a critique of the classification, which they said could be counterproductive for patients and families. “I don’t think it helps to tell people they are chronically diseased and therefore incapable of change. Then what hope do we have?” said Kirsten E. Smith, an assistant professor of psychiatry and behavioral sciences at Johns Hopkins School of Medicine and a co-author of the paper, published in the journal Psychopharmacology. “The brain is highly dynamic, as is our environment.” The recent scientific criticisms are driven by an ominous urgency: Despite addiction’s longstanding classification as a disease, the deadly public health disaster has only worsened. © 2024 The New York Times Company

Keyword: Drug Abuse
Link ID: 29461 - Posted: 09.04.2024

By Kevin Loria When you have obstructive sleep apnea, addressing it is key. Left untreated, sleep apnea is linked to daytime sleepiness and an increased risk of anxiety, diabetes, hypertension and stroke. With OSA, your breathing pauses during sleep because your tongue or relaxed throat muscles block your airway, explains Richard Schwab, chief of the division of sleep medicine at the University of Pennsylvania Perelman School of Medicine in Philadelphia. Losing weight, quitting smoking and limiting alcohol can all help ease obstructive sleep apnea symptoms such as snoring, says Ana Krieger, medical director of the Center for Sleep Medicine at Weill Cornell Medicine in New York City. Sleep apnea’s severity is determined by something called your apnea-hypopnea index (AHI): the number of times per hour you fully or partially stop breathing for 10 seconds or longer. The primary treatment for people with moderate (15 to 29 AHI) or severe (30 AHI and higher) obstructive sleep apnea is a continuous positive airway pressure (CPAP) machine, which keeps your airway open by pumping air through a mask you wear over your mouth and/or nose when you sleep. Many people have difficulty tolerating a CPAP and don’t stick with it, however. The good news is CPAP machines have become smaller and quieter, with more comfortable options available. And for some people with mild (5 to 14 AHI) or even moderate OSA, less-invasive alternatives to a CPAP may be worth considering. A dental device designed to move the jaw so that the tongue shifts toward the front of the mouth can help keep the airway open. It’s one of the primary alternatives to a CPAP, Schwab says, and can also be used with a CPAP to help make severe obstructive sleep apnea milder.

Keyword: Sleep
Link ID: 29460 - Posted: 09.04.2024

By Carl Zimmer The human brain, more than any other attribute, sets our species apart. Over the past seven million years or so, it has grown in size and complexity, enabling us to use language, make plans for the future and coordinate with one another at a scale never seen before in the history of life. But our brains came with a downside, according to a study published on Wednesday. The regions that expanded the most in human evolution became exquisitely vulnerable to the ravages of old age. “There’s no free lunch,” said Sam Vickery, a neuroscientist at the Jülich Research Center in Germany and an author of the study. The 86 billion neurons in the human brain cluster into hundreds of distinct regions. For centuries, researchers could recognize a few regions, like the brainstem, by hallmarks such as the clustering of neurons. But these big regions turned out to be divided into smaller ones, many of which were revealed only with the help of powerful scanners. As the structure of the human brain came into focus, evolutionary biologists became curious about how the regions evolved from our primate ancestors. (Chimpanzees are not our direct ancestors, but both species descended from a common ancestor about seven million years ago.) The human brain is three times as large as that of chimpanzees. But that doesn’t mean all of our brain regions expanded at the same pace, like a map drawn on an inflating balloon. Some regions expanded only a little, while others grew a lot. Dr. Vickery and his colleagues developed a computer program to analyze brain scans from 189 chimpanzees and 480 humans. Their program mapped each brain by recognizing clusters of neurons that formed distinct regions. Both species had 17 brain regions, the researchers found. © 2024 The New York Times Company

Keyword: Development of the Brain; Evolution
Link ID: 29459 - Posted: 08.31.2024

By Julian Nowogrodzki A newly devised ‘brain clock’ can determine whether a person’s brain is ageing faster than their chronological age would suggest1. Brains age faster in women, countries with more inequality and Latin American countries, the clock indicates. “The way your brain ages, it’s not just about years. It’s about where you live, what you do, your socio-economic level, the level of pollution you have in your environment,” says Agustín Ibáñez, the study’s lead author and a neuroscientist at Adolfo Ibáñez University in Santiago. “Any country that wants to invest in the brain health of the people, they need to address structural inequalities.” The work is “truly impressive”, says neuroscientist Vladimir Hachinski at Western University in London, Canada, who was not involved in the study. It was published on 26 August in Nature Medicine. Only connect The researchers looked at brain ageing by assessing a complex form of functional connectivity, a measure of the extent to which brain regions are interacting with one another. Functional connectivity generally declines with age. The authors drew on data from 15 countries: 7 (Mexico, Cuba, Colombia, Peru, Brazil, Chile and Argentina) that are in Latin America or the Caribbean and 8 (China, Japan, the United States, Italy, Greece, Turkey, the United Kingdom and Ireland) that are not. Of the 5,306 participants, some were healthy, some had Alzheimer’s disease or another form of dementia and some had mild cognitive impairment, a precursor to dementia. The researchers measured participants’ resting brain activity — that when they were doing nothing in particular — using either functional magnetic resonance imaging (fMRI) or electroencephalography (EEG). The first technique measures blood flow in the brain, and the second measures brain-wave activity. © 2024 Springer Nature Limited

Keyword: Development of the Brain; Stress
Link ID: 29458 - Posted: 08.31.2024

By Rebecca Dzombak Birds can be picky building their nests. They experiment with materials, waffle over which twig to use, take them apart and start again. It’s a complex, fiddly process that can seem to reflect careful thought. “It’s so fascinating,” Maria Tello-Ramos, a behavioral ecologist at the University of St. Andrews in Scotland, said. “But it hasn’t been studied much at all.” New research led by Dr. Tello-Ramos, published on Thursday in the journal Science, provides the first evidence that groups of birds that build their homes together learn to follow consistent architectural styles, distinct from groups just a few dozen feet away. The finding upends longstanding assumptions that nest building is an innate behavior based on the birds’ environment and adds to a growing list of behaviors that make up bird culture. As important for survival as nest building is, scientists know relatively little about it. Most of what is known about bird nests has come from studying their role in reproductive success, focusing on their usefulness in protecting birds and eggs from cold, wind and predators. “The focus has been on the structure, not the behavior that built it,” Dr. Tello-Ramos said. She said she found that surprising because nest building is one of the rare behaviors that has a tangible product, something that can be measured and provide insight into why birds behave the way they do. Part of the reason nest-building behaviors haven’t been researched much, Dr. Tello-Ramos said, boils down to one cliché: bird brain. Nest building is such a complex behavior that, for decades, scientists thought “the little brains of birds couldn’t possibly deal with such a large amount of information, so it must be innate,” she said. Recent work has shown birds repeating others’ nest building, but those studies were often limited to individuals or small groups in labs. © 2024 The New York Times Company

Keyword: Learning & Memory; Evolution
Link ID: 29457 - Posted: 08.31.2024

By Shaena Montanari Mammalian brains famously come with a built-in GPS system: “place cells” in the hippocampus that selectively activate when an animal enters a specific location and power spatial cognition. A comparable navigation system had not been described in fish—until now. As it turns out, zebrafish larvae, too, possess place cells that integrate multiple sources of information and generate new cognitive maps when the animal’s environment changes, according to a study out today in Nature. The search for these cells in fish became “kind of like a myth, almost,” says the study’s co-lead investigator Jennifer Li, research group leader at the Max Planck Institute for Biological Cybernetics. She and her team were hesitant to look for place cells in fish at first, Li says, “because we figured if nobody’s seeing them after all this time,” they might not exist. But Li and her colleagues had already custom-built a microscope that tracks calcium signaling in the brains of zebrafish larvae as they swim freely. The device helped them pinpoint the place cells in the larvae’s telencephalon region. “I think this work is definitely extremely interesting, because it demonstrates that, at least in some fish, you can find place cells,” says Ronen Segev, professor of life sciences at Ben-Gurion University of the Negev, who was not involved in the study. The finding also suggests that spatial cognition has origins deep in the vertebrate evolutionary tree, Li says. There is an idea that the “hippocampus and cortex are these structures that evolved at some point to enable flexible behavior,” but evolutionarily, “it was never clear when that happened.” © 2024 Simons Foundation

Keyword: Learning & Memory; Evolution
Link ID: 29456 - Posted: 08.31.2024

Tobi Thomas People who “catch up” on missed sleep at the weekend may have up to a 20% lower risk of heart disease compared with those who do not, according to a study. The findings, presented at a meeting of the European Society of Cardiology, looked at data from 90,903 adults taking part in the UK Biobank project, a database that holds medical and lifestyle records of 500,000 people in the UK. Of these, 19,816 met the criteria for being sleep-deprived, and over a follow-up period of 14 years the researchers found that the people who had the most extra sleep during the weekends were 19% less likely to develop heart disease than those who had the least amount of sleep at the weekends. Sleep deprivation in the study has been defined as those who self-reported having had less than seven hours of sleep per night. The video player is currently playing an ad. Those who got extra sleep at weekends ranged from an additional 1.28 hours to 16.06 hours, and those with the least sleep were losing 16.05 hours to 0.26 hours over the weekend. The study also looked at a sub-group of people with daily sleep deprivation and found that those who had the most compensatory sleep at the weekend had a 20% lower risk of developing heart disease than those with the least. Although the rest of the participants included in the study may have experienced inadequate sleep, on average their daily hours of sleep did not meet the criteria for being sleep deprived. Prof Yanjun Song, the study’s author, of China’s National Centre for Cardiovascular Disease in Beijing, said: “Sufficient compensatory sleep is linked to a lower risk of heart disease. The association becomes even more pronounced among individuals who regularly experience inadequate sleep on weekdays.” © 2024 Guardian News & Media Limited

Keyword: Sleep
Link ID: 29455 - Posted: 08.31.2024

By R. Douglas Fields It is late at night. You are alone and wandering empty streets in search of your parked car when you hear footsteps creeping up from behind. Your heart pounds, your blood pressure skyrockets. Goose bumps appear on your arms, sweat on your palms. Your stomach knots and your muscles coil, ready to sprint or fight. Now imagine the same scene, but without any of the body’s innate responses to an external threat. Would you still feel afraid? Experiences like this reveal the tight integration between brain and body in the creation of mind — the collage of thoughts, perceptions, feelings and personality unique to each of us. The capabilities of the brain alone are astonishing. The supreme organ gives most people a vivid sensory perception of the world. It can preserve memories, enable us to learn and speak, generate emotions and consciousness. But those who might attempt to preserve their mind by uploading its data into a computer miss a critical point: The body is essential to the mind. How is this crucial brain-body connection orchestrated? The answer involves the very unusual vagus nerve. The longest nerve in the body, it wends its way from the brain throughout the head and trunk, issuing commands to our organs and receiving sensations from them. Much of the bewildering range of functions it regulates, such as mood, learning, sexual arousal and fear, are automatic and operate without conscious control. These complex responses engage a constellation of cerebral circuits that link brain and body. The vagus nerve is, in one way of thinking, the conduit of the mind. Nerves are typically named for the specific functions they perform. Optic nerves carry signals from the eyes to the brain for vision. Auditory nerves conduct acoustic information for hearing. The best that early anatomists could do with this nerve, however, was to call it the “vagus,” from the Latin for “wandering.” The wandering nerve was apparent to the first anatomists, notably Galen, the Greek polymath who lived until around the year 216. But centuries of study were required to grasp its complex anatomy and function. This effort is ongoing: Research on the vagus nerve is at the forefront of neuroscience today. © 2024.Simons Foundation

Keyword: Emotions; Obesity
Link ID: 29454 - Posted: 08.28.2024

By Steve Paulson Oliver Sacks wasn’t always the beloved neurologist we remember today, sleuthing around the backwaters of the mind in search of mysterious mental disorders. For a few years in the 1960s, he was a committed psychonaut, often spending entire weekends blitzed out of his mind on weed, LSD, morning glory seeds, or mescaline. Once, after injecting himself with a large dose of morphine, he found himself hovering over an enormous battlefield, watching the armies of England and France drawn up for battle, and then realized he was witnessing the 1415 Battle of Agincourt. “I completely lost the sense that I was lying on my bed stoned,” he told me in 2012, a few years before he died. “I felt like a historian, seeing Agincourt from a celestial viewpoint. This was not ordinary imagination. It was absolutely real.” The vision seemed to last only a few minutes, but later, he discovered he’d been tripping for 13 hours. These early experiences with hallucinogens gave Sacks an appreciation for the strange turns the mind can take. He had a craving for direct experience of the numinous, but he believed his visions were nothing more than hallucinations. “At the physiological level, everything is electricity and chemistry, but it was a wonderful feeling,” he said. When I asked if he ever thought he’d crossed over into some transpersonal dimension of reality, he said, “I’m an old Jewish atheist. I have no belief in heaven or anything supernatural or paranormal, but there’s a mystical feeling of oneness and of beauty, which is not explicitly religious, but goes far beyond the aesthetic.” I’ve often thought about this conversation as I’ve watched today’s psychedelic renaissance. Clinical trials with psychedelic-assisted therapy show great promise for treating depression, addiction, and PTSD, and a handful of leading universities have recently created their own heavily endowed psychedelic centers. © 2024 NautilusNext Inc.,

Keyword: Drug Abuse; Consciousness
Link ID: 29453 - Posted: 08.28.2024

By Holly Barker Machine-learning models can predict a neuron’s location based on recorded bursts of activity, a new preprint suggests. The findings may provide novel insights into how the brain integrates signals from different regions, the researchers say. The algorithm—trained on electrode recordings of neurons in mice—appeared to learn a cell’s whereabouts from its interspike interval, the sequence of delays between blips of activity. And after deciphering the spike pattern from one mouse, the tool predicted neuronal locations based on recordings from another rodent. That conservation between animals suggests the information serves some useful brain function, or at least doesn’t get in the way, says lead investigator Keith Hengen, assistant professor of biology at Washington University in St. Louis. Although more research is needed, the anatomical information embedded in interspike intervals could—in theory—provide contextual information for neuronal computations. For example, the brain might process signals from thalamic neurons differently from those in the hippocampus, says study investigator Aidan Schneider, a graduate student in Hengen’s lab. Schneider and his colleagues trained the model using tens of thousands of Neuropixels probe recordings from 58 awake mice, published by the Allen Institute. When Schneider’s team presented the algorithm with fresh data, it could decipher whether a given neuron resided in the hippocampus, midbrain, thalamus or visual cortex 89 percent of the time, once the team removed noise from the data. (Random guesses would be correct 25 percent of the time.) But the tool was less able to pinpoint specific substructures within those regions. It’s a great example of the kinds of insights that labs poring over huge datasets can produce, says Drew Headley, assistant professor of molecular and behavioral neuroscience at Rutgers University, who was not involved in the study. But the findings may simply echo published reports of variations in spiking activity across different brain regions, he says. © 2024 Simons Foundation

Keyword: Brain imaging
Link ID: 29452 - Posted: 08.28.2024

By Rachel Nuwer One person felt a sensation of “slowly floating into the air” as images flashed around. Another recalled “the most profound sense of love and peace,” unlike anything experienced before. Consciousness became a “foreign entity” to another whose “whole sense of reality disappeared.” These were some of the firsthand accounts shared in a small survey of people who belonged to an unusual cohort: They had all undergone a near-death experience and tried psychedelic drugs. The survey participants described their near-death and psychedelic experiences as being distinct, yet they also reported significant overlap. In a paper published on Thursday, researchers used these accounts to provide a comparison of the two phenomena. “For the first time, we have a quantitative study with personal testimony from people who have had both of these experiences,” said Charlotte Martial, a neuroscientist at the University of Liège in Belgium and an author of the findings, which were published in the journal Neuroscience of Consciousness. “Now we can say for sure that psychedelics can be a kind of window through which people can enter a rich, subjective state resembling a near-death experience.” Near-death experiences are surprisingly common — an estimated 5 to 10 percent of the general population has reported having one. For decades, scientists largely dismissed the fantastical stories of people who returned from the brink of death. But some researchers have started to take these accounts seriously. “In recent times, the science of consciousness has become interested in nonordinary states,” said Christopher Timmermann, a research fellow at the Center for Psychedelic Research at Imperial College London and an author of the article. “To get a comprehensive account of what it means to be a human being requires incorporating these experiences.” © 2024 The New York Times Company

Keyword: Consciousness; Drug Abuse
Link ID: 29450 - Posted: 08.22.2024

By Elyse Weingarten In 2016, Canada enacted the Medical Assistance in Dying, or MAID, law, allowing individuals with a terminal illness to receive help from a medical professional to end their life. Following a superior court ruling, the legislation was expanded in 2021 to include nearly anyone with a “grievous and irremediable medical condition” causing “enduring physical or psychological suffering that is intolerable to them.” Whether mental illnesses such as depression, schizophrenia, and addiction should be considered “grievous and irremediable” quickly emerged as the subject of intense debate. Initially slated to go into effect in March 2023, a new mental health provision of the law was postponed a year due to public outcry both in Canada and abroad. Then, in February, Health Minister Mark Holland announced it had been delayed again — this time until 2027 — to allow more time for the country’s health care system to prepare. I was horrified by the news of the law’s latest expansion — a reaction that surprised me. Having grown up with a seriously mentally ill family member, I know first-hand how destructive mental illness can be, and I have no illusion that it is always treatable. Additionally, I support assisted suicide in cases of grave and terminal physical illness, so why do I find it so unacceptable to offer it to people who are intractably mentally ill? For nearly half a century, the Western understanding of mental illness has been shaped to adhere to the larger biomedical concepts of disease and wellness. Biological psychiatry, or the biomedical model, views mental illnesses as organically based disorders of the brain, physiologically indistinguishable from other diseases. The Canadian MAID law’s inclusion of mental illness is the culmination of this framework. Yet the widespread condemnation that the amendment received (that the bill’s previous iterations did not) demonstrates that mental and physical illness — though worthy of the same respect — are in no way equivalent, and that we can recognize this intuitively.

Keyword: Depression; Schizophrenia
Link ID: 29449 - Posted: 08.22.2024