By Sabrina Malhi Cannabis use is associated with a greater risk of an unhealthy pregnancy outcomes, especially low birth weight, according to a study funded by the National Institutes of Health. While the study did not identity why cannabis use might have these effects, it underscores the potentially damaging impact of the substance on fetal health, the authors say. Many pregnant people use cannabis to help manage symptoms, including nausea and pain. The prevalence of the drug has surged in the past decade as more states have legalized its use for medicine or recreation, and many people believe it is relatively safe. But the impact cannabis has on pregnancy has been understudied. For the new study, researchers analyzed urine samples from more than 9,000 pregnant people between 2010 and 2013 to determine whether cannabis was used at any point during pregnancy, at how many weeks of gestation it was used and the amount. The team measured THC, the psychoactive substance in cannabis, at three different periods roughly tracking with trimesters and used that data to calculate total cannabis exposure throughout the entire pregnancy. Their findings were published in JAMA on Tuesday. The authors determined that pregnant people who used cannabis experienced unfavorable birth outcomes at rates of 25.9 percent, compared with 17.4 percent among those who did not use cannabis. Low birth weight and cannabis use had the strongest association out of all the adverse outcomes, the study found. Low birth weight is defined as weighing less than 5 lbs., 8 ounces at birth. This can lead to a range of health complications and long-term risks, including an increased likelihood of chronic conditions later in life. Experts say the study adds to a growing body of evidence that no amount of cannabis is safe during pregnancy.

Keyword: Drug Abuse; Development of the Brain
Link ID: 29040 - Posted: 12.13.2023

By Yasemin Saplakoglu Erin Calipari comes from a basketball family. Her father, John Calipari, has coached college and professional basketball since 1998, leading six teams to the NCAA Final Four, and her brother coaches men’s basketball at Vanderbilt University in Nashville, Tennessee, where she now works. But when she joined her college team as an undergraduate, she realized her strengths lay elsewhere. “I was fine. I wasn’t great,” she said. “It was pretty clear to me a couple years in that it was not a career path.” Off the court, as a biology major she gravitated toward hormones and neurotransmitters. She grew fascinated with the neurobiology of how and why drugs such as cocaine and opioids are addictive, as she learned about the effects of ecstasy on the serotonin system. “I thought drugs were so cool because they hijack the brain,” she said. “Drugs essentially take the normal systems we have in our body and drive them in a way that makes you want to take drugs again.” After pursuing graduate work in neuroscience, in 2017 Calipari set up her lab at Vanderbilt to explore how addiction is connected to the ways the brain learns and makes decisions. “Deciding what to do and what not to do is really fundamental to everything we do,” Calipari said. “You put your hand on a hot stove, you learn really quickly not to do that again.” Addiction can diminish a person’s ability to learn that drug use is hurting them, and also their ability to learn anything at all. Her world still collides with sports, for instance when she gives talks to athletes about the dangers of substance use. Athletes can be vulnerable to addiction when they are prescribed pain medicines, such as opioids, for injuries. There is a risk of dependence if opioids are taken for long periods of time, even when patients follow doctors’ orders — a fact that has led to a nationwide public health emergency. Tennessee is an epicenter of the opioid epidemic. In 2022, Nashville had the second-highest rate of overdose deaths in the country. All Rights Reserved © 2023

Keyword: Drug Abuse
Link ID: 29039 - Posted: 12.09.2023

By Amitha Kalaichandran In May, I was invited to take part in a survey by the National Academies of Sciences, Engineering, and Medicine to better delineate how long Covid is described and diagnosed as part of The National Research Action Plan on Long Covid. The survey had several questions around definitions and criteria to include, such as “brain fog” often experienced by those with long Covid. My intuition piqued, and I began to wonder about the similarities between these neurological symptoms and those experienced by people with attention-deficit/hyperactivity disorder, or ADHD. As a medical journalist with clinical and epidemiological experience, I found the possible connection and its implications impossible to ignore. We know that three years of potential exposure to SARS-CoV-2, in combination with the shift in social patterns (including work-from-home and social isolation), has impacted several aspects of neurocognition, as detailed in a recent report from the Substance Abuse and Mental Health Services Administration. A 2021 systematic review found persistent neuropsychiatric symptoms in Covid-19 survivors, and a 2021 paper in the journal JAMA Network Open found that executive functioning, processing speed, memory, and recall were impacted in patients hospitalized with Covid-19. Long Covid may indeed be linked to developing chronic neurocognitive issues, and even dementia may be accelerated. The virus might impact the frontal lobe, the area that governs executive function — which involves how we make decisions and plan, use our working memory, and control impulses. In October, a paper in Cell reported that long Covid brain fog could be traced to serotonin depletion driven by immune system proteins called viral-associated interferons. Similarly, the symptoms of attention-deficit/hyperactivity disorder, or ADHD, are believed to be rooted structurally in the frontal lobe and possibly from a naturally low level of the neurotransmitter dopamine, with contributions from norepinephrine, serotonin, and GABA. This helps explain why people with ADHD, who experience inattention, hyperactivity, and impulsivity, among other symptoms, may seek higher levels of stimulation: to activate the release of dopamine. However, a deficit in serotonin can also trigger ADHD. The same neurotransmitter, when depleted, may be responsible for brain fog in long Covid.

Keyword: ADHD
Link ID: 29038 - Posted: 12.09.2023

By Carolyn Wilke Newborn bottlenose dolphins sport a row of hairs along the tops of their jaws. But once the animals are weaned, the whiskers fall out. “Everybody thought these structures are vestigial — so without any function,” said Guido Dehnhardt, a marine mammal zoologist at the University of Rostock in Germany. But Dr. Dehnhardt and his colleagues have discovered that the pits left by those hairs can perceive electricity with enough sensitivity that they may help the dolphins snag fish or navigate the ocean. The team reported its findings Thursday in The Journal of Experimental Biology. Dr. Dehnhardt first studied the whisker pits of a different species, the Guiana dolphin. He expected to find the typical structures of hair follicles, but those were missing. Yet the pits were loaded with nerve endings. He and his colleagues realized that the hairless follicles looked like the electricity-sensing structures on sharks and found that one Guiana dolphin responded to electrical signals. They wondered whether other toothed cetaceans, including bottlenose dolphins, could also sense electricity. For the new study, the researchers trained two bottlenose dolphins to rest their jaws, or rostrums, on a platform and swim away anytime they experienced a sensory cue like a sound or a flash of light. If they didn’t detect one of these signals, the dolphins were to stay put. “It’s basically the same as when we go to the doctor’s and do a hearing test — we have to press a button as soon as we hear a sound,” said Tim Hüttner, a biologist at the Nuremberg Zoo in Germany and a study co-author. Once trained, the dolphins also received electrical signals. “The dolphins responded correctly on the first trial,” Dr. Hüttner said. The animals were able to transfer what they had learned, revealing that they could also detect electric fields. Further study showed that the dolphins’ sensitivity to electricity was similar to that of the platypus, which is thought to use its electrical sense for foraging. © 2023 The New York Times Company

Keyword: Hearing
Link ID: 29037 - Posted: 12.09.2023

Sydney E. Smith When most people hear about electroconvulsive therapy, or ECT, it typically conjures terrifying images of cruel, outdated and pseudo-medical procedures. Formerly known as electroshock therapy, this perception of ECT as dangerous and ineffective has been reinforced in pop culture for decades – think the 1962 novel-turned-Oscar-winning film “One Flew Over the Cuckoo’s Nest,” where an unruly patient is subjected to ECT as punishment by a tyrannical nurse. Despite this stigma, ECT is a highly effective treatment for depression – up to 80% of patients experience at least a 50% reduction in symptom severity. For one of the most disabling illnesses around the world, I think it’s surprising that ECT is rarely used to treat depression. Contributing to the stigma around ECT, psychiatrists still don’t know exactly how it heals a depressed person’s brain. ECT involves using highly controlled doses of electricity to induce a brief seizure under anesthesia. Often, the best description you’ll hear from a physician on why that brief seizure can alleviate depression symptoms is that ECT “resets” the brain – an answer that can be fuzzy and unsettling to some. As a data-obsessed neuroscientist, I was also dissatisfied with this explanation. In our newly published research, my colleagues and I in the lab of Bradley Voytek at UC San Diego discovered that ECT might work by resetting the brain’s electrical background noise. To study how ECT treats depression, my team and I used a device called an electroencephalogram, or EEG. It measures the brain’s electrical activity – or brain waves – via electrodes placed on the scalp. You can think of brain waves as music played by an orchestra. Orchestral music is the sum of many instruments together, much like EEG readings are the sum of the electrical activity of millions of brain cells. © 2010–2023, The Conversation US, Inc.

Keyword: Depression
Link ID: 29036 - Posted: 12.09.2023

By Siddhant Pusdekar In the deepest stage of sleep, slow waves of electrical activity travel through your brain. They help consolidate memories and flush out the buildup of unwanted chemicals, getting you ready for the day. This midnight orchestra is responsible for many of the benefits of a good night’s sleep, such as improved attention, mood and energy levels. Scientists at the University of California, Berkeley, recently found that for some people, these waves could also serve as early warning signs of diabetes. The results, published in July in Cell Reports Medicine, suggest that getting a restful sleep may help control high blood sugar. People with type 2 diabetes are unable to metabolize sugar, leading to a damaging excess concentration in the blood. The approximately 515 million people globally with type 2 diabetes can manage blood sugar through diet, exercise and medications such as insulin. But researchers and clinicians have observed that quality of sleep seems to influence blood sugar, too. “We have known that something magic happens during sleep,” says New York University neuroscientist Gyorgy Buzsaki about the links between sleep and metabolism. Yet the mechanism behind that relationship has been a mystery, he says. To investigate, the July study’s co-lead author Raphael Vallat, then a postdoctoral researcher at U.C. Berkeley, analyzed blood glucose and sleep measurements from two large independent public datasets. In the first analysis, Vallat and his colleagues examined sleep patterns measured from polysomnography, a standard assessment that doctors recommend for people with sleep problems. The procedure, typically conducted at night, involves placing a bunch of wires on different parts of the head to record activity in specific brain regions. The ends of the wires act like “microphones” that “hear” brain waves, explains Vyoma Shah, a graduate student at U.C. Berkeley and co-lead author of the paper. Squiggles of different shapes and sizes on the polysomnography graphs represent the ebbs and flows of electrical activity in people’s head as they sleep throughout the night. It is only a surface-level view, however. © 2023 SCIENTIFIC AMERICAN,

Keyword: Sleep; Obesity
Link ID: 29035 - Posted: 12.09.2023

By Amanda Gefter On a February morning in 1935, a disoriented homing pigeon flew into the open window of an unoccupied room at the Hotel New Yorker. It had a band around its leg, but where it came from, or was meant to be headed, no one could say. While management debated what to do, a maid rushed to the 33rd floor and knocked at the door of the hotel’s most infamous denizen: Nikola Tesla. The 78-year-old inventor quickly volunteered to take in the homeless pigeon. “Dr. Tesla … dropped work on a new electrical project, lest his charge require some little attention,” reported The New York Times. “The man who recently announced the discovery of an electrical death-beam, powerful enough to destroy 10,000 airplanes at a swoop, carefully spread towels on his window ledge and set down a little cup of seed.” Nikola Tesla—the Serbian-American scientist famous for designing the alternating current motor and the Tesla coil—had, for years, regularly been spotted skulking through the nighttime streets of midtown Manhattan, feeding the birds at all hours. In the dark, he’d sound a low whistle, and from the gloom, hordes of pigeons would flock to the old man, perching on his outstretched arms. He was known to keep baskets in his room as nests, along with caches of homemade seed mix, and to leave his windows perpetually open so the birds could come and go. Once, he was arrested for trying to lasso an injured homing pigeon in the plaza of St. Patrick’s Cathedral, and, from his holding cell in the 34th Street precinct, had to convince the officers that he was—or had been—one of the most famous inventors in the world. It had been years since he’d produced a successful invention. He was gaunt and broke—living off of debt and good graces—having been kicked out of a string of hotels, a trail of pigeon droppings and unpaid rent in his wake. He had no family or close friends, except for the birds. © 2023 NautilusNext Inc.,

Keyword: Consciousness
Link ID: 29034 - Posted: 12.09.2023

By Carl Zimmer Traumatic brain injuries have left more than five million Americans permanently disabled. They have trouble focusing on even simple tasks and often have to quit jobs or drop out of school. A study published on Monday has offered them a glimpse of hope. Five people with moderate to severe brain injuries had electrodes implanted in their heads. As the electrodes stimulated their brains, their performance on cognitive tests improved. If the results hold up in larger clinical trials, the implants could become the first effective therapy for chronic brain injuries, the researchers said. “This is the first evidence that you can move the dial for this problem,” said Dr. Nicholas Schiff, a neurologist at Weill Cornell Medicine in New York who led the study. Gina Arata, one of the volunteers who received the implant, was 22 when a car crash left her with fatigue, memory problems and uncontrollable emotions. She abandoned her plans for law school and lived with her parents in Modesto, Calif., unable to keep down a job. In 2018, 18 years after the crash, Ms. Arata received the implant. Her life has changed profoundly, she said. “I can be a normal human being and have a conversation,” she said. “It’s kind of amazing how I’ve seen myself improve.” Dr. Schiff and his colleagues designed the trial based on years of research on the structure of the brain. Those studies suggested that our ability to focus on tasks depends on a network of brain regions that are linked to each other by long branches of neurons. The regions send signals to each other, creating a feedback loop that keeps the whole network active. Sudden jostling of the brain — in a car crash or a fall, for example — can break some of the long-distance connections in the network and lead people to fall into a coma, Dr. Schiff and his colleagues have hypothesized. During recovery, the network may be able to power itself back up. But if the brain is severely damaged, it may not fully rebound. Dr. Schiff and his colleagues pinpointed a structure deep inside the brain as a crucial hub in the network. Known as the central lateral nucleus, it is a thin sheet of neurons about the size and shape of an almond shell. © 2023 The New York Times Company

Keyword: Brain Injury/Concussion
Link ID: 29033 - Posted: 12.06.2023

By Esther Landhuis Dropping an ice crystal into a bottle of near-frozen water produces a dramatic effect: very quickly, the liquid crystallizes into a block of ice. At the molecular level, an ice crystal has a distinct shape—a lattice structure. As incoming water molecules reshape to join the lattice, the crystal grows. Some researchers think an analogous process underlies Alzheimer’s disease, Parkinson’s disease and other neurodegenerative illnesses. According to this theory, these diseases begin when a particular protein misfolds, or fails to assume the proper shape for its intended role. That misshapen molecule ensnares normal versions of the protein, causing them to similarly misfold, and over time, these rogue proteins clump into toxic clusters that spread through the brain. In mad cow disease—a brain disorder in cattle that can spread to people who eat meat from ill animals —the toxic proteins, called prions, ravage the mind quickly, leading to dementia and death within months. Prion diseases are rare. About 350 cases of the most common type, Creutzfeldt-Jakob disease, are reported each year in the U.S. By comparison, each year, nearly 500,000 people in the U.S. are diagnosed with Alzheimer’s, which develops more gradually. Plaques made up of abnormal beta-amyloid proteins can accumulate in the brain for years or even decades before a person notices signs of mental decline. While the time lines for toxicity differ, “the mechanism of misfolding is the same,” says Mathias Jucker, a neuroscientist at the Hertie Institute for Clinical Brain Research at the University of Tübingen in Germany. Just as all of the water in a bottle freezes after a “‘misfolded’ water molecule” slips into the vessel, if “you have one misfolded protein, all the other ones will take the same shape.” The idea that many diseases could arise from a common prionlike process raises an intriguing and troubling question: Under certain circumstances, could neurodegenerative disorders be transmitted from person to person? © 2023 SCIENTIFIC AMERICAN,

Keyword: Alzheimers; Prions
Link ID: 29032 - Posted: 12.06.2023

Saga Briggs Trauma is not merely a phenomenon of the mind but also a condition physically embedded in the body, often eluding our conscious awareness and affecting our overall health. That was the main argument in psychiatrist Bessel van der Kolk’s 2014 bestseller The Body Keeps the Score, which quickly became a modern classic among trauma researchers, clinicians, and survivors. The book shifted how many in the West view psychiatric illness, which was often viewed solely through a psychological or neurochemical lens, and it sparked new interest in more holistic treatments for trauma that had long been considered alternative: yoga, eye movement desensitization and reprocessing therapy (EMDR), the performing arts, and psychedelics, to name a few. But what does it really mean for the body to “keep the score”? Is it biologically possible for the viscera to actually store and release trauma? In his book, van der Kolk writes: “The body keeps the score. If the memory of trauma is encoded in the viscera, in heartbreaking and gut-wrenching emotions, in autoimmune disorders and skeletal/muscular problems, and if mind/brain/visceral communication is the royal road to emotion regulation, this demands a radical shift in our therapeutic assumptions.” Can the body “keep score”? Recently, neuroscientists have expressed skepticism over the notion that the body can “keep score” of anything. In a 2023 Big Think video, Lisa Feldman Barrett argued that everything, including trauma, is in our heads, and that “the brain keeps the score and the body is the scorecard.” In her view, everything we experience is constructed by the brain, which learns to predict how we will feel based on past experiences, issues, and sensations that seem to come from our body but actually come from our brain. “When you feel your heart beating, you are not feeling it in your chest, you are feeling it in your brain,” she said. “Your body is always sending sensory signals to the brain, of course, but emotions are made in the brain, not in the body. They are experienced in the brain, like everything else you experience, not in the body. If you experience a trauma, you experience it in your brain.”

Keyword: Emotions; Stress
Link ID: 29031 - Posted: 12.06.2023

By Ellen Barry At the root of post-traumatic stress disorder, or PTSD, is a memory that cannot be controlled. It may intrude on everyday activity, thrusting a person into the middle of a horrifying event, or surface as night terrors or flashbacks. Decades of treatment of military veterans and sexual assault survivors have left little doubt that traumatic memories function differently from other memories. A group of researchers at Yale University and the Icahn School of Medicine at Mount Sinai set out to find empirical evidence of those differences. The team conducted brain scans of 28 people with PTSD while they listened to recorded narrations of their own memories. Some of the recorded memories were neutral, some were simply “sad,” and some were traumatic. The brain scans found clear differences, the researchers reported in a paper published on Thursday in the journal Nature Neuroscience. The people listening to the sad memories, which often involved the death of a family member, showed consistently high engagement of the hippocampus, part of the brain that organizes and contextualizes memories. When the same people listened to their traumatic memories — of sexual assaults, fires, school shootings and terrorist attacks — the hippocampus was not involved. “What it tells us is that the brain is in a different state in the two memories,” said Daniela Schiller, a neuroscientist at the Icahn School of Medicine at Mount Sinai and one of the authors of the study. She noted that therapies for PTSD often sought to help people organize their memory so they can view it as distant from the present. “Now we find something that potentially can explain it in the brain,” she said. “The brain doesn’t look like it’s in a state of memory; it looks like it is a state of present experience.” Indeed, the authors conclude in the paper, “traumatic memories are not experienced as © 2023 The New York Times Company

Keyword: Learning & Memory; Stress
Link ID: 29030 - Posted: 12.02.2023

Anil Oza Researchers have long known that areas of songbird brains that are responsible for singing grow during mating season and then shrink when the season is over. But one species, Gambel’s white-crowned sparrow (Zonotrichia leucophrys gambelii), does this on a scale that scientists are struggling to understand. A part of the male sparrow’s brain called the HVC grows from around 100,000 neurons to about 170,000 — nearly doubling in size — during the bird’s mating season. Although how the bird pulls off this feat is still a mystery, scientists who presented data at the annual Society for Neuroscience meeting in Washington DC on 11–15 November are closing in on answers. They hope their findings might one day point to ways of treating anomalies in the human brain. In most animals, when a brain region grows and shrinks, “frequently, it’s pretty detrimental on behaviour and function of the brain”, says Tracy Larson, a neuroscientist at the University of Virginia in Charlottesville who led the work. In particular, growth on this scale in mammals would cause inflammation and increase the pressure inside their skulls. But when it comes to the sparrows, “there’s something really fascinating about these birds that they can manage to do this and not have detrimental impacts”, Larson adds. Larson’s research has so far hinted that the sparrow’s brain is using a slew of tactics to quickly form and then kill a large number of neurons. One question that Larson wanted to answer is how the sparrow’s brain shrinks dramatically at the end of mating season. So she and her colleagues tagged cells in and around the HVCs of male sparrows with a molecule called bromodeoxyuridine (BrdU), which can become incorporated into the DNA of dividing cells. They also used hormone supplements to simulate breeding season in the birds. © 2023 Springer Nature Limited

Keyword: Sexual Behavior; Hormones & Behavior
Link ID: 29029 - Posted: 12.02.2023

By Jake Buehler Nesting chinstrap penguins take nodding off to the extreme. The birds briefly dip into a slumber many thousands of times per day, sleeping for only seconds at a time. The penguins’ breeding colonies are noisy and stressful places, and threats from predatory birds and aggressive neighbor penguins are unrelenting. The extremely disjointed sleep schedule may help the penguins to protect their young while still getting enough shut-eye, researchers report in the Dec. 1 Science. The findings add to evidence “that avian sleep can be very different from the sleep of land mammals,” says UCLA neuroscientist Jerome Siegel. Nearly a decade ago, behavioral ecologist Won Young Lee of the Korea Polar Research Institute in Incheon noticed something peculiar about how chinstrap penguins (Pygoscelis antarcticus) nesting on Antarctica’s King George Island were sleeping. They would seemingly doze off for very short periods of time in their cacophonous colonies. Then in 2018, Lee learned about frigate birds’ ability to steal sleep while airborne on days-long flights. Lee teamed up with sleep ecophysiologist Paul-Antoine Libourel of the Lyon Neuroscience Research Center in France and other researchers to investigate the penguins’ sleep. In 2019, the team studied the daily sleep patterns of 14 nesting chinstrap penguins using data loggers mounted on the birds’ backs. The devices had electrodes surgically implanted into the penguins’ brains for measuring brain activity. Other instruments on the data loggers recorded the animals’ movements and location. Nesting penguins had incredibly fragmented sleep patterns, taking over 600 “microsleeps” an hour, each averaging only four seconds, the researchers found. At times, the penguins slept with only half of their brain; the other half stayed awake. All together, the oodles of snoozes added up, providing over 11 hours of sleep for each brain hemisphere across more than 10,000 brief sleeps each day. © Society for Science & the Public 2000–2023.

Keyword: Sleep; Evolution
Link ID: 29028 - Posted: 12.02.2023

By Taylor Beck One sunny day this fall, I caught a glimpse of the new psychiatry. At a mental hospital near Yale University, a depressed patient was being injected with ketamine. For 40 minutes, the drug flowed into her arm, bound for cells in her brain. If it acts as expected, ketamine will become the first drug to quickly stop suicidal drive, with the potential to save many lives. Other studies of ketamine are evaluating its effect as a vaccination against depression and post-traumatic stress. Between them, the goal is nothing less than to redefine our understanding of mental illness itself. Depression is the most common mental illness in the United States, affecting 30 percent of Americans at some point in their lives. But despite half a century of research, ubiquitous advertising, and blockbuster sales, antidepressant drugs just don’t work very well. They treat depression as if it were caused by a chemical imbalance: Pump in more of one key ingredient, or sop up another, and you will have fixed the problem. But the correspondence between these chemicals (like serotonin) and depression is relatively weak. An emerging competitive theory, inspired in part by ketamine’s effectiveness, has it that psychiatric disease is less about chemical imbalance than structural changes in the brain—and that a main cause of these changes is psychological stress. “I really do think stress is to mental illness as cigarettes are to heart disease,” says Gerard Sanacora, the psychiatry professor running the ketamine trial at Yale. The theory describes stress grinding down individual neurons gradually, as storms do roof shingles. This, in turn, changes the nature of their connections to one another and the structure of the brain. Ketamine, along with some similar molecules, acts to strengthen the neuron against that damage, affecting not just the chemistry of the brain but also its structure. © 2023 NautilusNext Inc.,

Keyword: Depression; Stress
Link ID: 29027 - Posted: 12.02.2023

By Meeri Kim A woman’s menstrual cycle is driven by the ebb and flow of hormones that prepare the body for pregnancy. This symphony of hormones not only transforms the reproductive organs, but, according to recent research, also reshapes the brain. Live well every day with tips and guidance on food, fitness and mental health, delivered to your inbox every Thursday. Two studies released in October performed detailed brain scans of women at multiple points across the menstrual cycle, finding that the volume or thickness of certain regions change in sync with hormone levels. The areas of the brain highlighted by both studies are those in the limbic system, a group of brain structures that govern emotions, memory and behavior. “It’s like the brain being on a roller coaster every 28 days or so, depending on the length of the cycle,” said Erika Comasco, associate professor of women and children’s health at Uppsala University in Sweden, who was not involved in the research. “The importance of these studies is that they are building knowledge about the impact of these hormonal fluctuations on how the brain is structured.” “These brain changes may or may not alter the way we actually act, think and feel in our everyday lives. So the important next steps for the science are to put those pieces of the puzzle together,” said Adriene Beltz, associate professor of psychology at the University of Michigan, who was also not involved in the research. “Do the hormonal effects on brain structure influence how the brain works?” How hormones drive the menstrual cycle During a woman’s period, which marks the beginning of the menstrual cycle, hormones are at low levels. But they rise dramatically over a few weeks. Estrogen levels in the blood become eight times higher at ovulation around Day 14, while progesterone levels increase by 80-fold approximately seven days later. The production of follicle-stimulating hormone prompts the growth of an ovarian follicle into a mature egg, while a surge of luteinizing hormone triggers the release of the egg.

Keyword: Hormones & Behavior; Sexual Behavior
Link ID: 29026 - Posted: 12.02.2023

By Simon Makin Our thoughts and feelings arise from networks of neurons, brain cells that send signals using chemicals called neurotransmitters. But neurons aren't alone. They're supported by other cells called glia (Greek for “glue”), which were once thought to hold nerve tissue together. Today glia are known to help regulate metabolism, protect neurons and clean up cellular waste—critical but unglamorous roles. Now, however, neuroscientists have discovered a type of “hybrid” glia that sends signals using glutamate, the brain's most common neurotransmitter. These findings, published in Nature, breach the rigid divide between signaling neurons and supportive glia. “I hope it's a boost for the field to move forward, to maybe begin studying why certain [brain] circuits have this input and others don't,” says study co-author Andrea Volterra, a neuroscientist at the University of Lausanne in Switzerland. Around 30 years ago researchers began reporting that star-shaped glia called astrocytes could communicate with neurons. The idea was controversial, and further research produced contradictory results. To resolve the debate, Volterra and his team analyzed existing data from mouse brains. These data were gathered using a technique called single-cell RNA sequencing, which lets researchers catalog individual cells' molecular profiles instead of averaging them in a bulk tissue sample. Of nine types of astrocytes they found in the hippocampus—a key memory region—one had the cellular machinery required to send glutamate signals. The small numbers of these cells, present only in certain regions, may explain why earlier research missed them. “It's quite convincing,” says neuroscientist Nicola Hamilton-Whitaker of King's College London, who was not involved in the study. “The reason some people may not have seen these specialized functions is they were studying different astrocytes.” © 2023 SCIENTIFIC AMERICAN,

Keyword: Glia
Link ID: 29025 - Posted: 11.26.2023

Jon Hamilton If this year's turkey seems over brined, blame your brain. The question of when salty becomes too salty is decided by a special set of neurons in the front of the brain, researchers report in the journal Cell. A separate set of neurons in the back of the brain adjusts your appetite for salt, the researchers showed in a series of experiments on mice. "Sodium craving and sodium tolerance are controlled by completely different types of neurons," says Yuki Oka, an author of the study and a professor of biology at Caltech. The finding could have health implications because salt ingestion is a "major issue" in many countries, including the United States, says Nirupa Chaudhari, a professor of physiology and biology at the University of Miami's Miller School of Medicine. Too much salt can cause high blood pressure and raise the risk for heart disease and stroke, says Chaudhari, who was not involved in the study. Craving, to a point The study sought to explain the complicated relationship that people and animals have with salt, also known as sodium chloride. We are happy to drink sodas, sports drinks, and even tap water that contain a little salt, Oka says. "But if you imagine a very high concentration of sodium like ocean water, you really hate it." This aversion to super salty foods and beverages holds unless your body is really low on salt, something that's pretty rare in people these days. But experiments with mice found that when salt levels plummet, the tolerance for salty water goes up. "Animals start liking ocean water," Oka says. The reason for this change involves at least two different interactions between the body and brain, Oka's team found. When the concentration of sodium in the bloodstream begins to fall below healthy levels, a set of neurons in the back of the brain respond by dialing up an animal's craving for salt. "If you stimulate these neurons, then animals run to a sodium source and start eating," Oka says. Meanwhile, a different set of neurons in the front of the brain monitors the saltiness of any food or water the mice are consuming. And usually, these neurons will set an upper limit on saltiness. © 2023 npr

Keyword: Chemical Senses (Smell & Taste); Obesity
Link ID: 29024 - Posted: 11.26.2023

By Catherine Offord As millions in the United States settle down to Thanksgiving dinner this week, few will be pondering a major question in neuroscience: Why, when so much of life across the animal kingdom revolves around finding and consuming food, do we ever stop eating? Scientists have identified brain regions and even specific cells involved in terminating meals. But exactly how this process is coordinated remains murky. Now, using brain recordings from mice tucking into food, researchers have for the first time identified how specific neurons in a region called the caudal nucleus of the solitary tract (cNTS) switch on during a meal to slow down and eventually end eating. “Nobody has really been able to [do this] in awake, behaving animals” before, says Nicholas Betley, a neuroscientist at the University of Pennsylvania who was not involved in the work. The findings, published today in Nature, suggest the brain manages a coordinated sequence of behavioral responses to food as it travels from the mouth through the gastrointestinal tract, and could provide new insight into humans’ eating behaviors and disorders, he adds. Previous research on what causes animals to stop eating has largely focused on two types of cells located in the cNTS. One is prolactin-releasing hormone (PRLH) neurons, which have been linked to many functions, including the inhibition of feeding behavior. The other is GCG neurons, which produce glucagon-like peptide-1—the appetite-suppressing hormone mimicked by newly popular weight loss drugs such as Wegovy. Studies of anesthetized animals have found that both neuron types become active in response to the stomach filling, which researchers mimic by inflating a balloon in the stomach or by directly infusing food. But such techniques are a poor proxy for what happens in real life, says Zachary Knight, a neurobiologist and Howard Hughes Medical Institute investigator at the University of California, San Francisco (UCSF). “You don’t really have any sense of what’s happening dynamically.”

Keyword: Obesity
Link ID: 29023 - Posted: 11.26.2023

Nell Greenfieldboyce If you've got itchy skin, it could be that a microbe making its home on your body has produced a little chemical that's directly acting on your skin's nerve cells and triggering the urge to scratch. That's the implication of some new research that shows how a certain bacteria, Staphylococcus aureus, can release an enzyme that generates an itchy feeling. What's more, a drug that interferes with this effect can stop the itch in laboratory mice, according to a new report in the journal Cell. "That's exciting because it's a drug that's already approved for another condition, but maybe it could be useful for treating itchy skin diseases like eczema," says Isaac Chiu, a scientist at Harvard Medical School who studies interactions between microbes and nerve cells. He notes that eczema or atopic dermatitis is actually pretty common, affecting about 20% of children and 10% of adults. In the past, says Chiu, research on itchy skin conditions has focused on the role of the immune response and inflammation in generating the itch sensation. People with eczema often take medications aimed at immune system molecules. But scientists have also long known that people with eczema frequently have skin that's colonized by Staphylococcus aureus, says Chiu, even though it's never been clear what role the bacteria might play in this condition. Chiu's previous lab work had made him realize that bacteria can directly act on nerve cells to cause pain. "So this made us ask: Could certain microbes like Staphylococcus aureus also particularly be in some way linked to itch?" says Chiu. "Is there a role for microbes in talking to itch neurons?" He and his colleagues first found that putting this bacteria on the skin of mice resulted in vigorous scratching by these animals, leading to damaged skin that spread beyond the original exposure site. © 2023 npr

Keyword: Pain & Touch
Link ID: 29022 - Posted: 11.26.2023

By Erin Garcia de Jesús A new brain-monitoring device aims to be the Goldilocks of anesthesia delivery, dispensing drugs in just the right dose. No physician wants a patient to wake up during surgery — nor do patients. So anesthesiologists often give more drug than necessary to keep patients sedated during medical procedures or while on lifesaving machines like ventilators. But anesthetics can sometimes be harmful when given in excess, says David Mintz, an anesthesiologist at Johns Hopkins University. For instance, elderly people with cognitive conditions like dementia or age-related cognitive decline may be at higher risk of post-surgical confusion. Studies also hint that long periods of use in young children might cause behavioral problems. “The less we give of them, the better,” Mintz says. An automated anesthesia delivery system could help doctors find the right drug dose. The new device monitored rhesus macaques’ brain activity and supplied a common anesthetic called propofol in doses that were automatically adjusted every 20 seconds. Fluctuating doses ensured the animals received just enough drug — not too much or too little — to stay sedated for 125 minutes, researchers reported October 31 in PNAS Nexus. The study is a step toward devising and testing a system that would work for people. © Society for Science & the Public 2000–2023.

Keyword: Consciousness; Pain & Touch
Link ID: 29021 - Posted: 11.26.2023