Jon Hamilton People who inherit one very rare gene mutation are virtually guaranteed to develop Alzheimer's before they turn 50. Except for Doug Whitney. "I'm 75 years old, and I think I'm functioning fairly well," says Whitney, who lives near Seattle. "I'm still not showing any of the symptoms of Alzheimer's." Now a team of scientists is trying to understand how Whitney's brain has defied his genetic destiny. "If we are able to learn what is causing the protection here, then we could translate that to therapeutic approaches and apply that to the more common forms of the disease," says Dr. Jorge Llibre-Guerra, an assistant professor of neurology at Washington University School of Medicine in St. Louis. One possibility is high levels of heat shock proteins found in Whitney's brain, the team reports in the journal Nature Medicine. There are hints that these proteins can prevent the spread of a toxic protein that is one of the hallmarks of Alzheimer's, Llibre-Guerra says. A genetic surprise Early-onset Alzheimer's is everywhere in Whitney's family. His mother and 11 of her 13 siblings all had the disease by about age 50. "None of them lasted past 60," Whitney says. Whitney's wife, Ione, saw this up close. "We went home for Thanksgiving, and his mom couldn't remember the pumpkin pie recipe," she says. "A year later when we went back, she was already wandering off and not finding her way back home." © 2025 npr

Keyword: Alzheimers; Genes & Behavior
Link ID: 29675 - Posted: 02.19.2025

By Sara Reardon A man who seemed genetically destined to develop Alzheimer’s disease while still young has reached his mid-70s without any cognitive decline — in only the third recorded case of such resistance to the disease. The findings, published today in Nature Medicine1, raise questions about the role of the proteins that ravage the brain during the disease and the drugs that target them. Since 2011, a study called the Dominantly Inherited Alzheimer Network (DIAN) has been following a family in which many members have a mutation in a gene called PSEN2. The mutation causes the brain to produce versions of the amyloid protein that are prone to clumping into the sticky plaques thought to drive neurodegeneration. Family members with the mutation invariably develop Alzheimer’s at around age 50. Then, a 61-year-old man from this family showed up at the DIAN study’s clinic with full cognitive function, and the researchers were shocked to discover that he had the fateful PSEN2 mutation. The man’s mother had had the same mutation, as had 11 of her 13 siblings; all had developed dementia around age 50. The researchers were even more shocked when scans revealed that his brain looked like that of someone with Alzheimer’s. “His brain was full of amyloid,” says behavioural neurologist and study co-author Jorge Llibre-Guerra at Washington University in St. Louis, Missouri. What the man’s brain didn’t contain, however, were clusters of tau — another protein that forms tangled threads inside neurons. Positron emission tomography (PET) scans revealed that he had a small amount of abnormal tau and that it was only in the occipital lobe, a brain region involved in visual perception that is not usually affected in Alzheimer’s disease. © 2025 Springer Nature Limited

Keyword: Alzheimers; Genes & Behavior
Link ID: 29667 - Posted: 02.12.2025

By Laura Hercher edited by Gary Stix It is impossible, of course, to identify the precise moment we first suspected the changes in my mother were something other than normal aging. In my own imperfect memory, what rises up is the first morning of a weeklong trip to Rome, when my mother woke up at 2 A.M., got dressed and went down for breakfast. A hotel employee found her wandering from room to room, looking for toast and coffee. She was jet-lagged, my brother and I told each other uneasily. It could happen to anyone. But weren’t there cues? Didn’t she notice the darkened lobby, the stillness, the clock? If we had known then, would it have helped? To date, no U.S. Food and Drug Administration–­approved therapy exists for asymptomatic people at risk of Alzheimer’s disease (AD). My mother was not a smoker, drank in moderation, read books, took classes, and spent that week in Italy soaking up everything the tour guide told her about Caravaggio and Bernini like she was prepping for a quiz. Five years passed after that trip before my mother received a diagnosis of dementia. Today, a simple blood test can detect changes in the brain that predict AD up to 15 years before the first symptoms emerge. For researchers, tools for early detection give a peek at the full spectrum of AD, pinpointing early seeds of pathology deep inside the brain. Cognitive decline—what we typically think of as the disease itself—is merely the illness’s denouement. “Dementia is a result. Dementia is a symptom,” explains Clifford R. Jack, Jr., a neuroradiologist at the Mayo Clinic in Rochester, Minn., and chair of the Alzheimer’s Association (AA) working group responsible for recent, controversial guidelines for the diagnosis of AD based on underlying biology, not clinical presentation. Scientific American is part of Springer Nature,

Keyword: Alzheimers
Link ID: 29657 - Posted: 02.05.2025

By Catherine Offord In scientists’ search to understand the causes of autism, a spotlight has fallen on maternal health during pregnancy. Based partly on association studies, researchers have proposed that conditions including obesity and depression during pregnancy could lead to autism in a child by affecting fetal neurodevelopment. But a study of more than 1 million Danish children and their families, published today in Nature Medicine, pushes back against this view. Researchers analyzed more than 200 health conditions that occurred in these children’s mothers before or during pregnancy. They conclude that many of the supposed links to a child’s autism diagnosis may not be causal, and instead reflect inherited genetic variants or environmental factors shared within families. “It’s a very comprehensive and well-done study,” says Håkan Karlsson, a neuroscientist at the Karolinska Institute who was not involved in the work. It suggests “conditions [pregnant people] suffered from during pregnancy are probably not the cause of autism in their kid.” The findings dovetail with a growing view in the field that shared genetics could explain a lot of the apparent connections between maternal health and autism, adds Drexel University epidemiologist Brian Lee. However, he and others caution the study doesn’t rule out that some conditions during pregnancy could have a causative role, nor does it identify factors that do influence the likelihood of autism. Previous research has linked conditions such as maternal obesity, psychiatric disorders, and pregnancy or birth complications to an increased likelihood of autism diagnoses in children. Such findings can lead some pregnant people to feel that “if they get this or that condition, their [child’s] chance of autism may increase,” says Magdalena Janecka, an epidemiologist at New York University’s Grossman School of Medicine and a co-author on the new paper. © 2025 American Association for the Advancement of Science.

Keyword: Autism
Link ID: 29652 - Posted: 02.01.2025

By Katharine Gammon Today more than 55 million people around the world have Alzheimer’s disease and other dementias, which ravage the minds of those who suffer from them and have devastating impacts on their family members. In spite of decades of research, the precise origins of these diseases continue to elude scientists, though numerous factors have been found to be associated with higher risk, including genetics and various lifestyle and environmental factors. Nautilus Members enjoy an ad-free experience. Log in or Join now . The quest has recently taken a turn to a newer model for studying the brain: brain organoids. These three-dimensional clumps of neuronal tissue derived from human stem cells have been used to study everything from epilepsy to the origins of consciousness. And now, researchers in Massachusetts are slamming them with miniature metal pistons to test out whether they can lend credence to a controversial hypothesis: that concussions might reactivate a common virus in the brain, increasing dementia risk. A decade of research suggests traumatic brain injury, whether from accidents or high-contact sports, is a standout risk factor for Alzheimer’s and other forms of neurodegenerative decline. Some estimates suggest that up to 10 percent of cases could be attributed to at least one prior head injury, but why is not fully understood. Separately, a growing body of research proposes that viral infection, including a common virus known as herpes simplex one, can also increase susceptibility to these diseases. But all three things—head trauma, viral infection, and dementia—have not been directly connected in experimental research, until now. One of the challenges in getting to the roots of dementia is that humans lead complex, messy lives. In the soup of risk factors—from high blood pressure to loneliness to genetic inheritance—it can be hard to filter out the most impactful forces that have contributed to the onset of any one dementia case. There are no ethical ways to test these questions on humans, of course, while using lab animals presents its own ethical and cost challenges. Animals are never a perfect match for humans anyway, and dementia-related findings in animals have so far not translated well to human patients. © 2025 NautilusNext Inc.,

Keyword: Alzheimers; Brain Injury/Concussion
Link ID: 29646 - Posted: 01.29.2025

By Holly Barker Previously unrecognized genetic changes on the X chromosome of autistic people could explain the higher prevalence of the condition among men and boys than among women and girls, according to two new studies. About 60 variants are more common in people with autism than in those without the condition, an analysis of roughly 15,000 X chromosomes revealed. Several of the variants are in Xp22.11, a region of the X chromosome linked to autism in boys and men. In the second study, the team pinpointed 27 autism-linked variants in DDX53, one of the genes in the vulnerable region that had not been tied to the condition in past research. Those findings could help explain why autism is diagnosed three to four times more often in boys than girls, according to the study investigators, led by Stephen Scherer, chief of research at SickKids Research Institute. Although that disparity is likely influenced by social factors—male-only studies could lead to autism being less recognizable in women and girls, and girls may be conditioned to mask their autism traits—there is also a clear biological component. The X chromosome plays an outsized role in brain development, and many genes on the chromosome are strongly linked to autism, previous studies have found. Still, the sex chromosomes have been mostly ignored in genetic searches of autism variants, says Aaron Besterman, associate clinical professor of psychiatry at the University of California, San Diego, who was not involved in the work. “It’s been a dirty little secret that for a long time the X chromosome has not been well interrogated from a genetics perspective,” he says. Sex chromosomes are often sidelined because of difficulties interpreting data, given that men possess half the number of X-linked genes as women. What’s more, random inactivation of X chromosomes makes it hard to tell how a single variant is expressed in female tissues. And the existence of pseudoautosomal regions—stretches of DNA that behave like regular chromosomes and escape inactivation—complicates matters further. © 2025 Simons Foundation

Keyword: Autism; Sexual Behavior
Link ID: 29638 - Posted: 01.22.2025

By Phie Jacobs For more than 30 years, scientists have known the genetic culprit behind Huntington disease, a devastating neurodegenerative disorder that causes cells deep in the brain to sicken and die. But they couldn’t account for why people who inherit the faulty gene variant take so long to develop symptoms, or why disease progression varies so widely from person to person. A study published today in Cell helps explain: In the brain cells that die off in Huntington, a repetitive stretch of a gene’s DNA gets longer and longer over a person’s life, and this accelerating expansion turns deadly to the cell—and ultimately to the person. The findings represent “a really remarkable insight,” says Leslie Thompson, a neuroscientist at the University of California, Irvine who wasn’t involved in the new research. “This study and some others are changing the way that we’re thinking about the disease.” People who develop Huntington inherit a flawed version of the HTT gene, which produces a protein called huntingtin. This gene contains an unusual stretch of DNA, where a sequence of three of its nucleotide bases—cytosine, adenine, and guanine, or CAG in genetic parlance—are repeated multiple times in a row. And although most people inherit versions of HTT with about 15 to 30 consecutive CAG repeats and never develop Huntington, those with 40 or more in the gene almost always have symptoms later in life, including psychological and cognitive problems and uncontrolled, jerking movements known as chorea. The genetic stutter produces an abnormally large, unstable version of the huntingtin protein, which forms clumps inside brain cells. The condition usually leads to early death, often from issues related to difficulty swallowing, injuries from falls, or suicide. The longer a person’s stretch of repeats, the earlier the disorder rears its head. Scientists originally thought the number of CAG repeats only increased as the HTT gene was passed down through generations; a child of a parent with Huntington might themselves develop the condition at an earlier age. But it turns out the length of this genetic “stutter” can change over a person’s life in at least some of their cells. A 2003 study analyzed brain samples donated by people who had died of Huntington and found shockingly large CAG expansions in a part of the brain known as the striatum.

Keyword: Huntingtons; Genes & Behavior
Link ID: 29634 - Posted: 01.18.2025

By Anna Victoria Molofsky Twenty years ago, a remarkable discovery upended our understanding of the range of elements that can shape neuronal function: A team in Europe demonstrated that enzymatic digestion of the extracellular matrix (ECM)—a latticework of proteins that surrounds all brain cells—could restore plasticity to the visual cortex even after the region’s “critical period” had ended. Other studies followed, showing that ECM digestion could also alter learning in the hippocampus and other brain circuits. These observations established that proteins outside neurons can control synaptic plasticity. We now know that up to 20 percent of the brain is extracellular space, filled with hundreds of ECM proteins—a “matrisome” that plays multiple roles, including modulating synaptic function and myelin formation. ECM genes in the human brain are different than those in other species, suggesting that the proteins they encode could be part of what makes our brains unique and keeps them healthy. In a large population study, posted as a preprint on bioRxiv last year, that examined blood protein biomarkers of organ aging, for example, the presence of ECM proteins was most highly correlated with a youthful brain. Matrisome proteins are also dysregulated in astrocytes from people at high risk for Alzheimer’s disease, another study showed. Despite the influence of these proteins and the ongoing work of a few dedicated researchers, however, the ECM field has not caught on. I would challenge a room full of neuroscientists to name one protein in the extracellular matrix. To this day, the only ECM components most neuroscientists have heard of are “perineuronal nets”—structures that play an important role in stabilizing synapses but make up just a tiny fraction of the matrisome. A respectable scientific journal, covering its own paper that identified a critical impact of ECM, called it “brain goop.” © 2025 Simons Foundation

Keyword: Learning & Memory; Glia
Link ID: 29633 - Posted: 01.18.2025

By Meghan Rosen Baby Boomers may drive a bigger-than-expected boom in dementia cases. By 2060, 1 million U.S. adults per year will develop dementia, scientists predict January 13 in Nature Medicine. Dementia is a broad term encompassing many symptoms, including memory, reasoning and language difficulties that interfere with people’s daily lives. Researchers estimate that it currently affects more than 6 million people in the United States. “This is a huge problem,” says Josef Coresh, an epidemiologist at New York University’s Grossman School of Medicine. A rise in the projected number of dementia cases is not surprising, given the aging U.S. population ­­— but the extent of the rise stands out, he says. His team predicts that 42 percent of people in the United States who are over 55 years old will develop dementia sometime during their lifetime. That’s about double the percentage estimated by previous researchers. Coresh’s new estimate is based on a study population that’s larger — more than 15,000 people — and more diverse than earlier work. His team followed participants for years, in some cases decades, using several methods to identify dementia cases. They pored over hospital and death records, evaluated participants in person and screened them by phone. For the last decade, the researchers have been calling participants twice a year, Coresh says. That gave the team a window into people’s lives, revealing dementia cases that might otherwise have gone unreported. Though the team focused on dementia in people over age 55, risk doesn’t typically start ticking up for decades. And some populations were at greater risk than others, including women, Black people and those with a particular gene variant linked to Alzheimer’s disease. © Society for Science & the Public 2000–2025.

Keyword: Alzheimers
Link ID: 29627 - Posted: 01.15.2025

By Roni Caryn Rabin Water fluoridation is widely seen as one of the great public health achievements of the 20th century, credited with substantially reducing tooth decay. But there has been growing controversy among scientists about whether fluoride may be linked to lower I.Q. scores in children. A comprehensive federal analysis of scores of previous studies, published this week in JAMA Pediatrics, has added to those concerns. It found a significant inverse relationship between exposure levels and cognitive function in children. Higher fluoride exposures were linked to lower I.Q. scores, concluded researchers working for the National Institute of Environmental Health Sciences. None of the studies included in the analysis were conducted in the United States, where recommended fluoridation levels in drinking water are very low. At those amounts, evidence was too limited to draw definitive conclusions. Observational studies cannot prove a cause-and-effect relationship. Yet in countries with much higher levels of fluoridation, the analysis also found evidence of what scientists call a dose-response relationship, with I.Q. scores falling in lock step with increasing fluoride exposure. Children are exposed to fluoride through many sources other than drinking water: toothpaste, dental treatments and some mouthwashes, as well as black tea, coffee and certain foods, such as shrimp and raisins. Some drugs and industrial emissions also contain fluoride. For every one part per million increase in fluoride in urinary samples, which reflect total exposures from water and other sources, I.Q. points in children decreased by 1.63, the analysis found. “There is concern that pregnant women and children are getting fluoride from many sources,” said Kyla Taylor, an epidemiologist at the institute and the report’s lead author, “and that their total fluoride exposure is too high and may affect fetal, infant and child neurodevelopment.” © 2025 The New York Times Company

Keyword: Intelligence; Development of the Brain
Link ID: 29625 - Posted: 01.11.2025

By Angie Voyles Askham Old age is the best predictor of Alzheimer’s disease, Parkinson’s disease and many other neurodegenerative conditions. And yet, as deeply studied as those conditions are, the process of healthy brain aging is not well understood. Without that knowledge, “how can we possibly fix something that goes wrong because of it?” asks Courtney Glavis-Bloom, senior staff scientist at the Salk Institute for Biological Sciences. “We don’t have the basics. It’s like running before we walk.” That said, mounting evidence suggests that aging takes a particular toll on non-neuronal and white-matter cells in mice. For example, white-matter cells display more differentially expressed genes in aged mice than in younger ones, according to a 2023 single-cell analysis of the frontal cortex and striatum. And glia present in white matter show accelerated aging when compared with cells in the cortex across 15 different brain regions, another 2023 mouse study revealed. “Different brain regions show totally different trajectories regarding aging,” says Andreas Keller, head of the Department of Clinical Bioinformatics at the Helmholtz Institute for Pharmaceutical Research Saarland, who worked on the latter study. Some of the cell types with the most extensive aging-related changes in gene expression occur in a small region of the hypothalamus, according to a new single-cell mouse atlas, the largest and broadest to date. Rare neuronal and non-neuronal cell populations within this “hot spot” are particularly vulnerable to the aging process, says Hongkui Zeng, executive vice president and director of the Allen Institute for Brain Science, who led the work. “This demonstrates the power of using the cell-type-specific approach that will identify highly susceptible, rare populations of interest in the brain,” she says. © 2025 Simons Foundation

Keyword: Alzheimers
Link ID: 29620 - Posted: 01.08.2025

Kat Lay Global health correspondent Pills that prevent Alzheimer’s disease or blunt its effects are on the horizon, as the fight against dementia enters a “new era”, experts have said. Scientific advances were on the cusp of producing medicines that could be used even in the most remote and under-resourced parts of the world, thereby “democratising” care, said Jeff Cummings, professor of brain science and health at the University of Nevada. An estimated 50 million people live with dementia globally, more than two-thirds of them in low- and middle-income countries. In 2024, the first drugs that can change the course of Alzheimer’s disease entered the market. Eisai and Biogen’s lecanemab and Eli Lilly’s donanemab were approved by medicine watchdogs in many western countries, including the UK and US. “I’m just so excited about this,” said Cummings. “We are truly in a new era. We have opened the door to understanding and manipulating the biology of Alzheimer’s disease for the benefit of our patients.” Cummings conceded that high prices, complicated administration techniques and requirements for advanced technology to monitor patients meant that those newly approved drugs were “not going to be made widely available in the world”. Neither is yet available on the NHS in the UK because of the high cost – about £20,000 to £25,000 a year for each patient. They require additional tests and scans that would probably double that figure. But Cummings said they offered evidence of how to target dementia and “this learning is going to open the door to new therapies of many types, and those drugs can be exported around the world”. There are currently 127 drugs in trials for Alzheimer’s disease. © 2025 Guardian News & Media Limited

Keyword: Alzheimers
Link ID: 29619 - Posted: 01.08.2025

By Joshua Cohen For decades, scientists have been trying to develop therapeutics for people living with Alzheimer’s disease, a progressive neurodegenerative disease that is characterized by cognitive decline. Given the global rise in cases, the stakes are high. A study published in The Lancet Public Health reports that the number of adults living with dementia worldwide is expected to nearly triple, to 153 million in 2050. Alzheimer’s disease is a dominant form of dementia, representing 60 to 70 percent of cases. Recent approvals by the Food and Drug Administration have focused on medications that shrink the sticky brain deposits of a protein called amyloid beta. The errant growth of this protein is responsible for triggering an increase in tangled threads of another protein called tau and the development of Alzheimer’s disease — at least according to the dominant amyloid cascade hypothesis, which was first proposed in 1991. Over the past few years, however, data and drugs associated with the hypothesis have been mired in various controversies relating to data integrity, regulatory approval, and drug safety. Nevertheless, the hypothesis still dominates research and drug development. According to Science, in fiscal year 2021 to 2022, the National Institutes of Health spent some $1.6 billion on projects that mention amyloids, about 50 percent of the agency’s overall Alzheimer’s funding. And a close look at the data for recently approved drugs suggests the hypothesis is not wrong, so much as incomplete. A few years ago, Matthew Schrag, a neurologist at Vanderbilt University, discovered possible image tampering in papers that supported the hypothesis, including in an influential 2006 Nature study that was eventually retracted. At roughly the same time, the FDA had been greenlighting medications that target amyloid beta.

Keyword: Alzheimers
Link ID: 29618 - Posted: 01.08.2025

By Sarah DeWeerdt A few months ago, Sergiu Paşca, professor of psychiatry and behavioral sciences at Stanford University, shared his lab’s new work at the Gordon Research Conference on Thalamocortical Interactions. His talk concerned assembloids, lab-grown combinations of spherical organoids that mimic different parts of the nervous system. Paşca showed a video depicting waves of calcium signals traveling along a line of organoids modeling sensory neurons; the dorsal root ganglia of the spinal cord; a subcortical structure called the thalamus; and, finally, the cerebral cortex. In the audience, Audrey Brumback, assistant professor of neurology and pediatrics at the University of Texas at Austin, felt something move through her own subcortical structures as she watched the video: a visceral feeling of awe. “I just thought, ‘Holy crap, this is amazing,’” she recalls. “‘The future is now.’” The work, described in a preprint posted on bioRxiv in March, is part of a series of recent studies from Paşca’s lab that highlight the potential of assembloids to help researchers understand brain development at the circuit level, and how these circuits go awry in autism and other neurodevelopmental conditions. Autism, after all, involves differences in how various parts of the brain connect with each other, Brumback points out. “So to be able to model that in vitro is exactly what we need to be doing to be able to understand these network dysfunction disorders,” she says. For example, a lack of synchrony between the cortex and the thalamus is known to be associated with autism and schizophrenia, whereas too much synchrony between the two regions is implicated in absence seizures in epilepsy. Using a two-part assembloid representing this pair of brain structures, Paşca and his team probed the roots of these alterations in a study published 16 October in Neuron. © 2024 Simons Foundation

Keyword: Development of the Brain
Link ID: 29610 - Posted: 12.28.2024

By Emily Baumgaertner When President-elect Donald J. Trump mused in a recent television interview about whether vaccines cause autism — a theory that has been discredited by dozens of scientific studies — autism researchers across the country collectively sighed in frustration. But during the interview, on NBC’s “Meet The Press,” Mr. Trump made one passing comment with which they could agree: “I mean, something is going on,” he said, referring to skyrocketing rates of autism. “I think somebody has to find out.” What is going on? Autism diagnoses are undeniably on the rise in the United States — about 1 in 36 children have one, according to data the Centers for Disease Control and Prevention collected from 11 states, compared with 1 in 150 children in 2000 — and researchers have not yet arrived at a clear explanation. They attribute most of the surge to increased awareness of the disorder and changes in how it is classified by medical professionals. But scientists say there are other factors, genetic and environmental, that could be playing a role too. Autism spectrum disorder, as it is officially called, is inherently wide-ranging, marked by a blend of social and communication issues, repetitive behaviors and thinking patterns that vary in severity. A mildly autistic child could simply struggle with social cues, while a child with a severe case could be nonverbal. There is no blood test or brain scan to determine who has autism, just a clinician’s observations. Because there is no singular cause of autism, scientists say there is therefore no singular driver behind the rise in cases. But at the heart of the question is an important distinction: Are more people exhibiting the traits of autism, or are more people with such traits now being identified? It seems to be both, but researchers really aren’t sure of the math. More than 100 genes have been associated with autism, but the disorder appears to result from a complex combination of genetic susceptibilities and environmental triggers. The C.D.C. has a large-scale study on the risk factors that can contribute to autism, and researchers have examined dozens of potential triggers, including pollution, exposure to toxic chemicals and viral infections during pregnancy. © 2024 The New York Times Company

Keyword: Autism
Link ID: 29609 - Posted: 12.28.2024

By Miryam Naddaf Researchers have identified 13 proteins in the blood that predict how quickly or slowly a person’s brain ages compared with the rest of their body. Their study1, published in Nature Aging on 9 December, used a machine-learning model to estimate ‘brain ages’ from scans of more than 10,000 people. The authors then analysed thousands of scans alongside blood samples and found eight proteins that were associated with fast brain ageing, and five linked to slower brain ageing. “Previous studies mainly focused on the association between the proteins and the chronological age, that means the real age of the individual,” says study co-author Wei-Shi Liu, a neurologist at Fudan University in Shanghai, China. However, studying biomarkers linked to a person’s brain age could help scientists to identify molecules to target in future treatments for age-related brain diseases. “These proteins are all promising therapeutic targets for brain disorders, but it may take a long time to validate them,” says Liu. Using machine learning to analyse brain-imaging data from 10,949 people, Liu and his colleagues created a model to calculate a person’s brain age, on the basis of features such as the brain’s volume, surface area and distribution of white matter. They wanted to identify proteins that are associated with a large brain age gap — the difference between brain age and chronological age. To do this, the researchers analysed levels of 2,922 proteins in blood samples from 4,696 people, more than half of whom were female, and compared them with the same people’s brain ages derived from the scans. They identified 13 proteins that seemed to be connected with large brain age gaps, some of which are known to be involved in movement, cognition and mental health.

Keyword: Development of the Brain
Link ID: 29597 - Posted: 12.11.2024

By Grace Huckins Genes on the X and Y chromosomes—and especially those on the Y—appear to be associated with autism likelihood, according to a study focused on people who have missing or extra sex chromosomes. The findings add to the ongoing debate about whether autism’s sex bias reflects a male vulnerability, a female protective effect or other factors. “The Y chromosome is often left out of genetic discovery studies. We really have not interrogated it in [autism] studies very much,” says Matthew Oetjens, assistant professor of human genetics at Geisinger Medical Center’s Autism and Developmental Medicine Institute, who led the new work. There is a clear sex difference in autism prevalence: Men are about four times as likely as women to have a diagnosis. But uncovering the reasons for that discrepancy has proved challenging and contentious. Multiple biological factors may play a role, in addition to social factors—such as the difficult-to-measure gulfs between how boys and girls are taught to behave. Add on the possibility of diagnostic bias and the question starts to look less like a scientific problem and more like a politically toxic Gordian knot. But there are some threads that researchers can pull to disentangle these effects, as the new study illustrates. People with sex chromosome aneuploidies—or unusual combinations of sex chromosomes, such as XXY in those with Klinefelter syndrome or a single X in Turner syndrome—provide a unique opportunity to examine how adding or taking away chromosomes can affect biology and behavior. Previous studies noted high rates of autism in people with sex chromosome aneuploidies, but those analyses were subject to ascertainment bias; perhaps those people found out about their aneuploidies only after seeking support for their neurodevelopmental conditions. © 2024 Simons Foundation

Keyword: Autism; Sexual Behavior
Link ID: 29596 - Posted: 12.11.2024

By Steven Strogatz Death might seem like a pure loss, the disappearance of what makes a living thing distinct from everything else on our planet. But zoom in closer, to the cellular level, and it takes on a different, more nuanced meaning. There is a challenge in simply defining what makes an individual cell alive or dead. Scientists today are working to understand the various ways and reasons that cells disappear, and what these processes mean to biological systems. In this episode, cellular biologist Shai Shaham talks to Steven Strogatz about the different forms of cell death, their roles in evolution and disease, and why the right kinds and patterns of cell death are essential to our development and well-being. STEVE STROGATZ: In the second that it took you to hit play on this episode, a million cells in your body died. Some were programmed to expire in natural, regulated processes, such as apoptosis. Some terminated their own lives after infection, to stop viral invaders from spreading. Others suffered physical damage and went through necrosis, their membranes splitting open and their contents spilling out. We know there are nearly a dozen different ways for our cells to kick the bucket. And learning how to control these processes can make all the difference in the world to a sick patient. In this episode, we ask cellular biologist Shai Shaham (opens a new tab), how can the death of a cell help other cells around it? And how do these insights help us understand life itself? Shai is a professor at The Rockefeller University (opens a new tab), where he studies programmed cell death during animal development and the complex role that glial cells play in the nervous system. There was an example near and dear to my heart, since we work on C. elegans, which is a nematode worm. And there was a recent description of a nematode that was extracted from permafrost in Siberia where it froze about 40,000 years ago and was revived back in the lab. And so you ask yourself, was that whole organism alive or dead for 40,000 years? © 2024 Simons Foundation

Keyword: Apoptosis; Development of the Brain
Link ID: 29591 - Posted: 12.07.2024

Aswathy Ammothumkandy, Charles Liu, Michael A. Bonaguidi Your brain can still make new neurons when you’re an adult. But how does the rare birth of these new neurons contribute to cognitive function? Neurons are the cells that govern brain function, and you are born with most of the neurons you will ever have during your lifetime. While the brain undergoes most of its development during early life, specific regions of the brain continue to generate new neurons throughout adulthood, although at a much lower rate. Whether this process of neurogenesis actually happens in adults and what function it serves in the brain is still a subject of debate among scientists. Past research has shown that people with epilepsy or Alzheimer’s disease and other dementias develop fewer neurons as adults than people without these conditions. However, whether the absence of new neurons contributes to the cognitive challenges patients with these neurological disorders face is unknown. We are part of a team of stem cell researchers, neuroscientists, neurologists, neurosurgeons and neuropsychologists. Our newly published research reveals that the new neurons that form in adults’ brains are linked to how you learn from listening to other people. Researchers know that new neurons contribute to memory and learning in mice. But in humans, the technical challenges of identifying and analyzing new neurons in adult brains, combined with their rarity, had led scientists to doubt their significance to brain function. To uncover the relationship between neurogenesis in adults and cognitive function, we studied patients with drug-resistant epilepsy. These patients underwent cognitive assessments prior to and donated brain tissue during surgical procedures to treat their seizures. To see whether how many new neurons a patient had was associated with specific cognitive functions, we looked under the microscope for markers of neurogenesis. © 2010–2024, The Conversation US, Inc.

Keyword: Neurogenesis; Learning & Memory
Link ID: 29590 - Posted: 12.07.2024

Amy Fleming Nine years ago, Nikki Schultek, an active and healthy woman in her early 30s, experienced a sudden cascade of debilitating and agonising symptoms – including cognitive and breathing problems and heart arrhythmia – and was investigated for multiple sclerosis. But three brain scans and numerous X-rays later, there was still no diagnosis or treatment plan. “It was like living in a nightmare, imagining not watching my children – three and five years old – grow up,” says Schultek. Now, speaking on a video call from North Carolina, she is as bright as a button and shows no signs of degenerative brain disease. It turned out she had multiple chronic infections, including Borrelia burgdorferi bacteria, which causes Lyme disease and which had stealthily reached her brain. Antibiotics restored her health, but B burgdorferi is hard to eradicate once in the brain. She may need maintenance treatment to keep the disease at bay. Schultek is not the only person whose neurological disorder turned out to be caused by microbes in the brain. A recent paper she jointly lead-authored, published in Alzheimer’s and Dementia, compiled a long list of case reports where infectious disease was discovered to be the primary cause of dementia, meaning that, in many cases, the dementia was reversible. A few of the patients died, but most survived and saw significant improvements in cognitive function, including a man in his 70s who had been diagnosed with Alzheimer’s disease after his swift cognitive decline saw him unable to drive or, eventually, leave the house alone. A sample of his cerebrospinal fluid was taken and revealed a fungal infection caused by Cryptococcus neoformans. Within two years of taking antifungal medication, he was driving again and back at work as a gardener. Richard Lathe, a professor of infectious medicine at the University of Edinburgh and another lead author of the paper, says these patients “were by accident found to be suffering from various fungal, bacterial or viral infections, and when they treated the patient with antifungals, antivirals or antibiotics, the dementia went away”. He, among others, has been investigating the possibility that, like the gut, the brain hosts a community of microbes – an area of largely scientifically uncharted waters, but with huge life-saving potential. © 2024 Guardian News & Media Limited

Keyword: Alzheimers; Obesity
Link ID: 29587 - Posted: 12.04.2024