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

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 29277 - Posted: 04.30.2024

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

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 29261 - Posted: 04.20.2024

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

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 29239 - Posted: 04.04.2024

By Holly Barker Sensory issues associated with autism may be caused by fluctuating neuronal noise — the background hum of electrical activity in the brain — according to a new mouse study. Up to 90 percent of autistic people report sensory problems, including heightened sensitivity to sounds or an aversion to certain smells. Yet others barely register sensory cues and may seek out sensations by making loud noises or rocking back and forth. But thinking in terms of hyper- or hyposensitivity may be an oversimplification, says Andreas Frick, lead investigator and research director at INSERM. “It’s becoming clear now that things are a lot more nuanced.” For instance, the brain’s response to visual patterns — measured using electroencephalography (EEG) recordings — varies more between viewings in autistic people than in those without the condition, one study found. And functional MRI has detected similar variability among autistic people, suggesting sensory problems may arise from inconsistent brain responses. In the new study, Frick and his colleagues found variability in the activity of individual neurons in a mouse model of fragile X syndrome, one of the leading causes of autism. That variability in neuronal response maps to fluctuations in the levels of noise in the brain, the study found. Noise within the brain isn’t necessarily a bad thing. In fact, an optimum amount is ideal: a little can give neurons the ‘push’ they might need to fire an action potential, while too much can make it difficult for the brain to distinguish between different stimuli. But in animals modeling fragile X syndrome, noise fluctuates such that they process sensory information less reliably, Frick says. © 2023 Simons Foundation.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 8: General Principles of Sensory Processing, Touch, and Pain
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 5: The Sensorimotor System
Link ID: 29105 - Posted: 01.18.2024

by Grace Huckins In 1961, the late psychiatrist Daniel Freedman made what would become one of the most replicated — and most mysterious — discoveries in the history of autism research. Comparing blood levels of the neurotransmitter serotonin in 4 non-autistic and 23 autistic children, he found significantly higher levels among the latter group. Since then, researchers have repeatedly identified this trait, called hyperserotonemia, in about a third of autistic people tested. It’s not difficult to theorize how hyperserotonemia might be linked to a range of autism traits. Neurons that release serotonin extend into practically every part of the brain, where they modulate signals sent among other neurons. Selective serotonin reuptake inhibitors (SSRIs), drugs that raise levels of serotonin in the brain’s synapses, treat psychiatric conditions, such as anxiety and obsessive-compulsive disorder, that can co-occur with autism. And serotonin prompts the gut to contract and facilitate digestion, which is often impaired in autistic people. So when Edwin Cook, professor of psychiatry at the University of Illinois at Chicago, began to study the biology of autism in the 1980s, hyperserotonemia seemed like an obvious place to start. “We didn’t have much [else],” he says. “There were plenty of mothers of older patients I saw who had been labeled refrigerator mothers,” a term that refers to the discredited idea that unaffectionate mothers cause autism. The serotonin finding offered a tangible, biological clue. Even today, with decades more autism research to look back on, the hyperserotonemia result stands out. “It’s one of the few robust biological clues that we’ve had in autism,” says Jeremy Veenstra-VanderWeele, professor of psychiatry at Columbia University and a former advisee of Cook’s. But so far, it has escaped explanation. Nor have researchers been able to definitively link hyperserotonemia to specific genetic, anatomical or behavioral traits in autistic people. This apparent lack of progress has led some to disregard work on the neurotransmitter, according to serotonin researcher Georgianna Gould, associate professor of physiology at the University of Texas Health Science Center at San Antonio. “I’ve actually seen reviews come back that say that serotonin has nothing to do with autism,” she says. © 2023 Simons Foundation

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 16: Psychopathology: Biological Basis of Behavior Disorders
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 12: Psychopathology: The Biology of Behavioral Disorders
Link ID: 28998 - Posted: 11.11.2023

By Mark Johnson Using a host of high-tech tools to simulate brain development in a lab dish, Stanford University researchers have discovered several dozen genes that interfere with crucial steps in the process and may lead to autism, a spectrum of disorders that affects about one in every 36 Americans, impairing their ability to communicate and interact with others. The results of a decade of work, the findings published in the journal Nature may one day pave the way for scientists to design treatments that allow these phases of brain development to proceed unimpaired. The study delves into a 20-year-old theory that suggests one cause of autism may be a disruption of the delicate balance between two types of nerve cells found in the brain’s cerebral cortex, the area responsible for higher-level processes such as thought, emotion, decision-making and language. Some nerve cells in this region of the brain excite other nerve cells, encouraging them to fire; other cells, called interneurons, do the opposite. Too much excitation can impair focus in the brain and cause epilepsy, a seizure disorder that is more common in people with autism than in the general population. Scientists therefore believe a proper balance requires more of the inhibiting interneurons. In the developing fetus, these nerve cells start out deep in the brain in a region called the subpallium, then migrate slowly to the cerebral cortex. The process begins mid-gestation and ends in the infant’s second year of life, said Sergiu Pasca, a Stanford University professor of psychiatry and behavioral sciences who led the study. Pasca’s team, which included researchers from the University of California at San Francisco and the Icahn School of Medicine at Mount Sinai, tested 425 genes that have been linked to neurodevelopmental disorders to determine which ones interfere with the generation and migration of interneurons. Genes linked to autism were among those identified in the study. “What’s really cool about this paper is that autism is a collection of different behaviors, but we don’t have [an] understanding of how those behaviors are connected to differences in the brain,” said James McPartland, a professor of child psychiatry and psychology at the Yale School of Medicine, who was not involved in the study. The new work advances research into autism by “beginning to create a fundamental understanding of the building blocks of brain development,” he said.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28947 - Posted: 10.07.2023

By Jacqueline Howard and Deidre McPhillips, Most families of children with autism may face long wait times to diagnose their child with the disorder, and once a diagnosis is made, it sometimes may not be definitive. But now, two studies released Tuesday suggest that a recently developed eye-tracking tool could help clinicians diagnose children as young as 16 months with autism – and with more certainty. Kids’ developmental disability diagnoses became more common during pandemic, but autism rates held steady, CDC report says “This is not a tool to replace expert clinicians,” said Warren Jones, director of research at the Marcus Autism Center at Children’s Healthcare of Atlanta and Nien Distinguished Chair in Autism at Emory University School of Medicine, who was an author on both studies. Rather, he said, the hope with this eye-tracking technology is that “by providing objective measurements that objectively measure the same thing in each child,” it can help inform the diagnostic process. The tool, called EarliPoint Evaluation, is cleared by the US Food and Drug Administration to help clinicians diagnose and assess autism, according to the researchers. Traditionally, children are diagnosed with autism based on a clinician’s assessment of their developmental history, behaviors and parents’ reports. Evaluations can take hours, and some subtle behaviors associated with autism may be missed, especially among younger children. “Typically, the way we diagnose autism is by rating our impressions,” said Whitney Guthrie, a clinical psychologist and scientist at the Children’s Hospital of Philadelphia’s Center for Autism Research. She was not involved in the new studies, but her research focuses on early diagnosis of autism.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 10: Vision: From Eye to Brain
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 7: Vision: From Eye to Brain
Link ID: 28904 - Posted: 09.13.2023

by Calli McMurray One of the co-directors of a now-shuttered Maryland psychology clinic implicated in 18 paper retractions has retired, Spectrum has learned. Prior to her retirement, Clara Hill was professor of psychology at the University of Maryland in College Park. Headshot of Clara Hill. Recent retirement: Clara Hill retired from the University of Maryland in the midst of 18 paper retractions after a 49-year career. Starting on 1 June, the American Psychological Association (APA) retracted 11 papers by Hill and her university colleagues Dennis Kivlighan, Jr. and Charles Gelso over issues with obtaining participant consent. The publisher plans to retract six more papers by the end of the year, according to an APA representative. On 13 August, Taylor & Francis retracted an additional paper led solely by Hill. The research was conducted at the Maryland Psychotherapy Clinic and Research Lab, where Hill, Kivlighan and Gelso were co-directors. The clinic had shut down as of 1 June. When asked about the circumstances surrounding Hill’s retirement, a university spokesperson told Spectrum in an email, “Dr. Clara Hill retired from UMD effective July 1, 2023.” After Spectrum asked again about the circumstances, a spokesperson replied, “This is all we’ll have for you on the faculty member’s retirement — thanks!” Hill worked at the university for 49 years. As of 1 August, Hill’s faculty page did not mention her retirement. By 14 August, her position had been amended to “Professor (Retired),” and a notice of her retirement had been added to the beginning of her biography. Spectrum left two voicemails on Hill’s university office phone and emailed her university address with requests for comment but did not hear back. The 11 papers retracted by the APA appeared in the Journal of Counseling Psychology, Dreaming and Psychotherapy. The additional retractions will come from the same titles, according to an APA representative. Hill conducted all 11 studies, whereas Kivlighan and Gelso conducted 10 and 6, respectively. © 2023 Simons Foundation

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28877 - Posted: 08.24.2023

by Giorgia Guglielmi Mice with a mutation that boosts the activity of the autism-linked protein UBE3A show an array of behaviors reminiscent of the condition, a new study finds. The behaviors differ depending on whether the animals inherit the mutation from their mother or their father, the work also reveals. The results add to mounting evidence that hyperactive UBE3A leads to autism. Duplications of the chromosomal region that includes UBE3A have been associated with autism, whereas deletions and mutations that destroy the gene’s function are known to cause Angelman syndrome, which is characterized by developmental delay, seizures, lack of speech, a cheerful demeanor and, often, autism. “UBE3A is on a lot of clinicians’ radar because it is well known to be causative for Angelman syndrome when mutated or deleted,” says lead investigator Mark Zylka, professor of cell biology and physiology at the University of North Carolina at Chapel Hill. “What our study shows is that just because you have a mutation in UBE3A, it doesn’t mean that it’s going to be Angelman syndrome.” In the cell, UBE3A is involved in the degradation of proteins, and “gain-of-function” mutations — which send the UBE3A protein into overdrive — result in enhanced degradation of its targets, including UBE3A itself. Studying the effects of these mutations could provide insight into how they affect brain development and suggest targets for therapies, says study investigator Jason Yi, assistant professor of neuroscience at Washington University in St. Louis, Missouri. Gain-of-function mutations in UBE3A can disrupt early brain development and may contribute to neurodevelopmental conditions that are distinct from Angelman syndrome, Yi and Zylka have shown in previous studies. One of the mutations they analyzed had been found in an autistic child, so the team used CRISPR to create mice with this mutation. © 2023 Simons Foundation

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28857 - Posted: 07.27.2023

By Harrison Smith As a young boy in small-town Mississippi, Donald Triplett was oddly distant, with no apparent interest in his parents or anyone else who tried to make conversation. He was obsessed with spinning round objects and had an unusual way of speaking, substituting “you” for “I” and repeating words like “business” and “chrysanthemum.” He also showed a savant-like brilliance, naming notes as they were played on the piano and performing mental calculations with ease. When a visitor asked “87 times 23,” he didn’t hesitate before answering — correctly — “2,001.” Mr. Triplett would make medical history as “Case 1,” the first person formally diagnosed with autism. His upbringing and behavior were described at length in a 1943 scientific article by Austrian American psychiatrist Leo Kanner, “Autistic Disturbances of Affective Contact,” which outlined the developmental disability now known as autism spectrum disorder, or ASD. The article went on to describe 10 other autistic children, most of whom were locked away in state schools and hospitals while experiencing communication and behavior challenges. Checking in with his former subjects almost 30 years later, Kanner would write that institutionalization was “tantamount to a life sentence … a total retreat to near-nothingness.” Mr. Triplett, by contrast, gained acceptance and admiration while remaining a part of his community. With support from his family, which could afford to send him to Kanner and which later set up a trust fund to look after him, he graduated from college, got a job as a bank teller and found companionship in a morning coffee club at City Hall. He played golf, sang in a choir and traveled the world, visiting at least three-dozen countries and making it to Hawaii 17 times. By choice, he traveled alone, surprising relatives when he would announce at Sunday dinner that he had recently returned from seeing a golf tournament in California or, in search of an oyster dinner, driven his Cadillac to New Orleans.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28826 - Posted: 06.21.2023

by Sarah DeWeerdt Many papers about autism-linked genes note that the genes are expressed throughout both the central and the peripheral nervous systems. The proportion of such prolific genes may be as high as two-thirds, according to one 2020 analysis. Yet few studies delve into what those genes are actually doing outside the brain. That’s starting to change. Although autism is typically thought of as a brain condition, a critical mass of researchers has started to investigate how the condition alters neurons elsewhere in the body. Their work — part of a broader trend in neuroscience to look beyond the brain — hints that the role of the peripheral nervous system in autism is, well, anything but peripheral: Neuronal alterations outside the brain may help to explain a host of the condition’s characteristic traits. Much of the research so far focuses on touch and the workings of the gut, but there is increasing interest in other sensory and motor neurons, as well as the autonomic nervous system, which orchestrates basic body functions such as heartbeat, blood pressure, breathing and digestion. It’s difficult to pinpoint whether some autism traits arise in the peripheral nervous system or the central nervous system; in many cases, complex feedback loops link the two. “Your nervous system doesn’t know that we’ve divided it that way,” says Carissa Cascio, associate professor of psychiatry and behavioral sciences at Vanderbilt University in Nashville, Tennessee. But at least some peripheral changes may offer novel treatment targets. And drugs that act in the peripheral nervous system could also prove more effective and have fewer side effects than brain-based therapies, says Julia Dallman, associate professor of biology at the University of Miami in Coral Gables, Florida. © 2023 Simons Foundation

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 13: Homeostasis: Active Regulation of the Internal Environment
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 9: Homeostasis: Active Regulation of the Internal Environment
Link ID: 28739 - Posted: 04.15.2023

By Azeen Ghorayshi Morénike Giwa Onaiwu was shocked when day care providers flagged some concerning behaviors in her daughter, Legacy. The toddler was not responding to her name. She avoided eye contact, didn’t talk much and liked playing on her own. But none of this seemed unusual to Dr. Onaiwu, a consultant and writer in Houston. “I didn’t recognize anything was amiss,” she said. “My daughter was just like me.” Legacy was diagnosed with autism in 2011, just before she turned 3. Months later, at the age of 31, Dr. Onaiwu was diagnosed as well. Autism, a neurodevelopmental disorder characterized by social and communication difficulties as well as repetitive behaviors, has long been associated with boys. But over the past decade, as more doctors, teachers and parents have been on the lookout for early signs of the condition, the proportion of girls diagnosed with it has grown. In 2012, the Centers for Disease Control and Prevention estimated that boys were 4.7 times as likely as girls to receive an autism diagnosis. By 2018, the ratio had dipped to 4.2 to 1. And in data released by the agency last month, the figure was 3.8 to 1. In that new analysis, based on the health and education records of more than 226,000 8-year-olds across the country, the autism rate in girls surpassed 1 percent, the highest ever recorded. More adult women like Dr. Onaiwu are being diagnosed as well, raising questions about how many young girls continue to be missed or misdiagnosed. “I think we just are getting more aware that autism can occur in girls and more aware of the differences,” said Catherine Lord, a psychologist and autism researcher at the University of California, Los Angeles. © 2023 The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 12: Sex: Evolutionary, Hormonal, and Neural Bases
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 8: Hormones and Sex
Link ID: 28737 - Posted: 04.12.2023

By Emily Anthes The prevalence of autism spectrum disorder in American children rose between 2018 and 2020, continuing a long-running trend, according to a study released by the Centers for Disease Control and Prevention on Thursday. In 2020, an estimated one in 36 8-year-olds had autism, up from one in 44 in 2018. The prevalence was roughly 4 percent in boys and 1 percent in girls. The rise does not necessarily mean that autism has become more common among children, and it could stem from other factors, such as increased awareness and screening. “I have a feeling that this is just more discovery,” said Catherine Lord, a professor of psychiatry at the University of California, Los Angeles medical school, who was not involved in the research. “The question is what’s happening next to these kids, and are they getting services?” The rise was especially sharp among Black, Hispanic, and Asian or Pacific Islander children. For the first time, autism was significantly more prevalent among 8-year-olds in these groups than in white children, who have traditionally been more likely to receive autism diagnoses. “These patterns might reflect improved screening, awareness and access to services among historically underserved groups,” the researchers wrote. But why the prevalence in these children has surpassed that in white children is an open question that requires more investigation, Dr. Lord said. An accompanying study, also published on Thursday, suggests that the pandemic may have disrupted or delayed the detection of autism in younger children. © 2023 The New York Times Company

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28717 - Posted: 03.25.2023

ByRachel Zamzow A long-smoldering debate among scientists studying autism has erupted. At issue is language—for example, whether researchers should describe autism as a “disorder,” “disability,” or “difference,” and whether its associated features should be called “symptoms” or simply “traits.” In scientific papers and commentaries published in recent months, some have decried ableist language among their colleagues whereas others have defended traditional terminology—with both sides saying they have the best interests of autistic people in mind. The vitriol is harming the field and silencing researchers, some fear, but others see it as a long-overdue reckoning. Since autism’s earliest descriptions in the academic literature as a condition affecting social interaction and communication, researchers and clinicians have framed it as a medical disorder, with a set of symptoms to be treated. Historically, autistic children have been institutionalized and subjected to treatments involving physical punishment, food restriction, and electric shocks. Even today, the most widely used autism therapy—applied behavior analysis—is seen by some as a harmful tool of normalization. Many autistic people and their families have instead embraced the view that their difficulties lie not with their autism, but with a society that isn’t built to support them. But according to some autism researchers, the field still too often defaults to terms with negative connotations. For example, in addition to “symptom” and “disorder,” many scientists use the term “comorbid” rather than the more neutral “co-occurring” to describe conditions that tend to accompany autism. Similarly, some argue the oft-used phrase “people with autism,” as opposed to “autistic person,” can imply that autism is necessarily an unwanted harmful condition. In a recent survey of 195 autism researchers, 60% of responses included views about autistic people the study authors deemed dehumanizing, objectifying, or stigmatizing. Some responses described autistic people as “shut down from the outside world” or “completely inexpressive and apparently without emotions,” according to the November 2022 Frontiers in Psychology study. “What is worse than I thought was how blatant a lot of the content was, which shows that, for [a] large proportion of participants, they did not consider the things they were saying to be problematic at all,” says lead author Monique Botha, a psychologist at the University of Stirling.

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 1: Introduction: Scope and Outlook
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 1: Cells and Structures: The Anatomy of the Nervous System
Link ID: 28660 - Posted: 02.08.2023

by Peter Hess An autism-linked mutation in the gene CHD8 yields wildly different physical and behavioral traits in mice depending on their genetic backgrounds, according to a study of 33 mouse strains. The findings were published today in Neuron. The results serve as a stark reminder that traits associated with an autism-linked mutation reflect more than just that mutation, says senior investigator Pat Levitt, chair of developmental neurogenetics at Children’s Hospital Los Angeles in California. Differences in genetic background could also explain why some findings from autism model mice have failed to replicate across labs, he adds. People with CHD8 mutations often have autism, intellectual disability, gastrointestinal issues and macrocephaly — larger-than-average head size — but not all of them have all of these traits. This variability may stem from interactions between the mutations and other variants across the genome, says study investigator Manal Tabbaa, a postdoctoral research fellow in Levitt’s lab. The new work does not reveal how the same CHD8 mutation can affect different mice — or people — differently. But researchers could use the genetically diverse rodents to answer this question, and to better understand and model autism’s heterogeneity, Tabbaa and Levitt say. “This is such a comprehensive approach to understand a really clinically relevant question, and it’s almost unbelievable that just three people could do this amount of work, considering how much it looks like was done,” says Joseph Gleeson, professor of neurosciences at the University of California, San Diego, who was not involved in the study. “They are just scratching the surface of what could be really fantastic future efforts.” © 2023 Simons Foundation

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28657 - Posted: 02.08.2023

by Giorgia Guglielmi About five years ago, Catarina Seabra made a discovery that led her into uncharted scientific territory. Seabra, then a graduate student in Michael Talkowski’s lab at Harvard University, found that disrupting the autism-linked gene MBD5 affects the expression of other genes in the brains of mice and in human neurons. Among those genes, several are involved in the formation and function of primary cilia — hair-like protrusions on the cell’s surface that sense its external environment. “This got me intrigued, because up to that point, I had never heard of primary cilia in neurons,” Seabra says. She wondered if other researchers had linked cilia defects to autism-related conditions, but the scientific literature offered only sparse evidence, mostly in mice. Seabra, now a postdoctoral researcher in the lab of João Peça at the Center for Neuroscience and Cell Biology at the University of Coimbra in Portugal, is spearheading an effort to look for a connection in people: The Peça lab established a biobank of dental stem cells obtained from baby teeth of 50 children with autism or other neurodevelopmental conditions. And the team plans to look at neurons and brain organoids made from those cells to see if their cilia show any defects in structure or function. Other neuroscientists, too, are working to understand the role of cilia during neurodevelopment. Last September, for example, researchers working with tissue samples from mice discovered that cilia on the surface of neurons can form junctions, or synapses, with other neurons — which means cilia defects could, at least in theory, hinder the development of neural circuitry and activity. Other teams have connected several additional autism-related genes, beyond MBD5, to the tiny cell antennae. © 2023 Simons Foundation

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 28623 - Posted: 01.07.2023

by David Dobbs For 40 years, Leo Kanner and Hans Asperger have dominated virtually every story about the ‘pioneers of autism research.’ These two men published in 1943 and 1944, respectively, what were long accepted as the first descriptions of, as Kanner’s seminal paper claimed, ”children whose condition differs … markedly and uniquely from anything reported so far.” Both papers are absorbing, touching and authoritative. Both describe young people whose challenges defied the known diagnoses of the time but clearly fall into what we now call autism. And both offered a new diagnostic category for such people. Kanner’s 1943 paper, ”Autistic Disturbances of Affective Contact,” drew almost immediate attention. Within a year, he renamed the condition these children shared, dubbing it ‘early infantile autism,’ which soon became known as ‘autism’ or ‘Kanner’s syndrome.’ His articulation of the condition, based on observations of 11 children he and his associates treated in his Baltimore, Maryland, clinic, remained the standard well into the 1980s and involved three elements: Autism was a condition marked by: (1) emergence early in childhood, (2) deficits in communication and social interaction, and (3) restricted or repetitive behaviors and a desire for sameness. Even today, these three elements anchor the official diagnostic criteria in the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders, as well as the widely used International Classification of Diseases and Related Health Problems. Asperger’s 1944 paper, which presented case studies on four children he and his colleagues had seen in his clinic in Vienna, Austria, made its impact far more slowly. In fact, because Asperger published in German (and in a German journal in the middle of a war that had essentially halted transatlantic scholarly exchange), the paper went largely unnoticed outside Europe for decades. Asperger’s descriptions resembled Kanner’s in many ways, although he outlined a wider apparent range of intelligence and capabilities than Kanner did, with some of his study participants reaching prominence in their fields. Asperger coined the diagnostic term ‘autistic psychopathy.’ © 2022 Simons Foundation

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior
Related chapters from MM:Chapter 13: Memory and Learning
Link ID: 28544 - Posted: 11.09.2022

by Angie Voyles Askham / Brain connectivity patterns in people with autism and other neuropsychiatric conditions are more closely related to genetics than to phenotypic traits, according to two new studies. The findings highlight why a single brain biomarker for autism has remained elusive, the researchers say. The condition’s genetic heterogeneity has hampered the search for a shared brain signature: More than 100 genes have been identified as strongly linked to autism, and multiple copy number variations (CNVs) — deleted or duplicated stretches of genetic code — can increase a person’s likelihood of the condition. Autism also often overlaps with other conditions, such as schizophrenia and attention-deficit/hyperactivity disorder (ADHD), making autism-specific markers difficult to disentangle. Common variants tied to autism overlap strongly with those linked to schizophrenia and high IQ, for example, whereas rare autism-linked variants track with low IQ. According to the new papers, however, autism’s genetic heterogeneity corresponds to similarly disparate maps of ‘functional connectivity’ — a measure of which brain areas activate in sync while the brain is at rest. “What we’re seeing is that these groups of variants have specific functional connectivity signatures,” says lead investigator Sébastien Jacquemont, associate professor of pediatrics at the University of Montreal in Canada. The findings need to be replicated, says Aaron Alexander-Bloch, assistant professor of psychiatry at the University of Pennsylvania and the Children’s Hospital of Philadelphia, who was not involved in the work, but they point to the importance of subgrouping study participants based on their underlying genetics. © 2022 Simons Foundation

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 2: Functional Neuroanatomy: The Cells and Structure of the Nervous System
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 2: Neurophysiology: The Generation, Transmission, and Integration of Neural Signals
Link ID: 28490 - Posted: 09.28.2022

by Charles Q. Choi Infection during pregnancy may be associated with having an autistic child simply because mothers of autistic children are prone to infections, a new study finds. The results suggest that “common infections during pregnancy do not seem increase their children’s risk of autism,” says study investigator Martin Brynge, a psychiatrist and doctoral student of global public health at the Karolinska Institutet in Stockholm, Sweden. “Prevention of maternal infections would likely not affect the prevalence of autism in the population.” A great deal of previous research has linked maternal infection during pregnancy with autism and intellectual disability in children. Whether the former causes the latter, however, has remained uncertain. For instance, both autism and intellectual disability are linked with gene variants that may influence the immune system, so mothers of children with either condition may also just be more vulnerable to serious infections. The new study analyzed data from 549,967 children, including 267,995 girls, living in Stockholm County who were born between 1987 and 2010; about 34,000 of the children had been exposed to a maternal infection requiring specialized health care, according to data from Sweden’s National Patient Register and National Medical Birth Register. Of the exposed children, 3.3 percent have autism, compared with 2.5 percent of unexposed children — a 16 percent increase in the chance of autism. But maternal infection in the year before pregnancy was also linked with a 25 percent greater chance of autism. “Mothers who had an infection during pregnancy may not be comparable to those mothers without infections,” Brynge says. “There may be systematic differences at the group level.” © 2022 Simons Foundation

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 15: Emotions, Aggression, and Stress
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 11: Emotions, Aggression, and Stress
Link ID: 28488 - Posted: 09.24.2022

by Nora Bradford A well-studied brain response to sound, called the M100, appears earlier in life in autistic children than in their non-autistic peers, according to a new longitudinal study. The finding suggests that the auditory cortex in children with autism matures unusually quickly, a growth pattern seen previously in other brain regions. “It’s a demonstration that when we look for autism markers in the brain, they can be very age-specific,” says lead investigator J. Christopher Edgar, associate professor of radiology at the Children’s Hospital of Philadelphia in Pennsylvania. For that reason, longitudinal studies such as this one — in which Edgar and his colleagues assessed children at up to three different ages — are essential, he adds. “If the two populations being studied have different rates of brain maturation, then the pattern of findings changes across time.” At the time of the first magnetoencephalography (MEG) scan, when the children were 6 to 9 years old, those with autism were more likely to have an M100 response to a barely audible tone in the right hemisphere than non-autistic children were. But this difference disappeared in the next two visits, presumably because the M100 response typically appears during early adolescence. By contrast, the M50 response, which occurs throughout life, beginning in utero, showed no significant difference between the two groups at any visit. The team also evaluated ‘phase locking,’ a measure of how similar a participant’s neural activity is from scan to scan within a certain frequency band. Autistic participants demonstrated more mature phase-locking patterns at the first visit, which then diminished at the later two visits. © 2022 Simons Foundation

Related chapters from BN: Chapter 7: Life-Span Development of the Brain and Behavior; Chapter 9: Hearing, Balance, Taste, and Smell
Related chapters from MM:Chapter 13: Memory and Learning; Chapter 6: Hearing, Balance, Taste, and Smell
Link ID: 28478 - Posted: 09.17.2022