Chapter 2. Functional Neuroanatomy: The Cells and Structure of the Nervous System

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Links 21 - 40 of 1423

By McKenzie Prillaman It was hailed as a potentially transformative technique for measuring brain activity in animals: direct imaging of neuronal activity (DIANA), held the promise of mapping neuronal activity so fast that neurons could be tracked as they fired. But nearly two years on from the 2022 Science paper1, no one outside the original research group and their collaborators have been able to reproduce the results. Now, two teams have published a record of their replication attempts — and failures. The studies, published on 27 March in Science Advances2,3, suggest that the original results were due to experimental error or data cherry-picking, not neuronal activity after all. But the lead researcher behind the original technique stands by the results. “I’m also very curious as to why other groups fail in reproducing DIANA,” says Jang-Yeon Park, a magnetic resonance imaging (MRI) physicist at Sungkyunkwan University in Suwon, South Korea. Science said in an e-mail to Nature that, although it’s important to report the negative results, the Science Advances studies “do not allow a definitive conclusion” to be drawn about the original work, “because there were methodological differences between the papers”. In conventional functional MRI (fMRI), researchers monitor changes in blood flow to different brain regions to estimate activity. But this response lags by at least one second behind the activity of neurons, which send messages in milliseconds. Park and his co-authors said that DIANA could measure neuronal activity directly, which is an “extraordinary claim”, says Ben Inglis, a physicist at the University of California, Berkeley. © 2024 Springer Nature Limited

Keyword: Brain imaging
Link ID: 29253 - Posted: 04.11.2024

By Claudia López Lloreda As animals carry out complex behaviors, multiple brain areas turn on and talk to one another. But neuroscientists have had limited means to measure that neuronal dialogue. Electrical recordings, for example, are typically constrained to one brain area at a time, or require that mice have their head fixed in a specific position. A new technology overcomes those restrictions. The device, called E-Scope, reported in a peer-reviewed preprint in eLife, effectively measures the activity of neurons in two different areas at the same time, even as rodents move freely. The headset captures images of calcium currents, made using a microscope, and recordings of neurons’ electrical activity through electrodes to show how the cerebellum communicates with other brain regions during social interaction in mice. “Everything [is] synchronized together that way,” says Peyman Golshani, assistant professor of neurology at the University of California, Los Angeles and a study investigator. This approach holds the potential to illuminate how coordination between brain areas in conditions marked by impaired social interaction, such as attention-deficit/hyperactivity disorder and autism, is disrupted, Golshani says. By combining technologies, researchers who use the E-Scope “don’t need separate electrophysiology and imaging hardware,” he adds. It’s also much more comfortable for the animals, according to Golshani. A single wire conveys all of the small headset’s data, so mice can move more freely than when wearing other devices. © 2024 Simons Foundation

Keyword: Brain imaging
Link ID: 29244 - Posted: 04.06.2024

By Nico Dosenbach, Scott Marek In 2022, we caused a stir when, together with Brenden Tervo-Clemmens and Damien Fair, we published an article in Nature titled “Reproducible brain-wide association studies require thousands of participants.” The study garnered a lot of attention—press coverage, including in Spectrum, as well as editorials and commentary in journals. In hindsight, the consternation we caused in calling for larger sample sizes makes sense; up to that point, most brain imaging studies of this type were based on samples with fewer than 100 participants, so our findings called for a major change. But it was an eye-opening experience that taught us how difficult it is to convey a nuanced scientific message and to guard against oversimplifications and misunderstandings, even among experts. Being scientific is hard for human brains, but as an adversarial collaboration on a massive scale, science is our only method for collectively separating how we want things to be from how they are. The paper emerged from an analysis of the Adolescent Brain Cognitive Development (ABCD) Study, a large longitudinal brain-imaging project. Starting with data from 2,000 children, Scott showed that an average brain connectivity map he made using half of the large sample replicated almost perfectly in the other half. But when he mapped the association between resting-state activity—a measure of the brain during rest—and intelligence in two matched sets of 1,000 children, he found large differences in the patterns. Even with a sample size of 2,000—large in the human brain imaging world—the brain-behavior maps showed poor reproducibility. For card-carrying statisticians, the result was not surprising. It reflected a pattern known as the winner’s curse, namely that large cross-sectional correlations can occur by chance in small samples. Paradoxically, the largest correlations will be “statistically significant” and therefore most likely to be published, even though they are the most likely to be wrong. © 2024 Simons Foundation

Keyword: Brain imaging
Link ID: 29215 - Posted: 03.26.2024

By Nora Bradford Early in her research, forensic anthropologist Alexandra Morton-Hayward came across a paper describing a 2,500-year-old brain preserved in a severed skull. The paper referenced another preserved brain. She found another. And another. By the time she’d reached 12, she noticed all of the papers described the brains as a unique phenomenon. She kept digging. Naturally preserved brains, it turns out, aren’t so rare after all, Morton-Hayward, of the University of Oxford, and colleagues report March 20 in Proceedings of the Royal Society B. The researchers have built an archive of 4,400 human brains preserved in the archaeological record, some dating back nearly 12,000 years. The archive includes brains from North Pole explorers, Inca sacrificial victims and Spanish Civil War soldiers. Because the brains have been described as exceptionally rare, little research has been done on them. “If they’re precious, one-of-a-kind materials, then you don’t want to analyze them or disturb them,” Morton-Hayward says. Less than 1 percent of the archive has been investigated. Matching where the brains were found with historical climate patterns hints at what might keep the brains from decaying. Over a third of the samples persisted because of dehydration; others were frozen or tanned. Depending on the conditions, the brains’ texture could be anywhere from dry and brittle to squishy and tofulike. © Society for Science & the Public 2000–2024.

Keyword: Brain imaging
Link ID: 29206 - Posted: 03.21.2024

By Claudia López Lloreda Loss of smell, headaches, memory problems: COVID-19 can bring about a troubling storm of neurological symptoms that make everyday tasks difficult. Now new research adds to the evidence that inflammation in the brain might underlie these symptoms. Not all data point in the same direction. Some new studies suggest that SARS-CoV-2, the virus that causes COVID-19, directly infects brain cells. Those findings bolster the hypothesis that direct infection contributes to COVID-19-related brain problems. But the idea that brain inflammation is key has gotten fresh support: one study, for example, has identified specific brain areas prone to inflammation in people with COVID-191. “The whole body of literature is starting to come together a little bit more now and give us some more concrete answers,” says Nicola Fletcher, a neurovirologist at University College Dublin. Immunological storm When researchers started looking for a culprit for the brain problems caused by COVID-19, inflammation quickly became a key suspect. That’s because inflammation — the flood of immune cells and chemicals that the body releases against intruders — has been linked to the cognitive symptoms caused by other viruses, such as HIV. SARS-CoV-2 stimulates a strong immune response throughout the body, but it was unclear whether brain cells themselves contributed to this response and, if so, how. Helena Radbruch, a neuropathologist at the Charité – Berlin University Medicine, and her colleagues looked at brain samples from people who’d died of COVID-19. They didn’t find any cells infected with SARS-CoV-2. But they did find these people had more immune activity in certain brain areas than did people who died from other causes. This unusual activity was noticeable in regions such as the olfactory bulb, which is involved in smell, and the brainstem, which controls some bodily functions, such as breathing. It was seen only in the brains of people who had died soon after catching the virus. © 2024 Springer Nature Limited

Keyword: Learning & Memory; Attention
Link ID: 29202 - Posted: 03.21.2024

By Clay Risen Mary Bartlett Bunge, who with her husband, Richard, studied how the body responds to spinal cord injuries and continued their work after his death in 1996, ultimately discovering a promising treatment to restore movement to millions of paralyzed patients, died on Feb. 17, at her home in Coral Gables, Fla. She was 92. The Miami Project to Cure Paralysis, a nonprofit research organization with which Dr. Bunge (pronounced BUN-ghee) was affiliated, announced the death. “She definitely was the top woman in neuroscience, not just in the United States but in the world,” Dr. Barth Green, a co-founder and dean at the Miami Project, said in a phone interview. Dr. Bunge’s focus for much of her career was on myelin, a mix of proteins and fatty acids that coats nerve fibers, protecting them and boosting the speed at which they conduct signals. Early in her career, she and her husband, whom she met as a graduate student at the University of Wisconsin in the 1950s, used new electron microscopes to describe the way that myelin developed around nerve fibers, and how, after because of injury or illness, it receded, in a process called demyelination. Treating spinal-cord injuries is one of the most frustrating corners of medical research. Thousands of people are left partially or fully paralyzed after automobile accidents, falls, sports injuries and gun violence each year. Unlike other parts of the body, the spinal cord is stubbornly difficult to rehabilitate. Through their research, the Bunges concluded that demyelination was one reason spinal-cord injuries have been so difficult for the body to repair — an insight that in turn opened doors to the possibility of reversing it through treatments. © 2024 The New York Times Company

Keyword: Glia; Regeneration
Link ID: 29175 - Posted: 03.05.2024

By Liam Drew The first person to receive a brain-monitoring device from neurotechnology company Neuralink can control a computer cursor with their mind, Elon Musk, the firm’s founder, revealed this week. But researchers say that this is not a major feat — and they are concerned about the secrecy around the device’s safety and performance. The company is “only sharing the bits that they want us to know about”, says Sameer Sheth, a neurosurgeon specializing in implanted neurotechnology at Baylor College of Medicine in Houston, Texas. “There’s a lot of concern in the community about that.” Threads for thoughts Musk announced on 29 January that Neuralink had implanted a brain–computer interface (BCI) into a human for the first time. Neuralink, which is headquartered in Fremont, California, is the third company to start long-term trials in humans. Some implanted BCIs sit on the brain’s surface and record the average firing of populations of neurons, but Neuralink’s device, and at least two others, penetrates the brain to record the activity of individual neurons. Neuralink’s BCI contains 1,024 electrodes — many more than previous systems — arranged on innovative pliable threads. The company has also produced a surgical robot for inserting its device. But it has not confirmed whether that system was used for the first human implant. Details about the first recipient are also scarce, although Neuralink’s volunteer recruitment brochure says that people with quadriplegia stemming from certain conditions “may qualify”.

Keyword: Robotics; Brain imaging
Link ID: 29163 - Posted: 02.25.2024

By Miryam Naddaf Moving a prosthetic arm. Controlling a speaking avatar. Typing at speed. These are all things that people with paralysis have learnt to do using brain–computer interfaces (BCIs) — implanted devices that are powered by thought alone. These devices capture neural activity using dozens to hundreds of electrodes embedded in the brain. A decoder system analyses the signals and translates them into commands. Although the main impetus behind the work is to help restore functions to people with paralysis, the technology also gives researchers a unique way to explore how the human brain is organized, and with greater resolution than most other methods. Scientists have used these opportunities to learn some basic lessons about the brain. Results are overturning assumptions about brain anatomy, for example, revealing that regions often have much fuzzier boundaries and job descriptions than was thought. Such studies are also helping researchers to work out how BCIs themselves affect the brain and, crucially, how to improve the devices. “BCIs in humans have given us a chance to record single-neuron activity for a lot of brain areas that nobody’s ever really been able to do in this way,” says Frank Willett, a neuroscientist at Stanford University in California who is working on a BCI for speech. The devices also allow measurements over much longer time spans than classical tools do, says Edward Chang, a neurosurgeon at the University of California, San Francisco. “BCIs are really pushing the limits, being able to record over not just days, weeks, but months, years at a time,” he says. “So you can study things like learning, you can study things like plasticity, you can learn tasks that require much, much more time to understand.” © 2024 Springer Nature Limited

Keyword: Brain imaging; Robotics
Link ID: 29159 - Posted: 02.22.2024

Nicola Davis Science correspondent From forgetfulness to difficulties concentrating, many people who have long Covid experience “brain fog”. Now researchers say the symptom could be down to the blood-brain barrier becoming leaky. The barrier controls which substances or materials enter and exit the brain. “It’s all about regulating a balance of material in blood compared to brain,” said Prof Matthew Campbell, co-author of the research at Trinity College Dublin. “If that is off balance then it can drive changes in neural function and if this happens in brain regions that allow for memory consolidation/storage then it can wreak havoc.” Writing in the journal Nature Neuroscience, Campbell and colleagues report how they analysed serum and plasma samples from 76 patients who were hospitalised with Covid in March or April 2020, as well 25 people before the pandemic. Among other findings, the team discovered that samples from the 14 Covid patients who self-reported brain fog contained higher levels of a protein called S100β than those from Covid patients without this symptom, or people who had not had Covid. caskets at a funeral home This protein is produced by cells within the brain, and is not normally found in the blood, suggesting these patients had a breakdown of the blood-brain barrier. The researchers then recruited 10 people who had recovered from Covid and 22 people with long Covid – 11 of whom reported having brain fog. None had, at that point, received a Covid vaccine, or been hospitalised for Covid. These participants underwent an MRI scan in which a dye was administered intravenously. The results reveal long Covid patients with brain fog did indeed show signs of a leaky blood-brain barrier, but not those without this symptom, or who had recovered. © 2024 Guardian News & Media Limited

Keyword: Neuroimmunology
Link ID: 29158 - Posted: 02.22.2024

Rob Stein Benjamin Franklin famously wrote: "In this world nothing can be said to be certain, except death and taxes." While that may still be true, there's a controversy simmering today about one of the ways doctors declare people to be dead. The debate is focused on the Uniform Determination of Death Act, a law that was adopted by most states in the 1980s. The law says that death can be declared if someone has experienced "irreversible cessation of all functions of the entire brain." But some parts of the brain can continue to function in people who have been declared brain dead, prompting calls to revise the statute. Many experts say the discrepancy needs to be resolved to protect patients and their families, maintain public trust and reconcile what some see as a troubling disconnect between the law and medical practice. The debate became so contentious, however, that the Uniform Law Commission, the group charged with rewriting model laws for states, paused its process last summer because participants couldn't reach a consensus. "I'm worried," says Thaddeus Pope, a bioethicist and lawyer at Mitchell Hamline School of Law in St. Paul, Minnesota. "There's a lot of conflict at the bedside over this at hospitals across the United States. Let's get in front of it and fix it before it becomes a crisis. It's such an important question that everyone needs to be on the same page." The second method, brain death, can be declared for people who have sustained catastrophic brain injury causing the permanent cessation of all brain function, such as from a massive traumatic brain injury or massive stroke, but whose hearts are still pumping through the use of ventilators or other artificial forms of life support. © 2024 npr

Keyword: Brain Injury/Concussion; Brain imaging
Link ID: 29147 - Posted: 02.13.2024

Nicholas J. Kelley In the middle of 2023, a study conducted by the HuthLab at the University of Texas sent shockwaves through the realms of neuroscience and technology. For the first time, the thoughts and impressions of people unable to communicate with the outside world were translated into continuous natural language, using a combination of artificial intelligence (AI) and brain imaging technology. This is the closest science has yet come to reading someone’s mind. While advances in neuroimaging over the past two decades have enabled non-responsive and minimally conscious patients to control a computer cursor with their brain, HuthLab’s research is a significant step closer towards accessing people’s actual thoughts. As Alexander Huth, the neuroscientist who co-led the research, told the New York Times: Combining AI and brain-scanning technology, the team created a non-invasive brain decoder capable of reconstructing continuous natural language among people otherwise unable to communicate with the outside world. The development of such technology – and the parallel development of brain-controlled motor prosthetics that enable paralysed patients to achieve some renewed mobility – holds tremendous prospects for people suffering from neurological diseases including locked-in syndrome and quadriplegia. In the longer term, this could lead to wider public applications such as fitbit-style health monitors for the brain and brain-controlled smartphones. On January 29, Elon Musk announced that his Neuralink tech startup had implanted a chip in a human brain for the first time. He had previously told followers that Neuralink’s first product, Telepathy, would one day allow people to control their phones or computers “just by thinking”. © 2010–2024, The Conversation US, Inc.

Keyword: Brain imaging
Link ID: 29136 - Posted: 02.08.2024

Jon Hamilton Scientists know that Black people are at a greater risk for health problems like heart disease, diabetes and Alzheimer's disease than white people. A growing body of research shows that racism in health care and in daily life contributes to these long-standing health disparities for Black communities. Now, some researchers are asking whether part of the explanation involves how racism, across individual interactions and systems, may physically alter the brain. "That could be behaviors like, let's say, a woman clutching her purse as a black man is walking next to her. Or they could be verbal, like someone saying, like... 'I didn't expect you to be so articulate,'" says Negar Fani, a clinical neuroscientist at Emory University who studies people experiencing Posttraumatic Stress Disorder, or PTSD. Recently, Fani has collaborated with Nate Harnett, an assistant professor of psychiatry at Harvard Medical School, to study how the brain responds to traumatic events and extreme stress, including the events and stress related to racism. So how does one go about measuring the impact of zoomed out, societal-scale issues on the individual? Harnett is the first to admit, it's not the simplest task. "It's very difficult for neuroimaging to look specifically at redlining," notes Harnett. But he can—indirectly. For example, Harnett has used inequities in neighborhood resources as a way of tracking or measuring structural racism. "We're able to look at these sort of proxy measures in these outcomes of structural racism and then correlate those with both brain and behavioral responses to stress or trauma and see how they tie with different psychiatric disorders like PTSD," Harnett says. In other research, Harnett and Fani have looked at correlations between racial discrimination and the response to threat in Black women who had experienced trauma. Fani says patients who experience PTSD tend to be more vigilant or show hyperarousal and be startled easily. Fani says their bodies are in a constant state of fight or flight—even when they're in a safe situation. But in patients who've also experienced racial discrimination, Fani says she sees the opposite effect: They show an increased activation in areas related to emotion regulation. In some ways, Fani says this activation can be adaptive. For example, people may experience microaggressions or discrimination at work and need to regulate their emotional response in order to get through the moment. But when people have to utilize this strategy over long periods of time, Fani and Harnett think it may contribute to the degradation they've seen in other areas in the brain. © 2024 npr

Keyword: Stress; Aggression
Link ID: 29114 - Posted: 01.27.2024

By Evelyn Lake Functional MRI (fMRI), though expensive, has many properties of an ideal clinical tool. It’s safe and noninvasive. It is widely available in some countries, and increasingly so on a global scale. Its “blood oxygen level dependent,” or BOLD, signal is altered in people with almost any neurological condition and is rich enough to contain information specific to each person, offering the potential for a personalized approach to medical care across a wide spectrum of neurological conditions. But despite enormous interest and investment in fMRI — and its wide use in basic neuroscience research — it still lacks broad clinical utility; it is mainly employed for surgical planning. For fMRI to inform a wider range of clinical decision-making, we need better ways of deciphering what underlying changes in the brain drive changes to the BOLD signal. If someone with Alzheimer’s disease has an increase in functional connectivity (a measure of synchrony between brain regions), for example, does this indicate that synapses are being lost? Or does it suggest that the brain is forming compensatory pathways to help the person avoid further cognitive decline? Or something else entirely? Depending on the answer, one can imagine different courses of treatment. Put simply, we cannot extract sufficient information from fMRI and patient outcomes alone to determine which scenarios are playing out and therefore what we should do when we observe changes in our fMRI readouts. To better understand what fMRI actually shows, we need to use complementary methodologies, such as the emerging optical imaging tool of wide-field fluorescence calcium imaging. Combining modalities presents significant technical challenges but offers the potential for deeper insights: observing the BOLD signal alongside other signals that report more directly on what is occurring in brain tissue. Using these more direct measurements instead of fMRI in clinical practice is not an option — they are unethical to use in people or invasive, requiring physical or optical access to the brain. © 2023 Simons Foundation.

Keyword: Brain imaging
Link ID: 29109 - Posted: 01.23.2024

By Mark Johnson In the first study of its kind in humans, researchers have discovered that it is safe to use sound waves fired into specific areas of the brain to open a protective barrier and clear the way for Alzheimer’s medications. The study, reported in the New England Journal of Medicine, involved just three patients, but it raises hope about the long-term potential of the treatment strategy known as focused ultrasound. “We want to be very cautious. This is the first three people in the world that have had this [treatment]. What we’ve learned from this, I think, can help us,” said Ali Rezai, lead author of the study and executive chair and director of the Rockefeller Neuroscience Institute at West Virginia University. Rezai stressed that the goal of the research is not to replace pharmaceutical treatments but to improve their benefits by helping more of the drug penetrate the brain. Nature has provided humans with a barrier made of tightly packed cells that blocks harmful toxins, such as viruses, bacteria and fungi, from reaching the brain. Known as the blood-brain barrier, this shield has for decades presented a major challenge to scientists trying to treat neurodegenerative diseases such as Alzheimer’s and Parkinson’s, which afflict at least 7 million Americans. The barrier is a locked door that stops about 98 percent of treatments from reaching the brain. With focused ultrasound, Rezai explained, “what we want to do is push individuals toward the milder stages of Alzheimer’s with less plaques to give them a fighting chance.” Two men and a woman suffering from mild loss of memory, learning, concentration and decision-making skills due to Alzheimer’s took part in the study. The patients, who ranged in age from 59 to 77, were given six monthly doses of the federally approved — if somewhat controversial — lab-made antibody aducanumab, sold under the brand name Aduhelm. The antibody, which is administered directly into a patient’s vein, reduces a sticky substance in the brain called amyloid beta, which clumps between neurons and disrupts their function.

Keyword: Alzheimers; Brain imaging
Link ID: 29085 - Posted: 01.09.2024

By Fletcher Reveley One afternoon in May 2020, Jerry Tang, a Ph.D. student in computer science at the University of Texas at Austin, sat staring at a cryptic string of words scrawled across his computer screen: “I am not finished yet to start my career at twenty without having gotten my license I never have to pull out and run back to my parents to take me home.” The sentence was jumbled and agrammatical. But to Tang, it represented a remarkable feat: A computer pulling a thought, however disjointed, from a person’s mind. For weeks, ever since the pandemic had shuttered his university and forced his lab work online, Tang had been at home tweaking a semantic decoder — a brain-computer interface, or BCI, that generates text from brain scans. Prior to the university’s closure, study participants had been providing data to train the decoder for months, listening to hours of storytelling podcasts while a functional magnetic resonance imaging (fMRI) machine logged their brain responses. Then, the participants had listened to a new story — one that had not been used to train the algorithm — and those fMRI scans were fed into the decoder, which used GPT1, a predecessor to the ubiquitous AI chatbot ChatGPT, to spit out a text prediction of what it thought the participant had heard. For this snippet, Tang compared it to the original story: “Although I’m twenty-three years old I don’t have my driver’s license yet and I just jumped out right when I needed to and she says well why don’t you come back to my house and I’ll give you a ride.” The decoder was not only capturing the gist of the original, but also producing exact matches of specific words — twenty, license. When Tang shared the results with his adviser, a UT Austin neuroscientist named Alexander Huth who had been working towards building such a decoder for nearly a decade, Huth was floored. “Holy shit,” Huth recalled saying. “This is actually working.”

Keyword: Brain imaging; Language
Link ID: 29073 - Posted: 01.03.2024

By Gary Stix This year was full of roiling debate and speculation about the prospect of machines with superhuman capabilities that might, sooner than expected, leave the human brain in the dust. A growing public awareness of ChatGPT and other so-called large language models (LLMs) dramatically expanded public awareness of artificial intelligence. In tandem, it raised the question of whether the human brain can keep up with the relentless pace of AI advances. The most benevolent answer posits that humans and machines need not be cutthroat competitors. Researchers found one example of potential cooperation by getting AI to probe the infinite complexity of the ancient game of Go—which, like chess, has seen a computer topple the highest-level human players. A study published in March showed how people might learn from machines with such superhuman skills. And understanding ChatGPT’s prodigious abilities offers some inkling as to why an equivalence between the deep neural networks that underlie the famed chatbot and the trillions of connections in the human brain is constantly invoked. Importantly, the machine learning incorporated into AI has not totally distracted mainstream neuroscience from avidly pursuing better insights into what has been called “the most complicated object in the known universe”: the brain. One of the grand challenges in science—understanding the nature of consciousness—received its due in June with the prominent showcasing of experiments that tested the validity of two competing theories, both of which purport to explain the underpinnings of the conscious self. The past 12 months provided lots of examples of impressive advances for you to store in your working memory. Now here’s a closer look at some of the standout mind and brain stories we covered in Scientific American in 2023. © 2023 SCIENTIFIC AMERICAN

Keyword: Brain imaging; Consciousness
Link ID: 29069 - Posted: 12.31.2023

By The Transmitter It has been a year of many firsts for the Transmitter team. Despite launching this site just over a month ago, though, we published dozens of news stories on a range of important topics in neuroscience research earlier in the year in Spectrum. Here, we bring you a short list of some of our favorites, which broke news about changes in research leadership, exposed issues in studies involving human participants, provided new insights into the brain’s neuropeptide signaling network and memory-encoding mechanisms, and gave glimpses into the lives neuroscientists lead outside of work. ‘Wireless’ connectomes detail signaling outside synapses Connectomes were once again all the rage this year. As some teams continued to map the complete circuitry of increasingly larger brains — including those of a larval and an adult fruit fly — other teams went back to basics, plugging some invisible gaps of the humble roundworm’s synaptic connectome. Those latter efforts detail how neurons communicate using short proteins called neuropeptides outside synapses, helping to address key criticisms of conventional wiring diagrams. Neural ‘barcodes’ help seed-stashing birds recall their hidden haul As we enter the throes of winter here in New York City, some of the resident non-migratory birds may begin to seek out the seeds they stashed earlier in the year to help them survive for the next few months. Their ability to relocate their caches may stem from memories stored in the hippocampus in the form of non-overlapping patterns of brain activity, or “barcodes,” new research suggests. These barcodes originate when a bird hides a seed and reappear only when the bird returns to that same seed — and may represent the basis for episodic memories of specific events in time. © 2023 Simons Foundation.

Keyword: Miscellaneous
Link ID: 29068 - Posted: 12.27.2023

Emily Baumgaertner This is not a work of art. It’s an image of microscopic blood flow in a rat’s brain, taken with one of many new tools that are yielding higher levels of detail in brain imaging. Here are seven more glorious images from neuroscience research → © 2023 The New York Times Company

Keyword: Brain imaging
Link ID: 29059 - Posted: 12.22.2023

By Yasemin Saplakoglu In the 16th century, the Belgian cartographer Abraham Ortelius created the world’s first modern atlas — a collection of maps that he called “The Theater of the World.” The maps, drawn by Ortelius and others, detailed what was at the time the best knowledge of the world’s continents, cities, mountains, rivers, lakes and oceans and helped usher in a new understanding of global geography. Similarly, the creation of cell atlases — maps of organs and bodies constructed cell by cell — is heralding a new era in our understanding of biology. Powerful sequencing and imaging technologies invented in the last decade are revealing with unprecedented detail the composition of human organs and tissues, from the pancreas and liver to the placenta, as well as those of other animals like the mouse and fruit fly. With these new tools, researchers can fingerprint individual cells based on which genes they are expressing. That information has revealed subtle and unsuspected distinctions among cells and has begun to illuminate how the diversity of cell types can be essential to the healthy functioning of organs. “We’re at this amazing point in time in science where we’re now able to understand the composition of these cell types,” said Steve Quake, a bioengineer and biophysicist at Stanford University who helped develop the technologies that make cell atlases possible. “It’s changed the way we understand how human biology works.” Two cell atlas efforts, part of the National Institutes of Health’s $250 million brain cell census, that just released their findings illustrate the excitement bubbling up in the field. Today in Nature, a coalition of laboratories published nine studies that collectively form a detailed atlas of the mouse brain — the most comprehensive mammalian brain atlas to date. It describes more than 5,300 types of cells found throughout the organ. How these cells are distributed and are related to one another suggests many intriguing ideas about the evolution of the mammalian brain. All Rights Reserved © 2023

Keyword: Development of the Brain; Brain imaging
Link ID: 29053 - Posted: 12.16.2023

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