Chapter 3. Neurophysiology: The Generation, Transmission, and Integration of Neural Signals

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By Charles Q. Choi With the help of headsets and backpacks on mice, scientists are using light to switch nerve cells on and off in the rodents’ brains to probe the animals’ social behavior, a new study shows. These remote control experiments are revealing new insights on the neural circuitry underlying social interactions, supporting previous work suggesting minds in sync are more cooperative, researchers report online May 10 in Nature Neuroscience. The new devices rely on optogenetics, a technique in which researchers use bursts of light to activate or suppress the brain nerve cells, or neurons, often using tailored viruses to genetically modify cells so they respond to illumination (SN: 1/15/10). Scientists have used optogenetics to probe neural circuits in mice and other lab animals to yield insights on how they might work in humans (SN: 10/22/19). Optogenetic devices often feed light to neurons via fiber-optic cables, but such tethers can interfere with natural behaviors and social interactions. While scientists recently developed implantable wireless optogenetic devices, these depend on relatively simple remote controls or limited sets of preprogrammed instructions. These new fully implantable optogenetic arrays for mice and rats can enable more sophisticated research. Specifically, the researchers can adjust each device’s programming during the course of experiments, “so you can target what an animal does in a much more complex way,” says Genia Kozorovitskiy, a neurobiologist at Northwestern University in Evanston, Ill. © Society for Science & the Public 2000–2021.

Keyword: Brain imaging
Link ID: 27812 - Posted: 05.12.2021

Researchers are now able to wirelessly record the directly measured brain activity of patients living with Parkinson’s disease and to then use that information to adjust the stimulation delivered by an implanted device. Direct recording of deep and surface brain activity offers a unique look into the underlying causes of many brain disorders; however, technological challenges up to this point have limited direct human brain recordings to relatively short periods of time in controlled clinical settings. This project, published in the journal Nature Biotechnology, was funded by the National Institutes of Health’s Brain Research Through Advancing Innovative Neurotechnologies (BRAIN) Initiative. “This is really the first example of wirelessly recording deep and surface human brain activity for an extended period of time in the participants’ home environment,” said Kari Ashmont, Ph.D., project manager for the NIH BRAIN Initiative. “It is also the first demonstration of adaptive deep brain stimulation at home.” Deep brain stimulation (DBS) devices are approved by the U. S. Food and Drug Administration for the management of Parkinson’s disease symptoms by implanting a thin wire, or electrode, that sends electrical signals into the brain. In 2018, the laboratory of Philip Starr, M.D., Ph.D. at the University of California, San Francisco, developed an adaptive version of DBS that adapts its stimulation only when needed based on recorded brain activity. In this study, Dr. Starr and his colleagues made several additional improvements to the implanted technology.

Keyword: Brain imaging
Link ID: 27800 - Posted: 05.05.2021

By Christine Kenneally The first thing that Rita Leggett saw when she regained consciousness was a pair of piercing blue eyes peering curiously into hers. “I know you, don’t I?” she said. The man with the blue eyes replied, “Yes, you do.” But he didn’t say anything else, and for a while Leggett just wondered and stared. Then it came to her: “You’re my surgeon!” It was November, 2010, and Leggett had just undergone neurosurgery at the Royal Melbourne Hospital. She recalled a surge of loneliness as she waited alone in a hotel room the night before the operation and the fear she felt when she entered the operating room. She’d worried about the surgeon cutting off her waist-length hair. What am I doing in here? she’d thought. But just before the anesthetic took hold, she recalled, she had said to herself, “I deserve this.” Leggett was forty-nine years old and had suffered from epilepsy since she was born. During the operation, her surgeon, Andrew Morokoff, had placed an experimental device inside her skull, part of a brain-computer interface that, it was hoped, would be able to predict when she was about to have a seizure. The device, developed by a Seattle company called NeuroVista, had entered a trial stage known in medical research as “first in human.” A research team drawn from three prominent epilepsy centers based in Melbourne had selected fifteen patients to test the device. Leggett was Patient 14. © 2021 Condé Nast.

Keyword: Robotics; Epilepsy
Link ID: 27791 - Posted: 04.28.2021

By Kim Tingley The brain is an electrical organ. Everything that goes on in there is a result of millivolts zipping from one neuron to another in particular patterns. This raises the tantalizing possibility that, should we ever decode those patterns, we could electrically adjust them to treat neurological dysfunction — from Alzheimer’s to schizophrenia — or even optimize desirable qualities like intelligence and resilience. Of course, the brain is so complex, and so difficult to access, that this is much easier to imagine than to do. A pair of studies published in January in the journal Nature Medicine, however, demonstrate that electrical stimulation can address obsessive-compulsive urges and symptoms of depression with surprising speed and precision. Mapping participants’ brain activity when they experienced certain sensations allowed researchers to personalize the stimulation and modify moods and habits far more directly than is possible through therapy or medication. The results also showed the degree to which symptoms that we tend to categorize as a single disorder — depression, for example — may involve electrical processes that are unique to each person. In the first study, a team from the University of California, San Francisco, surgically implanted electrodes in the brain of a woman whose severe depression had proved resistant to other treatments. For 10 days, they delivered pulses through the electrodes to different areas of the brain at various frequencies and had the patient record her level of depression, anxiety and energy on an iPad. The impact of certain pulses was significant and nuanced. “Within a minute, she would say, ‘I feel like I’m reading a good book,’” says Katherine W. Scangos, a psychiatrist and the study’s lead author. The patient described the effect of another pulse as “less cobwebs and cotton.” © 2021 The New York Times Company

Keyword: Depression
Link ID: 27712 - Posted: 02.28.2021

By Leslie Nemo Ironically, this tangle of brain cells is helping scientists tease apart a larger problem: how to help people with Alzheimer’s disease. Matheus Victor, a researcher at the Massachusetts Institute of Technology, photographed these neurons after coaxing them to life in a petri dish in the hope that the rudimentary brain tissue will reveal why a new therapy might alleviate Alzheimer’s symptoms. In humans and mice, a healthy memory is associated with a high level of synced neurons that turn on and off simultaneously. Those with neurological conditions such as Alzheimer’s and Parkinson’s disease often have fewer brain cells blinking unanimously. A couple of years ago Victor’s lab leader Li-Huei Tsai and her team at M.I.T. found that when they surrounded mice genetically predisposed to Alzheimer’s with sound pulses beating 40 times a second, the rodents performed better on memory-related tasks. The animals also lost some amyloid plaques, protein deposits in the brain that are characteristic of the disease. The researchers had previously performed a similar study with light flickering at the same rate, and the mice were found to experience additional improvements when the sound and light pulses were combined. Astoundingly, the mouse neurons synced up to the 40-beats-per-second rhythm of the audio pulses, though the mechanism behind this result and the reason the shift improves symptoms remain a mystery. To help solve it, the researchers want to watch how brain tissue responds to the stimulants at the cellular level. The goal is to one day understand how this exposure treatment might work for people, so the team is growing human brain cells in the lab and engineering them to respond to sound and light without eyes and ears. “We are trying to mimic the sensory stimulation in mice but missing a lot of the hardware that makes it possible. So this is a bit of a hack,” Victor says. © 2021 Scientific American

Keyword: Alzheimers; Brain imaging
Link ID: 27690 - Posted: 02.15.2021

By Diana Kwon Obsessive-compulsive disorder (OCD) is marked by repetitive, anxiety-inducing thoughts, urges and compulsions, such as excessive cleaning, counting and checking. These behaviors are also prevalent in the general population: one study in a large sample of U.S. adults found more than a quarter had experienced obsessions or compulsions at some point in their life. Although most of these individuals do not develop full-blown OCD, such symptoms can still interfere with daily life. A new study, published on January 18 in Nature Medicine, hints that these behaviors may be alleviated by stimulating the brain with an electrical current—without the need to insert electrodes under the skull. Robert Reinhart, a neuroscientist at Boston University, and his group drew on two parallel lines of research for this study. First, evidence suggests that obsessive-compulsive behaviors may arise as a result of overlearning habits—leading to their excessive repetition—and abnormalities in brain circuits involved in learning from rewards. Separately, studies point to the importance of high-frequency rhythms in the so-called high-beta/low-gamma range (also referred to as simply beta-gamma) in decision-making and learning from positive feedback. Drawing on these prior observations, Shrey Grover, a doctoral student in Reinhart’s lab, hypothesized with others in the team that manipulating beta-gamma rhythms in the orbitofrontal cortex (OFC)—a key region in the reward network located in the front of the brain—might disrupt the ability to repetitively pursue rewarding choices. In doing so, the researchers thought, the intervention could reduce obsessive-compulsive behaviors associated with maladaptive habits. To test this hypothesis, Grover and his colleagues carried out a two-part study. The first segment was aimed at identifying whether the high-frequency brain activity influenced how well people were able to learn from rewards. The team recruited 60 volunteers and first used electroencephalography to pinpoint the unique frequencies of beta-gamma rhythms in the OFC that were active in a given individual while that person took part in a task that involved associating symbols with monetary wins or losses. Previous work had shown that applying stimulation based on the particular patterns of rhythms in a person’s brain may enhance the effectiveness of the procedure. © 2021 Scientific American

Keyword: OCD - Obsessive Compulsive Disorder
Link ID: 27657 - Posted: 01.20.2021

By Diana Kwon Seizures are like storms in the brain—sudden bursts of abnormal electrical activity that can cause disturbances in movement, behavior, feelings and awareness. For people with epilepsy, not knowing when their next seizure will hit can be psychologically debilitating. Clinicians have no way of telling people with epilepsy whether a seizure will likely happen five minutes from now, five weeks from now or five months from now, says Vikram Rao, a neurologist at the University of California, San Francisco. “That leaves people in a state of looming uncertainty.” Despite the apparent unpredictability of seizures, they may not actually be random events. Hints of cyclical patterns associated with epilepsy date back to ancient times, when people believed seizures were tied to the waxing and waning of the moon. While this particular link has yet to be definitively proven, scientists have pinpointed patterns in seizure-associated brain activity. Studies have shown that seizures are more likely during specific periods in the day, indicating an association with sleep–wake cycles, or circadian rhythms. In 2018, Rao and his colleagues reported the discovery of long-term seizure-associated brain rhythms—most commonly in the 20- to 30-day range—which they dubbed as “multidien” (multiday) rhythms. By examining these rhythms in brain activity, the group has now demonstrated that seizures can be forecast 24 hours in advance—and in some patients, up to three days prior. Their findings, published December 17 in Lancet Neurology, raise the possibility of eventually providing epilepsy patients with seizure forecasts that could predict the likelihood that a seizure will occur days in advance. © 2020 Scientific American,

Keyword: Epilepsy
Link ID: 27631 - Posted: 12.19.2020

By Matt Richtel VALLEJO, Calif. — The adolescent patient turned sullen and withdrawn. He hadn’t eaten in 13 days. Treatment with steroids, phenobarbital and Valium failed to curb the symptoms of his epilepsy. Then, on Sept. 18, he had a terrible seizure — violently jerking his flippers and turning unconscious in the water. Cronutt, a 7-year-old sea lion, had to be rescued so he didn’t drown. His veterinarian and the caretakers at Six Flags Discovery Kingdom began discussing whether it was time for palliative care. “We’d tried everything,” said Dr. Claire Simeone, Cronutt’s longtime vet. “We needed more extreme measures.” On Tuesday morning, Cronutt underwent groundbreaking brain surgery aimed at reversing the epilepsy. If successful, the treatment could save increasing numbers of sea lions and sea otters from succumbing to a new plague of epilepsy. The cause is climate change. As oceans warm, algae blooms have become more widespread, creating toxins that get ingested by sardines and anchovies, which in turn get ingested by sea lions, causing damage to the brain that results in epilepsy. Sea otters also face risk when they consume toxin-laden shellfish. The animals who get stranded on land have been given supportive care, but often die. Cronutt may change that. “If this works, it’s going to be big,” said Mariana Casalia, a neuroscientist at the University of California, San Francisco, who helped pioneer the techniques that led to a procedure that took place a vet surgery center in Redwood City, Ca. © 2020 The New York Times Company

Keyword: Epilepsy; Neurotoxins
Link ID: 27516 - Posted: 10.10.2020

R. Stanley Williams For the first time, my colleagues and I have built a single electronic device that is capable of copying the functions of neuron cells in a brain. We then connected 20 of them together to perform a complicated calculation. This work shows that it is scientifically possible to make an advanced computer that does not rely on transistors to calculate and that uses much less electrical power than today’s data centers. Our research, which I began in 2004, was motivated by two questions. Can we build a single electronic element – the equivalent of a transistor or switch – that performs most of the known functions of neurons in a brain? If so, can we use it as a building block to build useful computers? Neurons are very finely tuned, and so are electronic elements that emulate them. I co-authored a research paper in 2013 that laid out in principle what needed to be done. It took my colleague Suhas Kumar and others five years of careful exploration to get exactly the right material composition and structure to produce the necessary property predicted from theory. Kumar then went a major step further and built a circuit with 20 of these elements connected to one another through a network of devices that can be programmed to have particular capacitances, or abilities to store electric charge. He then mapped a mathematical problem to the capacitances in the network, which allowed him to use the device to find the solution to a small version of a problem that is important in a wide range of modern analytics. © 2010–2020, The Conversation US, Inc.

Keyword: Learning & Memory; Robotics
Link ID: 27512 - Posted: 10.07.2020

Ian Sample Science editor Doctors believe they are closer to a treatment for multiple sclerosis after discovering a drug that repairs the coatings around nerves that are damaged by the disease. A clinical trial of the cancer drug bexarotene showed that it repaired the protective myelin sheaths that MS destroys. The loss of myelin causes a range of neurological problems including balance, vision and muscle disorders, and ultimately, disability. While bexarotene cannot be used as a treatment, because the side-effects are too serious, doctors behind the trial said the results showed “remyelination” was possible in humans, suggesting other drugs or drug combinations will halt MS. Advertisement “It’s disappointing that this is not the drug we’ll use, but it’s exciting that repair is achievable and it gives us great hope for another trial we hope to start this year,” said Prof Alasdair Coles, who led the research at the University of Cambridge. MS arises when the immune system mistakenly attacks the fatty myelin coating that wraps around nerves in the brain and spinal cord. Without the lipid-rich substance, signals travel more slowly along nerves, are disrupted, or fail to get through at all. About 100,000 people in the UK live with the condition. Funded by the MS Society, bexarotene was assessed in a phase 2a trial that used brain scans to monitor changes to damaged neurons in patients with relapsing MS. This is an early stage of the condition that precedes secondary progressive disease, where neurons die off and cause permanent disability. © 2020 Guardian News & Media Limited

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 27496 - Posted: 09.28.2020

By Gunjan Sinha Light therapy can help lift moods, heal wounds, and boost the immune system. Can it improve symptoms of Parkinson’s disease, too? A first-of-its-kind trial scheduled to launch this fall in France aims to find out. In seven patients, a fiber optic cable implanted in their brain will deliver pulses of near-infrared (NIR) light directly to the substantia nigra, a region deep in the brain that degenerates in Parkinson’s disease. The team, led by neurosurgeon Alim- Louis Benabid of the Clinatec Institute—a partnership between several government-funded research institutes and industry—hopes the light will protect cells there from dying. The study is one of several set to explore how Parkinson’s patients might benefit from light. “I am so excited,” says neuropsychologist Dawn Bowers of the University of Florida College of Medicine, who is recruiting patients for a trial in which NIR will be beamed into the skull instead of delivered with an implant. Small tests in people with Parkinson’s and animal models of the disease have already suggested benefits, but some mainstream Parkinson’s researchers are skeptical. No one has shown exactly how light might protect the key neurons—or why it should have any effect at all on cells buried deep in the brain that never see the light of day. Much or all of the encouraging hints seen so far in people may be the result of the placebo effect, skeptics say. Because there are no biomarkers that correlate well with changes in Parkinson’s symptoms, “we are reliant on observing behavior,” says neurobiologist David Sulzer of Columbia University Irving Medical Center, an editor of the journal npj Parkinson’s Disease. “It’s not easy to guard against placebo effects.” © 2020 American Association for the Advancement of Science

Keyword: Parkinsons
Link ID: 27482 - Posted: 09.19.2020

Ken Solt & Oluwaseun Akeju The state of dissociation is commonly described as feeling detached from reality or having an ‘out of body’ experience. This altered state of consciousness is often reported by people who have psychiatric disorders arising from devastating trauma or abuse. It is also evoked by a class of anaesthetic drug, and can occur in epilepsy. The neurological basis of dissociation has been a mystery, but writing in Nature, Vesuna et al.1 describe a localized brain rhythm that underlies this state. Their findings will have far-reaching implications for neuroscience. The authors first recorded brain-wide neuronal activity in mice using a technique called widefield calcium imaging. They studied changes in these brain rhythms in response to a range of drugs that have sedative, anaesthetic or hallucinogenic properties, including three that induce dissociation — ketamine, phencyclidine (PCP) and dizocilpine (MK801). Only the dissociative drugs produced robust oscillations in neuronal activity in a brain region called the retrosplenial cortex. This region is essential for various cognitive functions, including episodic memory and navigation2. The oscillations occurred at a low frequency, of about 1–3 hertz. By contrast, non-dissociative drugs such as the anaesthetic propofol and the hallucinogen lysergic acid diethylamide (LSD) did not trigger this rhythmic retrosplenial activity. Vesuna et al. examined the active cells in more detail using a high-resolution approach called two-photon imaging. This analysis revealed that the oscillations were restricted to cells in layer 5 of the retrosplenial cortex. The authors then recorded neuronal activity across multiple brain regions. Normally, other parts of the cortex and subcortex are functionally connected to neuronal activity in the retrosplenial cortex; however, ketamine caused a disconnect, such that many of these brain regions no longer communicated with the retrosplenial cortex. © 2020 Springer Nature Limited

Keyword: Drug Abuse; Consciousness
Link ID: 27481 - Posted: 09.19.2020

Jon Hamilton Scientists used light to control the firing of specific cells to artificially create a rhythm in the brain that acted like the drug ketamine enjoynz/Getty Images Out-of-body experiences are all about rhythm, a team reported Wednesday in the journal Nature. In mice and one person, scientists were able to reproduce the altered state often associated with ketamine by inducing certain brain cells to fire together in a slow, rhythmic fashion. "There was a rhythm that appeared, and it was an oscillation that appeared only when the patient was dissociating," says Dr. Karl Deisseroth, a psychiatrist and neuroscientist at Stanford University. Dissociation is a brain state in which a person feels separated from their own thoughts, feelings and body. It is common in people who have some mental illnesses or who have experienced a traumatic event. It can also be induced by certain drugs, including ketamine and PCP (angel dust). The study linking dissociation to brain rhythms represents "a big leap forward in understanding how these drugs produce this unique state," says Dr. Ken Solt, an anesthesiologist at Harvard Medical School and Massachusetts General Hospital. Solt is the co-author of an article that accompanied the study but was not involved in the research. The finding also could be a step toward finding non-drug methods to control states of consciousness, Solt says. Deisseroth's lab made the discovery while studying the brains of mice that had been given ketamine or other drugs that cause dissociation. The team was using technology that allowed them to monitor the activity of cells throughout the brain. © 2020 npr

Keyword: Drug Abuse; Consciousness
Link ID: 27480 - Posted: 09.19.2020

By Tanya Lewis During Musk’s demonstration, he strolled near a pen containing several pigs, some of which had Neuralink implants. One animal, named Gertrude, had hers for two months. The device’s electrodes were situated in a part of Gertrude’s cortex that connected to neurons in her snout. And for the purposes of the demo, her brain signals were converted to audible bleeps that became more frequent as she sniffed around the pen and enjoyed some tasty treats. Musk also showed off a pig whose implant had been successfully removed to show that the surgery was reversible. Some of the other displayed pigs had multiple implants. Neuralink implantable device Neuralink implantable device, v0.9. Credit: Neuralink Neuralink, which was founded by Musk and a team of engineers and scientists in 2016, unveiled an earlier, wired version of its implant technology in 2019. It had several modules: the electrodes were connected to a USB port in the skull, which was intended to be wired to an external battery and a radio transmitter that were located behind the ear. The latest version consists of a single integrated implant that fits in a hole in the skull and relays data through the skin via a Bluetooth radio. The wireless design makes it seem much more practical for human use but limits the bandwidth of data that can be sent, compared with state-of-the-art brain-computer interfaces. The company’s goal, Musk said in the demo, is to “solve important spine and brain problems with a seamlessly implanted device”—a far cry from his previously stated, much more fantastic aim of allowing humans to merge with artificial intelligence. This time Musk seemed more circumspect about the device’s applications. As before, he insisted the demonstration was purely intended as a recruiting event to attract potential staff. Neuralink’s efforts build on decades of work from researchers in the field of brain-computer interfaces. Although technically impressive, this wireless brain implant is not the first to be tested in pigs or other large mammals.] © 2020 Scientific American,

Keyword: Robotics; Movement Disorders
Link ID: 27457 - Posted: 09.07.2020

Rory Cellan-Jones He is the most charismatic figure in technology with some amazing achievements to his name, from making electric cars desirable to developing rockets that can return to earth and be reused. But dare to suggest that anything Elon Musk does is not groundbreaking or visionary and you can expect a backlash from the great man and his army of passionate fans. That is what happened when a British academic criticised Musk's demo on Friday of his Neuralink project - and the retaliation he faced was largely my fault. Neuralink is a hugely ambitious plan to link the human brain to a computer. It might eventually allow people with conditions such as Parkinson's disease to control their physical movements or manipulate machines via the power of thought. There are plenty of scientists already at work in this field. But Musk has far greater ambitions than most, talking of developing "superhuman cognition" - enhancing the human brain in part to combat the threat he sees from artificial intelligence. Friday night's demo involved a pig called Gertrude fitted with what the tech tycoon described as a "Fitbit in your skull". A tiny device recorded the animal's neural activity and sent it wirelessly to a screen. A series of beeps happened every time her snout was touched, indicating activity in the part of her brain seeking out food. "I think this is incredibly profound", commented Musk. Some neuroscience experts were not quite as impressed. The UK's Science Media Centre, which does a good job of trying to make complex scientific stories accessible, put out a press release quoting Prof Andrew Jackson, professor of neural interfaces at Newcastle University. "I don't think there was anything revolutionary in the presentation," he said. "But they are working through the engineering challenges of placing multiple electrodes into the brain. "In terms of their technology, 1,024 channels is not that impressive these days, but the electronics to relay them wirelessly is state-of-the-art, and the robotic implantation is nice. "The biggest challenge is what you do with all this brain data. The demonstrations were actually quite underwhelming in this regard, and didn't show anything that hasn't been done before." He went on to question why Neuralink's work was not being published in peer-reviewed papers. I took his words and his summary of the demo - "this is solid engineering but mediocre neuroscience" - and posted a tweet. © 2020 BBC.

Keyword: Brain imaging
Link ID: 27443 - Posted: 09.02.2020

by Nicholette Zeliadt An experimental drug prevents seizures and death in a mouse model of Dravet syndrome, a severe form of epilepsy that is related to autism, researchers reported 18 October 2019. The drug works by silencing a DNA segment called a ‘poison exon’ and is expected to enter clinical trials next year. If it works, it offers hope for treating not just Dravet, but other forms of autism as well: Another team has identified a poison exon in SYNGAP1, an autism gene that also causes epilepsy. Poison exons seem to impede the production of certain crucial proteins; blocking these segments would restore normal levels of the proteins. “The beauty of the technology,” says Gemma Carvill, assistant professor of neurology and pharmacology at Northwestern University in Chicago, Illinois, “is that “any gene that has a poison exon is potentially a target.” Several teams presented unpublished work on poison exons in a standing-room-only session at the 2019 American Society of Human Genetics meeting in Houston, Texas. People with Dravet often have autism, and most die in childhood2. The syndrome typically stems from mutations in a gene called SCN1A, which encodes an essential sodium channel in neurons. Only about 25 percent of mice with mutations in SCN1A live beyond 30 days of age. The new drug consists of short strands of ‘antisense’ RNA that restore normal levels of the channel, said Lori Isom of the University of Michigan, who presented the work. And all but 1 of 33 mice that received a single injection of the drug at 2 days of age remained alive 88 days later. © 2020 Simons Foundation

Keyword: Epilepsy; Autism
Link ID: 27437 - Posted: 08.29.2020

By Simon Makin New research could let scientists co-opt biology's basic building block—the cell—to construct materials and structures within organisms. A study, published in March in Science and led by Stanford University psychiatrist and bioengineer Karl Deisseroth, shows how to make specific cells produce electricity-carrying (or blocking) polymers on their surfaces. The work could someday allow researchers to build large-scale structures within the body or improve brain interfaces for prosthetic limbs. In the medium term, the technique may be useful in bioelectric medicine, which involves delivering therapeutic electrical pulses. Researchers in this area have long been interested in incorporating polymers that conduct or inhibit electricity without damaging surrounding tissues. Stimulating specific cells—to intervene in a seizure, for instance—is much more precise than flooding the whole organism with drugs, which can cause broad side effects. But current bioelectric methods, such as those using electrodes, still affect large numbers of cells indiscriminately. The new technique uses a virus to deliver genes to desired cell types, instructing them to produce an enzyme (Apex2) on their surface. The enzyme sparks a chemical reaction between precursor molecules and hydrogen peroxide, infused in the space between cells; this reaction causes the precursors to fuse into a polymer on the targeted cells. “What's new here is the intertwining of various emerging fields in one application,” says University of Florida biomedical engineer Kevin Otto, who was not involved in the research but co-authored an accompanying commentary in Science. “The use of conductive polymers assembled [inside living tissue] through synthetic biology, to enable cell-specific interfacing, is very novel.” © 2020 Scientific American

Keyword: Development of the Brain; Epigenetics
Link ID: 27411 - Posted: 08.11.2020

by Peter Hess / Infants with particular patterns of electrical activity in the brain go on to have high levels of autism traits as toddlers, a new study shows1. Specifically, babies who have unusually high or low synchrony between certain brain waves — as measured by electroencephalography (EEG) — at 3 months old tend to score high on a standardized scale of autism-linked behaviors when they are 18 months old. These levels of synchrony reflect underlying patterns of connectivity in the brain. The findings suggest that EEG could help clinicians identify autistic babies long before these children show behaviors flagged by standard diagnostic tests. The work “reinforces the concept and the truism that brain development is affected before autism diagnoses are made,” says lead researcher Shafali Spurling Jeste, associate professor of psychiatry and neurology at the University of California, Los Angeles. “We believe that we could work to start rewiring the brain if we intervene effectively and early enough. That message, quite simply, is a very important one.” The study involved ‘baby sibs,’ the younger siblings of autistic children. Baby sibs are 10 to 20 times more likely to have autism than the general population. Previous research showed similar patterns of altered connectivity in functional magnetic resonance imaging (MRI) data from infants who were later diagnosed with autism, but MRI is costly and prone to errors. EEG measurements, on the other hand, are relatively inexpensive and simple to perform, which makes them more practical for clinical use, says Charles Nelson, professor of pediatrics and neuroscience at Harvard University, who was not involved in the study. © 2020 Simons Foundation

Keyword: Autism
Link ID: 27380 - Posted: 07.25.2020

Salvatore Domenic Morgera How the brain works remains a puzzle with only a few pieces in place. Of these, one big piece is actually a conjecture: that there’s a relationship between the physical structure of the brain and its functionality. The brain’s jobs include interpreting touch, visual and sound inputs, as well as speech, reasoning, emotions, learning, fine control of movement and many others. Neuroscientists presume that it’s the brain’s anatomy – with its hundreds of billions of nerve fibers – that make all of these functions possible. The brain’s “living wires” are connected in elaborate neurological networks that give rise to human beings’ amazing abilities. It would seem that if scientists can map the nerve fibers and their connections and record the timing of the impulses that flow through them for a higher function such as vision, they should be able to solve the question of how one sees, for instance. Researchers are getting better at mapping the brain using tractography – a technique that visually represents nerve fiber routes using 3D modeling. And they’re getting better at recording how information moves through the brain by using enhanced functional magnetic resonance imaging to measure blood flow. But in spite of these tools, no one seems much closer to figuring out how we really see. Neuroscience has only a rudimentary understanding of how it all fits together. To address this shortcoming, my team’s bioengineering research focuses on relationships between brain structure and function. The overall goal is to scientifically explain all the connections – both anatomical and wireless – that activate different brain regions during cognitive tasks. We’re working on complex models that better capture what scientists know of brain function. t © 2010–2020, The Conversation US, Inc.

Keyword: Brain imaging
Link ID: 27373 - Posted: 07.18.2020

By Lisa Sanders, M.D. The early-morning light wakened the middle-aged man early on a Saturday morning in 2003. He felt his 51-year-old wife move behind him and turned to see her whole body jerking erratically. He was a physician, a psychiatrist, and knew immediately that she was having a seizure. He grabbed his phone and dialed 911. His healthy, active wife had never had a seizure before. But this was only the most recent strange episode his wife had been through over the past 18 months. A year and a half earlier, the man returned to his suburban Pittsburgh home after a day of seeing patients and found his wife sitting in the kitchen, her hair soaking wet. He asked if she had just taken a shower. No, she answered vaguely, without offering anything more. Before he could ask her why she was so sweaty, their teenage son voiced his own observations. Earlier that day, the boy reported, “She wasn’t making any sense.” That wasn’t like her. Weeks later, his daughter reported that when she arrived home from school, she heard a banging sound in a room in the attic. She found her mother under a futon bed, trying to sit up and hitting her head on the wooden slats underneath. Her mother said she was looking for something, but she was obviously confused. The daughter helped her mother up and brought her some juice, which seemed to help. With both episodes, the children reported that their mother didn’t seem upset or distressed. The woman, who had trained as a psychiatrist before giving up her practice to stay with the kids, had no recollection of these odd events. The Problem Is Sugar Her husband persuaded her to see her primary-care doctor. Upon hearing about these strange spells, the physician said she suspected that her patient was having episodes of hypoglycemia. Very low blood sugar sends the body into a panicked mode of profuse sweating, shaking, weakness and, in severe cases, confusion. She referred her to a local endocrinologist. © 2020 The New York Times Company

Keyword: Epilepsy
Link ID: 27341 - Posted: 07.02.2020