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

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By Katie Free, Joel Goldberg When it comes to our senses, we frequently focus on the external—the crack of thunder, the glare of sunlight, the fragrance of flowers—that captured our attention in the first place. But our bodies also have a whole host of internal senses that tell our brains whether our hearts are beating at the right speed, for example, or whether our blood pressure is too high. These signals travel constantly via hormones and nerves, including a mysterious 100,000-fiber network called the vagus nerve. Now, new techniques are helping scientists map the thin, twisting branches of the vagus nerve—which connects the brain to the heart, intestines, and other internal organs—and make surprising discoveries about its role in memory and emotion. These findings have spawned investigations into treatments for everything from Alzheimer’s disease to post-traumatic stress disorder and have led to the approval of medical implants to help treat epilepsy and depression. When it comes to understanding the brain-mind connection, a gut check might not hurt. © 2021 American Association for the Advancement of Science.

Keyword: Epilepsy; Depression
Link ID: 27867 - Posted: 06.23.2021

By Christof Koch Consider the following experiences: • You're headed toward a storm that's a couple of miles away, and you've got to get across a hill. You ask yourself: “How am I going to get over that, through that?” • You see little white dots on a black background, as if looking up at the stars at night. Advertisement • You look down at yourself lying in bed from above but see only your legs and lower trunk. These may seem like idiosyncratic events drawn from the vast universe of perceptions, sensations, memories, thoughts and dreams that make up our daily stream of consciousness. In fact, each one was evoked by directly stimulating the brain with an electrode. As American poet Walt Whitman intuited in his poem “I Sing the Body Electric,” these anecdotes illustrate the intimate relationship between the body and its animating soul. The brain and the conscious mind are as inexorably linked as the two sides of a coin. Recent clinical studies have uncovered some of the laws and regularities of conscious activity, findings that have occasionally proved to be paradoxical. They show that brain areas involved in conscious perception have little to do with thinking, planning and other higher cognitive functions. Neuroengineers are now working to turn these insights into technologies to replace lost cognitive function and, in the more distant future, to enhance sensory, cognitive or memory capacities. For example, a recent brain-machine interface provides completely blind people with limited abilities to perceive light. These tools, however, also reveal the difficulties of fully restoring sight or hearing. They underline even more the snags that stand in the way of sci-fi-like enhancements that would enable access to the brain as if it were a computer storage drive. © 2021 Scientific American,

Keyword: Consciousness
Link ID: 27865 - Posted: 06.19.2021

By Laura Sanders Some big scientific discoveries aren’t actually discovered. They are borrowed. That’s what happened when scientists enlisted proteins from an unlikely lender: green algae. Cells of the algal species Chlamydomonas reinhardtii are decorated with proteins that can sense light. That ability, first noticed in 2002, quickly caught the attention of brain scientists. A light-sensing protein promised the power to control neurons — the brain’s nerve cells — by providing a way to turn them on and off, in exactly the right place and time. Nerve cells genetically engineered to produce the algal proteins become light-controlled puppets. A flash of light could induce a quiet neuron to fire off signals or force an active neuron to fall silent. “This molecule is the light sensor that we needed,” says vision neuroscientist Zhuo-Hua Pan, who had been searching for a way to control vision cells in mice’s retinas. The method enabled by these loaner proteins is now called optogenetics, for its combination of light (opto) and genes. In less than two decades, optogenetics has led to big insights into how memories are stored, what creates perceptions and what goes wrong in the brain during depression and addiction. Using light to drive the activity of certain nerve cells, scientists have toyed with mouse hallucinations: Mice have seen lines that aren’t there and have remembered a room they had never been inside. Scientists have used optogenetics to make mice fight, mate and eat, and even given blind mice sight. In a big first, optogenetics recently restored aspects of a blind man’s vision. © Society for Science & the Public 2000–2021.

Keyword: Brain imaging; Learning & Memory
Link ID: 27861 - Posted: 06.19.2021

By Virginia Hughes Late one evening last March, just before the coronavirus pandemic shut down the country, Mingzheng Wu, a graduate student at Northwestern University, plopped two male mice into a cage and watched as they explored their modest new digs: sniffing, digging, fighting a little. Sign up for Science Times: Get stories that capture the wonders of nature, the cosmos and the human body. With a few clicks on a nearby computer, Mr. Wu then switched on a blue light implanted in the front of each animal’s brain. That light activated a tiny piece of cortex, spurring neurons there to fire. Mr. Wu zapped the two mice at the same time and at the same rapid frequency — putting that portion of their brains quite literally in sync. Within a minute or two, any animus between the two creatures seemed to disappear, and they clung to each other like long-lost friends. “After a few minutes, we saw that those animals actually stayed together, and one animal was grooming the other,” said Mr. Wu, who works in the neurobiology lab of Yevgenia Kozorovitskiy. Mr. Wu and his colleagues then repeated the experiment, but zapped each animal’s cortex at frequencies different from the other’s. This time, the mice displayed far less of an urge to bond. The experiment, published this month in Nature Neuroscience, was made possible thanks to an impressive new wireless technology that allows scientists to observe — and manipulate — the brains of multiple animals as they interact with one another. “The fact that you can implant these miniaturized bits of hardware and turn neurons on and off by light, it’s just mind-blowingly cool,” said Thalia Wheatley, a social neuroscientist at Dartmouth College who was not involved in the work. © 2021 The New York Times Company

Keyword: Aggression; Sexual Behavior
Link ID: 27832 - Posted: 05.27.2021

Linda Geddes Science correspondent A blind man has had his sight partly restored after a form of gene therapy that uses pulses of light to control the activity of nerve cells – the first successful demonstration of so-called optogenetic therapy in humans. The 58-year-old man, from Brittany in northern France, was said to be “very excited” after regaining the ability to recognise, count, locate and touch different objects with the treated eye while wearing a pair of light-stimulating goggles, having lost his sight after being diagnosed with retinitis pigmentosa almost 40 years ago. The breakthrough marks an important step towards the more widespread use of optogenetics as a clinical treatment. It involves modifying nerve cells (neurons) so that they fire electrical signals when they’re exposed to certain wavelengths of light, equipping neuroscientists with the power to precisely control neuronal signalling within the brain and elsewhere. Christopher Petkov, a professor of comparative neuropsychology at Newcastle University medical school, said: “This is a tremendous development to restore vision using an innovative approach. The goal now is to see how well this might work in other patients with retinitis pigmentosa.” This group of rare, genetic disorders, which involves the loss of light-sensitive cells in the retina, affects more than 2 million people worldwide, and can lead to complete blindness. © 2021 Guardian News & Media Limited

Keyword: Vision
Link ID: 27831 - Posted: 05.27.2021

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