Chapter 2. Neurophysiology: The Generation, Transmission, and Integration of Neural Signals

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by Laura Dattaro Autistic boys with large brains in early childhood still have large brains in adolescence, according to a new study. Autistic girls, too, have brains that grow differently from those of their non-autistic peers. The findings challenge the long-standing idea that brain enlargement in autism is temporary. Previous studies indicated that young children on the spectrum have larger brains than their non-autistic peers but older people with autism do not. To explain the difference, researchers speculated that a pruning process follows early brain overgrowth. But the changes are a mirage, the researchers behind the new study say: Because having a large brain is associated with a low intelligence quotient (IQ) and severe autism traits, and because older children with such characteristics are often excluded from imaging studies, the prior results reflect only a lack of older participants with large brains. “This whole idea of this early overgrowth followed by normalization is just an artifact of sampling bias,” says lead investigator Christine Wu Nordahl, associate professor of psychiatry and behavioral sciences at the University of California, Davis MIND Institute. “It was sort of like, ‘Wow, why didn’t we ever think about this before?’ But it’s pretty clear that that’s what’s happening.” Autistic and non-autistic children also show different development patterns in their white matter — fibers that connect regions of the brain — in early childhood, a second study from Nordahl’s group shows. Some of the differences correlate with changes in the children’s autism traits over time. © 2020 Simons Foundation

Keyword: Autism; Brain imaging
Link ID: 27598 - Posted: 11.30.2020

By Lindsay Gray When Herbert Weinstein stood trial for the murder of his wife in 1992, his attorneys were struck by the measured calm with which he recounted her death and the events leading up to it. He made no attempt to deny that he was culpable, and yet his stoicism in the face of his wildly uncharacteristic actions led his defense to suspect that he might not be. Weinstein underwent neuroimaging tests, which confirmed what his attorneys had suspected: a cyst had impinged upon large parts of Weinstein’s frontal lobe, the seat of impulse control in the brain. On these grounds, they reasoned he should be found not guilty by reason of insanity, despite Weinstein’s free admission of guilt. Guilt is difficult to define, but it pervades every aspect of our lives, whether we’re chastising ourselves for skipping a workout, or serving on the jury of a criminal trial. Humans seem to be hardwired for justice, but we’re also saddled with a curious compulsion to diagram our own emotional wiring. This drive to assign a neurochemical method to our madness has led to the generation of vast catalogs of neuroimaging studies that detail the neural underpinnings of everything from anxiety to nostalgia. In a recent study, researchers now claim to have moved us one step closer to knowing what a guilty brain looks like. Since guilt carries different weight depending on context or culture, the authors of the study chose to define it operationally as the awareness of having harmed someone else. A series of functional magnetic resonance imaging (fMRI) experiments across two separate cohorts, one Swiss and one Chinese, revealed what they refer to as a “guilt-related brain signature” that persists across groups. Since pervasive guilt is a common feature in severe depression and PTSD, the authors suggest that a neural biomarker for guilt could offer more precise insight into these conditions and, potentially, their treatment. But brain-based biomarkers for complex human behaviors also lend themselves to the more ethically fraught discipline of neuroprediction, an emergent branch of behavioral science that combines neuroimaging data and machine learning to forecast how an individual is likely to act based on how their brain scans compare to those of other groups. © 2020 Scientific American,

Keyword: Stress; Brain imaging
Link ID: 27591 - Posted: 11.21.2020

Researchers at the National Eye Institute (NEI) have decoded brain maps of human color perception. The findings, published today in Current Biology, open a window into how color processing is organized in the brain, and how the brain recognizes and groups colors in the environment. The study may have implications for the development of machine-brain interfaces for visual prosthetics. NEI is part of the National Institutes of Health. “This is one of the first studies to determine what color a person is seeing based on direct measurements of brain activity,” said Bevil Conway, Ph.D., chief of NEI’s Unit on Sensation, Cognition and Action, who led the study. “The approach lets us get at fundamental questions of how we perceive, categorize, and understand color.” The brain uses light signals detected by the retina’s cone photoreceptors as the building blocks for color perception. Three types of cone photoreceptors detect light over a range of wavelengths. The brain mixes and categorizes these signals to perceive color in a process that is not well understood. To examine this process, Isabelle Rosenthal, Katherine Hermann, and Shridhar Singh, post-baccalaureate fellows in Conway’s lab and co-first authors on the study, used magnetoencephalography or “MEG,” a 50-year-old technology that noninvasively records the tiny magnetic fields that accompany brain activity. The technique provides a direct measurement of brain cell activity using an array of sensors around the head. It reveals the millisecond-by-millisecond changes that happen in the brain to enable vision. The researchers recorded patterns of activity as volunteers viewed specially designed color images and reported the colors they saw.

Keyword: Vision; Brain imaging
Link ID: 27588 - Posted: 11.21.2020

In a 2009 TED Talk, Israeli neuroscientist Henry Markram made a shocking claim: he was going to create a machine version of human brain within 10 years. The project was catnip to filmmaker Noah Hutton, who began documenting Markram's quest. Ultimately, Hutton followed Markram for a decade — but the scientist's lofty goal remains conspicuously incomplete. The resulting film, In Silico, finally makes its world premiere as part of the online version of the DOC NYC film festival on November 11. The film traces Markram’s journey with the Human Brain Project, from the project’s inception to its $1.4 billion in funding from the European Commission — and how it failed to meet its 10-year goal by 2019. Following a neuroscientist for a decade reveals a lot of highs and lows. Hutton presents the controversies by interviewing both the Human Brain Project team and its critics, including Princeton neuroscientist Sebastian Seung, researcher Zach Mainen at the Champalimaud Centre for the Unknown based in Portugal, and experimental cognitive psychologist Stanislas Dehane, who is professor at Collège de France in Paris. The film also features candid interviews with neuroscientists Christof Koch, who head's up the Allen Institute's MindScope Program, Harvard University's Jeremy R. Knowles Professor of Molecular and Cellular Biology Jeff W. Lichtman, and Stanford University neuroscience adjunct professor David Eagleman. Neuroscientists Idan Segev of Hebrew University in Israel, Cori Bargmann, Torsten N. Weisel Professor of Genetics and Genomics and Neuroscience and Behavior at Rockefeller University, and Cold Spring Harbor Lab professor Anne Churchland.

Keyword: Brain imaging
Link ID: 27577 - Posted: 11.14.2020

By Sundas Hashmi It was the afternoon of Jan. 31. I was preparing for a dinner party and adding final touches to my cheese platter when everything suddenly went dark. I woke up feeling baffled in a hospital bed. My husband filled me in: Apparently, I had suffered a massive seizure a few hours before our guests were to arrive at our Manhattan apartment. Our children’s nanny found me and I was rushed to the hospital. That had been three days earlier. My husband and I were both mystified: I was 37 years old and had always been in excellent health. In due course, a surgeon dropped by and told me I had a glioma, a type of brain tumor. It was relatively huge but operable. I felt sick to my stomach. Two weeks later, I was getting wheeled to the operating theater. I wouldn’t know the pathology until much later. I said my goodbyes to everyone — most importantly to my children, Sofia, 6, and Nyle, 2 — and prepared to die. But right before the surgery, in a very drugged state, I asked the surgeon to please get photos of me and my brother from my husband. I wanted the surgeon to see them. My brother had died two decades earlier from a different kind of brain tumor — a glioblastoma. I was 15 at the time, and he was 18. He died within two years of being diagnosed. Those two years were the worst period of my life. Doctors in my home country of Pakistan refused to take him, saying his case was fatal. So, my parents gathered their savings and flew him to Britain, where he was able to get a biopsy (his tumor was in an inoperable location) and radiation. Afterward, we had to ask people for donations so he could get the gamma knife treatment in Singapore that my parents felt confident would save him. In the end, nothing worked, and he died, taking 18 years of memories with him. © 2020 The New York Times Company

Keyword: Glia
Link ID: 27536 - Posted: 10.21.2020

Adrian Owen DR. ADRIAN OWEN: Imagine this scenario. You've unfortunately had a terrible accident. You're lying in a hospital bed and you're aware—you're aware but you're unable to respond, but the doctors and your relatives don't know that. You have to lie there, listening to them deciding whether to let you live or die. I can think of nothing more terrifying. Communication is at the very heart of what makes us human. It's the basis of everything. What we're doing is we're returning the ability to communicate to some patients who seem to have lost that forever. The vegetative state is often referred to as a state of wakefulness without awareness. Patients open their eyes, they'll just gaze around the room. They'll have sleeping and waking cycles, but they never show any evidence of having any awareness. So, typically, the way that we assess consciousness is through command following. We ask somebody to do something, say, squeeze our hand, and if they do it, you know that they're conscious. The problem in the vegetative state is that these patients by definition can produce no movements. And the question I asked is, well, could somebody command follow with their brain? It was that idea that pushed us into a new realm of understanding this patient population. When a part of your brain is involved in generating a thought or performing an action, it burns energy in the form of glucose, and it's replenished through blood flow. As blood flows to that part of the brain, we're able to see that with the FMRI scanner. I think one of the key insights was the realization that we could simply get somebody to lie in the scanner and imagine something and, based on the pattern of brain activity, we will be able to work out what it is they were thinking. We had to find something that produces really a quite distinct pattern of activity that was more or less the same for everybody. So, we came up with two tasks. One task, imagine playing tennis, produces activity in the premotor cortex in almost every healthy person we tried this in. A different task, thinking about moving from room to room in your house, produces an entirely different pattern of brain activity; particularly, it involves a part of the brain known as the parahippocampal gyrus. And again, it's very consistent across different people.

Keyword: Consciousness; Brain imaging
Link ID: 27513 - Posted: 10.07.2020

by Angie Voyles Askham Autistic people share some brain structure differences with people who have other neuropsychiatric conditions, including schizophrenia and attention deficit hyperactivity disorder (ADHD), according to a massive new brain-imaging study1. These shared differences stem from the atypical development of one particular type of neuron, the findings suggest. The results provide “further evidence that our understanding of autism can really be advanced by explicitly studying autism in the context of other disorders,” says Armin Raznahan, chief of the Section on Developmental Neurogenomics at the U.S. National Institute of Mental Health in Bethesda, Maryland, who was not involved in the study. The researchers looked at brain scans from 28,321 people to identify structural changes associated with any of six conditions: autism, ADHD, bipolar disorder, major depressive disorder, obsessive-compulsive disorder and schizophrenia. The team found that the brains of people with these conditions differ from controls in a specific way: They have similar patterns of thickness across the cortex, the brain’s outer layer. The cortical regions with the biggest differences in thickness are typically rich in a particular type of excitatory neuron. “We were able to put our fingers on what might be behind that commonality,” says lead researcher Tomas Paus, professor of psychology and psychiatry at the University of Toronto in Canada. “That was very exciting.” The work combined data from 145 cohorts within the Enhancing Neuroimaging Genetics through Meta-Analysis (ENIGMA) consortium, an international group of researchers who collect and analyze brain-scan data in a standardized way so that they can pool their results. © 2020 Simons Foundation

Keyword: Autism; Brain imaging
Link ID: 27503 - Posted: 10.03.2020

By Rebekah Tuchscherer Call it neuroscience on the go. Scientists have developed a backpack that tracks and stimulates brain activity as people go about their daily lives. The advance could allow researchers to get a sense of how the brain works outside of a laboratory—and how to monitor diseases such as Parkinson’s and post-traumatic stress disorder in real-world settings. The technology is “an inspiring demonstration of what’s possible” with portable neuroscience equipment, says Timothy Spellman, a neurobiologist at Weill Cornell Medicine who was not involved with the work. The backpack and its vast suite of tools, he says, could broaden the landscape for neuroscience research to study the brain while the body is in motion. Typically, when scientists want to scan the brain, they need a lot of room—and a lot of money. Functional magnetic resonance imaging (fMRI) scanners, which detect activity in various regions of the brain, are about the size of a pickup truck and can cost more than $1 million. And patients must stay still in the machine for about 1 hour to ensure a clear, readable scan. © 2020 American Association for the Advancement of Science.

Keyword: Brain imaging
Link ID: 27479 - 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

by Peter Hess Early behavioral signs predict seizures in autistic children, according to a new study1. Previous work has shown that 5 to 46 percent of people with autism experience seizures. And autistic adults with epilepsy have, on average, less cognitive ability and weaker daily living skills than their autistic peers who do not have seizures2. The new study shows that people with autism who begin having seizures during childhood show small but significant behavioral differences before they ever experience a seizure, compared with those who do not develop epilepsy. They score lower than their peers on measures of quality of life and adaptive behaviors, which include communication, daily living skills, socialization and motor skills. They score higher on a measure of hyperactivity. The results suggest that seizures and certain behavioral issues in autism could have common origins, says co-lead investigator Jamie Capal, associate professor of pediatrics and neurology at the University of North Carolina at Chapel Hill. “I think it really does show us that in individuals with autism who eventually have epilepsy, there is some shared mechanism early on that we just haven’t been able to identify,” Capal says. Early signs: To investigate the relationship between childhood behaviors in autism and the development of seizures, the researchers analyzed data on 472 autistic children aged 2 to 15 from the Autism Treatment Network, a medical registry that includes 12 clinics in the United States and Canada. None of the children had experienced seizures before enrolling in the network, but 22 developed seizures two to six years after enrollment. © 2020 Simons Foundation

Keyword: Autism; Epilepsy
Link ID: 27294 - Posted: 06.09.2020

By Lisa Sanders, M.D. “I know what Danny has,” said the boy’s aunt to the boy’s mother, her sister-in-law. Her voice on the phone cracked with excitement. “I saw someone just like him on TV!” This was last fall, and Danny was 18. He had been a medical mystery since he was 7 months old. His mother recalled that she had just finished changing his diaper and picked him up when she heard him make a strange clicking noise, his mouth opening and closing oddly. And then his head flopped back as she held him. She hurried to the living room of their Queens home to show her husband, but by the time she got there, Danny was fine. Those sudden episodes of clicking and collapse happened again and again, eventually occurring more than 100 times a day. His first doctors thought these episodes could be tiny seizures. But none of the antiseizure medications they prescribed helped. Then, when Danny was 8, and almost too big for his mother to catch when he slow-motion slumped to the floor, his parents found a doctor who was willing to explore a different diagnosis and treatment. Could this be a rare disease known as cataplexy? In this disorder, patients have episodes of sudden weakness in the skeletal muscles of the body. In some, cataplexy may affect only the face or neck, causing the eyelids to droop or the head to fall forward. But in others, it can also affect the entire body. These episodes are often triggered by strong emotion, which was the case for Danny. Cataplexy is usually part of another rare disorder, narcolepsy, in which the normal control of sleep and wakefulness is somehow lost. Those with narcolepsy have sudden episodes of sleep that invade their waking hours and transient periods of wakefulness that disrupt their sleep. © 2020 The New York Times Company

Keyword: Sleep; Epilepsy
Link ID: 27290 - Posted: 06.08.2020

by Chloe Williams / A new flexible electrode array can detect the activity of neurons in a rat’s brain at high resolution for more than a year1. The device could be used to study how neuronal activity is altered in autism. Arrays usually have wires connected to each electrode to pick up its signal, but this design is bulky and works only in arrays consisting of 100 electrodes or fewer, limiting the array’s coverage and resolution. Devices with thousands of electrodes have integrated switches to consolidate signals into fewer wires. But these devices usually have a lifespan of only a few days. Their polymer-based coatings are often permeable to water or contain tiny defects that allow body fluids to seep into the device and current to leak out, damaging both the device and brain tissue. The new device combines electronic switches and a specialized protective coating so that scientists can record activity at the surface of the brain at high resolution over extended periods of time. The array, called Neural Matrix, consists of 1,008 surface electrodes laid out in 28 columns and 36 rows. Switches, or transistors, built into the array combine signals from all the electrodes in a column to a single output wire. The signals from each electrode in the column are recorded via the wire in a specific sequence, making it possible to separate them later. © 2020 Simons Foundation

Keyword: Brain imaging
Link ID: 27282 - Posted: 06.04.2020

By Robert Martone When a concert opens with a refrain from your favorite song, you are swept up in the music, happily tapping to the beat and swaying with the melody. All around you, people revel in the same familiar music. You can see that many of them are singing, the lights flashing to the rhythm, while other fans are clapping in time. Some wave their arms over their head, and others dance in place. The performers and audience seem to be moving as one, as synchronized to one another as the light show is to the beat. A new paper in the journal NeuroImage has shown that this synchrony can be seen in the brain activities of the audience and performer. And the greater the degree of synchrony, the study found, the more the audience enjoys the performance. This result offers insight into the nature of musical exchanges and demonstrates that the musical experience runs deep: we dance and feel the same emotions together, and our neurons fire together as well. In the study, a violinist performed brief excerpts from a dozen different compositions, which were videotaped and later played back to a listener. Researchers tracked changes in local brain activity by measuring levels of oxygenated blood. (More oxygen suggests greater activity, because the body works to keep active neurons supplied with it.) Musical performances caused increases in oxygenated blood flow to areas of the brain related to understanding patterns, interpersonal intentions and expression. Data for the musician, collected during a performance, was compared to those for the listener during playback. In all, there were 12 selections of familiar musical works, including “Edelweiss,” Franz Schubert’s “Ave Maria,” “Auld Lang Syne” and Ludwig van Beethoven’s “Ode to Joy.” The brain activities of 16 listeners were compared to that of a single violinist. © 2020 Scientific American,

Keyword: Hearing
Link ID: 27277 - Posted: 06.03.2020

Diana Kwon What if you could boost your brain’s processing capabilities simply by sticking electrodes onto your head and flipping a switch? Berkeley, California–based neurotechnology company Humm has developed a device that it claims serves that purpose. Their “bioelectric memory patch” is designed to enhance working memory—the type of short-term memory required to temporarily hold and process information—by noninvasively stimulating the brain. In recent years, neurotechnology companies have unveiled direct-to-consumer (DTC) brain stimulation devices that promise a range of benefits, including enhancing athletic performance, increasing concentration, and reducing depression. Humm’s memory patch, which resembles a large, rectangular Band-Aid, is one such product. Users can stick the device to their forehead and toggle a switch to activate it. Electrodes within the patch generate transcranial alternating current stimulation (tACS), a method of noninvasively zapping the brain with oscillating waves of electricity. The company recommends 15 minutes of stimulation to give users up to “90 minutes of boosted learning” immediately after using the device. The product is set for public release in 2021. Over the last year or so, Humm has generated much excitement among investors, consumers, and some members of the scientific community. In addition to raising several million dollars in venture capital funding, the company has drawn interest both from academic research labs and from the United States military. According to Humm cofounder and CEO Iain McIntyre, the US Air Force has ordered approximately 1,000 patches to use in a study at their training academy that is set to start later this year. © 1986–2020 The Scientist

Keyword: Learning & Memory
Link ID: 27269 - Posted: 05.29.2020