Chapter 3. The Chemistry of Behavior: Neurotransmitters and Neuropharmacology

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James Brunton Badenoch Monkeypox’s effect on the skin – the disfiguring rashes – and the flu-like symptoms have been well described, but few have investigated the neurological and psychiatric problems the virus might cause. There are historic reports of neurological complications in people infected with the related smallpox virus and in people vaccinated against smallpox, which contains the related vaccinia virus. So my colleagues and I wanted to know whether monkeypox causes similar problems. We looked at all the evidence from before the current monkeypox pandemic of neurological or psychiatric problems in people with a monkeypox infection. The results are published in the journal eClinicalMedicine. A small but noticeable proportion of people (2% to 3%) with monkeypox became very unwell and developed serious neurological problems, including seizure and encephalitis (inflammation of the brain that can cause long-term disability). We also found that confusion occurred in a similar number of people. It’s important to note, though, that these figures are based on a few studies with few participants. Besides the severe and rare brain problems, we found evidence of a broader group of people with monkeypox who had more common neurological symptoms including headache, muscle ache and fatigue. From looking at the studies, it was unclear how severe these symptoms were and how long they lasted. It was also unclear how many people with monkeypox had psychiatric problems - such as anxiety and depression - as few studies looked into it. Of those that did, low mood was frequently reported.. © 2010–2022, The Conversation US, Inc.

Keyword: Epilepsy; Learning & Memory
Link ID: 28475 - Posted: 09.14.2022

By Kurt Kleiner The human brain is an amazing computing machine. Weighing only three pounds or so, it can process information a thousand times faster than the fastest supercomputer, store a thousand times more information than a powerful laptop, and do it all using no more energy than a 20-watt lightbulb. Researchers are trying to replicate this success using soft, flexible organic materials that can operate like biological neurons and someday might even be able to interconnect with them. Eventually, soft “neuromorphic” computer chips could be implanted directly into the brain, allowing people to control an artificial arm or a computer monitor simply by thinking about it. Like real neurons — but unlike conventional computer chips — these new devices can send and receive both chemical and electrical signals. “Your brain works with chemicals, with neurotransmitters like dopamine and serotonin. Our materials are able to interact electrochemically with them,” says Alberto Salleo, a materials scientist at Stanford University who wrote about the potential for organic neuromorphic devices in the 2021 Annual Review of Materials Research. Salleo and other researchers have created electronic devices using these soft organic materials that can act like transistors (which amplify and switch electrical signals) and memory cells (which store information) and other basic electronic components. The work grows out of an increasing interest in neuromorphic computer circuits that mimic how human neural connections, or synapses, work. These circuits, whether made of silicon, metal or organic materials, work less like those in digital computers and more like the networks of neurons in the human brain. © 2022 Annual Reviews

Keyword: Robotics; Learning & Memory
Link ID: 28449 - Posted: 08.27.2022

Diana Kwon People’s ability to remember fades with age — but one day, researchers might be able to use a simple, drug-free method to buck this trend. In a study published on 22 August in Nature Neuroscience1, Robert Reinhart, a cognitive neuroscientist at Boston University in Massachusetts, and his colleagues demonstrate that zapping the brains of adults aged over 65 with weak electrical currents repeatedly over several days led to memory improvements that persisted for up to a month. Previous studies have suggested that long-term memory and ‘working’ memory, which allows the brain to store information temporarily, are controlled by distinct mechanisms and parts of the brain. Drawing on this research, the team showed that stimulating the dorsolateral prefrontal cortex — a region near the front of the brain — with high-frequency electrical currents improved long-term memory, whereas stimulating the inferior parietal lobe, which is further back in the brain, with low-frequency electrical currents boosted working memory. “Their results look very promising,” says Ines Violante, a neuroscientist at the University of Surrey in Guildford, UK. “They really took advantage of the cumulative knowledge within the field.” Using a non-invasive method of stimulating the brain known as transcranial alternating current stimulation (tACS), which delivers electrical currents through electrodes on the surface of the scalp, Reinhart’s team conducted a series of experiments on 150 people aged between 65 and 88. Participants carried out a memory task in which they were asked to recall lists of 20 words that were read aloud by an experimenter. The participants underwent tACS for the entire duration of the task, which took 20 minutes. © 2022 Springer Nature Limited

Keyword: Learning & Memory
Link ID: 28445 - Posted: 08.24.2022

By Erin Garcia de Jesús As Tanina Agosto went through her normal morning routine in July 2007, she realized something was wrong. The 29-year-old couldn’t control her left side, even her face. “Literally the top of my head to the bottom of my foot on the left side of my body could not feel anything.” The next day, Agosto spoke with a doctor at the New York City hospital where she works as a medical secretary. He told her that she probably had a pinched nerve and to see a chiropractor. But chiropractic care didn’t help. Months later, Agosto needed a cane to get around, and moving her left leg and arm required lots of concentration. She couldn’t work. Numbness and tingling made cooking and cleaning difficult. It felt a bit like looping a rubber band tightly around a finger until it loses sensation, Agosto says. Once the rubber band comes off, the finger tingles for a bit. But for her, the tingling wouldn’t stop. Finally, she recalls, one chiropractor told her, “I’m not too big of a person to say there’s something very wrong with you, and I don’t know what it is. You need to see a neurologist.” In November 2008, tests confirmed that Agosto had multiple sclerosis. Her immune system was attacking her brain and spinal cord. Agosto knew nothing about MS except that a friend of her mother’s had it. “At the time, I was like, there’s no way I’ve got this old lady’s condition,” she says. “To be hit with that and know that there’s no cure — that was just devastating.” Why people develop the autoimmune disorder has been a long-standing question. Studies have pointed to certain gene variations and environmental factors. For decades, a common virus called Epstein-Barr virus has also been high on the list of culprits. © Society for Science & the Public 2000–2022.

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 28428 - Posted: 08.11.2022

Mo Costandi We spend approximately one-third of our lives sleeping, but why sleep is important is a big unanswered question, one which science has only begun to answer recently. We now know, for example, that the brain cleans itself while we sleep, and that long-term memories form during the rapid eye movement (REM) stage of sleep. Your brain is highly active during sleep Sleep can be defined as a temporary state of unconsciousness, during which our responses to the outside world are reduced. Yet, we also know that the brain is active during sleep, and there is growing evidence that it remains highly responsive: For instance, your sleeping brain will respond to your name, categorize words and then prepare appropriate actions, and even learn new information. Now, a new study by researchers at UCLA and Tel Aviv University shows that the human brain remains highly responsive to sound during sleep, but it does not receive feedback from higher order areas — sort of like an orchestra with “the conductor missing.” The findings could point to a better understanding of the extent to which the brain processes information in disorders of consciousness such as coma and vegetative states, and to the neural mechanisms of conscious awareness. The missing conductor Hanna Hayat and her colleagues had the rare opportunity to record the activity of cells directly from the brains of 13 patients with drug-resistant epilepsy, who were being evaluated for brain surgery and gave written consent to participate in the study during the evaluation. The researchers implanted depth electrodes in multiple regions of the patients’ brains, primarily to identify the source of their seizures, so that the abnormal tissue could be surgically removed. Over the course of eight overnight sessions and six daytime naps, they played various sounds — including words, sentences and music — to the patients through bedside loudspeakers. They also used standard electroencephalogram (EEG) to monitor the patients’ sleep stages and recorded their sleep behavior with video. © Copyright 2007-2022 & BIG THINK,

Keyword: Sleep
Link ID: 28416 - Posted: 08.03.2022

By Hilary Achauer I sat in a dark room, eyes closed, with a device strapped to my head that looked like a futuristic bike helmet. For 10 minutes, while I concentrated on not accidentally opening my eyes, the prongs sticking out of this gadget and onto my scalp measured a health marker I never thought to assess: my cognitive health. When I booked my brain wave recording (also known as electroencephalography, or EEG), I expected to pull up to an office park with medical clinic vibes, but instead my GPS led me to an ocean-view storefront decorated like a cross between a surf shop and a luxury spa, with a sign in the window promising “Mental Wellness, Reimagined.” Located in Cardiff-by-the-Sea, a wealthy coastal town north of San Diego, Wave Neuroscience promises to help your brain perform better with a noninvasive treatment that uses magnets on the brain. We’re talking mental clarity, improved focus and concentration, and even a shift in mood. As a 48-year-old whose work requires focus and creativity, I was intrigued, but also nervous. Should I mess with a brain that, while not perfect, functions reasonably well? Advertisement Getting the EEG, which costs $100, was like meditating with a device strapped to my head, but it was more relaxing than that sounds. The tech gave me periodic updates, letting me know how much time had elapsed, and afterward I was ushered into an office where I met with Alexander Ring, director of applied science at Wave Neuroscience, via Zoom. Together we reviewed my “braincare report,” a one-page analysis generated in five minutes, comparing my brain waves with Wave Neuroscience’s database of tens of thousands of EEGs. Ring said my brain was generally performing well and that I showed cognitive flexibility and a capability to focus under pressure, but that I had a little bit more theta activity, or slow brain waves, than they normally like to see. He also pointed out a slight frequency mismatch between the back and front of my brain, which might affect my concentration and cause me to have to reread a paragraph to absorb the information. Rude, but accurate. © 2022 The Slate Group LLC. All rights reserved.

Keyword: Brain imaging; Attention
Link ID: 28347 - Posted: 06.01.2022

By Peter Kendall As he gets ready for sleep each night, Don Tucker slips on an electrode cap and checks a little computer on his bedside table. Many workers at the private lab, run by the professor emeritus at the University of Oregon, follow the same routine. The experimental device monitors the nightly voyage through sleep. After sensing light sleep for a few minutes, it pulses electric current through the scalp and skull, nudging the brain into that nirvana known as deep sleep. The goal is not just a more restful slumber. Groundbreaking discoveries made in the past decade have revealed that the brain has a power-washing system that switches into high gear during deep sleep, flushing away harmful waste. This nightly cleanup is part of the restorative power of sleep and revives concentration, memory and motor skills. As we age, however, this cleansing system gets sloppier, and it can begin to leave behind some of the metabolic detritus of the day, including the amyloid beta proteins found in the plaque that characterize Alzheimer’s disease and other devastating neurological disorders. The controversial approval of an Alzheimer’s drug reignites the battle over the underlying cause of the disease The stunning revelation in 2012 of this previously unknown brain infrastructure — dubbed the glymphatic system — has ushered in a new age of research and invention not only about sleep but also aging, dementia and brain injury. Nearly 300 research papers were published last year on the glymphatic system. © 1996-2022 The Washington Post

Keyword: Sleep
Link ID: 28346 - Posted: 06.01.2022

by Niko McCarty A new miniature, head-mounted microscope can simultaneously record the activity of thousands of neurons at different depths within the brains of freely moving mice. The smallest functional two-photon microscope to date, it can image neurons almost anywhere in the brain, with subcellular resolution. The device, called MINI2P (miniature two-photon microscope), can also collect data from the same cluster of neurons over several weeks, making it useful for long-term behavioral studies. “If you really want to understand what is behind cognition or failures in cognition, like in autism, you need to look at the interaction between neurons,” says lead investigator Edvard Moser, professor of neuroscience at the Kavli Institute for Systems Neuroscience in Trondheim, Norway. Other devices that measure neuronal activity, such as Neuropixels 2.0, record signals from more than 10,000 sites in the brain at once. But they have a low spatial resolution and cannot always determine which specific neuron is firing at any given time. Other miniature microscopes have also, traditionally, relied on visible light, which illuminates the surface of tissue, but are limited to imaging about 2,000 neurons. The new device can monitor a brain area measuring 500 by 500 micrometers and can capture data on more than 10,000 neurons at once. A typical mouse brain is roughly the size of a pea and contains about 85 million neurons. The MINI2P uses infrared light to capture the activity of neurons engineered to express GCaMP, a protein that binds to calcium ions during an action potential and emits a fluorescent signal in reply. The microscope measures that fluorescence using an infrared laser beam. © 2022 Simons Foundation

Keyword: Brain imaging
Link ID: 28282 - Posted: 04.13.2022

Yasemin Saplakoglu Imagine that while you are enjoying your morning bowl of Cheerios, a spider drops from the ceiling and plops into the milk. Years later, you still can’t get near a bowl of cereal without feeling overcome with disgust. Researchers have now directly observed what happens inside a brain learning that kind of emotionally charged response. In a new study published in January in the Proceedings of the National Academy of Sciences, a team at the University of Southern California was able to visualize memories forming in the brains of laboratory fish, imaging them under the microscope as they bloomed in beautiful fluorescent greens. From earlier work, they had expected the brain to encode the memory by slightly tweaking its neural architecture. Instead, the researchers were surprised to find a major overhaul in the connections. What they saw reinforces the view that memory is a complex phenomenon involving a hodgepodge of encoding pathways. But it further suggests that the type of memory may be critical to how the brain chooses to encode it — a conclusion that may hint at why some kinds of deeply conditioned traumatic responses are so persistent, and so hard to unlearn. “It may be that what we’re looking at is the equivalent of a solid-state drive” in the brain, said co-author Scott Fraser, a quantitative biologist at USC. While the brain records some types of memories in a volatile, easily erasable form, fear-ridden memories may be stored more robustly, which could help to explain why years later, some people can recall a memory as if reliving it, he said. Memory has frequently been studied in the cortex, which covers the top of the mammalian brain, and in the hippocampus at the base. But it’s been examined less often in deeper structures such as the amygdala, the brain’s fear regulation center. The amygdala is particularly responsible for associative memories, an important class of emotionally charged memories that link disparate things — like that spider in your cereal. While this type of memory is very common, how it forms is not well understood, partly because it occurs in a relatively inaccessible area of the brain. All Rights Reserved © 2022

Keyword: Learning & Memory; Brain imaging
Link ID: 28241 - Posted: 03.16.2022

by Niko McCarty The ‘opto’ in optogenetics — the powerful method some autism researchers use to control neurons in mice and other animals — comes from the Greek optós, meaning visible. It’s a nod to the blue light used to switch on select neurons. A new technique can do the same, albeit with something invisible: sound. In a study published in Nature Communications this month, researchers engineered neurons in the motor cortex of mice to express an ultrasound-sensitive ion channel protein called hsTRPA1. They placed an ultrasound transducer near the animal’s skull and switched it on. The response? A flex of a muscle, a perceptible twitch. The approach, called sonogenetics, enables noninvasive control over any neural circuit that can be manipulated with optogenetics, an invasive method, says lead investigator Sreekanth Chalasani, associate professor in the Molecular Neurobiology Laboratory at the Salk Institute for Biological Studies in La Jolla, California. Spectrum spoke to Chalasani about his early experiments in Caenorhabditis elegans, lucky number 63 and how sonogenetics could one day have clinical applications. Spectrum: Our readers might be familiar with optogenetics, but I’m assuming sonogenetics is new for most people. Sreekanth Chalasani: Yeah. Well, the idea in sonogenetics is that we want to manipulate things noninvasively. Ultrasound can travel through bone and skin, into the body. We’ve been using it for decades. It’s safe. The question is: Can we leverage it to get in the body and control cells, like with optogenetics? S: Literally controlling cells with sound. SC: Right. In optogenetics, light triggers action potentials in cells that have a channelrhodopsin, or opsin, protein. In sonogenetics, we wanted a protein that would let us have that same level of cellular control. But finding that protein has been difficult. Lots of groups have been looking for these proteins, and we were fortunate to find one. © 2022 Simons Foundation

Keyword: Brain imaging
Link ID: 28227 - Posted: 03.02.2022

By Kim Tingley Denis Burkitt, an Irish surgeon, traveled to Africa during World War II as a member of the Royal Army Medical Corps, and afterward he settled in Uganda to practice medicine. There he observed that a surprising number of children developed strange jaw tumors, a cancer that would come to be known as Burkitt lymphoma. Eventually, Burkitt sent samples of the tumor cells to Middlesex Hospital Medical School in London, where Michael Anthony Epstein, a pathologist, and his colleagues Yvonne Barr and Bert Achong examined them through an electron microscope. Their findings — they noticed particles shaped like a herpesvirus, only smaller — were published in a landmark paper in The Lancet in 1964 and spurred the realization that this newly identified member of the Herpes​viridae family, subsequently named Epstein-Barr virus, was a cause of Burkitt lymphoma. It was the first evidence that a viral infection could lead to cancer. The virus has since been shown to increase the risk of Hodgkin lymphoma, as well as nasopharyngeal and stomach cancer. It is also the virus most often responsible for infectious mononucleosis, a disease usually characterized by extreme fatigue, sore throat, fever and swollen lymph nodes in the neck. These symptoms can last for weeks and, in chronic cases, recur for years. We now know that upward of 90 percent of adults have the Epstein-Barr virus. As happens with other herpes​viruses, once you have been infected, the virus stays with you forever — it deposits its DNA alongside yours in the nucleus of many of your cells. (RNA viruses, like SARS-CoV-2, can be cleared from your body.) Most people contract Epstein-Barr in childhood: It is spread through body fluids, usually saliva; kissing is a frequent route of transmission (as may be the sharing of utensils). Young children, if they get sick at all, typically develop symptoms indistinguishable from those of a cold or flu; mono is more common when the first infection happens after puberty. “Most people never know they’re infected,” says Jeffrey Cohen, the chief of the Laboratory of Infectious Diseases at the National Institute of Allergy and Infectious Diseases. © 2022 The New York Times Company

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 28223 - Posted: 02.26.2022

Natalia Mesa More than a decade ago, scientists developed optogenetics, a method to turn cells on and off with light. The technique allows scientists to spur or suppress cells' electrical activity with just the flip of a switch to tease apart the roles of specific cell types. But because light doesn’t penetrate deep into tissues, scientists need to surgically implant light sources to illuminate cells below the surface of the skin or skull. In a new study published today (February 9) in Nature Communications, researchers report they’ve found a way to use ultrasound to noninvasively activate mouse neurons, both in culture and in the brains of living animals. The technique, which the authors call sonogenetics, elicits electrical activity in a subset of brain cells that have been genetically engineered to respond to sound waves. “We know that ultrasound is safe,” study coauthor Sreekanth Chalasani, a neuroscientist in Salk’s Molecular Neurobiology Laboratory, tells The Scientist. “The potential for neuronal control is huge. It has applications for pacemakers, insulin pumps, and other therapies that we’re not even thinking about. Jamie Tyler, a biomedical engineer at the University of Alabama at Birmingham who was not involved in the study but has previously collaborated with some of its authors, tells The Scientist that the work represents “more than just a step forward” in being able to use ultrasound to control neural activity: “It shows that sonogenetics is a viable technique in mammalian cells.” © 1986–2022 The Scientist.

Keyword: Brain imaging
Link ID: 28199 - Posted: 02.12.2022

Anastasia Brodovskaya Jaideep Kapur Epilepsy is a disease marked by recurrent seizures, or sudden periods of abnormal, excessive or synchronous neuronal activity in the brain. One in 26 people in the U.S. will develop epilepsy at some point in their life. While people with mild seizures might experience a brief loss of awareness and muscle twitches, more severe seizures could last for several minutes and lead to injury from falling down and losing control of their limbs. Many people with epilepsy also experience memory problems. Patients often experience retrograde amnesia, where they cannot remember what happened immediately before their seizure. Electroconvulsive therapy, a form of treatment for major depression that intentionally triggers small seizures, can also cause retrograde amnesia. So why do seizures often cause memory loss? We are neurology researchers who study the mechanisms behind how seizures affect the brain. Our brain-mapping study found that seizures affect the same circuits of the brain responsible for memory formation. Understand new developments in science, health and technology, each week One of the earliest descriptions of seizures was written on a Babylonian tablet over 3,000 years ago. Seizures can be caused by a number of factors, ranging from abnormalities in brain structure and genetic mutations to infections and autoimmune conditions. Often, the root cause of a seizure isn’t known. The most common type of epilepsy involves seizures that originate in the brain region located behind the ears, the temporal lobe. Some patients with temporal lobe epilepsy experience retrograde amnesia and are unable to recall events immediately before their seizure. © 2010–2022, The Conversation US, Inc.

Keyword: Epilepsy; Learning & Memory
Link ID: 28187 - Posted: 02.05.2022

Rupert Neate The billionaire entrepreneur Elon Musk’s brain chip startup is preparing to launch clinical trials in humans. Musk, who co-founded Neuralink in 2016, has promised that the technology “will enable someone with paralysis to use a smartphone with their mind faster than someone using thumbs”. The Silicon Valley company, which has already successfully implanted artificial intelligence microchips in the brains of a macaque monkey named Pager and a pig named Gertrude, is now recruiting for a “clinical trial director” to run tests of the technology in humans. “As the clinical trial director, you’ll work closely with some of the most innovative doctors and top engineers, as well as working with Neuralink’s first clinical trial participants,” the advert for the role in Fremont, California, says. “You will lead and help build the team responsible for enabling Neuralink’s clinical research activities and developing the regulatory interactions that come with a fast-paced and ever-evolving environment.” Musk, the world’s richest person with an estimated $256bn fortune, said last month he was cautiously optimistic that the implants could allow tetraplegic people to walk. “We hope to have this in our first humans, which will be people that have severe spinal cord injuries like tetraplegics, quadriplegics, next year, pending FDA [Food and Drug Administration] approval,” he told the Wall Street Journal’s CEO Council summit. “I think we have a chance with Neuralink to restore full-body functionality to someone who has a spinal cord injury. Neuralink’s working well in monkeys, and we’re actually doing just a lot of testing and just confirming that it’s very safe and reliable and the Neuralink device can be removed safely.” © 2022 Guardian News & Media Limited

Keyword: Brain imaging; Robotics
Link ID: 28164 - Posted: 01.22.2022

By Gina Kolata For decades, researchers have suspected that people infected with an exceedingly common virus, Epstein-Barr, might be more likely to develop multiple sclerosis, a neurological illness that affects a million people in the United States. Now, a team of researchers reports what some say is the most compelling evidence yet of a strong link between the two diseases. The virus infects nearly everyone in their teen or young adult years, and very few go on to develop multiple sclerosis. The researchers also note that it is not the only known risk factor for people who develop the illness. But they say their data points to it being the clearest of them all. While it remains to be seen whether the finding will result in treatments or cures for multiple sclerosis, the study may further motivate research into therapies and vaccines for the condition. In their study, published Thursday in Science, the group examined data from 10 million people on active duty in the United States Armed Forces over two decades. The strength of their study, said its principal investigator, Dr. Alberto Ascherio, an epidemiologist at the Harvard T.H. Chan School of Public Health, is that they were able to follow people for years and ask whether infections with Epstein-Barr preceded multiple sclerosis. Among the service members in the study, 801 developed multiple sclerosis, a disabling disease that occurs when the immune system attacks the fatty insulation that protects nerves in the brain and spinal cord. Most who develop the disease are diagnosed between the ages of 20 and 50. The disease is rare, though — an individual’s chance of getting multiple sclerosis is half of one percent. At the same time, the virus in question, Epstein-Barr, is common, infecting nearly everyone in the population at some point. Although few are aware that they were infected, some develop mononucleosis. The virus remains in the body for life. © 2022 The New York Times Company

Keyword: Multiple Sclerosis; Neuroimmunology
Link ID: 28154 - Posted: 01.15.2022

by Anna Goshua A variety of traits, including developmental delay and intellectual disability, characterize people with mutations in the autism-linked gene MYT1L, according to a new study. The gene encodes a transcription factor important for cells that make myelin, which insulates nerve cells and is deficient in some forms of autism. The work, published 8 November in Human Genetics, represents the most detailed study of the traits associated with MYT1L mutations to date. “We wanted to gather more cases to bring a clearer clinical and molecular picture of the condition for lab scientists, clinicians and also for patients and families,” says study investigator Juliette Coursimault, a physician-researcher in the genetics department at Rouen University Hospital in France. She and her co-researchers described 62 people, whereas previous literature included only 12 cases. The new characterization will “benefit clinicians’ diagnosis and treatment strategies when a patient with MYT1L mutation arrives in their clinic,” says Brady Maher, a lead investigator at the Lieber Institute for Brain Development at Johns Hopkins University in Baltimore, Maryland, who was not part of the study. The researchers identified and reviewed data for 22 people with MYT1L mutations who had been described in the academic literature, and collected clinical and molecular data from an additional 40 people, aged 1 to 34 years old, with likely or confirmed pathogenic variants of MYT1L. They recruited the participants through Rouen University Hospital and data-sharing networks such as GeneMatcher, which connects clinicians and researchers. © 2021 Simons Foundation

Keyword: Autism; Genes & Behavior
Link ID: 28122 - Posted: 12.22.2021

by Anna Goshua Mice that lack one copy of TBX1, a gene in the autism-linked 22q11.2 chromosomal region, produce too little myelin — the fatty insulation that surrounds neurons — and perform poorly on tasks that measure cognitive speed, according to a new study. The work, published 5 November in Molecular Psychiatry, may offer insight into the mechanisms that underlie impaired cognitive function in some people with a 22q11.2 deletion, and possibly other copy number variants (CNVs). “The myelin changes could potentially emerge as a common neuronal deficit that mediates cognitive changes among many CNV cases,” says lead investigator Noboru Hiroi, professor of pharmacology at the University of Texas Health Science Center at San Antonio. Neuronal axons — the projections that conduct nerve impulses — are coated with myelin, which serves to speed up electrical transmission. The brains of autistic people and several mouse models of autism have disruptions in myelin, previous research has shown. These connecting fibers are the “highways of the brain,” says Valerie Bolivar, research scientist at the New York State Department of Health’s Wadsworth Center in Albany. “If the highway doesn’t work, you can’t get your goods from one place to another as fast.” TBX1 encodes a protein that regulates the expression of other genes during brain development. Deleting one copy of TBX1 leads to social and communication deficits in mice, according to previous studies by Hiroi’s team. © 2021 Simons Foundation

Keyword: Autism; Glia
Link ID: 28103 - Posted: 12.08.2021

By Kelly Servick For patients whose depression resists treatment with drugs and electroconvulsive therapy, surgically implanted wires that stimulate the brain might bring relief. But in recent years, two randomized, controlled trials of this approach, known as deep brain stimulation (DBS), were halted after underwhelming results in interim analyses. “It was like the air was let out of the room,” Sameer Sheth, a neurosurgeon at Baylor College of Medicine, says of those results. “It was a big let-down.” Now, researchers are testing more sophisticated, personalized DBS techniques they hope will yield stronger results. The tests to date have involved just one or a few patients, far from proof of effectiveness. But researchers hope they’ll inform larger studies that finally cement the effectiveness of DBS in depression. “With all these irons in the fire … we will hopefully build up enough understanding and evidence,” says Sheth, an author of a case study published this week. DBS is already approved in the United States to treat epilepsy, obsessive compulsive disorder, and movement disorders such as Parkinson’s disease. Could it also shift patterns of abnormal activity in neural circuits that may drive depression symptoms? Early studies without control groups yielded promising results, but two randomized, controlled trials, sponsored by the medical device companies Medtronic and St. Jude Medical, Inc. (which was later acquired by Abbott Laboratories) did not show significant benefits after several months of DBS, teams reported in 2015 and 2017. Long-term follow-up of participants has revived some optimism. For example, many people in the 30-participant Medtronic trial improved over 1 year or more—beyond the timeline of the initial study, says Stanford University psychiatrist Mahendra Bhati, a co-investigator. Last month, he and colleagues published a follow-up study of eight trial patients, most of whom continue to use their implant about 10 years later. About one-half have had at least a 50% improvement over their pretreatment score on a depression scale. © 2021 American Association for the Advancement of Science.

Keyword: Depression
Link ID: 28089 - Posted: 11.24.2021

Allison Whitten Every time a human or machine learns how to get better at a task, a trail of evidence is left behind. A sequence of physical changes — to cells in a brain or to numerical values in an algorithm — underlie the improved performance. But how the system figures out exactly what changes to make is no small feat. It’s called the credit assignment problem, in which a brain or artificial intelligence system must pinpoint which pieces in its pipeline are responsible for errors and then make the necessary changes. Put more simply: It’s a blame game to find who’s at fault. AI engineers solved the credit assignment problem for machines with a powerful algorithm called backpropagation, popularized in 1986 with the work of Geoffrey Hinton, David Rumelhart and Ronald Williams. It’s now the workhorse that powers learning in the most successful AI systems, known as deep neural networks, which have hidden layers of artificial “neurons” between their input and output layers. And now, in a paper published in Nature Neuroscience in May, scientists may finally have found an equivalent for living brains that could work in real time. A team of researchers led by Richard Naud of the University of Ottawa and Blake Richards of McGill University and the Mila AI Institute in Quebec revealed a new model of the brain’s learning algorithm that can mimic the backpropagation process. It appears so realistic that experimental neuroscientists have taken notice and are now interested in studying real neurons to find out whether the brain is actually doing it. Simons Foundation All Rights Reserved © 2021

Keyword: Learning & Memory
Link ID: 28044 - Posted: 10.20.2021

By Dave Itzkoff Selma Blair could only talk for a half-hour in our first session. That was as long as she trusted her brain and her body to cooperate — any longer and she feared that her focus might start to wander or her speech might begin to trail. “We’re being responsible in knowing that smaller moments will be clearer moments,” she said. For Blair no day is free from the effects of multiple sclerosis, the autoimmune disease that she learned she had in 2018 but that she believes began attacking her central nervous system many years earlier. This particular Friday in September had started out especially tough: She said she woke up in her Los Angeles home feeling “just bad as all get out,” but she found that talking with people helped alleviate her discomfort. Blair said she had had good conversations earlier in the day and that she had been looking forward to ours. So, if she needed to take a break during this interview, she said with a delighted cackle, “it just means you’re boring me.” An unparalleled lack of inhibition has always defined Blair’s best-known work. She is 49 now, with a résumé that includes seminal works of teensploitation (“Cruel Intentions”), comedy (“Legally Blonde”) and comic-book adventure (“Hellboy”). ImageBlair in one of her signature roles, as a fellow law student opposite Reese Witherspoon in “Legally Blonde.” That same unbridled bluntness persists in all her interactions, whether scripted or spontaneous, with cameras on or off, even when she is sharing her account of the time she went on “The Tonight Show” wearing a strappy top she accidentally put on sideways. It is a story she told me proudly, within five minutes of our introduction on a video call, while her fingers made a maelstrom of her close-cropped, bleached-blond hair. (By way of explaining this style choice, she burst into a brassy, Ethel Merman-esque voice and sang, “I want to be a shiksa.”) But Blair’s candor has come to mean something more in the three years since she went public about her M.S. diagnosis. Now, whether she is posting personal diaries on social media or appearing on a red carpet, she understands she is a representative with an opportunity to educate a wider audience about what she and others with M.S. are experiencing. © 2021 The New York Times Company

Keyword: Multiple Sclerosis
Link ID: 28030 - Posted: 10.13.2021