Posts Tagged ‘brain’


S. Inami et al., “Environmental light is required for maintenance of long-term memory in Drosophila,” J Neurosci, 40:1427–39, 2020.

by Diana Kwon

As Earth rotates around its axis, the organisms that inhabit its surface are exposed to daily cycles of darkness and light. In animals, light has a powerful influence on sleep, hormone release, and metabolism. Work by Takaomi Sakai, a neuroscientist at Tokyo Metropolitan University, and his team suggests that light may also be crucial for forming and maintaining long-term memories.

The puzzle of how memories persist in the brain has long been of interest to Sakai. Researchers had previously demonstrated, in both rodents and flies, that the production of new proteins is necessary for maintaining long-term memories, but Sakai wondered how this process persisted over several days given cells’ molecular turnover. Maybe, he thought, an environmental stimulus, such as the light-dark cycles, periodically triggered protein production to enable memory formation and storage.

Sakai and his colleagues conducted a series of experiments to see how constant darkness would affect the ability of Drosophila melanogaster to form long-term memories. Male flies exposed to light after interacting with an unreceptive female showed reduced courtship behaviors toward new female mates several days later, indicating they had remembered the initial rejection. Flies kept in constant darkness, however, continued their attempts to copulate.

The team then probed the molecular mechanisms of these behaviors and discovered a pathway by which light activates cAMP response element-binding protein (CREB)—a transcription factor previously identified as important for forming long-term memories—within certain neurons found in the mushroom bodies, the memory center in fly brains.

“The fact that light is essential for long-term memory maintenance is fundamentally interesting,” says Seth Tomchick, a neuroscientist at the Scripps Research Institute in Florida who wasn’t involved in the study. However, he adds, “more work will be necessary” to fully characterize the molecular mechanisms underlying these effects.

https://www.the-scientist.com/the-literature/lasting-memories-67441?utm_campaign=TS_DAILY%20NEWSLETTER_2020&utm_source=hs_email&utm_medium=email&utm_content=87927085&_hsenc=p2ANqtz-_7gIn7Nu8ghtWiBtiy6oqTctJuYb31bx6bzhbcV3gVpx0-YoIVNtAhnXXNJT0GC496PAntAiSvYpxLdVAnvITlfOG96g&_hsmi=87927085

Astronauts’ brains increase in volume after long space flights, causing pressure to build up inside their heads. This may explain why some astronauts experience worsened vision after prolonged periods in space.

“This raises additional concerns for long-duration interplanetary travel, such as the future mission to Mars,” says Larry Kramer at the University of Texas Health Science Center at Houston, who led the study.

Kramer and his colleagues scanned the brains of 11 astronauts before they spent about six months on the International Space Station, and at six points over the year after they returned to Earth. They found that all the astronauts had increased brain volume – including white matter, grey matter and cerebrospinal fluid around the brain – after returning from space.

Under normal gravity, it is thought that fluid in the brain naturally moves downwards when we stand upright. But there is evidence that microgravity prevents this, resulting in accumulation of fluid in the brain and skull.

The astronauts’ brain volume increased by 2 per cent on average and the increases were still present one year after they returned to Earth, which could result in higher intracranial pressure, Kramer says. He suspects this might press on the optic nerve, potentially explaining the vision problems frequently reported by astronauts.

Kramer and his team also observed that part of the brain called the pituitary gland was deformed in six out of the 11 astronauts. These results add to a body of evidence suggesting that brain structure can be altered after space flight.

“This study is important because it provides data, for the first time in NASA astronauts, demonstrating the persistence of structural brain changes even up to one year following return to Earth,” says Donna Roberts at the Medical University of South Carolina.

“We are currently working on methods to counteract the changes we are observing in the brain using artificial gravity,” says Kramer. These methods to pull blood back towards the feet could include a human-sized centrifuge that would spin a person around at high speed, or a vacuum chamber around the lower half of the body.

“Hopefully one of these or other methods will be tested in microgravity and show efficacy,” he says.

Journal reference: Radiology, DOI: 10.1148/radiol.2020191413

Read more: https://www.newscientist.com/article/2240405-long-space-flights-can-increase-the-volume-of-astronauts-brains/#ixzz6Jh5CtujT

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by Emma Yasinski

Researchers at RIKEN and the University of Tokyo report the existence of a new class of proteins in Drosophila and human cell extracts that may serve as shields that protect other proteins from becoming damaged and causing disease. An excess of the proteins, known as Hero proteins, was associated with a 30 percent increase in the lifespan of Drosophila, according to the study, which was published last week (March 12) in PLOS Biology.

“The discovery of Hero proteins has far-reaching implications,” says Caitlin Davis, a chemist at Yale University who was not involved in the study, “and should be considered both at a basic science level in biochemistry assays and for applications as a potential stabilizer in protein-based pharmaceuticals.”

Nearly 10 years ago, Shintaro Iwasaki, then a graduate student studying biochemistry at the University of Tokyo, discovered a strangely heat-resistant protein in Drosophila that seemed to help stabilize another protein, Argonaute, in the face of high temperatures that would denature most proteins. Although he didn’t publish the work at the time, Iwasaki called the new type of protein a Heat-resistant obscure (Hero) protein—not because of their ability to rescue Argonaute from destruction, but because in Japan, the term “hero” means “weak or not rigid,” and Hero proteins don’t have stiff 3-D structures like other proteins do.
But recognition of a more widespread role for Hero proteins in protecting other molecules in the cell gives the name new meaning.

“It is generally assumed that proteins are folded into three-dimensional structures, which determine their functions,” says Kotaro Tsuboyama, a biochemist at the University of Tokyo and the lead author of the new study. But these 3-D structures are disrupted when the proteins are exposed to extreme conditions. When proteins are denatured, they lose the ability to function normally, and sometimes begin to aggregate, forming pathologic clumps that can lead to disease.

Hero proteins can survive these biologically challenging conditions. Heat-resistant proteins have been found in extremophiles—organisms known to live in extreme environments—but were thought to be rare in other organisms. In the new study, Tsuboyama and his team boiled lysates from Drosophila and human cell lines, identifying hundreds of Hero proteins that withstood the temperature.

The researchers selected six of these proteins and mixed them with “client” proteins—other functional proteins that on their own would be denatured by extreme conditions—before exposing them to high temperatures, drying, chemicals, and other harsh treatments. The Hero proteins prevented certain clients from losing their shape and function.

Next, the team tested the effects of Hero proteins in cellular models of two neurodegenerative disorders characterized by pathologic protein clumps: Huntington’s disease and amyotrophic lateral sclerosis (ALS). When the Hero proteins were present, there was a significant reduction in protein clumping in both models.

“This is an extremely important finding as it may pave new therapeutic and preventive strategies for neurodegenerative diseases, such as Alzheimer and Parkinson diseases,” Morteza Mahmoudi, who studies regenerative medicine at Michigan State University and was not involved in the research, writes in an email to The Scientist.

Lastly, the team genetically engineered Drosophila to produce an excess of Hero proteins. These flies lived up to 30 percent longer than their wildtype counterparts.

Not everyone is convinced that the Hero proteins play a major protective role. “Although they show these proteins help their proven targets remain folded/shielded etc, I don’t think there’s a broader application at all,” Nihal Korkmaz, who designs proteins at the University of Washington Institute of Protein Design and also did not participate in the study, tells The Scientist in an email. She adds that many proteins she works with can withstand high temperatures and the researchers “don’t mention at all if [Hero proteins] are found throughout the brain or in CSF [cerebrospinal fluid],” where they’d be able to protect against Huntington’s or ALS.

The authors emphasized that there is a lot left to learn about the proteins. Each Hero protein seems able to protect some client proteins, but not all of them. Moreover, amino acid sequences differ considerably between Hero proteins, making it difficult to predict their functions. The researchers write in the study that they hope future studies will help them identify which clients each Hero might work with.

Whatever discoveries future work might hold, Tsuboyama says, the scientific community’s reaction to the team’s new study has been consistent: “Almost everyone says that Hero proteins are interesting but mysterious.”

K. Tsuboyama et al., “A widespread family of heat-resistant obscure (Hero) proteins protect against protein instability and aggregation,” PLOS Biol, doi:10.1371/journal.pbio.3000632, 2020.

https://www.the-scientist.com/news-opinion/hero-proteins-may-shield-other-proteins-from-harm-67293?utm_campaign=TS_OTC_2020&utm_source=hs_email&utm_medium=email&utm_content=86341663&_hsenc=p2ANqtz–kkYtO3Wn5lK7HmDq3SWf1KLtul94Crlb2ELPzvFBQWGep0tFzWAy3UdVi_w7ml_E1bn1g9HU_2SVNp–jib-1JCCU_w&_hsmi=86341663


A patient is moved out of Gateway Care and Rehabilitation Center, a skilled nursing facility in Hayward, Calif., on Thursday.

People with severe COVID-19 may experience neurological symptoms, including confusion, delirium and muscle pain, and could be at higher risk for a stroke, a new study out of Wuhan, China has suggested.

Nearly 40 percent of people with the disease caused by the new coronavirus suffered brain-related complications, according to findings published Friday in JAMA Neurology.

Among those with serious infection as a result of the virus, nearly 6 percent experienced a stroke or stenosis, roughly 15 percent had dementia-like symptoms and roughly 20 percent reported severe muscle pain, researchers in China reported.

“This study indicates that neurological complications are relatively common in people who have COVID-19,” S. Andrew Josephson, professor and chair of the Department of Neurology at the University of California, San Francisco and editor-in-chief of JAMA Neurology, told UPI. Josephson also co-authored a related commentary on the study findings.

“However, the majority of those complications are are also relatively common in people with severe pneumonia and viral infections in hospital intensive care units,” he added.

That includes symptoms such as muscle pain and “confusion or difficulty thinking,” according to Josephson, although he emphasizes that if these neurological issues develop in people who know they have COVID-19 — or have symptoms of the disease and are among those at high risk for serious illness — they should be considered a “red flag like shortness of breath,” he said.

“Somebody who has COVID-19 and is at home and experiences difficulty thinking or confusion or anything that indicates a possible stroke, that is a sign they should come into the hospital for additional care,” Josephson continued. “But a symptom like muscle pain is common in viral infections. People don’t need to come into hospital with that.”

To date, nearly 1.7 million people worldwide have been infected with COVID-19, and nearly 100,000 have died from the disease. Although numbers vary by country and region, it is believed that approximately 20 percent of people infected by the new coronavirus become ill enough to require hospital care, and roughly 5 percent experience life-threatening symptoms, including pneumonia.

Those at highest risk for serious illness are believed to be the elderly, as are people with a history of diabetes, high blood pressure and heart disease. Of course these same people are also at increased risk for cerebrovascular diseases like stroke and stenosis, Josephson noted.

The new study looked at 214 patients with the disease at three Wuhan hospitals, all of whom were hospitalized between Jan. 16 and Feb. 19.

Of the 214 patients, who had mean age of 53, 87 were men and 126, or 59 percent, had severe infection based on respiratory status — with shortness of breath caused by a severe lower respiratory tract infection, like pneumonia.

As in prior studies, those with serious illness were older, had more underlying conditions — particularly high blood pressure — and had fewer typical symptoms of COVID-19, like fever and cough, when compared to patients with mild to moderate infection.

Additionally, 6 percent of patients experienced “taste impairment” and 5 percent had “smell impairment.” What causes people with the virus to experience these neurological complications remains unclear, according to Josephson. Because of the known heart-related complications associated with the virus, it’s possible they are the result of blood clots emanating from the heart, he added.

“As with all of the research coming out about the virus, this study shows we still have a lot more to learn,” Josephson said. “The bottom line is that people should be aware of these neurological symptoms, and seek medical attention if they need it.”

https://www.upi.com/Health_News/2020/04/10/40-of-people-with-severe-COVID-19-experience-neurological-complications/2491586526495/?ur3=1

By Edd Gent

The idea of a machine that can decode your thoughts might sound creepy, but for thousands of people who have lost the ability to speak due to disease or disability it could be game-changing. Even for the able-bodied, being able to type out an email by just thinking or sending commands to your digital assistant telepathically could be hugely useful.

That vision may have come a step closer after researchers at the University of California, San Francisco demonstrated that they could translate brain signals into complete sentences with error rates as low as three percent, which is below the threshold for professional speech transcription.

While we’ve been able to decode parts of speech from brain signals for around a decade, so far most of the solutions have been a long way from consistently translating intelligible sentences. Last year, researchers used a novel approach that achieved some of the best results so far by using brain signals to animate a simulated vocal tract, but only 70 percent of the words were intelligible.

The key to the improved performance achieved by the authors of the new paper in Nature Neuroscience was their realization that there were strong parallels between translating brain signals to text and machine translation between languages using neural networks, which is now highly accurate for many languages.

While most efforts to decode brain signals have focused on identifying neural activity that corresponds to particular phonemes—the distinct chunks of sound that make up words—the researchers decided to mimic machine translation, where the entire sentence is translated at once. This has proven a powerful approach; as certain words are always more likely to appear close together, the system can rely on context to fill in any gaps.

The team used the same encoder-decoder approach commonly used for machine translation, in which one neural network analyzes the input signal—normally text, but in this case brain signals—to create a representation of the data, and then a second neural network translates this into the target language.

They trained their system using brain activity recorded from 4 women with electrodes implanted in their brains to monitor seizures as they read out a set of 50 sentences, including 250 unique words. This allowed the first network to work out what neural activity correlated with which parts of speech.

In testing, it relied only on the neural signals and was able to achieve error rates of below eight percent on two out of the four subjects, which matches the kinds of accuracy achieved by professional transcribers.

Inevitably, there are caveats. Firstly, the system was only able to decode 30-50 specific sentences using a limited vocabulary of 250 words. It also requires people to have electrodes implanted in their brains, which is currently only permitted for a limited number of highly specific medical reasons. However, there are a number of signs that this direction holds considerable promise.

One concern was that because the system was being tested on sentences that were included in its training data, it might simply be learning to match specific sentences to specific neural signatures. That would suggest it wasn’t really learning the constituent parts of speech, which would make it harder to generalize to unfamiliar sentences.

But when the researchers added another set of recordings to the training data that were not included in testing, it reduced error rates significantly, suggesting that the system is learning sub-sentence information like words.

They also found that pre-training the system on data from the volunteer that achieved the highest accuracy before training on data from one of the worst performers significantly reduced error rates. This suggests that in practical applications, much of the training could be done before the system is given to the end user, and they would only have to fine-tune it to the quirks of their brain signals.

The vocabulary of such a system is likely to improve considerably as people build upon this approach—but even a limited palette of 250 words could be incredibly useful to a paraplegic, and could likely be tailored to a specific set of commands for telepathic control of other devices.

Now the ball is back in the court of the scrum of companies racing to develop the first practical neural interfaces.

How a New AI Translated Brain Activity to Speech With 97 Percent Accuracy

Taking up meditation while sheltering-in-place may not only help you cope with the stress of the coronavirus pandemic, it may even keep your brain from aging.

A recently pubished 18-year analysis of the mind of a Buddhist monk by the Center for Healthy Minds at the University of Wisconsin-Madison found daily, intensive meditation slowed the monk’s brain aging by as much as eight years when compared to a control group.

The project started in the 1990s with neuroscientist Richard Davidson’s relationship with the Dalai Lama. Davidson started making connections between positive emotions and brain health, which jump-started research for the study.

“[The Dalai Lama] was really encouraging me to take the practices from this tradition and investigate them with the tools of modern science,” said Davidson, founder and director of the Center for Healthy Minds. “And if we find through these investigations that these practices are valuable to then disseminate them widely.”

The study began with a Buddhist monk

Using MRI and a machine learning framework which estimates “brain-age” from brain imaging, Davidson and lead scientist Nagesh Adluru studied the mind of Tibetan Buddhist meditation master Yongey Mingyur Rinpoche over the course of 18 years.

The goal, Davidson said, was to find out whether there was a difference in the rate of aging between the brains of seasoned meditation masters compared to those who were novice practitioners. Rinpoche was first scanned in 2002 at the age of 27. At the time, he had already completed nine years of meditation retreats. He was scanned again at the respective ages of 30, 32 and 41 years old.

The last time he was scanned, he had just returned from a four-and-a-half-year wandering retreat, and his brain was calculated to be 33-years-old, eight years younger than his biological age.
The researchers compared Rinpoche’s aging brain to a control group and his appeared to age much slower than the general focus group.

The results could have lasting implications on health

The magnitude of the effect was pronounced even with a margin of error that is plus or minus two to three years, Davidson said.

“If these effects accumulate over time, we think there will be very important health and well-being implications.”

Everyone, especially now amid the coronavirus pandemic, can benefit from meditation because it is designed to remind us of our own basic goodness, Davidson said.

“I think what is exciting is the invitation that we can impact our own brain … and change the rate at which it ages through engaging in practices that are nourishing and helpful for our well-being.”

The researchers said they are excited to see how Rinpoche’s brain will continue to develop, and how this data can help improve overall well-being.

https://www.cnn.com/2020/03/20/health/meditation-slows-brain-age-trnd-wellness/index.html