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Category: neuroscience – Page 854

Scientists Uncover Brain Mechanism That May Explain Why Sleep Helps You Learn

Scientists uncover a potential mechanism behind sleep-induced memory changes.

The morphing structure of the brain’s “cartilage cells” may regulate how memories change while you snooze, according to new research in eNeuro.

Sleep lets the body rest, but not the brain. During sleep, the brain accounts for a day of learning by making strong memories stronger and weak memories weaker, a process known as memory consolidation. But changing memories requires changing synapses, the connections between neurons. Sleep-induced changes need to overcome perineuronal nets, cartilage-like sheaths that not only surround and protect neurons, but also prevent changes in synapses.

Brain cell types identified that may push males to fight and have sex

Two groups of nerve cells may serve as “on-off switches” for male mating and aggression, suggests a new study in rodents. These neurons appear to send signals between two parts of the brain—the back tip, or posterior, of the amygdala and the hypothalamus—that together regulate emotions including fear, anxiety, and aggression.

Led by researchers at NYU Grossman School of Medicine, the study showed that male mice struggled to have sex in experiments that blocked signals from one cell group that communicates with the hypothalamus (MPN-signaling ). When the same signals were instead bolstered, the animals were not only able to mate but would repeatedly court unreceptive females, something they would not do normally.

Similarly, when the action of a second cell group in the amygdala that also communicates with the hypothalamus (VMHvl-signaling cells) was blocked, the rodents attacked unfamiliar males half as often. When these same neurons were triggered, the mice became unusually aggressive, even attacking their female mates and familiar males.

New Argonne supercomputer, built for next-gen AI, will be most powerful in U.S.

“‘Aurora will enable us to explore new frontiers in artificial intelligence and machine learning,’ said Narayanan ‘Bobby’ Kasthuri, assistant professor of neurobiology at the University of Chicago and researcher at Argonne. ‘This will be the first time scientists have had a machine powerful enough to match the kind of computations the brain can do.’”

Super computer Aurora will help map the human brain at “quintillion—or one billion billion—calculations per second, 50 times quicker than today’s most powerful supercomputers.”

Note: the article discusses implications beyond neuroscience.

Argonne, DOE and Intel announce exascale computer built for next-generation AI and machine learning.

Brain Thickness and Connectivity, Not Just Location, Correlates With Behavior

Summary: Cortical thickness and regional brain connectivity pay an equally important role in linking brain and behavior.

Source: Penn State

Most people think of the brain as divided into regions that are each responsible for different functions, such as language and fine motor skills. A new study by Penn State researchers suggests that there’s more to the story: The thickness of the brain’s tissue and a brain region’s connectivity may play an equally important role in linking brain and behavior.

Novel Drug Delivery Particles Use Neurotransmitters as a ‘Passport’ Into the Brain

Summary: Tufts researchers have developed neurotransmitter-lipid hybrids that help transport therapeutic drugs and gene editing proteins across the blood-brain barrier in mice.

Source: Tufts University

Biomedical engineers at the Tufts University School of Engineering have developed tiny lipid-based nanoparticles that incorporate neurotranmitters to help carry drugs, large molecules, and even gene editing proteins across the blood-brain barrier and into the brain in mice. The innovation, published today in Science Advances, could overcome many of the current limitations encountered in delivering therapeutics into the central nervous system, and opens up the possibility of using a wide range of therapeutics that would otherwise not have access to the brain.

The people with hidden immunity against Covid-19

The clues have been mounting for a while. First, scientists discovered patients who had recovered from infection with Covid-19, but mysteriously didn’t have any antibodies against it. Next it emerged that this might be the case for a significant number of people. Then came the finding that many of those who do develop antibodies seem to lose them again after just a few months.

In short, though antibodies have proved invaluable for tracking the spread of the pandemic, they might not have the leading role in immunity that we once thought. If we are going to acquire long-term protection, it looks increasingly like it might have to come from somewhere else.

But while the world has been preoccupied with antibodies, researchers have started to realise that there might be another form of immunity – one which, in some cases, has been lurking undetected in the body for years. An enigmatic type of white blood cell is gaining prominence. And though it hasn’t previously featured heavily in the public consciousness, it may well prove to be crucial in our fight against Covid-19. This could be the T cell’s big moment.

While the latest research suggests that antibodies against Covid-19 could be lost in just three months, a new hope has appeared on the horizon: the enigmatic T cell.

Why the Brain Never Processes the Same Input in the Same Way

Summary: Depending on the network state, certain neurons in the primary somatosensory cortex can be more or less excitable, which shapes stimulus processing in the brain.

Source: Max Planck Institute

Rustling leaves, light rain at the window, a quietly ticking clock – muffled sounds, just above the threshold of hearing. One moment we perceive them, the next we don’t, even if we, or the sounds, don’t seem to change. Many studies have shown that we never process an incoming stimulus, be it a sound, an image, or a touch, in the same way. This is true, even if the stimulus is exactly the same. This occurs because the impact a stimulus makes, on the brain regions that process it, depends on the momentary state of the networks those brain regions belong to. However, the factors that influence and underlie the constantly fluctuating momentary state of the networks and whether these states are random or follow a rhythm, was previously unknown.

Neurotransmitter-derived lipidoids (NT-lipidoids) for enhanced brain delivery through intravenous injection

Utilizing neurotransmitters as a passport into the brain:

Safe and efficient delivery of blood-brain barrier (BBB)–impermeable cargos into the brain through intravenous injection remains a challenge. Here, we developed a previously unknown class of neurotransmitter–derived lipidoids (NT-lipidoids) as simple and effective carriers for enhanced brain delivery of several BBB-impermeable cargos. Doping the NT-lipidoids into BBB-impermeable lipid nanoparticles (LNPs) gave the LNPs the ability to cross the BBB. Using this brain delivery platform, we successfully delivered amphotericin B (AmB), antisense oligonucleotides (ASOs) against tau, and genome-editing fusion protein (−27)GFP-Cre recombinase into the mouse brain via systemic intravenous administration. We demonstrated that the NT-lipidoid formulation not only facilitates cargo crossing of the BBB, but also delivery of the cargo into neuronal cells for functional gene silencing or gene recombination. This class of brain delivery lipid formulations holds great potential in the treatment of central nervous system diseases or as a tool to study the brain function.

BCI training to move a virtual hand reduces phantom limb pain

Objective To determine whether training with a brain–computer interface (BCI) to control an image of a phantom hand, which moves based on cortical currents estimated from magnetoencephalographic signals, reduces phantom limb pain.

Methods Twelve patients with chronic phantom limb pain of the upper limb due to amputation or brachial plexus root avulsion participated in a randomized single-blinded crossover trial. Patients were trained to move the virtual hand image controlled by the BCI with a real decoder, which was constructed to classify intact hand movements from motor cortical currents, by moving their phantom hands for 3 days (“real training”). Pain was evaluated using a visual analogue scale (VAS) before and after training, and at follow-up for an additional 16 days. As a control, patients engaged in the training with the same hand image controlled by randomly changing values (“random training”). The 2 trainings were randomly assigned to the patients. This trial is registered at UMIN-CTR (UMIN000013608).

Results VAS at day 4 was significantly reduced from the baseline after real training (mean [SD], 45.3 [24.2]–30.9 [20.6], 1/100 mm; p = 0.009 < 0.025), but not after random training (p = 0.047 0.025). Compared to VAS at day 1, VAS at days 4 and 8 was significantly reduced by 32% and 36%, respectively, after real training and was significantly lower than VAS after random training (p < 0.01).

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