. Scientific Frontline: Neuroscience
Showing posts with label Neuroscience. Show all posts
Showing posts with label Neuroscience. Show all posts

Monday, March 18, 2024

Two artificial intelligences talk to each other

A UNIGE team has developed an AI capable of learning a task solely on the basis of verbal instructions. And to do the same with a «sister» AI.
Prompts by Scientific Frontline
Image Credit: AI Generated by Copilot / Designer / DALL-E

Performing a new task based solely on verbal or written instructions, and then describing it to others so that they can reproduce it, is a cornerstone of human communication that still resists artificial intelligence (AI). A team from the University of Geneva (UNIGE) has succeeded in modelling an artificial neural network capable of this cognitive prowess. After learning and performing a series of basic tasks, this AI was able to provide a linguistic description of them to a ‘‘sister’’ AI, which in turn performed them. These promising results, especially for robotics, are published in Nature Neuroscience.

Performing a new task without prior training, on the sole basis of verbal or written instructions, is a unique human ability. What’s more, once we have learned the task, we are able to describe it so that another person can reproduce it. This dual capacity distinguishes us from other species which, to learn a new task, need numerous trials accompanied by positive or negative reinforcement signals, without being able to communicate it to their congeners.

A sub-field of artificial intelligence (AI) - Natural language processing - seeks to recreate this human faculty, with machines that understand and respond to vocal or textual data. This technique is based on artificial neural networks, inspired by our biological neurons and by the way they transmit electrical signals to each other in the brain. However, the neural calculations that would make it possible to achieve the cognitive feat described above are still poorly understood.

Wednesday, March 13, 2024

The integrity of the blood-brain barrier depends on a protein that is altered in some neurodegenerative diseases

From left to right, Pilar Villacampa, Víctor Arribas and Eloi Montañez.
Photo Credit: Courtesy of University of Barcelona

Defects in the blood vessel network of the central nervous system have been linked to early symptoms of neurodegenerative diseases such as Alzheimer's disease and amyotrophic lateral sclerosis (ALS). It is this complex vascular network that provides the necessary nutrients, especially glucose and oxygen to activate all neuronal functions. Now, a study led by the University of Barcelona and the Bellvitge Biomedical Research Institute (IBIDELL) reveals that the TDP-43 protein is essential for forming a stable and mature blood vessel network in the central nervous system.

According to the study the TDP-43 protein is also critical in maintaining the integrity of the blood-brain barrier, which prevents toxins and pathogens from reaching the central nervous system.

The project is led by Professor Eloi Montañez, from the Faculty of Medicine and Health Sciences of the University of Barcelona and IDIBELL, and involves teams from the Faculty of Biology and the Institute of Biomedicine of the UB (IBUB), the Josep Carreras Leukemia Research Institute, and the National Centre for Genomic Analysis (CNAG-CRG).

Monday, March 11, 2024

Brain Waves Travel in One Direction When Memories Are Made and the Opposite When Recalled

Traveling wave propagation directions in the memory task reveal how the brain quickly coordinates activity and shares information across multiple regions.
Photo Credit: Hongui Zhang

In the space of just a few seconds, a person walking down a city block might check their phone, yawn, worry about making rent, and adjust their path to avoid a puddle. The smell from a food cart could suddenly conjure a memory from childhood, or they could notice a rat eating a slice of pizza and store the image as a new memory. 

For most people, shifting through behaviors quickly and seamlessly is a mundane part of everyday life. 

For neuroscientists, it’s one of the brain’s most remarkable capabilities. That’s because different activities require the brain to use different combinations of its many regions and billions of neurons. How it manages to do this so rapidly has been an open question for decades. 

The study

In a paper published in Nature Human Behaviour, a team of researchers, led by Joshua Jacobs, associate professor of biomedical engineering at Columbia Engineering, shed new light on this question. By carefully monitoring neural activity of people who were recalling memories or forming new ones, the researchers managed to detect how a newly appreciated type of brainwave — traveling waves — influences the storage and retrieval of memories. 

“Broadly, we found that waves tended to move from the back of the brain to the front while patients were putting something into their memory,” said the paper’s co-author Uma R. Mohan, a postdoctoral researcher at NIH and former postdoctoral researcher in the Electrophysiology, Memory, and Navigation Laboratory at Columbia Engineering. “When patients were later searching to recall the same information, those waves moved in the opposite direction, from the front towards the back of the brain,” she said. 

Researchers uncover protein responsible for cold sensation

Image Credit: Copilot AI Generated 

University of Michigan researchers have identified the protein that enables mammals to sense cold, filling a long-standing knowledge gap in the field of sensory biology.

The findings, published in Nature Neuroscience, could help unravel how we sense and suffer from cold temperatures in the winter, and why some patients experience cold differently under particular disease conditions.

“The field started uncovering these temperature sensors over 20 years ago, with the discovery of a heat-sensing protein called TRPV1,” said neuroscientist Shawn Xu, a professor at the U-M Life Sciences Institute and a senior author of the new research.

“Various studies have found the proteins that sense hot, warm, even cool temperatures—but we’ve been unable to confirm what senses temperatures below about 60 degrees Fahrenheit.”

In a 2019 study, researchers in Xu’s lab discovered the first cold-sensing receptor protein in Caenorhabditis elegans, a species of millimeter-long worm that the lab studies as a model system for understanding sensory responses.

Saturday, March 9, 2024

What Makes Birds So Smart?

The avian brain is smaller than that of many mammals, but just as capable.
Photo Credit: Kevin Mueller

Researchers at Ruhr University Bochum explain how it is possible for the small brains of pigeons, parrots and corvids to perform equally well as those of mammals, despite their significant differences.

Since the late 19th century, it has been a common belief among researchers that high intelligence requires the high computing capacity of large brains. They also discovered that the cerebral cortex as typical of mammals, is necessary to analyze and link information in great detail. Avian brains, by contrast, are very small and lack any structure resembling a cortex. Nevertheless, scientists showed that parrots and corvids are capable of planning for the future, forging social strategies, recognizing themselves in the mirror and building tools. These and similar aptitudes put them on a par with chimpanzees. Even less gifted birds, such as pigeons, learn orthographic rules that enable them to recognize typos in short words or classify pictures according to categories such as “impressionism”, “water” or “man-made”. How do they do it with such small brains and without a cortex? With their article in Trends in Cognitive Science, Professor Onur Güntürkün, Dr. Roland Pusch and Professor Jonas Rose from Ruhr University Bochum come closer to solving this more than one hundred-year-old puzzle.

How the Body Copes With Airway Closure

Image Credit: Scientific Frontline stock image

There is perhaps no bodily function more essential for humans and other mammals than breathing. With each breath, we suffuse our bodies with oxygen-rich air that keeps our organs and tissues healthy and working properly — and without oxygen, we can survive mere minutes.

But sometimes, our breathing becomes restricted, whether due to infection, allergies, exercise, or some other cause, forcing us to take deep, gasping breaths to quickly draw in more air.

Now, researchers at Harvard Medical School have identified a previously unknown way in which the body counteracts restricted breathing — a new reflex of the vagus nerve that initiates deep breathing. Their work is published in Nature.

The research, conducted in mice, reveals a rare and mysterious cell type in the lungs that detects airway closure and relays the signal to the vagus nerve — the information highway that connects the brain to almost every major organ. After the signal reaches the brain, a gasping reflex is initiated that helps the animal compensate for the lack of air.

Tuesday, March 5, 2024

Earliest-yet Alzheimer’s biomarker found in mouse model could point to new targets

Illinois graduate student Yeeun Yook, left, and professor Nien-Pei Tsai worked with their team to find the earliest marker of Alzheimer’s disease yet reported in the brains of mice. The work could create new targets for early detection or treatment options.
Photo Credit: Fred Zwicky

A surge of a neural-specific protein in the brain is the earliest-yet biomarker for Alzheimer’s disease, report University of Illinois Urbana-Champaign researchers studying a mouse model of the disease. Furthermore, the increased protein activity leads to seizures associated with the earliest stages of neurodegeneration, and inhibiting the protein in the mice slowed the onset and progression of seizure activity. 

The neural-specific protein, PSD-95, could pose a new target for Alzheimer’s research, early diagnosis and treatment, said study leader Nien-Pei Tsai, an Illinois professor of molecular and integrative physiology. 

Tsai’s group studies mice that make more of the proteins that form amyloid-beta, which progressively aggregates in Alzheimer’s disease to form plaques in the brain that hamper neural activity. However, in the new work, the group focused on a time frame much earlier in the mouse lifespan than others have studied – when no other markers or abnormalities have been reported, Tsai said.

Monday, March 4, 2024

Dopamine production is not behind vulnerability to cocaine abuse

Averaged parametric brain maps of [18F]-FDOPA kicer, and index of dopamine synthesis capacity, in high- and low-impulsive rats before and after repeated cocaine self-administration.
Image Credit: © 2024 Urueña-Méndez et al.

Why do some people who try drugs struggle with substance abuse while others don’t? This question has long puzzled scientists. A team from the University of Geneva (UNIGE) explored the complex interplay between personality traits and brain chemistry. The scientists studied the role of impulsivity and the production of dopamine – the so-called "happiness hormone" – in influencing the risk of cocaine abuse. These results, published in eNeuro, offer new keys to understanding vulnerability to drug abuse, which could lead to the development of more targeted interventions for people at risk.

When a person consumes an addictive drug, his or her dopamine release surges, creating a “high” feeling. With repeated drug use, this dopamine release drops, potentially driving the person to increase drug consumption. This mechanism varies between individuals, with some showing a greater propensity to consume the drug while others don’t. However, the reasons for these differences are unknown.

Wednesday, February 28, 2024

Neurons help flush waste out of brain during sleep

Researchers at Washington University School of Medicine in St. Louis have found that brain cell activity during sleep is responsible for propelling fluid into, through and out of the brain, cleaning it of debris.
Image Credit: Scientific Frontline stock image.

There lies a paradox in sleep. Its apparent tranquility juxtaposes with the brain’s bustling activity. The night is still, but the brain is far from dormant. During sleep, brain cells produce bursts of electrical pulses that cumulate into rhythmic waves — a sign of heightened brain cell function.

But why is the brain active when we are resting?

Slow brain waves are associated with restful, refreshing sleep. And now, scientists at Washington University School of Medicine in St. Louis has found that brain waves help flush waste out of the brain during sleep. Individual nerve cells coordinate to produce rhythmic waves that propel fluid through dense brain tissue, washing the tissue in the process.

“These neurons are miniature pumps. Synchronized neural activity powers fluid flow and removal of debris from the brain,” explained first author Li-Feng Jiang-Xie, a postdoctoral research associate in the Department of Pathology & Immunology. “If we can build on this process, there is the possibility of delaying or even preventing neurological diseases, including Alzheimer’s and Parkinson’s disease, in which excess waste — such as metabolic waste and junk proteins — accumulate in the brain and lead to neurodegeneration.”

Monday, February 26, 2024

Gut-brain communication turned on its axis

How the gut communicates with the brain
Image Credit: Copilot AI

The mechanisms by which antidepressants and other emotion-focused medications work could be reconsidered due to an important new breakthrough in the understanding of how the gut communicates with the brain.

New research led by Flinders University has uncovered major developments in understanding how the gut communicates with the brain, which could have a profound impact on the make-up and use of medications such as antidepressants.

“The gut-brain axis consists of complex bidirectional neural communication pathway between the brain and the gut, which links emotional and cognitive centers of the brain,” says Professor Nick Spencer from the College of Medicine and Public Health.

“As part of the gut-brain axis, vagal sensory nerves relay a variety of signals from the gut to the brain that play an important role in mental health and wellbeing.

“The mechanisms by which vagal sensory nerve endings in the gut wall are activated has been a major mystery but remains of great interest to medical science and potential treatments for mental health and wellbeing.”

Human stem cells coaxed to mimic the very early central nervous system

Jianping Fu, Ph.D., Professor of Mechanical Engineering at the University of Michigan and the corresponding author of the paper being published at Nature discusses his team’s work in their lab with Jeyoon Bok, Ph.D. candidate at the Department of Mechanical Engineering.
Photo Credit: Marcin Szczepanski, Michigan Engineering

The first stem cell culture method that produces a full model of the early stages of the human central nervous system has been developed by a team of engineers and biologists at the University of Michigan, the Weizmann Institute of Science, and the University of Pennsylvania.

“Models like this will open doors for fundamental research to understand early development of the human central nervous system and how it could go wrong in different disorders,” said Jianping Fu, U-M professor of mechanical engineering and corresponding author of the study in Nature.

The system is an example of a 3D human organoid—stem cell cultures that reflect key structural and functional properties of human organ systems but are partial or otherwise imperfect copies.

“We try to understand not only the basic biology of human brain development, but also diseases—why we have brain-related diseases, their pathology, and how we can come up with effective strategies to treat them,” said Guo-Li Ming, who along with Hongjun Song, both Perelman Professors of Neuroscience at UPenn and co-authors of the study, developed protocols for growing and guiding the cells and characterized the structural and cellular characteristics of the model.

Study sheds light on how neurotransmitter receptors transport calcium, a process linked with origins of neurological disease

Illustration Credit: Courtesy of McGill University

A new study from a team of McGill University and Vanderbilt University researchers is shedding light on our understanding of the molecular origins of some forms of autism and intellectual disability.

For the first time, researchers were able to successfully capture atomic resolution images of the fast-moving ionotropic glutamate receptor (iGluR) as it transports calcium. iGluRs and their ability to transport calcium are vitally important for many brain functions such as vision or other information coming from sensory organs. Calcium also brings about changes in the signaling capacity of iGluRs and nerve connections which are a key cellular events that lead to our ability to learn new skills and form memories.

iGluRs are also key players in brain development and their dysfunction through genetic mutations has been shown to give rise to some forms of autism and intellectual disability. However, basic questions about how iGluRs trigger biochemical changes in the brain’s physiology by transporting calcium have remained poorly understood.

In the study, the researchers took millions of snapshots of the iGluR protein in the act of transporting calcium, and unexpectedly discovered a temporary pocket that traps calcium on the outside of the protein. With this information at hand, they then used high-resolution electrophysiological recordings to watch the protein in motion as it transported calcium into the nerve cell.

Arterial Connections Improve Treatment Outcomes Following Stroke

Visualization of the blood vessels in the brain of a patient without early venous filling, meaning without excessive reperfusion of the brain area after removal of the blood clot in the blocked artery.
Image Credit: P. Thurner und Z. Kulcsar, USZ

Blood vessels that cross-connect adjacent arterial trees regulate blood flow to the brain in stroke patients. Researchers at the University of Zurich have now shown that these vessels prevent brain hemorrhage following treatment to remove blood clots. They play a crucial role in the recovery of stroke patients.

Ischemic strokes are a major health burden. They occur when a blood vessel that supplies the brain becomes blocked, impairing blood flow to the brain. As a result, brain tissue suffers from a lack of oxygen and nutrients, which causes symptoms such as paralysis, confusion, dizziness, headache, trouble speaking or even death.

Many stroke patients recover poorly despite timely treatment

To treat these symptoms and restore blood flow to the brain, the obstructed vessel needs to be “declogged”, or recanalized. Contemporary treatments to remove the clot include intravenous thrombolysis or mechanical thrombectomy using a catheter. However, even with timely clot removal, many stroke patients only recover poorly.

The research group of Susanne Wegener, professor at the University of Zurich (UZH) and senior leading physician at the Department of Neurology of the University Hospital Zurich (USZ), has now demonstrated that the outcome of stroke treatments depends on the collateral network. Collaterals are blood vessels that cross-connect adjacent arterial trees, providing potential detour networks in case of a vascular blockage. “These vascular bridges maintain cerebral autoregulation and allow for a slower, gradual reperfusion, which results in smaller infarcts,” says Wegener.

Thursday, February 22, 2024

How bats distinguish different sounds

Seba's short-tailed bat (Carollia perspicillata) filters out important signals from ambient sound and distinguishes between echolocation and communication calls.
Photo Credit: Julio Hechavarría, Goethe University Frankfurt

Bats live in a world of sounds. They use vocalizations both to communicate with their conspecifics and for navigation. For the latter, they emit sounds in the ultrasonic range, which echo and enable them to create an “image" of their surroundings. Neuroscientists at Goethe University Frankfurt have now discovered how Seba's short-tailed bat, a species native to South America, manages to filter out important signals from ambient sound and especially to distinguish between echolocation and communication calls. 

Seba's short-tailed bat (Carollia perspicillata) lives in the subtropical and tropical forests of Central and South America, where it mostly feeds on pepper fruit. The animals spend their days in groups of 10 to 100 individuals in hollow trunks and rocky caverns, and at night they go foraging together. They communicate using sounds that create distinct ambient noise in the colony – like the babble of voices at a lively party. At the same time, the bats also use vocalizations to navigate their surroundings: a phenomenon known as echolocation, for which they emit ultrasonic sounds that reflect off solid surfaces. The animals then assemble these echoes into an “image" of their surroundings. 

Newly discovered brain cells play a key role in right and left turns

Researchers have discovered a new group of neurons in the brainstem which control the right-left circuit.
Graphic Credit: Canva. Courtesy of University of Copenhagen

Researchers have discovered a network of neurons in the brain of mice that help them make right and left turns. In the future, the discovery may be used in treatment for Parkinson’s disease.

Have you ever wondered what happens in the brain when we move to the right or left? Most people don’t; they just do it without thinking about it. But this simple movement is actually controlled by a complex process. 

In a new study, researchers have discovered the missing piece in the complex nerve-network needed for left-right turns. The discovery was made by a research team consisting of Assistant Professor Jared Cregg, Professor Ole Kiehn, and their colleagues from the Department of Neuroscience at the University of Copenhagen. 

In 2020, Ole Kiehn, Jared Creeg and their colleagues identified the ‘brain’s steering wheel’ – a network of neurons in the lower part of the brainstem that commands right- and left- movements when walking. At the time, though, it was not clear to them how this right-left circuit is controlled by other parts of the brain, such as the basal ganglia. 

“We have now discovered a new group of neurons in the brainstem which receives information directly from the basal ganglia and controls the right-left circuit,” Ole Kiehn explains. 

Eventually, this discovery may be able to help people suffering from Parkinson’s disease. The study has been published in the scientific journal Nature Neuroscience.  

Wednesday, February 21, 2024

How Does the Brain Make Decisions?

Image Credit: Generated by HM News with AI in Adobe Firefly

Scientists have gained new insights into how neurons in the brain communicate during a decision, and how the connections between neurons may help reinforce a choice.

The study — conducted in mice and led by neuroscientists at Harvard Medical School — is the first to combine structural, functional, and behavioral analyses to explore how neuron-to-neuron connections support decision-making.

“How the brain is organized to help make decisions is a big, fundamental question, and the neural circuitry — how neurons are connected to one another — in brain areas that are important for decision-making isn’t well understood,” said Wei-Chung Allen Lee, associate professor of neurobiology in the Blavatnik Institute at HMS and professor of neurology at Boston Children’s Hospital. Lee is co-senior author on the paper with Christopher Harvey, professor of neurobiology at HMS, and Stefano Panzeri, professor at University Medical Center Hamburg-Eppendorf.

In the research, mice were tasked with choosing which way to go in a maze to find a reward. The researchers found that a mouse’s decision to go left or right activated sequential groups of neurons, culminating in the suppression of neurons linked to the opposite choice.

These specific connections between groups of neurons may help sculpt decisions by shutting down neural pathways for alternative options, Lee said.

NIH study offers new clues into the causes of post-infectious ME/CFS

In-depth study finds brain, immune, and metabolic abnormalities linked to debilitating chronic disease.
Image Credit: John A Beal
(CC BY 4.0 DEED)

In a detailed clinical study, researchers at the National Institutes of Health have found differences in the brains and immune systems of people with post-infectious myalgic encephalomyelitis/chronic fatigue syndrome (PI-ME/CFS). They also found distinct differences between men and women with the disease. The findings were published in Nature Communications.

“People with ME/CFS have very real and disabling symptoms, but uncovering their biological basis has been extremely difficult,” said Walter Koroshetz, M.D., director of NIH’s National Institute of Neurological Disorders and Stroke (NINDS). “This in-depth study of a small group of people found a number of factors that likely contribute to their ME/CFS. Now researchers can test whether these findings apply to a larger patient group and move towards identifying treatments that target core drivers of the disease.”

A team of multidisciplinary researchers discovered how feelings of fatigue are processed in the brains of people with ME/CFS. Results from functional magnetic resonance imaging (fMRI) brain scans showed that people with ME/CFS had lower activity in a brain region called the temporal-parietal junction (TPJ), which may cause fatigue by disrupting the way the brain decides how to exert effort.

They also analyzed spinal fluid collected from participants and found abnormally low levels of catecholamines and other molecules that help regulate the nervous system in people with ME/CFS compared to healthy controls. Reduced levels of certain catecholamines were associated with worse motor performance, effort-related behaviors, and cognitive symptoms. These findings, for the first time, suggest a link between specific abnormalities or imbalances in the brain and ME/CFS.

Sleep improves ability to recall complex events

Sleep is important for reinforcing complex associations, the basis for completing memories of entire events
Photo Credit: Shane

Researchers have known for some time that sleep consolidates our memories of facts and episodic events. However, the research to date has concentrated mainly on simple associations – that is to say, connections between elements, such as we make when learning new vocabulary. “But in real life, events are generally made up of numerous components – for example, a place, people, and objects – which are linked together in the brain,” explains Dr. Nicolas Lutz from LMU’s Institute of Medical Psychology. These associations can vary in strength and some elements might be connected with each other only indirectly. “Thanks to the neural connections that underlie these associations, a single cue word is often all it takes for somebody to recall not only individual aspects of an event but multiple aspects at once.” This process, which is known as pattern completion, is a fundamental feature of episodic memory. Lutz is lead author of a study recently published in the journal Proceedings of the National Academy of Sciences (PNAS), which investigated the effect of sleep on memory of such complex events.

Tuesday, February 20, 2024

Where Neural Stem Cells Feel at Home

In the laboratory, the Bochum researchers are investigating which environment offers neural stem cells the best chances of survival.
Photo Credit: © RUB, Marquard

Injuries in the central nervous system heal poorly because cavities scar. Researchers hope to remedy this problem by filling the cavities in such a way that stem cells feel comfortable in them.

Researchers from Bochum and Dortmund have created an artificial cell environment that could promote the regeneration of nerves. Usually, injuries to the brain or spinal cord don’t heal easily due to the formation of fluid-filled cavities and scars that prevent tissue regeneration. One starting point for medical research is therefore to fill the cavities with a substance that offers neural stem cells optimal conditions for proliferation and differentiation. The team from Ruhr University Bochum and TU Dortmund University, both in Germany, showed that positively charged hydrogels can promote the survival and growth of stem cells.

Dr. Kristin Glotzbach and Professor Andreas Faissner from the Department of Cell Morphology and Molecular Neurobiology in Bochum cooperated with Professor Ralf Weberskirch and Dr. Nils Stamm from the Faculty of Chemistry and Chemical Biology at TU Dortmund University. The team describes the findings in the American Chemical Society Journal Biomaterials Science and Engineering.

Monday, February 19, 2024

Oregon State study sheds light on links between cognitive and motor skill development in children with autism

Image Credit: Aedrian

A recent study by Oregon State University researchers highlighted the ways motor skills and cognitive skills develop in connection with each other in young children with autism, and found an opportunity for behavioral and physical therapists to work together to improve care.

“We know they’re highly linked, but we often talk about them in different domains,” said study co-author Megan MacDonald, head of the School of Exercise, Sport, and Health Science in OSU’s College of Health. “When we look at wraparound services and talk about academic, social, physical and cognitive services, there’s so much we could do together.”

When assessing, diagnosing and providing services for young children with autism, providers are often siloed from each other, MacDonald said. Occupational and physical therapists focus on fine and gross motor skills, while behavioral therapists focus on emotional regulation and executive function.

But in many situations, the two sides depend on each other, she said. Fine motor skills are closely linked to cognition, such as the combination of moves kids must remember and perform in the correct order to write their name. The gross motor skills used in a playground game of kickball work in tandem with the social and emotional skills used to interact with other students and work as a team.

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Two artificial intelligences talk to each other

A UNIGE team has developed an AI capable of learning a task solely on the basis of verbal instructions. And to do the same with a «sister» A...

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