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Category: neuroscience – Page 160

A quantitative theory unlocks the mysteries of why we sleep

Comparing our findings across species with those across growth led us to a final question. If the purpose of sleep shifts from being about neural reorganisation as children to being about repair once we’re grown, when exactly does that transition occur, and how sudden is it? Armed with our new theory plus human developmental data, we could answer this question with surprising accuracy: the transition occurs when we’re extremely young – at about 2.5 years of age – and it happens extremely abruptly, like water freezing at 0°C.

We were delighted with this stunning result. First, it gave us an even greater appreciation for the critical importance of sleep: never again would we underestimate its importance for our children, especially in their first few years of life when their sleep is doing something so fundamentally different and extraordinarily important, something that seemingly can’t be made up for later in life. Second, we had discovered that these two states of sleep, while they looked remarkably similar from the outside, are actually analogous to completely different states of matter before and after the stark dividing line of 2.5 years of age. Before 2.5 years, our brains are more fluid and plastic, enabling us to learn and adapt quickly, similar to the state of water flowing around obstacles. After 2.5 years, our brains are much more crystalline and frozen, still capable of learning and adapting but more like glaciers slowly pushing across a landscape.

Many questions still remain. How much does sleep vary across humans and across species? Can this early fluid phase of sleep be extended? Is this phase already extended or shortened in some individuals, and what costs or benefits are associated with that? What other functions of sleep have piggybacked on to the primary functions of repair and neural reorganisation? How do the different reasons for sleep compete for or share sleep time, either across ages or even within a single night? It will take much more work to fully unravel the mysteries of sleep, but our recent insights – about age-based shifts in the purpose of sleep and the mathematical, predictive theories that quantify them – represent an essential tool to plumb these depths even further.

Looking to study neurological conditions, researchers produce over 400 different types of nerve cells

Nerve cells are not just nerve cells. Depending on how finely we distinguish, there are several hundred to several thousand different types of nerve cells in the human brain, according to the latest calculations. These cell types vary in their function, in the number and length of their cellular appendages, and in their interconnections. They emit different neurotransmitters into our synapses, and depending on the region of the brain—for example, the cerebral cortex or the midbrain—different cell types are active.

When scientists produced from in Petri dishes for their experiments in the past, it was not possible to take their vast diversity into account. Until now, researchers had only developed procedures for growing a few dozen different types of nerve cell in vitro. They achieved this using or by adding signaling molecules to activate particular cellular signaling pathways. However, they never got close to achieving the diversity of hundreds or thousands of different nerve cell types that actually exist.

“Neurons derived from stem cells are frequently used to study diseases. But up to now, researchers have often ignored which precise types of neuron they are working with,” says Barbara Treutlein, Professor at the Department of Biosystems Science and Engineering at ETH Zurich in Basel.

From injury to agony: Scientists discover brain pathway that turns pain into suffering

Pain isn’t just a physical sensation—it also carries emotional weight. That distress, anguish, and anxiety can turn a fleeting injury into long-term suffering.

Researchers at the Salk Institute have now identified a that gives physical pain its emotional tone, revealing a new potential target for treating chronic and affective pain conditions such as fibromyalgia, migraine, and post-traumatic stress disorder (PTSD).

Published in Proceedings of the National Academy of Sciences, the study identifies a group of neurons in a central brain area called the thalamus that appears to mediate the emotional (affective) side of pain in mice. This new pathway challenges the textbook understanding of how pain is processed in the brain and body.

The brain can selectively recognize glucose, offering clues to treat obesity and diabetes

Starting with the question “How does our brain distinguish glucose from the many nutrients absorbed in the gut?” a KAIST research team has demonstrated that the brain can selectively recognize specific nutrients—particularly glucose—beyond simply detecting total calorie content. Their study, published in Neuron, is expected to offer a new paradigm for appetite control and the treatment of metabolic diseases.

Professor Greg S.B. Suh’s team in the Department of Biological Sciences, in collaboration with Professor Young-Gyun Park’s team (BarNeuro), Professor Seung-Hee Lee’s team (Department of Biological Sciences), and the Albert Einstein College of Medicine in New York, have identified the existence of a gut– circuit that allows animals in a hungry state to selectively detect and prefer glucose in the gut.

Organisms derive energy from various nutrients, including sugars, proteins, and fats. Previous studies have shown that total caloric information in the gut suppresses hunger neurons in the hypothalamus to regulate appetite. However, the existence of a gut–brain circuit that specifically responds to glucose and corresponding brain cells had not been demonstrated until now.

Computational models explore how regions of the visual cortex jointly represent visual information

Understanding how the human brain represents the information picked up by the senses is a longstanding objective of neuroscience and psychology studies. Most past studies focusing on the visual cortex, the network of regions in the brain’s outer layer known to process visual information, have focused on the contribution of individual regions, as opposed to their collective representation of visual stimuli.

Researchers at Freie Universität Berlin recently carried out a study aimed at shedding new light on how regions across the human visual cortex collectively encode and process visual information, by simulating their contribution using computational models. Their findings, published in Nature Human Behaviour, highlight specific rules that could govern the relations between these different regions of the visual cortex.

“Most of us take seeing for granted, but the process is surprisingly complex,” Alessandro Gifford, first author of the paper, told Medical Xpress. “When we look at the world, it’s not just our eyes doing the work—it’s our brain, specifically an area at the back called the visual cortex. Think of the visual cortex as a team of specialists. Each member of the team (or brain region) handles a different aspect of what we see—one might focus on shapes, another on motion, another on faces.”

Cheap Daily Supplement Appears to Boost Brain Function in Older People

What’s good for your aging gut may also be good for your aging brain. The first study of its kind in twins found that taking daily protein and prebiotic supplements can improve scores on memory tests in people over the age of 60.

Published early last year, the findings are food for thought, especially as the same visual memory and learning test is used to detect early signs of Alzheimer’s disease.

The double-blinded trial involved two cheap plant fiber prebiotics that are available over the counter in numerous nations around the world.

Peripheral nerve regeneration driven by hundreds of unknown RNA molecules

Unlike the brain and spinal cord, peripheral nerve cells, whose long extensions reach the skin and internal organs, are capable of regenerating after injury. This is why injuries to the central nervous system are considered irreversible, while damage to peripheral nerves can, in some cases, heal, even if it takes months or years. Despite decades of research, the mechanisms behind peripheral nerve regeneration remain only partially understood.

In a new study published in Cell, researchers from Prof. Michael (Mike) Fainzilber’s lab at the Weizmann Institute of Science discovered that a family of hundreds of RNA molecules with no known physiological function is essential to nerve .

Remarkably, the study showed that these molecules can stimulate growth not only in the peripheral nervous system of mice but also in their central nervous system. These findings could pave the way for new treatments for a variety of nerve injuries and neurodegenerative diseases.

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