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Category: neuroscience – Page 17

Neural maps used to locate rewards may be disrupted in dementia and heightened in addiction

Imagine you’re walking to work when the unspeakable occurs: Your favorite coffee shop—where you stop every day—is closed. You groggily navigate to a newly opened coffee shop a couple blocks away, which, you’re pleased to discover, actually makes quite a good morning brew. Soon, you find yourself looking forward to stopping at the new location instead of the old one.

That switch probably alters more than just your morning routine. Each time you visit that new coffee shop, the experience likely strengthens a neural map marking the positions of rewarding experiences—a map that can guide you back to those experiences even from miles away.

While the existence of a reward map is familiar from previous work, Wu Tsai Neuro researchers working with were surprised to find that the map persists even when mice move many meters away from a treat, and that it updates almost immediately when the of the treat changes.

Stem cell platform aims to recreate brain’s immune system using lab-grown human microglia cells

Microglia are a specialized type of immune cell that accounts for about 10% of all cells within the brain and spinal cord. They function by eliminating infectious microbes, dead cells, and aggregated proteins, as well as soluble antigens that may endanger the brain and, during development, also help shape neural circuits enabling specific brain functions.

When microglia don’t function properly, they can trigger neuroinflammation and fail to clear away damaged cells and harmful protein clumps—such as the neurofibrillary tangles and amyloid plaques seen in Alzheimer’s disease. This contributes to numerous neurodegenerative diseases, including Alzheimer’s, Parkinson’s and Huntington’s disease, as well as amyotrophic lateral sclerosis (ALS), multiple sclerosis, and other disorders. In fact, neuroinflammation can occur even before proteins start to form pathogenic aggregates and, in turn, accelerates protein aggregation.

Researchers and drug developers aiming to better understand and target microglia functions in the brain are challenged by the fact that human microglia can only be obtained through biopsies, and rodents’ microglia differ from their human counterparts in many critical features. This supply issue prompted them to work on methods to create microglia in the culture dish using stem cells as a starting point. However, to date, this process has remained inefficient, and requires weeks to complete at significant costs.

Tracing brain circuits that tell us when to eat—and when to stop

Scientists know the stomach talks to the brain, but two new studies from Rutgers Health researchers suggest the conversation is really a tug-of-war, with one side urging another bite, the other signaling “enough.”

Together, the papers in Nature Metabolism and Nature Communications trace the first complementary wiring diagram of hunger and satiety in ways that could refine today’s blockbuster weight-loss drugs and blunt their side effects.

One study, led by Zhiping Pang of Robert Wood Johnson Medical School’s Center for NeuroMetabolism, pinpointed a slender bundle of neurons that runs from the hypothalamus to the brainstem.

How the brain synchronizes itself with rhythmic stimuli

Our brain is adept at synchronizing with rhythmic sounds, whether it’s the beat of a song or the steady patter of rain. This ability helps us recognize and process sounds more effectively.

A research team led by the Max Planck Institute for Empirical Aesthetics (MPIEA) in Frankfurt am Main has shown that stimulation with weak electrical currents, known as transcranial alternating current stimulation (tACS), can influence this ability. The new study is published in the journal PLOS Biology.

The study builds on previous work showing that tACS can either enhance or suppress brain rhythms depending on how it’s timed with incoming sound. In order to investigate the interaction between electrical stimulation and brain rhythms, 50 participants took part in three experiments where they listened to noisy sounds and were asked to identify short, barely perceptible pauses. The researchers then transmitted electrical rhythms to the participants’ brains via electrodes placed on their scalps several times to see how this influenced their brain activity.

How the ELAV protein shapes the brain’s unique circular RNA landscape

Deep within our nerve cells, a molecule is at work that has no beginning and no end. Instead of a straight chain, as is common for most RNA strands, it forms a closed loop. Known as circular RNAs (circRNAs), these molecules are crucial for development, thought, and synaptic function, yet their high prevalence in neurons has long been a scientific mystery. How does the brain produce so many of them?

Now, Max Planck researchers from Freiburg have discovered a crucial mechanism that explains the remarkable abundance of circRNAs in the nervous system. Published in Genes & Development, the study reveals that the protein ELAV acts as a global master switch for the production of these molecules.

CircRNAs are found across all life forms. They are expressed in specific patterns during different developmental stages and in different cells—especially abundant in cells of the nervous system. While their roles are not as well-studied as normal, linear RNAs, circRNAs are known to be important in , cognition, and even in conditions like neurodegeneration and addiction.

Fewer than 500 neurons are associated with the suppression of binge drinking, new research finds

Among the billions of neurons in the brain, fewer than 500 are responsible for suppressing binge drinking, according to new research by Gilles E. Martin, Ph.D., associate professor of neurobiology.

Published in Nature Neuroscience, these findings provide insights into binge-drinking behavior and that may lead to new therapeutic targets.

“It’s really hard to comprehend how only a few neurons can have such a profound effect on behavior,” said Dr. Martin, a member of the Brudnick Neuropsychiatric Research Institute at UMass Chan. “This is exciting because we are starting to understand how only a handful of cells are involved in very specific behaviors. Truly, this study is about finding a needle in a haystack.”