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Category: neuroscience – Page 962

Newly discovered organ may be lurking under your skin

Most people who’ve been jabbed by a needle know the drill: First the pierce, then the sharp, searing pain and an urge to pull away, or at least wince. While the exact circuitry behind this nearly universal reaction is not fully understood, scientists may have just found an important piece of the puzzle: a previously unknown sensory organ inside the skin.

Dubbed the nociceptive glio-neural complex, this structure is not quite like the typical picture of a complex organ like the heart or the spleen. Instead, it’s a simple organ made up of a network of cells called glial cells, which are already known to surround and support the body’s nerve cells. In this case, the glial cells form a mesh-like structure between the skin’s outer and inner layers, with filament-like protrusions that extend into the skin’s outer layer. (Also find out about a type of simple organ recently found in humans, called the interstitium.)

As the study team reports today in the journal Science, this humble organ seems to play a key role in the perception of mechanical pain—discomfort caused by pressure, pricking, and other impacts to the skin. Until now, individual cells called nociceptive fibers were thought to be the main starting points for this kind of pain.

Neuroscientists decode brain speech signals into written text

When Stephen Hawking wanted to speak, he chose letters and words from a synthesiser screen controlled by twitches of a muscle in his cheek.

But the painstaking process the cosmologist used might soon be bound for the dustbin. With a radical new approach, doctors have found a way to extract a person’s speech directly from their brain.

The breakthrough is the first to demonstrate how a person’s intention to say specific words can be gleaned from brain signals and turned into text fast enough to keep pace with natural conversation.

Scientists reverse aging process in rat brain stem cells

New research, published today in Nature, reveals how increasing brain stiffness as we age causes brain stem cell dysfunction, and demonstrates new ways to reverse older stem cells to a younger, healthier state.

The results have far reaching implications for how we understand the ageing process, and how we might develop much-needed treatments for age-related diseases.

As our bodies age, muscles and joints can become stiff, making everyday movements more difficult. This study shows the same is true in our brains, and that age-related brain stiffening has a significant impact on the function of brain stem cells.

A Newfound Neuron Might Help Keep the Brain’s Cells in Sync

A long-standing controversy in neuroscience centers on a simple question: How do neurons in the brain share information? Sure, it’s well-known that neurons are wired together by synapses and that when one of them fires, it sends an electrical signal to other neurons connected to it. But that simple model leaves a lot of unanswered questions—for example, where exactly in neurons’ firing is information stored? Resolving these questions could help us understand the physical nature of a thought.

Two theories attempt to explain how neurons encode information: the rate code model and the temporal code model. In the rate code model, the rate at which neurons fire is the key feature. Count the number of spikes in a certain time interval, and that number gives you the information. In the temporal code model, the relative timing between firings matters more—information is stored in the specific pattern of intervals between spikes, vaguely like Morse code. But the temporal code model faces a difficult question: If a gap is “longer” or “shorter,” it has to be longer or shorter relative to something. For the temporal code model to work, the brain needs to have a kind of metronome, a steady beat to allow the gaps between firings to hold meaning.

Every computer has an internal clock to synchronize its activities across different chips. If the temporal code model is right, the brain should have something similar. Some neuroscientists posit that the clock is in the gamma rhythm, a semiregular oscillation of brain waves. But it doesn’t stay consistent. It can speed up or slow down depending on what a person experiences, such as a bright light. Such a fickle clock didn’t seem like the full story for how neurons synchronize their signals, leading to ardent disagreements in the field about whether the gamma rhythm meant anything at all.

The human brain in ‘unprecedented’ detail, thanks to powerful MRI

S cientists are very careful about claiming that no one else has ever done something before — the last thing they need is some overlooked lab saying, um, right here! — but researchers at Massachusetts General Hospital are confident they’re on solid ground. Their high-resolution MRIs of a complete, intact human brain, they say, are “unprecedented.”

Other labs have sliced up brains and seen features down to 80 or even 50 microns. (One micron is a 10,000th of a centimeter, and 75 of them is about the width of a human hair.) The MGH team got 100-micron resolution in a whole brain, producing the most detailed three-dimensional images of an intact brain ever seen.

The scientists started with an MRI machine with a 7-tesla magnet, a significantly stronger magnetic field than the 0.5-to-3 teslas of most MRIs in clinical use, which optimized the signal-to-noise ratio. But they also built custom state-of-the-art software that, depending which physics parameters it directs the MRI to optimize, reveals particular features of the tissue, from tiny bleeds to swelling to white and gray matter.

Scientists Agree on 5 Foods to Boost Brain Health and Longevity

With the rise of fad diets, “superfoods,” and a growing range of dietary supplement choices, it’s sometimes hard to know what to eat.

This can be particularly relevant as we grow older and are trying to make the best choices to minimize the risk of health problems such as high blood pressure, obesity, type 2 diabetes, and heart (cardiovascular) problems.

We now have evidence these health problems also all affect brain function: they increase nerve degeneration in the brain, leading to a higher risk of Alzheimer’s disease and other brain conditions including vascular dementia and Parkinson’s disease.

Did we evolve to see reality as it exists? No, says cognitive psychologist Donald Hoffman

What is reality and how do we know? For many the answer is simple: What you see — hear, feel, touch, and taste — is what you get.

Your skin feels warm on a summer day because the sun exists. That apple you just tasted sweet and that left juices on your fingers, it must have existed. Our senses tell us that reality is there, and we use reason to fill in the blanks — that is, we know the sun doesn’t cease to exist at night even if we can’t see it.

But cognitive psychologist Donald Hoffman says we’re misunderstanding our relationship with objective reality. In fact, he argues that evolution has cloaked us in a perceptional virtual reality. For our own good.

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