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Category: neuroscience – Page 349

A team at the National Institute of Standards and Technology in Boulder, Colorado, has reported the successful implementation of a 400,000 pixel superconducting nanowire single-photon detector (SNSPD) that they say will pave the way for the development of extremely light-sensitive large-format superconducting cameras. The camera will also prove invaluable for those doing medical research, where the ability to examine organs such as the brain without disturbing tissue is critical.

Superconducting detectors operate at very low temperatures and generate a minimum of excess noise, making them ideal for testing the non-local nature of reality, investigating dark matter, mapping the early universe, and performing quantum computation and communication. Previously there were no large-scale superconducting cameras – even the largest demonstrations have never exceeded 20 thousand pixels.

This was especially true for one of the most promising detector technologies, the superconducting nanowire single-photon detector (SNSPD). These detectors have been demonstrated with system detection efficiencies of 98.0%, sub-3-ps timing jitter, sensitivity from the ultraviolet (250nm) to the mid-infrared (10um), and dark count rates below 6.2e-6 counts per second (cps), but despite more than two decades of development they have never achieved an array size larger than a kilopixel. Here, we report on the implementation and characterization of a 400,000 pixel SNSPD camera, a factor of 400 improvement over the previous state-of-the-art. The array spanned an area 4×2.5 mm with a 5x5um resolution, reached unity quantum efficiency at wavelengths of 370 nm and 635 nm, counted at a rate of 1.1e5 cps, and had a dark count rate of 1e-4 cps per detector (corresponding to 0.13 cps over the whole array).

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New research into the hormone somatostatin has the potential to change the general scientific consensus on how it influences Alzheimer’s and how the disease begins to develop in the brain.

Somatostatin plays a role in many parts of our body. In previous studies, the hormone was also thought to drive the production of the enzyme neprilysin, which can degrade amyloid beta, the protein that clumps together and damages neurons in the brains of people with Alzheimer’s.

The new study suggests that somatostatin actually influences amyloid-beta more directly, putting the brakes on the mechanisms by which the protein’s monomer (single molecule) form combines into an oligomer (multi-molecule) form.

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This was a surprise. Animals have brain maps for vision and touch, but these are built from visual images and touch receptors that map onto the brain through direct point‑to‑point projections. With ears, it’s entirely different. The brain compares information received from each ear about the timing and intensity of a sound and then translates the differences into a unified perception of a single sound issuing from a specific region of space. The resulting auditory map allows owls to “see” the world in two dimensions with their ears.

This proved to be a big leap toward understanding how the brain of any animal, including humans, learns to grasp its environment through sound. Think of it. Standing in a forest, you hear the crack of a falling branch or the rustle of a deer’s step in the dry leaves. Your brain calculates the time and intensity of sound to determine where it’s coming from. Owls do this task with incredible speed and accuracy. Each cochlea in the owl provides the brain with the precise timing of the sound reaching that ear within 20 microseconds. This determines how accurately the brain can calculate the interaural time difference, which in turn determines the accuracy of the localization of a sound in the azimuth. “The precision in microseconds provided by the owl cochlea is better than in any other animal that has been tested,” says Köppl. “We have big heads, so the interaural time differences are larger, making the task for cochlea and brain easier. In a nutshell, it is the combination of a small head and very precise localization that makes the owl unique.”

And here’s a finding to drop the jaw. José Luis Peña, a neuroscientist at the Albert Einstein College of Medicine, and his collaborators have discovered that the sound localization system in a barn owl’s brain performs sophisticated mathematical computations to execute this pinpointing of prey. The space‑specific neurons in the owl’s specialized auditory brain do advanced math when they transmit their information, not just adding and multiplying incoming signals but averaging them and using a statistical method called “Bayesian inference,” which involves updating as more information becomes available.

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A new study conducted by researchers at Washington University School of Medicine in St Louis has explored the composition of gut bacteria in individuals in the earliest stage of Alzheimer’s disease. The research, which is published in Science Translational Medicine, not only identifies potential indicators of heightened dementia risk, but also offers prospects for developing microbiome-altering preventive treatments to combat cognitive decline.

Longevity. Technology: Previously, science has noted differences in the gut microbiomes of individuals with symptomatic Alzheimer’s compared with their healthy counterparts. However, the current study delves deeper, focusing on the gut microbiomes of individuals in the crucial pre-symptomatic phase. During this phase, individuals accumulate amyloid beta and tau proteins in their brains without exhibiting neurodegeneration or cognitive decline, which can persist for over two decades. Earlier diagnosis would enable people to access support and resources, plan for the future and well as onboarding treatments that could slow the progression of the disease. An idea of future numbers of patients would also allow health care infrastructure to be better prepared.

The researchers evaluated participants who volunteered at the Charles F and Joanne Knight Alzheimer Disease Research Center at Washington University, specifically selecting cognitively normal individuals. These participants provided samples of stool, blood, and cerebrospinal fluid, recorded their dietary habits, and underwent PET and MRI brain scans.

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There’s a bouncer in everyone: The blood-brain barrier, a layer of cells between blood vessels and the rest of the brain, kicks out toxins, pathogens and other undesirables that can sabotage the brain’s precious gray matter.

When the bouncer is off its guard and a rowdy element gains entry, a variety of conditions can crop up. Barrier-invading cancer cells can develop into tumors, and multiple sclerosis can occur when too many white blood cells slip pass the barrier, leading to an autoimmune attack on the protective layer of brain nerves, hindering their communication with the rest of the body.

“A leaky blood-brain barrier is a common pathway for a lot of brain diseases, so to be able to seal off the barrier has been a long sought-after goal in medicine,” said Calvin Kuo, MD, PhD, the Maureen Lyles D’Ambrogio Professor and a professor of hematology.

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Brain tissue is one of the most intricate tissue specimens that scientists have arguably ever dealt with. Packed with an immeasurable amount of information, the human brain is the most sophisticated computational device with its network of around 86 billion neurons.

Understanding such complexity is a difficult task, and therefore making progress requires technologies to unravel the tiny, taking place in the brain at microscopic scales. Imaging is therefore an enabling tool in neuroscience.

The new imaging and virtual reconstruction technology developed by Johann Danzl’s group, at the Institute of Science and Technology Austria (ISTA), is a big leap in imaging and is aptly named LIONESS—Live Information Optimized Nanoscopy Enabling Saturated Segmentation. Their work has been published in Nature Methods.

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Summary: A novel study suggests that silence can indeed be ‘heard.’ Philosophers and psychologists, using auditory illusions, demonstrated how silence distorts our perception of time, much like sounds do.

The study indicates that the brain perceives and processes silence in a manner similar to sounds. The research establishes a novel method to study the perception of absence, broadening the scope for future exploration in the realm of sensory perception.

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Summary: Deep-sleep brain waves could be a significant factor in regulating blood sugar. The research shows that a combination of sleep spindles and slow waves can predict an increase in insulin sensitivity, subsequently lowering glucose levels.

This discovery highlights sleep as a potential lifestyle adjustment to improve blood sugar control and manage diabetes. Furthermore, these deep-sleep brain waves could also be used to predict an individual’s next-day glucose levels, proving more accurate than traditional sleep metrics.

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