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Category: neuroscience – Page 5

‘Weird shading’ tricks the brain into seeing 3D forms from simple lines

Shading brings 3D forms to life, beautifully carving out the shape of objects around us. Despite the importance of shading for perception, scientists have long been puzzled about how the brain actually uses it. Researchers from Justus-Liebig-University Giessen and Yale University recently came out with a surprising answer.

Previously, it has been assumed that one interprets shading like a physics-machine, somehow “reverse-engineering” the combination of and lighting that would recreate the shading we see. Not only is this extremely challenging for advanced computers, but the visual is not designed to solve that sort of problem. So, these researchers decided to start instead by considering what is known about the brain when it first gets signals from the eye.

“In some of the first steps of visual processing, the brain passes the image through a series of ‘edge-detectors,’ essentially tracing it like an etch-a-sketch,” Professor Roland W. Fleming of Giessen explains. “We wondered what shading patterns would look like to a brain that’s searching for lines.” This insight led to an unexpected, but clever short-cut to the shading inference problem.

More misfolded proteins than previously known may contribute to Alzheimer’s and dementia

For decades, the story of Alzheimer’s research has been dominated by a battle between A-beta and tau amyloids, both of which can kill neurons and impact the brain’s ability to function. A new study suggests, however, that these sticky brain plaques may not be operating alone.

Johns Hopkins University researchers have identified more than 200 types of in rats that could be associated with age-related cognitive decline.

The findings could lead the way to finding new therapeutic targets and treatments in humans that could provide relief for the millions of people over 65 who suffer from Alzheimer’s, dementia, or other diseases that rob them of their memories and independence as they age.

Scientists Succeed in Reversing Parkinson’s Symptoms in Mice

In 2017, he led a study that identified for the first time an abnormal form of a protein called SOD1 in Parkinson’s patients. Under normal conditions, this protein acts as an antioxidant enzyme, protecting brain cells from damage caused by free radicals, highly reactive molecules that contain oxygen and can deteriorate cells if not properly neutralized. Free radicals are produced by natural bodily processes as well as by external factors, like diet, smoking, and exposure to pollution.

In people with Parkinson’s disease, SOD1 suffers alterations that prevent it from fulfilling its protective function, with it instead accumulating in the brain and causing neuronal damage, according to the findings of Double’s team.

Based on these results, the team then conducted further research, with results suggesting that copper supplementation in the brain could be an effective way to slow and even reverse the symptoms of Parkinson’s (copper is crucial to SOD1’s function). To test this hypothesis, they evaluated the efficacy of a drug called CuATSM, designed to cross the blood-brain barrier and deliver copper directly to brain tissue.

Switching on a silent gene revives tissue regeneration in mice

Research led by the National Institute of Biological Sciences in Beijing has discovered that switching on a single dormant gene enables mice to regenerate ear tissue.

Some vertebrates such as salamanders and fish can regenerate complex tissue structures with precision. A lost limb can be regrown, a damaged heart or eye can be repaired. Salamanders are so remarkable at reconstructing damaged tissues that even a spinal cord injury with severed neural motor connectivity can be restored.

Mammals occasionally showcase the ability to regenerate. Deer antlers and goat horns are examples of living tissue regeneration. Mice can regrow fingertips if they are lost. A healthy human liver can experience up to 70% loss of tissue and regrow to near full size within several weeks.

Mathematical model reveals how humans store narrative memories using ‘random trees’

Humans can remember various types of information, including facts, dates, events and even intricate narratives. Understanding how meaningful stories are stored in people’s memory has been a key objective of many cognitive psychology studies.

Inverse Graphics: How Your Brain Turns 2D Into 3D

“This gives us evidence that the goal of vision is to establish a 3D understanding of an object,” said study senior author Ilker Yildirim, an assistant professor of psychology in Yale’s Faculty of Arts and Sciences.

“When you open your eyes, you see 3D scenes — the brain’s visual system is able to construct a 3D understanding from a stripped-down 2D view.”

Researchers have dubbed this process “inverse graphics,” describing how the brain’s visual processing system works like a computer graphics process, but in reverse, from a 2D image through a less view-dependent “2.5D” intermediate representation, and up to a much more view-tolerant 3D object.

Over 400 different types of nerve cell have been grown — far more than ever before

Nerve cells are not just nerve cells. Depending on how finely we distinguish, there are several hundred to several thousand different types of nerve cell 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 nerve cells from stem cells 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 genetic engineering or by adding signalling molecules to activate particular cellular signalling pathways. However, they never got close to achieving the diversity of hundreds or thousands of different nerve cell types that actually exists.

“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. However, this is not the best approach to such work. “If we want to develop cell culture models for diseases and disorders such as Alzheimer’s, Parkinson’s and depression, we need to take the specific type of nerve cell involved into consideration.”

For the first time, researchers at ETH Zurich have successfully produced hundreds of different types of nerve cell from human stem cells in Petri dishes. In the future, it will thus be possible to investigate neurological disorders using cell cultures instead of animal testing.