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Ultrastructural and Histological Cryopreservation of Mammalian Brains by Vitrification

Studies of whole brain cryopreservation are rare but are potentially important for a variety of applications. It has been demonstrated that ultrastructure in whole rabbit and pig brains can be cryopreserved by vitrification (ice-free cryopreservation) after prior aldehyde fixation, but fixation limits the range of studies that can be done by neurobiologists, including studies that depend upon general molecular integrity, signal transduction, macromolecular synthesis, and other physiological processes. We now show that whole brain ultrastructure can be preserved by vitrification without prior aldehyde fixation. Rabbit brain perfusion with the M22 vitrification solution followed by vitrification, warming, and fixation showed an absence of visible ice damage and overall structural preservation, but osmotic brain shrinkage sufficient to distort and obscure neuroanatomical detail. Neuroanatomical preservation in the presence of M22 was also investigated in human cerebral cortical biopsies taken after whole brain perfusion with M22. These biopsies did not form ice upon cooling or warming, and high power electron microscopy showed dehydrated and electron-dense but predominantly intact cells, neuropil, and synapses with no signs of ice crystal damage, and partial dilution of these samples restored normal cortical pyramidal cell shapes. To further evaluate ultrastructural preservation within the severely dehydrated brain, rabbit brains were perfused with M22 and then partially washed free of M22 before fixation. Perfusion dilution of the brain to 3-5M M22 resulted in brain re-expansion and the re-appearance of well-defined neuroanatomical features, but rehydration of the brain to 1M M22 resulted in ultrastructural damage suggestive of preventable osmotic injury caused by incomplete removal of M22. We conclude that both animal and human brains can be cryopreserved by vitrification with predominant retention of ultrastructural integrity without the need for prior aldehyde fixation. This observation has direct relevance to the feasibility of human cryopreservation, for which direct evidence has been lacking until this report. It also provides a starting point for perfecting brain cryopreservation, which may be necessary for lengthy space travel and could allow future medical time travel.

The authors have declared no competing interest.

The surprising way the brain’s dopamine-rich reward center adapts as a romance matures

A new study published in the journal Social Cognitive and Affective Neuroscience provides evidence that the human brain processes romantic partners differently than close friends, specifically within the reward system. The research suggests that while the brain creates a unique neural signature for a partner early in a relationship, this distinction tends to fade as the bond matures. These findings offer insight into how the biological drivers of romantic love may evolve from passion to companionship over time.

Relationships involve complex psychological states that differentiate a committed partner from a platonic friend. Scientists have sought to map these differences in the brain to understand the biological foundations of human bonding. Much of this research focuses on the nucleus accumbens. This small region deep within the brain, which relies heavily on the neurotransmitter dopamine, plays a central role in processing rewards and motivation.

Evidence from animal studies indicates that the nucleus accumbens is essential for forming pair bonds. Research on monogamous prairie voles shows that neurochemical signaling in this area drives the preference for a specific partner. The brain appears to undergo plastic changes that reinforce the bond.

Mutation in one Parkinson’s protein eases cellular traffic jams caused by another

A hallmark of Parkinson’s disease is the buildup of Lewy bodies—misfolded clumps of the protein known as alpha-synuclein. Long before Lewy bodies form, alpha-synuclein can interfere with neurons’ ability to transport proteins and other cargo along their axons to the synapses. When present at high levels, alpha-synuclein binds too tightly to structures inside the axon, creating the cellular equivalent of traffic jams. These disruptions may even help set the stage for the later accumulation of Lewy bodies in the brain.

Now, University at Buffalo researchers have identified a way to reduce these traffic jams and restore flow—by altering how alpha-synuclein interacts with another Parkinson’s-related protein known as leucine-rich repeat kinase 2 (LRRK2).

In a study published last month, the researchers increased levels of specific mutant forms of LRRK2 in fruit fly larvae. They found that one mutation had a downstream effect on alpha-synuclein, limiting its ability to bind to cargo and disrupt axonal transport. The research is published in the journal Frontiers in Molecular Neuroscience.

A new way to communicate with neurons using focused ultrasound stimulation

I still vividly remember the first time we observed neurons responding not to audible sound, but to concentrated, precisely calibrated ultrasonic pulses. On the screen in front of us, calcium signals from brain cells began to rise and fall in little waves. It was less about forcing the brain to adapt and more about listening to the brain and responding subtly.

Understanding how neurons interact and how neurological conditions like Parkinson’s disease affect this communication has been the focus of my study for many years. Calcium, a small ion that functions as a potent messenger inside cells, is at the center of this communication.

Neurons struggle to survive, connect, and operate correctly when calcium transmission is disrupted. Our team began to wonder if we might safely modify this fundamental signaling function without requiring invasive operations or drugs.

Preclinical study successfully reverses loss of blood flow to brain, an early sign of Alzheimer’s disease

Supriya Chakraborty might have been studying insects in a lab had it not been for an immunology college instructor in India who taught him about the superheroes inside him—immune cells that wage a battle against bacteria, parasites, and a host of other adversaries that invade our bodies. “That really fascinated me,” Chakraborty recalled. “My focus shifted from entomology to wanting to solve illnesses that affect humans, specifically neurodegenerative disorders.”

Zeynab Tabrizi would take quite a different path to studying conditions that damage and destroy parts of the human nervous system. She had long been a student of immunology and neuroscience in her native Iran, conducting research that explored the causes of disorders like schizophrenia and autism. “I had some experience working in industry,” she said, “but my heart was in academia.”

Now, their paths have intersected at the University of Miami. As Ph.D. students in the College of Arts and Sciences’ Department of Biology, Chakraborty and Tabrizi conduct research that could help blaze a trail to more effective treatments for Alzheimer’s disease, perhaps even leading to a cure for the memory-robbing disorder that affects more than 7 million older adults in the U.S.

Understanding the path from genetic changes to Parkinson’s disease opens possibilities for early diagnosis

A team led by researchers at Baylor College of Medicine and the Duncan Neurological Research Institute (Duncan NRI) at Texas Children’s Hospital has uncovered a chain of events that connects genetic alterations, disruptions in lipid metabolism and the manifestation of Parkinson’s disease in patients. The findings, published in the journal Brain, bring forward the possibility of identifying people at risk before symptoms appear and developing strategies to treat the disease rather than manage the symptoms.

“Parkinson’s disease is the second most common neurodegenerative disease after Alzheimer’s disease, affecting more than 10 million people worldwide. We know more than 100 genes that increase the risk of developing the disease but, in most cases, we do not understand how the genetic change leads to the condition,” said corresponding author Dr. Joshua Shulman, professor of neurology, neuroscience and molecular and human genetics at Baylor. He also is an investigator and co-director of the Duncan NRI.

Previous studies have shown that many Parkinson’s susceptibility genes participate in lipid metabolism and that disrupting some lipid functions may directly promote brain alterations that have been linked to the disease’s onset and progression.

Gentle implant can illuminate, listen and deliver medication to the brain

A new type of brain implant may have implications for both brain research and future treatments of neurological diseases such as epilepsy. Researchers from DTU, the University of Copenhagen, University College London, and other institutions have developed a long, needle-thin brain electrode with channels—a so-called microfluidic Axialtrode (mAxialtrode), named for its ability to distribute functional interfaces along the length of the implant, enabling both neural signal recording and precisely targeted medication delivery across different brain regions. The research results have been published in Advanced Science.

The technology has primarily been developed for basic research into the brain. It can help researchers better understand how signals move across brain layers, for example in epilepsy, memory, or decision-making. In the longer term, the researchers point out that the mAxialtrode may be important for treatment—for example, in targeted drug delivery combined with electrical or light-based stimulation of specific areas of the brain.

Postdoc Kunyang Sui, who led the development of the mAxialtrode concept together with Associate Professor Christos Markos, emphasizes that it has made it possible to combine several functions in a single implant which makes brain research less invasive and more precise.

Nanoengineered extrusion-aligned tract bioprinting enables functional repair of spinal cord injuries

Gu et al. present NEAT, a nanoengineered extrusion-aligned tract bioprinting strategy that fabricates aligned, human neural stem cell-laden collagen hydrogel constructs through shear-induced fibrillar organization. In a rat model of complete spinal cord transection, NEAT enables axonal reconnection and functional locomotor recovery, demonstrating its translational potential for spinal cord repair and neural tissue engineering.

Sleep disruption damages gut’s self-repair ability via stress signals from brain: A biological chain reaction

Chronic sleep disruption doesn’t just leave people tired and irritable. It may quietly undermine the gut’s ability to repair itself, increasing vulnerability to serious digestive diseases. A new study from the University of California, Irvine, the University of Chinese Academy of Sciences and the China Agricultural University reveals, step by step, how disturbed sleep causes the brain to send harmful signals to the intestines, ultimately damaging the stem cells responsible for maintaining a healthy gut lining.

The research uncovers a previously unknown biological chain reaction linking the brain’s sleep center to intestinal health. The findings are published in Cell Stem Cell and offer new insight into why people with chronic sleep problems are more likely to develop gastrointestinal disorders such as inflammatory bowel disease, diabetes-related gut complications and chronic inflammation.

Physicians have long known that irregular or insufficient sleep is associated with a wide range of health problems, from mood disorders to high blood pressure. Yet how changes in sleep can directly harm organs that do not sleep themselves, such as the intestines, has remained largely elusive. This study answers that question by tracing the damage from its neurological origins all the way to the gut’s regenerative machinery.

We Learned a Bit More About How Human Brains Became So Complex

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Hello and welcome! My name is Anton and in this video, we will talk about a few studies that explain how the human brain developed complexity.
Links:
https://linkinghub.elsevier.com/retrieve/pii/S0092867423009170
https://www.science.org/doi/10.1126/science.ade5645
https://www.biorxiv.org/content/10.1101/2024.05.01.592020v5.full.pdf.
https://www.science.org/doi/10.1126/science.abm1696
https://www.nature.com/articles/s41559-022-01925-6
https://www.microbiologyresearch.org/content/journal/mgen/10…01322#tab2
Other videos:
https://www.youtube.com/watch?v=qyMbXCzcS0k.
https://www.youtube.com/watch?v=e10yOoP-x3g.

#brain #biology #evolution.

0:00 Discoveries about the evolution of the brain.
1:20 800 Million years ago… how it all began.
3:10 Did nervous system evolve multiple times? Comb jellies.
4:45 Big brains — primates vs octopuses.
9:20 Human brains and human intelligence genes.
11:20 Gut microbes and fuel for the brain.
12:20 Conclusions and implications.

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