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Scientists revive activity in frozen mouse brains for the first time

A familiar trope in science fiction is the cryopreserved time traveller, their body deep-frozen in suspended animation, then thawed and reawakened in another decade or century with all of their mental and physical capabilities intact.

Researchers attempting the cryogenic freezing and thawing of brain tissue from humans and other animals — mostly young vertebrates — have already shown that neuronal tissue can survive freezing on a cellular level and, after thawing, a functional one to some extent. But it has not been possible to fully restore the processes necessary for proper brain functioning — neuronal firing, cell metabolism and brain plasticity.

A team in Germany has now demonstrated a method for cryopreserving and thawing mouse brains that leaves some of this functionality intact. The study, published on 3 March in Proceedings of the National Academy of Sciences 3, details the authors’ use of a method called vitrification, which preserves tissue in a glass-like state, along with a thawing process that preserves living tissue.

“If brain function is an emergent property of its physical structure, how can we recover it from complete shutdown?” asks Alexander German, a neurologist at the University of Erlangen–Nuremberg in Germany and lead author of the study. The findings, he says, hint at the potential to one day protect the brain during disease or in the wake of severe injury, set up organ banks and even achieve whole-body cryopreservation of mammals.

Mrityunjay Kothari, who studies mechanical engineering at the University of New Hampshire in Durham, agrees that the study advances the state of the art in cryopreservation of brain tissue. “This kind of progress is what gradually turns science fiction into scientific possibility,” he says. However, he adds that applications such as the long-term banking of large organs or mammals remain far beyond the capabilities of the study.

Article Featured in Nature.


Parallel realities solve this time travel paradox | Jim Al-Khalili

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Time is the one thing every human being experiences identically, or so we assume.

Physicist Jim Al-Khalili dismantles that assumption, explaining how velocity and gravity don’t just affect clocks but actually alter the rate at which time passes for the person experiencing it.

Preorder Jim Al-Khalili’s forthcoming book, On Time: The Physics That Makes the Universe, here: https://www.amazon.com/Time-Physics-T?tag=lifeboatfound-20

About Jim Al-Khalili: Jim is a multiple award-winning science communicator renowned for his public engagement around the world through writing and broadcasting and a leading academic making fundamental contributions to theoretical physics, particularly in nuclear reaction theory, quantum effects in biology, open quantum systems and the foundations of quantum mechanics. Jim is a theoretical physicist at the University of Surrey where he holds a Distinguished Chair in physics as well as a university chair in the public engagement in science. He received his PhD in nuclear reaction theory in 1989 and has published widely in the field. His current interest is in open quantum systems and the application of quantum mechanics in biology.

About Jim Al-Khalili:

Gödel Handed Einstein a Universe With Time Travel

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    Read more

    Quantum entanglement and the illusion of time, in 79 minutes

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    Preorder Jim Al-Khalili’s forthcoming book, On Time: The Physics That Makes the Universe, here: https://www.amazon.com/Time-Physics-T?tag=lifeboatfound-20

    Up next.
    Brian Cox: The quantum roots of reality | Full Interview ► • Brian Cox: The quantum roots of reality |…

    Time feels obvious, but physics tells a stranger story about its existence: Theoretical physicist Jim Al-Khalili explores why our sense of time may be incredibly misleading, including the idea that past, present, and future might all exist at once.

    0:00 Chapter 1: Does time flow?
    2:42 Why Time Feels Faster as We Age.
    3:56 Time and Change in Philosophy and Physics.
    5:28 Einstein and the End of Absolute Time.
    6:19 Time in the Equations of Physics.
    7:50 Chapter 2: How do we reconcile quantum field theory with the general theory of relativity?
    12:10 Evidence for Time Dilation: Muons.
    14:29 Gravity Slows Time: General Relativity.
    19:22 Space-Time and the Block Universe.
    21:55 Does Time Really Exist?
    26:33 The Debate: Eternalism vs Presentism.
    34:12 Chapter 3: Is There a “Now”?
    40:40 Chapter 4: Why Does Thermodynamics Have a Direction in Time?
    49:38 Quantum Entanglement and the Direction of Time.
    55:10 Did Time Begin at the Big Bang?
    45:00 Will Time End?
    1:05:40 Chapter 5: Is Time Travel Possible?

    Read more

    The deep mystery physicists call “the problem of time” | Jim Al-Khalili: Full Interview

    Become a Big Think member to unlock expert classes, premium print issues, exclusive events and more: https://bigthink.com/membership/?utm_

    Preorder Jim Al-Khalili’s forthcoming book, On Time: The Physics That Makes the Universe, here: https://www.amazon.com/Time-Physics-T?tag=lifeboatfound-20

    Up next.
    Brian Cox: The quantum roots of reality | Full Interview ► • Brian Cox: The quantum roots of reality |…

    Time feels obvious, but physics tells a stranger story about its existence: Theoretical physicist Jim Al-Khalili explores why our sense of time may be incredibly misleading, including the idea that past, present, and future might all exist at once.

    0:00 Chapter 1: Does time flow?
    2:42 Why Time Feels Faster as We Age.
    3:56 Time and Change in Philosophy and Physics.
    5:28 Einstein and the End of Absolute Time.
    6:19 Time in the Equations of Physics.
    7:50 Chapter 2: How do we reconcile quantum field theory with the general theory of relativity?
    12:10 Evidence for Time Dilation: Muons.
    14:29 Gravity Slows Time: General Relativity.
    19:22 Space-Time and the Block Universe.
    21:55 Does Time Really Exist?
    26:33 The Debate: Eternalism vs Presentism.
    34:12 Chapter 3: Is There a “Now”?
    40:40 Chapter 4: Why Does Thermodynamics Have a Direction in Time?
    49:38 Quantum Entanglement and the Direction of Time.
    55:10 Did Time Begin at the Big Bang?
    45:00 Will Time End?
    1:05:40 Chapter 5: Is Time Travel Possible?

    On the number of digital pictures Let’s switch from Go positions to digital pictures

    There is an art project to display every possible picture. The project admits this will take a long time, because there are many possible pictures. But how many? We will assume the very common color model known as True Color, in which each pixel can be one of 224 ≅ 17 million distinct colors. The digital camera shown below left has 12 million pixels. We’ll also consider much smaller pictures: the array below middle, with 300 pixels, and the array below right with just 12 pixels. Shown are some of the possible pictures:

    12,000,000 pixels 300 pixels 12 pixels.

    Quiz: Which of these produces a number of pictures similar to the number of atoms in the universe?

    Answer: An array of n pixels produces (17 million)n different pictures. (17 million)12 ≅ 1,086, so the tiny 12-pixel array produces a million times more pictures than the number of atoms in the universe!

    How about the 300 pixel array? It can produce 102,167 pictures. You may think the number of atoms in the universe is big, but that’s just peanuts to the number of pictures in a 300-pixel array. And 12M pixels? 1,086,696,638 pictures. Fuggedaboutit!

    So the number of possible pictures is really, really, really big. And the number of atoms in the universe is looking relatively small, at least as a number of combinations.

    On counting combinations People often underestimate the number of combinations of things. I think there are two main reasons: Combinations of things are multiplicative, while collections of things are additive. If you see a line of 6 people, it is easy to visualize a line of 60 people—it is ten times longer. But even if you know that there are 720 different orderings (permutations) in which those 6 people can line up, there is no way you can visualize the number of orderings for 60 people, because it is—you guessed it—larger than the number of atoms in the universe. Big numbers are hard. Even with simple collections of things, it takes practice to get a real intuition for the difference between 6 million and 6 billion people. When it comes to combinations, growth is faster and therefore intuition fails earlier. Authors are sloppy. Doug Smith reports that the New York Times confused “million” and “billion” over a dozen times per year; other sources also make similar mistakes. See the book by Unix co-creator Brian Kernighan for more on this. So beware, and be sure to use some simple math to augment your intuition when dealing with combinations.

    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.

    How the Incas Performed Skull Surgery More Successfully Than U.S. Civil War Doctors

    Granted access to a time machine, few of us would presumably opt first for the experience of skull surgery by the Incas. Yet our chances of survival would be better than if we underwent the same procedure 400 years later, at least if it took place on a Civil War battlefield.

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