If discovery is feasible in humans it could be used to send astronauts into suspended animation:
[...] In science fiction, space crews are often spared the boredom and inconvenience of long-distance space travel by being placed into a state of suspended animation. Now this goal may have come a step closer after scientists showed that hibernation can be artificially triggered in rodents using ultrasonic pulses.
The advance is seen as significant because the technique was effective in rats – animals that do not naturally hibernate. This raises the prospect that humans may also retain a vestigial hibernation circuit in the brain that could be artificially reactivated.
"If this proves feasible in humans, we could envision astronauts wearing a helmet-like device designed to target the hypothalamus region for inducing a hypothermia and hypometabolism state," said Hong Chen, an associate professor at Washington University in St Louis, who led the work.
The team first identified a specific group of neurons in a deep brain region called the hypothalamus preoptic area, which were found to be involved in regulating body temperature and metabolism during hibernation. They showed that, in mice, these neurons could be artificially activated using ultrasound, delivered non-invasively through a helmet.
When stimulated, the mice showed a drop in body temperature of about 3C for about one hour. The mice's metabolism also shifted from using both carbohydrates and fat for energy to only fat, a key feature of torpor, and their heart rates fell by about 47%, all while at room temperature.
The scientists also developed an automatic closed-loop feedback system that delivered an ultrasound pulse to keep the mice in the induced torpor if they showed signs of warming up. This allowed the mice to be kept at 33C in the hibernation-like state for 24 hours. When the ultrasound system was switched off, they woke up again.
The experiments, described in the journal Nature Metabolism, showed that the same device worked in rats, which had a 1C drop in core body temperature when the same brain region was targeted. Chen said the result was "surprising and fascinating" and the team planned to test the technique in larger animals.
In humans, inducing a torpor-like state has potential medical applications, with some suggesting that slowing down metabolism could buy critical time for treating life-threatening conditions such as heart attack and stroke. "By extending the window for medical intervention, this technique offers promising prospects for improving patients' chances of survival," said Chen. "Additionally, the non-invasive nature of the technique opens the possibility of developing wearable ultrasound devices, such as helmets, for easy access in emergency situations."
Journal Reference:
Yang, Y., Yuan, J., Field, R.L. et al. Induction of a torpor-like hypothermic and hypometabolic state in rodents by ultrasound. Nat Metab (2023). https://doi.org/10.1038/s42255-023-00804-z
(Score: 0) by Anonymous Coward on Sunday May 28 2023, @05:42AM (1 child)
Um... so that just leaves the question of space travel to be solved, and what to do at the other end.
(Score: 4, Funny) by maxwell demon on Sunday May 28 2023, @12:35PM
More importantly, it leaves the question open how to prevent those rodents from eating the cables of the space ship after they awake from hibernation.
The Tao of math: The numbers you can count are not the real numbers.
(Score: 3, Touché) by RamiK on Sunday May 28 2023, @10:15AM
One giant leap to stun grenades.
compiling...
(Score: 3, Interesting) by JoeMerchant on Sunday May 28 2023, @02:26PM
Picture a thick hollow sphere of ice in elliptical orbit between Earth and Mars. Ice serving as radiation shield and water repository.
Humans transiting between Earth and Mars transfer into the ice sphere for a long, relatively radiation safe trip, preferably in hibernation.
Just have to find asteroids rich in ice, and move them into "place".
🌻🌻 [google.com]
(Score: 3, Interesting) by ElizabethGreene on Sunday May 28 2023, @06:23PM (1 child)
I'm excited they are making progress in this area, but I'm a little scared at the idea of prolonged ultrasonic stimulation of a specific brain region.
(The DOI link was broken for me and I did not dive deeper.)
$searchEngine says Transcranial ultrasonic stimulation uses frequencies of ~200-650khz. That's a wavelength of 2-7 mm. Working from the ignorant non-expert assumption that the stimulation consists of creating a resonant node with the maximum stimulation equivalent to an eighth of that wavelength that means they are stimulating roughly a sphere of 250 microns in diameter. My first thought was that's a very large area of a very small rat brain to jiggle about, but I mathed it and that assumption was incorrect. It's a surprisingly small area of less than 100 neurons. Still, I'm a little hesitant about the idea of mechanically stimulating dozens of neurons like that in a brain region that controls critical autonomic life support systems.
I'm already signed up for Cryonics to freeze me croak, and I'd welcome a breakthrough in long-term hibernation to make investment more likely to work out. To quote Siv Palpatine:
(Score: 1) by Splodgy Emoji on Wednesday May 31 2023, @12:23PM
Yes. For anybody interested in the details:
velocity V of sound in fat = ~1530m/s (velocity of sound in air at STP = ~330m/s), wavelength L = V/f (200kHz) 1530/650000 = ~2mm, (650kHz) 1530/200000 = ~7mm
Reference: https://radiopaedia.org/articles/propagation-speed [radiopaedia.org]
(Score: 2) by mcgrew on Monday May 29 2023, @04:18PM (1 child)
If the hibernation didn't extend their lives, it's worthless and the time spent sleeping is wasted.
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(Score: 2) by higuita on Monday May 29 2023, @10:10PM
nope, it still matter!
Even if the life is reduced by a small part, for space travel, spending 3 years hibernating would save huge amount of food, water and oxygen. Even if that reduction is just 10% , it would save a huge amount of fuel to put in orbit and travel all that extra mass. It also reduce the size of the ship and the required fuel. Each Kg saved will also save extra Kg in other parts. It would probably also save space and mass for entertainment, as we can't expect spending 3 years doing nothing all day, and also save the humans from the travel stress (assuming this do not cause other side effects too)