Zapping a rodent's brain can put it into suspended animation. Scientists want to one day use the same technique for humans traveling to Mars.

Scientists have zapped mice and rats into a suspended-animation-like state called torpor. The state was induced by beaming ultrasound waves into a precise spot in the rodent's brains. This technique could one day be used on humans for space travel and medical purposes. Scientists have been able to induce a torpor state in mice and rats using ultrasound, bringing them a step closer to finding a way to induce suspended animation in humans. They hope this could one day save on energy and costs of long-haul space travel to planets like Mars. "We could envision astronauts wearing a helmet-like device designed to target the hypothalamus region to induce a torpor-like state," she said. Torpor is a state of suspended animation whereby animals may look like they are going to sleep, but they are actually drastically reducing their metabolic activity, usually in response to extremely adverse conditions. Mice and rats were fitted with tiny helmets to send ultrasonic waves to the brain. The scientists observed that these waves were effectively able to push the rodents into a state of torpor. For about an hour after the ultrasound pulse, the mice's body temperatures and metabolism dropped, a state similar to torpor seen in nature. The mice's average body temperatures dropped by up to 6.25 degrees Fahrenheit (3.5 degrees Celsius) and their heart rate and oxygen usage dropped as well. The rats' body temperatures also dropped, though to a lesser level, up to 3.57 F (2 C). The fact that this state was triggered in rats is encouraging, as these rodents "do not naturally enter torpor, suggesting the possibility that similar effects could be induced in humans," the scientists said in the study. For Spaceworks, astronauts would be induced into torpor for 14 days at a time and woken for three or four days. That way, there would always be an active astronaut on shift to monitor proceedings. The rapid progress in the basic science to support this innovation is encouraging. Other studies, like this recent one, suggest hacking the brain's dormant torpor mechanism to induce this state. Previous studies had suggested torpor could be induced with drugs, but the advantage of the approach in this recent study, is that it is noninvasive, precise, and safe, scientists said in the study. "As far as we know, there is nothing unique about homo sapiens that would prevent our species from hibernating, and I believe the capacity is there but it needs to be unlocked," Vladyslav Vyazovskiy, professor of sleep physiology at the University of Oxford, told the BBC. "To me, the real question is not whether we can hibernate, but how… How do neurons in the hypothalamus 'know' that it is time to hibernate? Who tells them? This is the real question," he said. Nevertheless, most of the research into long-ranging suspended animation is still only being done on animals, and we're likely still a long way away from testing it on humans. "Further research is still required to determine the safety and feasibility of this approach in humans," Chen told Live Science.