Our leading hypothesis for how our memories are stored is that when you learn something, the connections among neurons involved get stronger and physically larger, and that constitutes the memory. The trouble is that these connections significantly change over time—they’re plastic.

“If you compare the arrangement of these connections on day one with the same on day four or five, it's very, very different," says Kazumasa Tanaka, a neuroscientist at the Okinawa Institute of Science and Technology Graduate University in Japan. To learn how a memory that can last for years can sit on hardware that shifts every few days, Tanaka’s team made the shift a bit more dramatic. In a recent Science study, they induced a hibernation-like state in mice, which basically erased the state of more than half of their synapses. And yet the mice apparently have kept their memories.

Hibernation on demand

Hibernation is a specialty of squirrels, hamsters, and bears, but the neural circuit that triggers it is conserved across mammals, and is present in species that never hibernate in the wild—like mice. In June 2020, a team of researchers led by Takeshi Sakurai, a neuroscientist at the University of Tsukuba and a collaborator on Tanaka’s study, developed a technique to artificially activate this hibernation circuit. This can be done by activating a population called Q neurons in a region of the hypothalamus.

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Pause for a moment and listen. What do you hear? Chances are, somewhere in the background, is the ever-present hum of a road.

More than 4.2 million miles of public roads crisscross the lower 48 states—enough to reach the Moon and back almost nine times. This vast network of roads spiderwebs its way across the contiguous US, leaving only about 5 percent as an inventoried roadless area or wilderness.

Now, some of those last remaining lands free of roads are under threat from the Trump administration’s proposed rollback of the 2001 Roadless Rule. That includes southeast Alaska’s Tongass National Forest, where eagles, bears, salmon, and many other species thrive in old-growth coastal forest along the Inside Passage.

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A new national space transportation policy signed by President Donald Trump on Thursday calls for the development of more spaceports to support more than 1,000 launches and reentries per year by 2030.

The presidential memorandum replaces a 2013 policy signed by former President Barack Obama. Both policies share an emphasis on supporting the commercial space industry and underscore the importance of assured access to space. But the launch sector has changed immensely since then. There were 176 orbital launch attempts from US soil last year, nearly 10 times the number in 2013. SpaceX led the pack last year with 165 orbital launches of its Falcon 9 rocket, plus five suborbital test flights of the much larger Starship.

"By 2030, our space transportation ranges must grow to support more than 1,000 launches and reentries every year," the policy says. "The policies set forth in this memorandum will secure America's continued superiority in space."

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