Plus, science advocates react to the U.S. midterm elections ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏ ͏
November 4, 2026—The neurobiology of mental exhaustion. Plus, science advocates react to the U.S. midterm elections, and the polar vortex is about to get wonky.
—Andrea Gawrylewski,
Chief Newsletter Editor
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Cold air movements during a polar vortex disruption in January 2019. NASA/JPL-Caltech AIRS Project
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The Arctic polar vortex, a spinning mass of air high above the North Pole, is collapsing far earlier than it normally does. Meteorologists don't know what to make of it. | 2 min read
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We checked in with science advocates to get their reaction to the U.S. midterm election results, which could signal more accountability after two years of attacks on science. | 3 min read
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NASA’s Neil Gehrels Swift Observatory was scheduled to burn up in Earth's atmosphere early this morning. The agency made a last-ditch effort to save the sinking craft in July, but that mission failed. | 2 min read
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Approximately 60 percent of processed foods contain some form of soy. We sat down with environmental historian Edward Melillo to learn how the bean came to play such a huge role in the U.S. food system. | 16 min podcast
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Hackers have been hijacking European supermarket freezers by attacking built-in defrost controls, spoiling millions of euros’ worth of food. | 3 min read
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SpaceX plans to wind down its Falcon 9 rocket within the next few years and focus on its Starship megarocket. But many entities still depend on Falcon 9. | 7 min read
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This week the Southwest’s Four Corners region and Florida’s central coast experienced major flood events. And the super El Niño is only going to bring more rain across the U.S. | 3 min read
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The Science of Mental Exhaustion
Scientists have long debated whether mental fatigue is a neurobiological or psychological process. Now, researchers have shown that the accumulation of the neurotransmitter glutamate in the brain causes mental fatigue and kills motivation. In a recent experiment, scientists used electrodes to stimulate the dorsolateral prefrontal cortex in participants’ brains as they tried to remember letters they’d seen flashed on a screen. Those whose brains were stimulated performed better, but they crashed harder, and had higher mental fatigue. The researchers showed it was because of increased levels of glutamate.
Why this is interesting: The findings could help explain why mental fatigue feels unpleasant. In large enough concentrations, glutamate can damage brain cells. When you feel like you're losing motivation, it may actually be a safety signal telling you to take a break, the scientists conjecture. If our minds are constantly running at full throttle, potentially harmful molecules might keep piling up faster than the brain can dispose of them.
Other explanations: Glutamate may not be the only molecule involved in mental fatigue. Other labs are investigating both glutamate and lactate, an important energy source for the brain, as well as the contribution of the anterior cingulate cortex, a region of the brain involved in attention and decision-making.
Join the discussion: How does cognitive burnout affect you? And what are the ways you restore your brainpower? Share your experience here.
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Y-Less Mouse Clones
For the first time, scientists transformed cloned male mouse embryos into viable female animals. The new study, a preprint, successfully tested a CRISPR gene-editing tool the researchers called Y-CUT, to cut out the Y chromosome from 13 mice embryos cloned with cells from a single male donor. They then transferred the embryos to surrogate mice, who gave birth to healthy, fertile clones—10 of which had female genitalia and a single X chromosome.
Weird, but useful: The clones of both sexes were fertile and began breeding with each other. And those offspring were born both male and female, with XX and XY chromosomes. Researchers say the tool could be useful for rescuing endangered species—scientists could create fertile breeding pairs using just one male donor.
What the experts say: “I think it’s a really neat foundational breakthrough in reproductive science,” says Ben Novak, a wildlife conservation scientist who wasn’t involved in the study. “Being able to manipulate chromosome counts and chromosome makeup will open up a new avenue of functional genomic science.” —Emma Gometz, Newsletter Editor
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After a brain injury from a motorcycle accident, this middle school teacher became a musical genius. | The New York Times($)
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Tens of thousands of documents on contamination, clean power, and Trump’s climate policy changes are scheduled to disappear from the EPA's website. | Mother Jones
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The U.S. is taking steps to remove nonhuman primates from research. Here's what that would mean for the study of the brain. | The Transmitter
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Data centers became a deciding issue in yesterday's U.S. midterm elections. Several winning candidates for Senate won races in areas where data centers that power AI are fueling controversy. Democrat Justin Pearson ran in a red district in Tennessee and performed better than expected after making data center pollution in Memphis the centerpiece of his campaign (as of now it looks like he'll lose by less than 2 percentage points in a newly redrawn district). Read more about the controversy over data centers in the Memphis area in our October feature. It's a good one.
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—Andrea Gawrylewski,
Chief Newsletter Editor
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