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Coloured functional magnetic resonance imaging scan of a healthy human brain at rest.

Activity in the brain’s medial prefrontal cortex shows similar patterns in optimistic people.Credit: Mark and Mary Stevens Neuroimaging and Informatics Institute/SPL

Optimists are on the same wavelength

Optimistic people share patterns of brain activity, whereas pessimists have more varying, idiosyncratic ones, a brain-imaging study reveals. Optimists also make more of a distinction between positive and negative events than pessimists do. The findings could have implications in mental-health research, researchers say, because pessimism is linked to conditions such as depression. The “dramatic part of this research was seeing a very abstract, everyday feeling — the sense that some people think alike — become literally visible in the patterns of brain activity”, says social psychologist and study co-author Kuniaki Yanagisawa.

Nature | 4 min read

Reference: Proceedings of the National Academy of Sciences paper

COVID aged our brains beyond their years

The brains of healthy people aged faster during the COVID-19 pandemic than did the brains of people analysed before the pandemic began. The accelerated ageing — recorded as structural changes seen in brain scans — occurred even in people who didn’t become infected with SARS-CoV-2, but cognitive tests revealed that mental agility declined only in those who had COVID-19. This suggests that faster brain ageing doesn’t necessarily lead to impaired thinking and memory. As yet, it’s unclear whether this pandemic-associated ageing can be reversed.

Nature | 5 min read

Reference: Nature Communications paper

Some tenured staff take their foot off the gas

US academics’ research-publication patterns shift fundamentally after they secure coveted tenure status. By analysing the output of more than 12,000 academics, researchers found that faculty members tend to publish the most in the year before they’re granted tenure. But once they’ve attained the job security of a tenured position, their output begins to vary across disciplines: it plateaus for biologists and others who tend to work in the laboratory, and dips for those in fields such as mathematics that generally do not require lab research.

Nature | 5 min read

Reference: Proceedings of the National Academy of Sciences paper

Octopuses fall for ‘rubber arm’ illusion

If I cover your hand and then stroke a fake one placed nearby — for purely scientific reasons, I assure you — you will ‘feel’ the touch to the fake hand as if it’s your own. This illusion demonstrates the link between vision, touch and proprioception — the ability to sense our body’s position and movement. Now we know that octopuses have the same sense of body ownership. Researchers finagled a fake arm for a plain-body octopus (Callistoctopus aspilosomatis) and saw that the animal reacted to a gentle pinch in the same way it would to a tweak of the real thing.

Science | 3 min read

Reference: Current Biology paper

Features & opinion

There’s a new acid in our rain

A chemical called trifluoroacetic acid (TFA) is falling in rain and its levels are rising across the planet — in lakes and rivers, food crops, trees, and in our own bodies. TFA’s strong carbon–fluorine bonds are unbreakable by natural processes, making it, by some definitions, a member of the suite of per- and poly-fluoroalkyl substances (PFASs) known as ‘forever chemicals’. Some PFASs have been deemed harmful and banned, but TFA is not widely regulated. Questions about its safety could have a far-reaching impact on industries as diverse as refrigeration and pharmaceuticals.

Nature | 12 min read

TFA: a controversial molecule. The chemical structure of trifluoroacetic acid (TFA) and Perfluorooctanoic acid (PFOA). Levels of the human-made chemical TFA are rising in the environment. The molecule is a fluorinated analogue of vinegar (acetic acid), in which hydrogen atoms in the molecule’s tail are replaced by fluorines.

Made-to-order DNA goes big

Scientists are perfecting their methods for making industrial volumes of custom DNA — the raw material of synthetic biology. Advances in both enzymatic and chemical synthesis are making it easier to generate highly repetitive or complex sequences. Ultimately this could help tackle a range of challenges, from cleaning up pollutants with designer bacteria to the creation of bespoke gene therapies.

Nature | 5 min read

Ping! Potential asteroid impact notification

Earlier this year, astronomers spent a few months measuring the odds of asteroid 2024 YR4 hitting Earth in 2032. At its peak, the risk was more than 3% — enough to trigger alerts to the United Nations and the US Space Force. We got away with it this time, but what would happen if such a space rock did turn out to be on a collision course? Plans are in place — 2024 YR4 actually arrived in the midst of a months-long simulation being run by scientists in the UN’s planetary-defense group. But the leaders of the nation best-equipped to head off such an event — the United States — are looking to cut related funding, and it’s unclear whether they’re still interested in protecting the planet, anyway.

Financial Times | 19 min read (free registration required)

QUOTE OF THE DAY

“This is total victory for the polluters right now.”

Epidemiologist Thomas Burke, a former advisor to the US Environmental Protection Agency, responds to the dissolution of its scientific research arm, which will see hundreds of scientists fired and their research on environmental hazards ended. (Science | 4 min read)