Daily briefing: Gentle brain stimulation could treat depression at home

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Fringe protests help mainstream causes

Disruptive protests by fringe activists might increase public support for conventional activists with a similar cause. In 2022, activists from the UK-based climate-action group Just Stop Oil forced the closure of London’s M25 motorway for four days. Researchers at the Social Change Lab, who had been tipped off about the protest, polled public opinions on Friends of the Earth, another climate-action group that favours more mainstream tactics, before and after the protest. The percentage of respondents who said they at least somewhat supported Friends of the Earth was 3.3% higher after the motorway blockage.

Nature | 4 min read

Reference: Nature Sustainability paper

At-home brain stimulation helps depression

Gentle brain stimulation using a swimming cap-like device could be an effective at-home treatment for depression. The non-invasive therapy, known as transcranial direct current stimulation (tDCS), is designed to stimulate areas of the brain linked to mood regulation, and delivers a painless, weak electrical current through electrodes placed on the scalp. Clinical trial participants that received tDCS showed a greater reduction in depressive symptoms than a control group, without the need for visits to a specialized clinic. The trial “really starts to substantiate the ability to take mental health treatments into a home setting”, says clinical neuropsychologist Shawn McClintock.

Nature | 5 min read

Reference: Nature Medicine paper

Teensiest dinosaur egg unearthed

Researchers in China have dug up the smallest known non-avian dinosaur egg at a construction site near the city of Ganzhou. At 29 millimetres long, the egg is about the size of a small strawberry. It was found in 2021 as part of a cluster of six eggs, and dated to be 80 million years old. Electron microscopy revealed that the eggs belonged to an unknown species, which the team named Minioolithus ganzhouensis.

Popular Science | 2 min read

Reference: Historical Biology paper

Name-dropping AI boosts citations

Papers with titles or abstracts that mention certain artificial intelligence (AI) methods are more likely to be among the top 5% most-cited works in their field for a given year than are those that don’t reference those techniques. These papers also tend to receive more citations from outside their field than do studies that don’t refer to AI terms. However, researchers from groups that have been historically underrepresented in science do not receive the same citation ‘boost’ as their counterparts, suggesting that AI could exacerbate existing inequalities.

Nature | 4 min read

Reference: Nature Human Behaviour paper

Features & opinion

Rethinking the energy cost of reproduction

Evolutionary biologist Dustin Marshall thinks that researchers might have vastly underestimated the energy it takes to reproduce. Many influential mathematical models of species’ energy demands estimate only the ‘direct’ energy cost to produce young — the energy invested and stored in the offspring. This ignores a big energy-spend by mothers, the ‘indirect costs’ of making and carrying a baby. Marshall’s team has even found that the indirect costs might greatly exceed the direct ones, particularly in mammals. These findings could influence theories about aspects of animal lifestyles and improve predictions about how animals will respond to climate change, Marshall says.

Nature | 7 min read

How we get our heads around zero

“Zero is, by many mathematicians, definitely considered one of the greatest — or maybe the greatest — achievement of mankind,” says neuroscientist Andreas Nieder. Zero wasn’t first used until relatively recently in our history, compared to other numbers. A unique digit, it requires our minds to make a cognitive leap: recognize absence as a mathematical object. Now, Nieder’s research has shown that our brains might handle the concept of zero differently, with more neurons coding for zero than any other small number.

Quanta | 10 min read

Quantum tech needs ethical regulation

As countries around the world are investing in quantum technologies for national defence, their design and implementation need ethical guidance urgently, argue three digital ethicists. We can build on lessons learnt from AI ethics in some instances. However, the unique characteristics of quantum technologies mean that the likelihood and impact of ethical risks can differ from case to case. The trio has set out six principles that defence organizations can use as a framework to ensure these technologies are developed responsibly, such as considering strategies to limit the access of authoritarian governments to quantum technologies.

Nature | 12 min read

Where I work

Having grown up in rural Vietnam, computer scientist Minh Ha Quang credits mathematics as his “passport to world travel”. His journey has led him to the RIKEN Centre for Advanced Intelligence Project (AIP) in Tokyo, where he leads a team researching artificial intelligence. “A main motivation of my work is its use in brain–computer interfaces (BCIs),” he says. “Creating links between the brain and computers might one day help people who are paralysed to regain freedom of movement. The aim of BCIs here is to decode brain signals to control the movements of body parts, perhaps with robotic help, just by using thoughts.” (Nature | 3 min read)