Hello Nature readers,
Today we learn why Huntington’s disease takes so long to show symptoms, hear a call for the secure and ethical use of DNA testing to reunite families separated by war and ponder how to reimburse young people for their participation in research.

Paralysed man flies virtual drone

Researchers have developed a device that let a 69-year-old man with paralysis fly a virtual drone using only his thoughts. The brain–computer interface (BCI) decoded the man’s brain activity as he imagined moving three groups of digits in real time. By associating neural signals with the movements of multiple fingers, the work builds on previous BCI research, most of which has focused on moving a single computer cursor or whole virtual hand.

Study hints at the health effects of Ozempic

Blockbuster weight-loss drugs such as Ozempic could raise a person’s likelihood of developing arthritis and a potentially deadly condition called pancreatitis. Researchers compared the health of more than 200,000 people with diabetes on Ozempic-like drugs, with about 1.7 million people using other blood-sugar-lowering medications over 3.5 years. They found that the drugs were associated with an 11% increase in arthritis risk and a 146% higher risk of pancreatitis, although they did lower the risk of dozens of physical and mental health conditions.

Why Huntington’s takes so long to kick in

A faulty DNA-repair mechanism in neurons explains why people who inherit the deadly brain disease Huntington’s often show no symptoms until well into adulthood. The errors ramp up over the years until they hit a critical threshold and the neurons start to die, according to a study of the neurons hit hardest by the disease. Developing therapies that target these DNA-repair proteins could help to delay the onset of symptoms, say researchers.

Can we curb AI’s hallucinations?

Ask an artificial intelligence (AI) chatbot for a scientific reference and it might give you the citation you’re looking for. Or, it could ‘hallucinate’, spitting out an only partially correct, or totally false, answer. Researchers say that preventing AI from erring altogether is impossible, but they’re working on measures that could make hallucinations less frequent and less problematic. These include making a chatbot refer to a trusted text before responding and conducting “brain scans” of a large language model’s artificial neurons to reveal patterns of deception. For now, the best defence might simply be to take the output of a chatbot with a large pinch of salt.

DNA database can help find stolen children

Since Russia’s invasion of Ukraine almost three years ago, nearly 20,000 Ukrainian children have been taken to Russia, and some might lose all evidence of where they came from. “Now is the time to develop a DNA kinship resource to aid Ukrainian families and communities seeking missing children,” writes Sara Huston, who co-founded DNA Bridge, a non-profit organization to advance the secure and ethical use of DNA testing to assist family reunifications in humanitarian settings. “As a geneticist and ethicist, I am familiar with the risks that come with DNA testing,” she says. But this “might be the only way to reconnect them with their families”.

How to pay young people who help research

A growing recognition of the unique perspectives that young people can bring to research has boosted the number of studies that involve them as participants and contributors. That’s a good thing, say four experts in the area, but it raises ethical and practical issues about how best to compensate children. Some form of payment can “be crucial to enabling some young people to participate, especially those from low-resource settings”, they write. But there’s a thicket of issues about what’s appropriate in different socio-economic and cultural contexts, and how compensation might risk creating expectations and dependencies.