University of Barcelona

Babies' brains specialise in their native language from pregnancy, according to a study carried out in France. The research team used encephalograms to measure the brain activity of 33 infants born to French-speaking mothers while listening to a story in French, English or Spanish. The results provide "the most compelling evidence to date that language experience already shapes the functional organization of the infant brain, even before birth," the authors write in Science Advances.

The absence of visits from friends and family is associated with a higher mortality rate, according to an analysis of data from more than 450,000 people followed for more than a decade in the UK. The study, published in BMC Medicine, focussed on five indicators of loneliness, and concluded that having no visits from family or friends was associated with higher all-cause mortality and cardiovascular disease mortality. According to the authors, this kind of study helps to identify at-risk populations and measures of social connectedness that could provide the most benefit.

Researchers at Northwestern University in the United States have studied the effect of a temporary decrease in sleep on the mood of mice. According to their results, the animals became more hyperactive and hypersexual for a few hours. In addition, the occasional lack of sleep had an antidepressant effect that lasted for a few days and is explained by an increase in the release of dopamine. The results are published in the journal Neuron.

A US study measures the risk of breast cancer overdiagnosis in screening campaigns for women over 70. These are women who are misdiagnosed with cancer after a mammogram, leading to unnecessary treatments that can cause complications, anxiety and financial costs. The study includes more than 54,000 women over the age of 70 who have had a screening mammogram. The retrospective analysis compares the cumulative incidence of breast cancer between two groups: women who continued screening up to 15 years later, and women who did not. The research estimates that 31% of breast cancer cases in women aged 70-74 result from overdiagnosis: it finds 6.1 cases per 100 women who had continued screening, compared with 4.2 cases per 100 women in the second group. The percentage of overdiagnosis increases with the age of the women. The article is published in the Annals of Internal Medicine, along with an editorial.

The World Meteorological Organisation (WMO) has declared the onset of El Niño conditions on Tuesday. "The declaration of El Niño by the WMO is the signal for governments around the world to mobilise preparations to limit the impacts on our health, our ecosystems and our economies," said WMO Secretary-General Petteri Taalas. According to the WMO statement, El Niño conditions have developed in the tropical Pacific for the first time in seven years, setting the stage for a likely rise in global temperatures and altered weather and climate patterns.

A commentary published last Friday in the journal Molecular Psychiatry, signed by more than 30 researchers, challenges the conclusions of the systematic review published in the same journal in July 2022, in which the authors concluded that there was no evidence that low serotonin levels cause depression. The researchers in the new paper blame the earlier study for flaws in methodology, among other weaknesses.

The Guardian newspaper reported on Wednesday that Magdalena Zernicka-Goetz's team had announced the generation of synthetic human embryos from stem cells at the annual meeting of the International Society for Stem Cell Research in Boston. The author later denied on Twitter that they were synthetic human embryos and spoke only of models, warning that it was pending publication in a scientific journal. The day after the publication in The Guardian, and as reported in El País, Jacob Hanna and his team published a preprint - a publication that has not been peer-reviewed - in bioRxiv on models of human embryos generated from stem cells without genetic editing. A few hours later, Zernicka-Goetz's team posted their preprint on bioRxiv.

After three years in which the planet's climate has experienced a phenomenon known as La Niña, in 2023 it gives way to its opposite, El Niño. This has led the World Meteorological Organization to warn that this event, added to climate change, could cause the 1.5 °C limit to be exceeded in the next five years. But what are these "children", how do they affect Spain, how long will they last?

In a series of three articles and a companion article - collected in Nature Biotechonology - Nature publishes the first draft of the human pangenome reference, which contains highly detailed data from 47 genetically diverse individuals. The first human genome was published more than two decades ago but, being from a single person, it does not represent human diversity, whereas the pangenome refers to the gene pool of our entire species. The ultimate goal of the Human Pangenome Reference Consortium project is to include genetic material from 350 people by 2024. It is hoped that this data will allow more clinically relevant genetic variants to be identified.

Two studies have found changes in the microbiome of patients affected by chronic fatigue syndrome. In particular, they have found a decrease in both butyrate and certain bacteria that produce butyrate. Butyrate is a factor related to the protection of the intestinal barrier and appears to play a role in the regulation of the immune system. Both papers are published in the journal Cell Host and Microbe.