science

Sometimes the hardest part of doing an unpleasant task is simply getting started – typing the first word of a long report, lifting the dirty dish atop an overfilled sink, or removing the clothes from an unused exercise machine. The obstacle isn’t necessarily a lack of interest in completing the task, but the brain’s resistance to taking the first step.

Now, scientists may have identified the neural circuit behind this resistance, and a way to ease it. In a study published today in Current Biology, researchers describe a pathway in the brain that seems to act as a ‘motivation brake’, dampening the drive to begin a task. When the team selectively suppressed this circuit in macaque monkeys, goal-directed behaviour rebounded.

Previous work on task initiation has implicated a neural circuit connecting two parts of the brain known as the ventral striatum and ventral pallidum[...] But attempts to isolate the circuit’s role have fallen short[...] In the new study, Amemori and his team used a more precise approach. They first trained two male macaque monkeys to perform two decision-making tasks. In one, completion earned a water reward; in the other, the reward was paired with an unpleasant puff of air to the face. Each trial required the monkeys to initiate the task by fixing their gaze on a central spot on a screen until the reward-punishment offer appeared. This allowed the researchers to measure motivation by how often the monkeys failed to begin.

Not surprisingly, monkeys were more hesitant when the possibility of punishment loomed. But that changed when the team used a targeted genetic technique to suppress signalling from the ventral striatum to the ventral pallidum. Although the suppression had little effect on the monkeys’ behaviour during the reward-only trials, it made them significantly more willing to start in the face of a potentially unpleasant outcome. The suppression did not, however, alter how the animals weighed reward against punishment.

If confirmed in humans, the findings could shift how clinicians approach one of depression’s most debilitating symptoms. Treatments often aim to restore enjoyment or reduce anxiety, yet many patients continue to struggle to start simple tasks. By pinpointing a circuit that selectively dampens motivation in the face of discomfort, the study opens the door to therapies aimed at lowering that barrier.

Note that the authors acknowledged that this is a smaller study that was done on only two male monkeys, so future studies should include females, find specific cell types, and find biochemical pathways across the signaling circuit

The paper (should be open access): https://doi.org/10.1016/j.cub.2025.12.035

Researchers have discovered a brain activity pattern that can predict which people with mild cognitive impairment are likely to develop Alzheimer’s disease. Using a noninvasive brain scanning technique and a custom analysis tool, they detected subtle changes in electrical signals tied to memory processing years before diagnosis. The findings point to a new way of spotting Alzheimer’s early—by listening directly to how neurons behave.

Apologies for the previous click-bait title -- some communities take title editing seriously and I was unaware of the etiquette.

For more than a decade, the United States has faced a relentless and heartbreaking increase in fatal drug overdoses driven by synthetic opioids. A new analysis suggests this trend has suddenly reversed due to a major disruption in the global supply chain of illicit fentanyl. Published in Science, the study indicates that regulatory actions taken by the Chinese government, following high-level diplomatic engagement with the Biden administration, may be the primary driver behind this unexpected decline in mortality.

An experimental mRNA treatment has converted the liver into an immune cell "nursery" that pumped out greater numbers of healthy T cells in mice. Since the immune system has a powerful effect on other things like organ health and inflammation, it is hoped that such a treatment in humans might significantly expand our "healthspan", keeping us healthier and more disease-free later in life.

Any dog owner will tell you that dogs understand many words, and studies support this impression. In addition to dogs with regular, “family dog” knowledge levels are dogs with an extraordinary level of word comprehension. These dogs have been called “gifted word learners” and they appear idiosyncratically across countries, breeds, and households. Dror et al. examined the ability of these dogs to pick up words through conversations not directed at them. Using an approach designed to study understanding in toddlers, they found that the dogs were able learn words through overhearing just like, or even better than, 1.5-year-old children. —Sacha Vignieri [Editor]

From abstract:

... In this study, we demonstrated that a small group of Gifted Word Learner dogs, which possess an extensive vocabulary of object labels, can learn new labels by overhearing their owners’ interactions. Moreover, we show that these dogs can acquire novel object-label mappings even when the labels and objects are not presented simultaneously. Taken together, these results suggest that Gifted Word Learner dogs possess sociocognitive skills functionally parallel to those of 18-month-old children.

Note that this is only for what the authors described as a subset of "gifted dogs": "Although dogs readily learn action labels (23), to date, behavioral evidence of learning object labels were documented in only a small group of dogs (24). We previously defined this small group as Gifted Word Learner dogs..."

The full article seems to be behind paywall/institutional access. If anyone finds a full-text link please definitely share here

Experts decry move to leave UNFCCC as ‘embarrassing’ as president orders withdrawal from 66 international groups

Donald Trump has sparked outrage by announcing the US will exit the foundational international agreement to address the climate crisis, cementing the US’s utter isolation from the global effort to confront dangerously escalating temperatures.

In a presidential memorandum issued on Wednesday, Trump stated that the UN Framework Convention on Climate Change (UNFCCC) is, along with 65 other organizations, agencies and commissions, “contrary to the interests of the United States” and will be ditched.

The UNFCCC treaty forms the bedrock of international co-operation to deal with the climate crisis and has been agreed to by every country in the world since its inception 34 years ago. The US Senate ratified the treaty in October 1992.

Trump has, however, routinely ridiculed climate science as a “scam” and a “hoax” and has actively hobbled clean energy projects and other climate policies as president, attempting to force the US and other countries to stay wedded to the fossil fuels that are driving disastrous heatwaves, storms, droughts and conflicts that imperils billions of people around the world.

Don't read just the title.