Expectations shape our perception, profoundly influencing how we interpret the world. Positive expectations about sensory stimuli can alleviate distress and reduce pain through what’s known as the placebo effect, while negative expectations may heighten anxiety and exacerbate pain. In the new study, Luo, Kishida, and colleagues investigated the impact of the hedonic aspect of expectations on subjective experiences.

Specifically, the researchers measured neurobehavioral responses to the taste of hot sauce among individuals with a wide range of taste preferences. In total, 47 participants completed the tasks while undergoing functional magnetic resonance imaging scanning. The researchers identified participants who liked versus those who strongly disliked spicy flavors and provided contextual cues about the spiciness of the sauce to be tasted. That way, they were able to dissociate the effects of positive and negative expectations from sensory stimuli (i.e., visual and taste stimuli), which were the same across all participants.

The results showed that positive expectations lead to modulations in the intensity of subjective experience. These modulations were accompanied by increased activity in brain regions previously linked to pleasure, information integration, and the placebo effect, including the anterior insula, dorsolateral prefrontal cortex, and dorsal anterior cingulate cortex. By contrast, negative expectations decreased hedonic experience and increased neural activity in the Neurological Pain Signature network.

Taken together, these findings demonstrate that hedonic aspects of one’s expectations asymmetrically shape how the brain processes sensory input and associated behavioral reports of one’s subjective experiences of intensity, pleasure, and pain. The results suggest a dissociable impact of hedonic information. While positive expectations facilitate higher-level information integration and reward processing, negative expectations prime lower-level processes related to pain and emotions. According to the authors, this study demonstrates the powerful role of hedonic expectations in shaping subjective reality and suggests potential avenues for consumer and therapeutic interventions targeting expectation-driven neural processes.

The authors add, “Our study highlights how hedonic expectations shape subjective experiences and neural responses, offering new insights into the mechanisms behind pain perception.”

‘We wanted to go beyond isolated events,’ says research leader Ana Triana. ‘Our behaviour and mental states are constantly shaped by our environment and experiences. Yet, we know little about the response of brain functional connectivity to environmental, physiological, and behavioral changes on different timescales, from days to months.’

The study found that our brains do not respond to daily life in immediate, isolated bursts. Instead, brain activity evolves in response to sleep patterns, physical activity, mood, and respiration rate over many days. This suggests that even a workout or a restless night from last week could still affect your brain — and therefore your attention, cognition and memory — well into next week.

The research also revealed a strong link between heart rate variability — a measure of the heart’s adaptability — and brain connectivity, particularly during rest. This suggests that impacts on our body’s relaxation response, like stress management techniques, could shape our brain’s wiring even when we are not actively concentrating on a task. Physical activity was also found to positively influence the way brain regions interact, potentially impacting memory and cognitive flexibility. Even subtle shifts in mood and heart rate left lasting imprints for up to fifteen days.

Study goes beyond a snapshot

The research is unusual in that few brain studies involve detailed monitoring over days and weeks. ‘The use of wearable technology was crucial’, says Triana. ‘Brain scans are useful tools, but a snapshot of someone lying still for half an hour can only show so much. Our brains do not work in isolation.’

Triana was herself the subject of the research, monitored as she went about her daily life. Her unique role as both lead author and study participant added complexity, but also brought firsthand insights into how best to maintain research integrity over several months of personalized data collection.

‘At the beginning, it was exciting and a bit stressful. Then, routine settles in and you forget,’ says Triana. Data from the devices and twice-weekly brain scans were complemented by qualitative data from mood surveys.

The researchers identified two distinct response patterns: a short-term wave lasting under seven days and a long-term wave up to fifteen days. The former reflects rapid adaptations, like how focus is impacted by poor sleep, but it recovers quickly. The long wave suggests more gradual, lasting effects, particularly in areas tied to attention and memory.

Single-subject studies offer opportunities for improving mental health care

The researchers hope their innovative approach will inspire future studies that combine brain data with everyday life to help personalise mental health treatment.

‘We must bring data from daily life into the lab to see the full picture of how our habits shape the brain, but surveys can be tiring and inaccurate,’ says study co-author, neuroscientist and physician Dr Nick Hayward. ‘Combining concurrent physiology with repeated brain scans in one person is crucial. Our approach gives context to neuroscience and delivers very fine detail to our understanding of the brain.’

The study is also a proof-of-concept for patient research. Tracking brain changes in real time could help detect neurological disorders early, especially mental health conditions where subtle signs might be missed.

“Linking brain activity with physiological and environmental data could revolutionize personalized healthcare, opening doors for earlier interventions and better outcomes,” says Triana.

Ribosomes turn upside-down in hungry cells

Scientists have observed that yeast cells have a remarkable adaptation to starvation: their mitochondria get coated by a swarm of massive molecular complexes called ribosomes. Intrigued by this odd phenomenon, the Mattei Team at EMBL Heidelberg and the Jomaa Lab at the University of Virginia School of Medicine explored it in greater detail using single-particle cryo-electron microscopy and cryo-electron tomography.

Ribosomes are the cell’s heavyweight molecular machinery that produces proteins. It turned out, however, that in hungry yeast cells, the ribosomes that crowd on the surface of the mitochondria don’t produce anything. They are hibernating.

“One way for a cell to survive stressful conditions until better days is to reduce its use of energy to a minimum,” explained Olivier Gemin, EIPOD Postdoctoral Fellow in the Mattei Team who led this new study. “Producing proteins demands a lot of energy, which can be saved by blocking ribosomes.”

Why the hibernating ribosomes attach to the surface of mitochondria is a mystery.

“There could be different explanations,” said Team Leader Simone Mattei. “A starved cell will eventually start digesting itself, so the ribosomes might be coating the mitochondria to protect them. They might also attach to trigger a signalling cascade inside the mitochondria.”

Another possibility that Mattei is investigating relates to the fact that starving cells need a way to quickly start producing energy once food (in the form of glucose) is available again. Since mitochondria are the energy producers of the cell, having ribosomes nearby to produce necessary proteins might help this process along.

What made the scientists’ jaws drop was noticing that the ribosomes attach to the mitochondrial outer membrane in a way that contradicts what’s been known about them before.

“So far, ribosomes were known to interact with membranes only via their large subunit. But in starved cells, we saw that they do this upside-down, via the small subunit!” said Mattei.

In their future studies, the team will investigate how and why the ribosomes attach in such an unusual way.

Cancer cells go through the hell they create

The struggles of the starved yeast cells have some similarities to those of cancer cells.

Believe it or not, being a cancer cell is really tough. When a tumour becomes aggressive, its cells grow so rapidly that their demand for nutrients and oxygen outpaces the supply. This means most cancer cells are constantly starving in a kind of hell they create for themselves.

Yet, they survive and even multiply.

“That’s why we need to understand the basics of adaptation to starvation and how these cells become dormant to stay alive and avoid death,” said Ahmad Jomaa, Assistant Professor and Group Leader at the University of Virginia’s School of Medicine and a senior co-author of the study. “For that, we use yeast first, because we can manipulate it much more easily. Beyond this, we try to starve cultured cancer cells too, which is not easy, to figure out how they overcome starvation and can sometimes lead to cancer relapse.”

Understanding the principles of this adaptation could help us find ways to override it, making cancer cells vulnerable to starvation and thus more susceptible to treatment.

The Antarctic Peninsula, like many polar regions, is warming faster than the global average, with extreme heat events in Antarctica becoming more common.

The new study — by the universities of Exeter and Hertfordshire, and the British Antarctic Survey — used satellite data to assess how much the Antarctic Peninsula has been “greening” in response to climate change.

It found that the area of vegetation cover across the Peninsula increased from less than one square kilometre in 1986 to almost 12 square kilometres by 2021.

Published in the journal Nature Geoscience, the study also found this greening trend accelerated by over 30% in recent years (2016-2021) relative to the full study period (1986-2021) — expanding by over 400,000 square metres per year in this period.

In a previous study, which examined core samples taken from moss-dominated ecosystems on the Antarctic Peninsula, the team found evidence that rates of plant growth had increased dramatically in recent decades.

This new study uses satellite imagery to confirm that a widespread greening trend, across the Antarctic Peninsula, is under way and accelerating.

“The plants we find on the Antarctic Peninsula — mostly mosses — grow in perhaps the harshest conditions on Earth,” said Dr Thomas Roland, from the University of Exeter.

“The landscape is still almost entirely dominated by snow, ice and rock, with only a tiny fraction colonised by plant life.

“But that tiny fraction has grown dramatically — showing that even this vast and isolated ‘wilderness’ is being affected by anthropogenic climate change.”

Dr Olly Bartlett, from the University of Hertfordshire, added: “As these ecosystems become more established — and the climate continues to warm — it’s likely that the extent of greening will increase.

“Soil in Antarctica is mostly poor or non-existent, but this increase in plant life will add organic matter, and facilitate soil formation — potentially paving the way for other plants to grow.

“This raises the risk of non-native and invasive species arriving, possibly carried by eco-tourists, scientists or other visitors to the continent.”

The researchers emphasise the urgent need for further research to establish the specific climate and environmental mechanisms that are driving the “greening” trend.

“The sensitivity of the Antarctic Peninsula’s vegetation to climate change is now clear and, under future anthropogenic warming, we could see fundamental changes to the biology and landscape of this iconic and vulnerable region,” said Dr Roland.

He added: “Our findings raise serious concerns about the environmental future of the Antarctic Peninsula, and of the continent as a whole. In order to protect Antarctica, we must understand these changes and identify precisely what is causing them.”

The researchers are now investigating how recently deglaciated (ice-free) landscapes are colonised by plants, and how the process might proceed into the future.

Some of these environmental phenols are known to have cardiac toxicities. Now, an interdisciplinary study involving four University of Cincinnati College of Medicine professors is revealing their adverse impact on the heart’s electrical properties, and the research has been published in the journal Environmental Health.

“This is the first study to look at the impact of phenol exposure on cardiac electrical activity in humans,” said Hong-Sheng Wang, PhD, professor in the Department of Pharmacology, Physiology and Neurobiology and the study’s lead author.

Researchers used data from the Fernald Community Cohort, which includes nearly 10,000 people who lived near the former U.S. Department of Energy uranium processing site at Fernald, outside Cincinnati, and participated in the Fernald Medical Monitoring Program between 1990 and 2008.

Much of the cohort did not experience exposure to uranium beyond the radiation received by the general population. Wang and his team used their data, including biological samples and medical records, in the study so uranium exposure would not be a factor in the findings — making them relevant to the general population. Because urine samples and electrocardiograms, or EKGs, were collected on the same day, the results were significant for analyzing exposure to environmental phenols.

The EKGs, which measure cardiac electrical activities, were read by board-certified physicians, and the urine samples were sent to the Centers for Disease Control and Prevention for exposure analysis.

One goal of the study was to identify any changes in EKG parameters associated with environmental phenol exposure.

The heart is driven by electrical activity, so anything affecting its electrical properties can have a detrimental impact and possibly result in arrhythmias.

The research concluded higher exposure to some environmental phenols is associated with altered cardiac electrical activity.

Researchers found higher exposure to BPA, BPF and BPA+F in women is associated with a longer PR interval, a delay in the time it takes for electrical signals to move from the atria at the top of the heart to the ventricles.

“Our findings were highly sex-specific,” said Wang. In women, researchers identified an association with longer QRS duration, or contraction of the ventricles, and dysfunction of the electrical impulses of the heart.

“It was particularly pronounced in women with higher body mass indexes,” said Wang.

In men, researchers found higher exposure to triclocarban (TCC), an antimicrobial agent, led to longer QT intervals in the heart — meaning the heart’s electrical system is taking too long to recharge, a situation that can contribute to heart rhythm dysfunction. TCC has since been banned in the United States.

Wang also pointed out that typical exposure levels alone are unlikely to cause clinically significant heart disease in healthy people.

“These were not dramatic changes that we observed, but moderate changes to cardiac electrical activity,” he said. “However, they were particularly pronounced in certain subpopulations.”

He said the altered cardiac activity could exacerbate existing heart disease or arrhythmias in a patient, especially older adults or those with other risk factors.

“Now there are new chemicals out there, so the next step would be to examine these newer environmental chemicals and to focus on their impact on an individual level in those who are predisposed to heart disease,” said Wang.

Other contributors in this study included Susan Pinney, PhD, FACE, professor of epidemiology in the Department of Environmental and Public Health Sciences; Jack Rubinstein, MD, FACC, professor of clinical cardiology in the Department of Internal Medicine; and Changchun Xie, PhD, professor in the Department of Biostatistics, Health Informatics and Data Sciences.

This study was funded by grants from the National Institute of Environmental Health and the University of Cincinnati Center for Environmental Genetics.

A team of astronomers led by University of Arizona researchers has used NASA’s James Webb Space Telescope to obtain some of the most detailed insights into the forces that shape protoplanetary disks. The observations offer glimpses into what our solar system may have looked like 4.6 billion years ago.

Specifically, the team was able to trace so-called disk winds in unprecedented detail. These winds are streams of gas blowing from the planet-forming disk out into space. Powered largely by magnetic fields, these winds can travel tens of miles in just one second. The researchers’ findings, published in Nature Astronomy, help astronomers better understand how young planetary systems form and evolve.

According to the paper’s lead author, Ilaria Pascucci, a professor at the U of A’s Lunar and Planetary Laboratory, one of the most important processes at work in a protoplanetary disk is the star eating matter from its surrounding disk, which is known as accretion.

“How a star accretes mass has a big influence on how the surrounding disk evolves over time, including the way planets form later on,” Pascucci said. “The specific ways in which this happens have not been understood, but we think that winds driven by magnetic fields across most of the disk surface could play a very important role.”

Young stars grow by pulling in gas from the disk that’s swirling around them, but in order for that to happen, gas must first shed some of its inertia. Otherwise, the gas would consistently orbit the star and never fall onto it. Astrophysicists call this process “losing angular momentum,” but how exactly that happens has proved elusive.

To better understand how angular momentum works in a protoplanetary disk, it helps to picture a figure skater on the ice: Tucking her arms alongside her body will make her spin faster, while stretching them out will slow down her rotation. Because her mass doesn’t change, the angular momentum remains the same.

For accretion to occur, gas across the disk has to shed angular momentum, but astrophysicists have a hard time agreeing on how exactly this happens. In recent years, disk winds have emerged as important players funneling away some gas from the disk surface — and with it, angular momentum — which allows the leftover gas to move inward and ultimately fall onto the star.

Because there are other processes at work that shape protoplanetary disks, it is critical to be able to distinguish between the different phenomena, according to the paper’s second author, Tracy Beck at NASA’s Space Telescope Science Institute.

While material at the inner edge of the disk is pushed out by the star’s magnetic field in what is known as X-wind, the outer parts of the disk are eroded by intense starlight, resulting in so-called thermal winds, which blow at much slower velocities.

“To distinguish between the magnetic field-driven wind, the thermal wind and X-wind, we really needed the high sensitivity and resolution of JWST (the James Webb Space Telescope),” Beck said.

Unlike the narrowly focused X-wind, the winds observed in the present study originate from a broader region that would include the inner, rocky planets of our solar system — roughly between Earth and Mars. These winds also extend farther above the disk than thermal winds, reaching distances hundreds of times the distance between Earth and the sun.

“Our observations strongly suggest that we have obtained the first images of the winds that can remove angular momentum and solve the longstanding problem of how stars and planetary systems form,” Pascucci said.

For their study, the researchers selected four protoplanetary disk systems, all of which appear edge-on when viewed from Earth.

“Their orientation allowed the dust and gas in the disk to act as a mask, blocking some of the bright central star’s light, which otherwise would have overwhelmed the winds,” said Naman Bajaj, a graduate student at the Lunar and Planetary Laboratory who contributed to the study.

By tuning JWST’s detectors to distinct molecules in certain states of transition, the team was able to trace various layers of the winds. The observations revealed an intricate, three-dimensional structure of a central jet, nested inside a cone-shaped envelope of winds originating at progressively larger disk distances, similar to the layered structure of an onion. An important new finding, according to the researchers, was the consistent detection of a pronounced central hole inside the cones, formed by molecular winds in each of the four disks.

Next, Pascucci’s team hopes to expand these observations to more protoplanetary disks, to get a better sense of how common the observed disk wind structures are in the universe and how they evolve over time.

“We believe they could be common, but with four objects, it’s a bit difficult to say,” Pascucci said. “We want to get a larger sample with James Webb, and then also see if we can detect changes in these winds as stars assemble and planets form.”