Vivid dreaming makes sleep feel deeper, researchers discover

Researchers  have discovered a key relationship between dreaming and the feeling of having had a good night's sleep. Published in PLOS Biology, the study shows that the feeling of deep sleep is not determined solely by slow-wave brain activity. Rather, immersive dreaming that comes with increases in wake-like brain activity leads to a greater feeling of deep sleep.

Why is it that sometimes we sleep eight hours and don't feel rested, while other times we feel like we had a great night's sleep after only five hours? Research has shown that our feeling of deep sleep is related to a shift from high- to low-frequency brain waves, which is thought to drive unconsciousness. At the same time, other reports indicate that dream (REM) sleep is also perceived as deep, despite its wake-like brain waves.

To better characterize the effects of dream sleep on perceived sleep depth, the researchers analyzed EEG recordings from 44 adults who were repeatedly awoken during non-REM sleep over the course of four nights.

Analysis showed that shifts from faster to slower waves were indeed associated with a feeling of deep sleep. However, this relationship weakened when participants reported having had a dream, even if they could not remember the content.

Perceived sleep depth was thus higher after dreaming, even though this state is associated with wake-like brain activity. Specifically, vivid, bizarre, and emotionally intense dreams were all associated with subjectively deeper sleep, while abstract, reflective thought-like dreams with meta-awareness were related to more shallow feeling sleep.

These findings are contrary to the longstanding view that the feeling of deep sleep is governed solely by slow brain waves and the depth of unconsciousness, and suggest that perceptually immersive dreaming is what allows us to feel well rested—even if we can't remember what we dreamed.

This study suggests that dreams may help shape how we experience sleep by immersing us in an internal world that keeps us disconnected from the external environment.

Understanding how dreams contribute to the feeling of deep sleep opens new perspectives on sleep health and mental well-being.

Michalak A, et al. Immersive NREM2 dreaming preserves subjective sleep depth against declining sleep pressure. PLOS Biology (2026). DOI: 10.1371/journal.pbio.3003683

Severe infections may raise dementia risk

Severe infections increase the risk of dementia independently of other coexisting illnesses, according to a new study published in the open-access journal PLOS Medicine 

In the new study, researchers used nationwide Finnish health registry data covering more than 62,000 individuals aged 65 or older who were diagnosed with late-onset dementia between 2017 and 2020, along with more than 312,000 matched dementia-free controls.
Taking a broad approach, they examined all hospital-treated diseases recorded during the previous twenty years, identifying 29 diseases that were robustly associated with increased dementia risk. Nearly half (47%) of dementia cases had at least one of the 29 identified diseases before their diagnosis.

Of those diseases, two were infections: cystitis (a urinary tract infection) and bacterial infection of an unspecified site. Among the non-infectious diseases, the strongest associations with dementia were seen for mental disorders due to brain damage or physical disease, Parkinson's disease, and alcohol-related mental and behavioral disorders.

When the researchers then adjusted for all 27 non-infectious dementia-related diseases identified, the association between both infections and dementia remained largely intact. Less than one-seventh of the excess dementia risk among individuals with hospital-treated cystitis or bacterial infections was attributable to pre-existing conditions.

The link between infections and dementia was even stronger for early-onset dementia (diagnosed before age 65), where five types of infection—including pneumonia and dental caries—were associated with elevated risk.

The role of noninfectious comorbidities in the association between severe infections and risk of dementia in Finland: A nationwide registry study, PLOS Medicine (2026). DOI: 10.1371/journal.pmed.1004688. plos.io/4qY5nix

CERN hails delicate test on transporting antimatter as a scientific success

CERN successfully transported antiprotons by road for the first time, using a cryogenic, magnetically shielded vacuum trap to prevent contact with matter and annihilation. The test demonstrated the feasibility of moving antimatter safely, enabling future high-precision studies of fundamental symmetries outside CERN, though current containment is limited to about four hours.
Manipulating antimatter, like antiprotons, can be tricky business. As scientists understand the universe today, for every type of particle that exists, there is a corresponding antiparticle, exactly matching the particle but with an opposite charge.
If those opposites come into contact, they "annihilate" each other, setting off lots of energy, depending on the masses involved. Any bumps in the road on the test journey that aren't compensated for by the specially-designed box could spoil the whole exercise.

Scientists in Geneva took some antiprotons out for a spin—a very delicate one—in a truck, in a never-tried-before test drive that has been deemed a success.
If this so-called antimatter had come into contact with actual matter, even for a fraction of an instant, it would have been annihilated in a quick flash of energy. So experts at the European Organization for Nuclear Research, known as CERN, had to be extra careful when they took 92 antiprotons on the road for a short ride on Tuesday.

The antiprotons were suspended in a vacuum inside a specially designed box and held in place by supercooled magnets.

In methodical exercise over about three hours, the nearly 1,000-kilogram (2,200-pound) cryogenic box was craned up slowly and moved through a cavernous lab the onto the truck.

The drive on CERN's campus itself lasted only about a half-hour to test how—if at all—the infinitesimal particles could be transported by road without seeping out.
The antiprotons were then placed back in their usual lab area, and the operation was concluded with applause, claims of success

Source: CERN