Balancing Excitation - Inequality & Brains - Facial Movements - Super Sleep

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Oct 1, 2025, 7:20:22 AM (yesterday) Oct 1

https://www.quantamagazine.org/how-the-brain-balances-excitation-and-inhibition-20250929/

How the Brain Balances Excitation and Inhibition

By Yasemin Saplakoglu

From Santiago Ramón y Cajal’s hand came branches and whorls, spines and webs. Now-famous drawings by the neuroanatomist in the late 19th and early 20th centuries showed, for the first time, the distinctiveness and diversity of the fundamental building blocks of the mammalian brain that we call neurons.

In the century or so since, his successors have painstakingly worked to count, track, identify, label and categorize these cells. There is now a dizzying number of ways to put neurons in buckets, often presented in colorful, complex brain cell atlases. With such catalogs, you might organize neurons based on function by separating motor neurons that help you move from sensory neurons that help you see or number neurons that help you estimate quantities. You might distinguish them based on whether they have long axons or short ones, or whether they’re located in the hippocampus or the olfactory bulb. But the vast majority of neurons, regardless of function, form or location, fall into one of two fundamental categories: excitatory neurons that trigger other neurons to fire and inhibitory neurons that stop others from firing.

Maintaining the correct proportion of excitation to inhibition is critical for keeping the brain healthy and harmonious. “Imbalances in either direction can be really catastrophic,” said Mark Cembrowski (opens a new tab), a neuroscientist at the University of British Columbia, or lead to neurological conditions. Too much excitation and the brain can produce epileptic seizures. Too little excitation can be associated with conditions such as autism.

Neuroscientists are working to uncover how these two classes of cells work — and specifically, how they interact with a rarer third category of cells that influence their behavior. These insights could eventually help reveal how to restabilize networks that get out of balance, which can even occur as a result of normal aging.

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https://www.theguardian.com/science/2025/sep/30/study-links-greater-inequality-to-structural-changes-in-childrens-brains

Study links greater inequality to structural changes in children’s brains

Tobi Thomas Health and inequalities correspondent

Scientists have linked the impact of living in an unequal society to structural changes in the brains of children – regardless of individual wealth – for the first time.

A study of more than 10,000 young people in the US discovered altered brain development in children from wealthy and lower-income families in areas with higher rates of inequality, which were also associated with poorer mental health.

The data was gathered from the Adolescent Brain Cognitive Development study and published in the journal Nature Mental Health.

Researchers at King’s College London, Harvard University, and the University of York then measured inequality within a particular US state by scoring how evenly income is measured. States with higher levels of inequality included New York, Connecticut, California and Florida, while Utah, Wisconsin, Minnesota and Vermont were more equal.

MRI scans were analysed to study the surface area and thickness of regions in the cortex, including those involved in higher cognitive functions including memory, emotion, attention and language. Connections between different regions of the brain were also analysed by the scans, where changes in blood flow indicate brain activity.

The research found that children living in areas with higher levels of societal inequality, including socioeconomic imbalances and deprivation for example, were linked to having a reduced surface area of the brain’s cortex, and altered connections between multiple regions of the brain.

The findings, the first to reveal the impact societal inequality has on the structures of the brain, also provided evidence that the impacted neurodevelopment might relate to future mental health and cognitive function. Notably, these brain changes in children were seen regardless of their economic background.

https://www.thetransmitter.org/motor-behavior/facial-movements-telegraph-cognition-in-mice/

Facial movements telegraph cognition in mice

By Lauren Schneider

Bad news for mouse poker players: Their facial movements offer “tells” about decision-making variables that the animals track without always acting on them, according to a study published today in Nature Neuroscience.

The findings indicate that “cognition is embodied in some surprising ways,” says study investigator Zachary Mainen, a researcher at the Champalimaud Center for the Unknown. And this motor activity holds promise as a noninvasive bellwether of cognitive patterns.

The study builds on mounting evidence that mouse facial expressions are not solely the result of a task’s motor demands and provides a “very clear” illustration of how this movement reflects cognitive processes, says Marieke Schölvinck, a researcher at the Ernst Strüngmann Institute for Neuroscience, who was not involved with the work.

For years, mouse facial movements have mostly served as a way for researchers to gauge an animal’s pain levels. Now, however, machine-learning technology has made it possible to analyze this fine motor behavior in greater detail, says Schölvinck, who has investigated how facial expressions reflect inner states in mice and macaques.

Evidence that mouse facial expressions correspond to emotional states inspired the new analysis, according to Fanny Cazettes, who conducted the experiments as a postdoctoral researcher in Mainen’s lab. She says she wondered what other ways the “internal, private thoughts of animals” might manifest on their faces.

Two variables shape most mouse decisions over different foraging sites, the team found: the number of failures at a site (unrewarded licks from a source of sugar water) and the site’s perceived value (the difference between reward and failure).
© 2025 Simons Foundation
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https://nautil.us/deep-sleep-is-this-mammals-super-power-1239714/?_sp=33b0540a-5645-403f-b701-c7676f178387.1759316561333

Deep Sleep Is This Mammal’s Super Power

By Katarina Zimmer

Few mammals sleep as deeply as the ampurta. When the blonde, rat-like marsupial returns to its burrow after a night of hunting in the Australian desert, it drifts into a slumber known as torpor. While many other mammals quickly burn through their energy reserves in order to maintain stable body temperatures as they fall asleep, ampurtas allow their bodies to cool down to as low as 50 degrees Fahrenheit, saving energy critical to survival in this harsh desert environment.

“I’ve held some when they’re in torpor, and they feel like they’ve been in a freezer,” says wildlife ecologist Dympna Cullen of the University of New South Wales in Sydney. Instead of using their own energy to warm up again, upon waking, the animals drag themselves to the mouths of their burrows to soak up the morning sun.

Some scientists say this energy-saving trick helped the ampurta—once thought doomed to extinction—to make a comeback during a severe drought. In what they call a “rare and hopeful conservation signal,” the authors document in a new study in Biological Conservation how, during a two-year drought that lasted from 2017 to 2019—one of the region’s harshest droughts on record—the vulnerable marsupials actually significantly extended their range, reclaiming a large chunk of lost habitat. “Everything crashes during a drought,” Cullen says, “so it was quite unexpected that not only were [ampurtas] increasing in abundance but also increasing their area of occupancy by quite a significant amount during a drought.”

Like many other Australian mammals, the ampurta—the Aboriginal name for Dasycercus hillieri or the crest-tailed mulgara—once seemed like it might vanish from the Earth. Rabbits brought to Australia by European colonists in the 19th century wreaked ecological havoc on the continent. They ravaged Australia’s vegetation, robbing small native herbivores of cover and food, including some of the ampurta’s prey, such as smaller mammals. The rabbit boom also fed the spread of non-native foxes and cats, which picked off ampurtas and other native wildlife. But in 1996, the Australian government released a rabbit-killing virus to quash rabbit populations, which allowed some native species populations to recover. Ampurtas were downgraded from endangered in the mid-1990s to “vulnerable” in 2013, and eventually to a species of “least concern.”

https://www.nature.com/articles/d41586-025-03148-8

How to get the best night’s sleep: what the science says

Lynne Peeples

From TikTok videos touting mouth tape and weighted blankets, to magazines ranking insomnia-curbing pillows, sleep advice is everywhere. And it’s no wonder. People all over the world complain of insomnia and not getting enough sleep, driving a market for sleep aids worth more than US$100 billion annually.

But scientists warn that online hacks and pricey tools aren’t always effective. And failed attempts to remedy the situation could have negative effects, says Andrew McHill, a circadian scientist at Oregon Health & Science University in Portland. “It could discourage people from finding help, and things could get worse,” he says.

Instead, researchers point to the lessons coming from circadian science, which over the past five decades has exposed a network of biological clocks throughout the body. This timekeeping machinery ensures that physiological systems are primed to do the right things at the right times — such as defend against pathogens, digest food and sleep. But circadian clocks don’t cycle precisely on their own. To stay in sync and function optimally, they need regular calibration from sunlight, daily routines and other cues.

Modern life doesn’t often cooperate. People spend much of their time indoors. They eat late into the night. They shift sleep schedules between workdays and weekends, effectively jet-lagging themselves. The toll is steep. In the short term, circadian disruption and insufficient sleep can reduce cognition, mood and reaction time. In the long term, they can increase risks of infections, diabetes, depression, dementia, cancer, heart disease and premature death.

For better sleep and overall health, McHill and other scientists emphasize three basics: contrasting light and dark, consolidating mealtimes and keeping sleep times consistent. “Simply taking a walk outside during the day and reducing our light exposure in the evening could have great effect,” says McHill.

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https://www.nytimes.com/2025/10/01/health/autism-spectrum-neurodiversity-kennedy.html

Should the Autism Spectrum Be Split Apart?

By Azeen Ghorayshi

As a child, Jodie Singer barely spoke. She could repeat words that people said to her or recite the book “Madeline” from beginning to end, but she could not answer yes or no when her mother asked if she wanted juice.

Sometimes she hurt herself, compulsively tearing at the skin and hair on the nape of her neck. She threw tantrums, thrashing and refusing to be comforted.

When she was almost 3, Jodie was given a diagnosis of autism. Now 28, she still speaks only in short, repetitive phrases and requires round-the-clock care, including help eating, getting dressed and using the toilet.

At the time Jodie’s diagnosis was first made, the definition of autism was expanding, as it would continue to do over the next 25 years. Once primarily limited to severely disabled people, autism began to be viewed as a spectrum that included far less impaired children and adults. Along the way, it also became an identity, embraced by college graduates and even by some of the world’s most successful people, like Elon Musk and Bill Gates.

That broadening of the diagnosis, autism experts believe, along with the increasing awareness of the disorder, is largely responsible for the steep rise in autism cases that Health Secretary Robert F. Kennedy Jr. has called “an epidemic” and has attributed to theories of causality that mainstream scientists reject, like vaccines and, more recently, Tylenol.

And the diagnostic expansion has now become a flashpoint in a long-running debate over how autism should defined, one that has divided parents and activists, ignited social media battles and grown fiercer with Mr. Kennedy’s laser focus on autism.

Speaking of autistic children in the spring, Mr. Kennedy said, “These are kids who will never pay taxes, they’ll never hold a job, they’ll never play baseball, they’ll never write a poem, they’ll never go out on a date.”

His words drew a swift backlash from many autistic adults, who called his characterization of their lives false and dehumanizing. But Jodie’s mother, Alison Singer, said that, though she disagrees with Mr. Kennedy’s views on the causes of autism, his words about the harsh realities of living with the disorder spoke to families like her own.