Interoception - Apnea & Parkinson's - Estradiol & Reward - 5 Stages of Brain Development

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Nov 26, 2025, 7:11:14 AM (22 hours ago) Nov 26

https://www.nytimes.com/2025/11/25/science/brain-neuroscience-interoception.html

Mapping the Sense of What’s Going On Inside

By Carl Zimmer

Last year, Ardem Patapoutian got a tattoo. An artist drew a tangled ribbon on his right arm, the diagram of a protein called Piezo. Dr. Patapoutian, a neuroscientist at Scripps Research in San Diego discovered Piezo in 2010, and in 2021 he won a Nobel Prize for the work. Three years later, he decided to memorialize the protein in ink.

Piezo, Dr. Patapoutian had found, allows nerve endings in the skin to sense pressure, helping to create the sense of touch. “It was surreal to feel the needle as it was etching the Piezo protein that I was using to feel it,” he recalled.

Dr. Patapoutian is no longer studying how Piezo informs us about the outside world. Instead, he has turned inward, to examine the flow of signals that travel from within the body to the brain. His research is part of a major new effort to map this sixth, internal sense, which is known as interoception.

Scientists are discovering that interoception supplies the brain with a remarkably rich picture of what is happening throughout the body — a picture that is mostly hidden from our consciousness. This inner sense shapes our emotions, our behavior, our decisions, and even the way we feel sick with a cold. And a growing amount of research suggests that many psychiatric conditions, ranging from anxiety disorders to depression, might be caused in part by errors in our perception of our internal environment.

Someday it may become possible to treat those conditions by retuning a person’s internal sense. But first, Dr. Patapoutian said, scientists need a firm understanding of how interoception works. “We’ve taken our body for granted,” he said.

Everyone has a basic awareness of interoception, whether it’s a feeling of your heart racing, your bladder filling or a flock of butterflies fluttering in your stomach. And neuroscientists have long recognized interoception as one function of the nervous system. Dr. Charles Sherrington, a Nobel Prize-winning neuroscientist, first proposed the existence of “intero-ceptors,” in 1906.

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https://www.nytimes.com/2025/11/24/well/mind/sleep-apnea-parkinsons-disease.html

Sleep Apnea Linked to Parkinson’s Disease

By Caroline Hopkins Legaspi

In a study published Monday in JAMA Neurology, researchers linked obstructive sleep apnea, a condition that causes temporary pauses in breathing during sleep, with Parkinson’s disease.

Parkinson’s disease is a progressive nervous system disorder that causes tremors, stiffness, and difficulty speaking, moving and swallowing. It is the second-most common neurodegenerative disease in the United States, after Alzheimer’s disease, with 90,000 people diagnosed each year.

There is no cure for Parkinson’s disease, said Dr. Lee Neilson, a neurologist at Oregon Health & Science University who led the study. But the researchers did find that treating sleep apnea with a continuous positive airway pressure (or CPAP) machine was associated with a reduced likelihood of developing Parkinson’s.

So identifying those at highest risk for the neurological condition — and intervening early, Dr. Neilson said, “might make the biggest impact.”

The researchers analyzed medical records from more than 11 million U.S. veterans treated through the Department of Veterans Affairs between 1999 and 2022. The group was predominantly male with an average age of 60, representing those at highest risk for sleep apnea, experts said.

The researchers found that about 14 percent of the participants had been diagnosed with sleep apnea between 1999 and 2022, according to their medical records. When the researchers looked at their health six years after those diagnoses, they found that the veterans with sleep apnea were nearly twice as likely to have developed Parkinson’s disease compared with those who had not been diagnosed with sleep apnea.

This held even after controlling for other factors that could influence the development of sleep apnea or Parkinson’s disease, including high body mass index and conditions like diabetes, high blood pressure, traumatic brain injuries and depression.

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https://www.thetransmitter.org/sex-hormones/sex-hormone-boosts-female-rats-sensitivity-to-unexpected-rewards/

Sex hormone boosts female rats’ sensitivity to unexpected rewards

By Angie Voyles Askham

Rats, like people, jump at the chance to repeat a task that rewards them handsomely, but they are less eager when the reward is paltry: They learn from past experience and update their behavior accordingly.

That learning is shaped by the hormone estradiol, according to a new study. And when estradiol levels peak during the estrus cycle, female rats adapt their behavior in response to reward size more quickly than they do during other phases—and faster than males overall. The female rats also have a larger release of dopamine in response to an unexpected reward, along with reduced expression of dopamine transporters in a reward center of their brain after the hormone peaks, the new work shows.

“It’s giving mechanistic insight into how estrogen modulates reinforcement learning—all the way down to the molecular mechanism,” says Ilana Witten, professor of neuroscience at Princeton University and Howard Hughes Medical Institute investigator, who was not involved in the study.

The team behind the new work used a task that measures how much an animal values an anticipated reward: Thirsty rats poke their nose into a central port and then listen for a tone that indicates how much water one of two side ports will dispense. The animals choose to either hold out at the cued location for the reward or to abandon the trial and start a new one by poking their nose into the other side.

Rats learn to initiate their next trial more quickly when the experiment is doling out large rewards and to hold off on initiating new trials when rewards are small, previous work from the group has shown. “It takes a lot of energy to initiate a trial, so if there are small rewards, it’s not as motivating,” says study investigator Carla Golden, a postdoctoral researcher in Christine Constantinople’s lab at New York University.

https://www.theguardian.com/science/2025/nov/25/brain-human-cognitive-development-life-stages-cambridge-study

Brain has five ‘eras’, scientists say – with adult mode not starting until early 30s

Hannah Devlin Science correspondent

Scientists have identified five major “epochs” of human brain development in one of the most comprehensive studies to date of how neural wiring changes from infancy to old age.

The study, based on the brain scans of nearly 4,000 people aged under one to 90, mapped neural connections and how they evolve during our lives. This revealed five broad phases, split up by four pivotal “turning points” in which brain organisation moves on to a different trajectory, at around the ages of nine, 32, 66 and 83 years.

“Looking back, many of us feel our lives have been characterised by different phases. It turns out that brains also go through these eras,” said Prof Duncan Astle, a researcher in neuroinformatics at Cambridge University and senior author of the study.

“Understanding that the brain’s structural journey is not a question of steady progression, but rather one of a few major turning points, will help us identify when and how its wiring is vulnerable to disruption.”

The childhood period of development was found to occur between birth until the age of nine, when it transitions to the adolescent phase – an era that lasts up to the age of 32, on average.

In a person’s early 30s the brain’s neural wiring shifts into adult mode – the longest era, lasting more than three decades. A third turning point around the age of 66 marks the start of an “early ageing” phase of brain architecture. Finally, the “late ageing” brain takes shape at around 83 years old.

The scientists quantified brain organisation using 12 different measures, including the efficiency of the wiring, how compartmentalised it is and whether the brain relies heavily on central hubs or has a more diffuse connectivity network.

From infancy through childhood, our brains are defined by “network consolidation”, as the wealth of synapses – the connectors between neurons – in a baby’s brain are whittled down, with the more active ones surviving. During this period, the study found, the efficiency of the brain’s wiring decreases.
© 2025 Guardian News & Media Limited
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https://www.nytimes.com/2025/11/24/health/ozempic-wegovy-alzheimers-novo-nordisk.html

GLP-1 Drug Fails to Quell Alzheimer’s in Novo Nordisk Trials

By Gina Kolata

Hopes were high. In retrospect, perhaps too high.

On Monday, Novo Nordisk announced that two large studies failed to find any effect of the drug semaglutide on cognition and functioning in people with mild cognitive impairment — an early stage of Alzheimer’s — or with dementia. The participants were randomly assigned to take a pill of semaglutide, the compound at the heart of the weight-loss injections Ozempic and Wegovy, or a placebo for two years.

“Today we announced that our efforts to slow down the progression of Alzheimer’s disease has come to an end,” said Maziar Mike Doustdar, chief executive at Novo Nordisk, in a video posted on LinkedIn.

He added, “Based on the indicative data points we had, this is not the outcome we had hoped for.”

The studies, involving 1,855 people in one trial and 1,953 in the other, seemed to stem an initial phase of optimism. The drugs appeared miraculous in their treatment of obesity, diabetes, heart disease and kidney disease. Alzheimer’s and other brain illnesses looked like the next frontier.

But there had been other recent warnings, in two smaller studies of brain diseases. One, done by researchers in Britain, asked if a similar drug could help with Parkinson’s disease. That drug had no effect.

Another study found that semaglutide did not help with cognitive impairment in people with major depression, a severe form of the disease.

The company will present more detailed results from its Alzheimer’s study at a conference on Dec. 3, and another in March of 2026.

Novo Nordisk’s stock was down nearly 6 percent on Monday, deepening a monthslong slump for the once-surging company.

“We always knew there would be a low likelihood of success, but it was important to determine if semaglutide could take on one of medicine’s most challenging frontiers,” Mr. Doustdar said.

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https://www.sciencenews.org/article/steps-slow-alzheimers-walk-physical

3,000 steps per day might slow Alzheimer’s disease

By Meghan Rosen

Taking just a few thousand steps daily could potentially stave off Alzheimer’s disease.

People with the disease tend to experience debilitating cognitive challenges, like memory loss and difficulty communicating, that worsen over time. But physical activity may slow that steady downward march.

In an observational study of people at risk for Alzheimer’s, researchers linked walking between 3,000 and 5,000 steps per day to a three-year delay in cognitive decline, compared with sedentary individuals. For people who walked between 5,000 and 7,500 steps per day, the reprieve appeared to last even longer — seven years, Harvard Medical School behavioral neurologist Jasmeer Chhatwal and his colleagues report November 3 in Nature Medicine.

The association still needs to be tested in a clinical trial, Chhatwal says, but his team’s results hint at something important. Quality of life for people with Alzheimer’s and their families often plummets in the later stages of the disease. “If the disease can be delayed,” he says, “that can have a very big impact on people’s lives.”

Previous studies have reported links between physical activity and delayed Alzheimer’s progression, says Deborah Barnes, an epidemiologist who studies dementia at the University of California, San Francisco, and who was not part of the research team. But the new study pinpoints the step count where people begin to see benefits. It also “helps to explain how,” she says.

Chhatwal’s team reported a connection between exercise and less accumulation of certain Alzheimer’s proteins in the brain. It’s a mechanism that illustrates how physical activity probably works to slow Alzheimer’s progression, Barnes says.

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