Visualizing Nerves - Adult Neurogenesis - Keeping Time - Antidepressant Withdrawal
Breedlove, S
https://www.nature.com/articles/d41586-025-02156-y
Giant map details nerves across a mouse’s body: see stunning pics
Mariana Lenharo
A speedy imaging method can map the nerves running from a mouse’s brain and spinal cord to the rest of its body at micrometre-scale resolution, revealing details such as individual fibres travelling from a key nerve to distant organs1.
Previous efforts have mapped the network of connections between nerve cells, known as the connectome, in the mouse brain. But tracing the complex paths of nerves through the rest of the body has been challenging. To do so, the creators of the new map used a custom-built microscope to scan exposed tissue, completing the process in just 40 hours.
Nerves look blue in the reconstructed view of a genetically engineered mouse (left) whose neurons produce a fluorescent marker. In a separate animal (right), antibodies detail the sympathetic nerves (purple). Credit: M.-Y. Shi et al./Cell (CC-BY-4.0)
The method, described today in Cell, is an important technical achievement, says Ann-Shyn Chiang, a neuroscientist at the National Tsing Hua University in Hsinchu, Taiwan, who was not involved with the research. “This work is a major step forward in expanding connectomics beyond the brain,” he says.
To prepare a mouse’s body for the scan, researchers treat it with chemicals that make its tissues transparent by removing fat, calcium and other components that block light. This provides a clear view of the nerves, which have been labelled with fluorescent marker proteins. The see-through body is then placed into a device that combines a slicing tool and a microscope that takes 3D images.
A piston gradually pushes the mouse towards the slicing blade, 400 micrometres at a time. After each slice, a microscope images the newly exposed surface of the mouse, capturing details up to 600 micrometres deep — roughly the thickness of six sheets of paper — below the surface. The body then advances for the next cut. The cycle repeats around 200 times without pause, to cover the entire body. The images are then combined.
© 2025 Springer Nature Limited
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Machine learning spots neural progenitors in adult human brains
By Claudia López Lloreda
Neural progenitor cells exist in the adult human hippocampus all the way into old age, a new transcriptomics study published today in Science suggests.
The results strengthen the claim that adults can form new neurons, according to the team behind the work. But not everyone is convinced that the study shows progenitors are prevalent enough in adulthood to really matter.
“Look, there might be something,” says Juan Arellano, a research scientist in neuroscience at Yale University who was not involved with the study. But the cells seem to be rare, because the team could not identify them without the help of a machine-learning algorithm, he adds. “Are they really so relevant in the circuit?”
Although the researchers did not quantify the number of cells in their study, newborn neurons are highly excitatory and plastic, so they might still contribute functionally even if there are few, says study investigator Ionut Dumitru, research specialist in Jonas Frisén’s lab at the Karolinska Institutet.
Proliferating neurons in adults were first documented in a 1998 study that used a synthetic nucleoside to track newly synthesized DNA in newborn cells. Subsequent work involving carbon dating, lineage tracing and tissue-staining techniques bolstered the idea that people can continue to produce new neurons after childhood.
But other studies that stained for cellular markers of neurogenesis suggest that few neurons are born in adults, and the rate of neurogenesis declines dramatically during the first few years of life. These results led some researchers in the field to question the extent and role of neurogenesis in the adult brain, says Shawn Sorrells, assistant professor of neuroscience at the University of Pittsburgh, who conducted some of these cellular marker studies but was not involved with the new one.
© 2025 Simons Foundation
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Does Anybody Really Know What Time Is?
By Dan Falk
I’ve been fascinated by time for as long as I can remember. In my undergraduate physics classes, time always lurked in the background—it was the “t” that the professors sprinkled into their equations—but it was never quite clear what time actually was. Years later, I wrote a book about time, but even with chapters on Newton and Einstein, and a solid dose of philosophy, something was missing.
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For starters, we know clocks and watches work, but how do we tell time? If you’re watching network TV and a commercial break begins, you know you have time to use the bathroom or perhaps make a sandwich—in fact, you can probably arrange to be back in front of the TV just as the ads are ending. What makes you so good at judging these intervals of time?
I figured that Dean Buonomano, being a neuroscientist, might have some of the answers. Buonomano is known for developing the idea that the key mechanism is not a single clock-like structure in the brain but rather networks of neurons working together, known as “neural dynamics.”
But as Buonomano sees it, the brain does much more than keep track of time; in fact, it might be said to create it. It’s thanks to our brains that we feel time’s “flow,” even though nothing in physics points to such a flow out there in the world. Perhaps even more crucially, the brain allows us to engage in “mental time travel”—the ability to recall past events and imagine future happenings. This capability, he argues, was essential in shaping humanity’s path from the African savannah to today’s globe-spanning civilization.
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https://www.nytimes.com/2025/07/09/health/antidepressants-withdrawal-symptoms.html
New Research Questions Severity of Withdrawal From Antidepressants
By Ellen Barry
Few practices in mental health are debated more than the long-term use of antidepressant medications, which are prescribed to roughly one in nine adults in the United States, according to data from the Centers for Disease Control and Prevention.
A reassessment began in 2019, when two British researchers published a study that found that 56 percent of patients suffered from withdrawal symptoms when they stopped antidepressant medications and that 46 percent of those described their symptoms as severe.
The findings made headlines in Britain and had a powerful ripple effect, forcing changes to psychiatric training and prescribing guidelines. And they fed a growing grass-roots movement calling to rein in the prescription of psychotropic drugs that has, in recent months, gained new influence in the United States with the rise of Robert F. Kennedy Jr. as health secretary.
A new study, published on Wednesday in the journal JAMA Psychiatry, makes the case that these warnings were overblown. The authors of the new paper found that a week after quitting antidepressants, patients reported symptoms like dizziness, nausea and vertigo, but that they remained, on average, “below the threshold for clinically significant” withdrawal.
Dr. Sameer Jauhar, one of the authors, said the new analysis should reassure both patients and prescribers.
“The messaging that came out in 2019 was all antidepressants can cause this and this can happen in this proportion of people, and that just doesn’t survive any scientific scrutiny,” said Dr. Jauhar, a professor of psychiatry at Imperial College London.
He criticized the earlier study for including data from online surveys as a quantitative measure, for failing to control for the placebo effect, and for failing to distinguish between various types of antidepressants. These methodologies, he said, led to inflated estimates of withdrawal.
© 2025 The New York Times Company
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Why a new opioid alternative is out of reach for some pain patients
Sydney Lupkin
Jerry Abrams, a 64-year-old marketing strategist in Minneapolis, used to run marathons.
But two decades of degenerative spine disease have left him unable to run — and he's grieving.
For Abrams, losing running felt like "the loss of a loved one – that friend who's been with you every day you needed him.
"You know, having that taken away from you because of pain is the hardest thing of all," he says.
The constant pain in his lower back makes running impossible. Sometimes, when the pain isn't under control, he can't get out of bed.
Abrams has tried taking opioids. They help, but he feels he has to be careful because they're potentially addictive. He's also worried about building up a tolerance to them
"I don't ever want to be in a situation where I need surgery and need to recover and opioid medication no longer does what it needs to do," he explains.
The Food and Drug Administration approved a new non-opioid drug earlier this year called Journavx. It's a pill for severe acute pain that works by blocking plain signals from where someone hurts.
It's offered hope for the 1 in 5 Americans who suffer from chronic pain, but it's also just out of reach. Journavx is the first new kind of painkiller in more than 20 years, and the medical community is cautiously optimistic that Journavx doesn't have the same addictive potential as opioids do.
But the new pills are expensive, and not everyone has been able to access them, thanks to a narrowly-focused FDA approval and limited insurance coverage
Abrams' doctor wanted him to be able to try Journavx. But the FDA only approved the medication for short-term use for acute pain, which is usually defined as lasting less than three months, such as right after surgery.
Because Abrahm's pain is chronic, his insurance wouldn't cover it.
A single Journavx pill costs around $15 without insurance, according to Vertex Pharmaceuticals, the drug's manufacturer.
© 2025 npr
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