In a new study, the researchers found that movement-induced chronic back pain was tied to increased activity in the brain's default mode network, a group of connected brain regions that lights up during self-reflection and mind wandering. This finding was unexpected because the network typically becomes less active during acute pain, such as transient pain triggered from touching a hot stove or banging your knee on a table.

The new study, published Oct. 5 in the British Journal of Anaesthesia, suggests that chronic-pain flare-ups may involve brain processes beyond those responsible for detecting painful sensations.

How the brain responds to chronic pain

Chronic lower back pain, defined as lasting at least three months, is a leading cause of disability worldwide. It's thought that when chronic pain first begins, a network of regions in the brain called the "pain neuromatrix" becomes sensitized so that the pain persists even after the painful stimulus is gone. Although scientists know that chronic pain is associated with changes in brain activity, they don't fully understand what happens when movements trigger sudden increases in that ongoing pain.

To investigate, researchers recruited 114 adults with chronic lower back pain and used functional magnetic resonance imaging (fMRI) to examine their brain activity. fMRI measures changes in blood flow, which acts as an indirect measure of brain activity.

After an initial scan, a researcher helped lift each participant's leg until their back pain increased, held it in position for 10 seconds, and then lowered it. The researchers scanned the participants' brains immediately after this pain-inducing leg movement and compared the results with scans collected beforehand. On average, the test increased the participants' reported pain intensity by 23%.

As expected, during the leg movement, the researchers observed increased blood flow in brain regions involved in processing pain and movement. But they also detected increased activity in key regions of the default mode network, which typically becomes more active when a person is thinking about themselves or their autobiographical memories or just letting their mind wander.

Acute pain lowers activity in the default mode network, studies show, presumably because it induces an awareness of something separate from yourself.

"When we saw just the first round of analysis, we're like, 'Did we do it right?'" study co-author Morgan Gianola, a postdoctoral scholar at the University of California, San Diego, told Live Science.

"We did not expect [the default mode network] to be involved at all," said study co-author Fadel Zeidan, a neuroscientist at UC San Diego, told Live Science. "We expected it to be deactivated to the point that we had to triple-check our work to make sure that the results were legit."

The researchers also exposed participants' calves to painful heat ‪—‬ a common method of studying brain activity during acute pain. Unlike the movement-induced back pain, the heat was associated with reduced activity in part of the default mode network, suggesting a different mechanism was at play.

When pain becomes part of our internal experience

Participants who reported more severe chronic back pain had stronger connectivity between the default mode network and brain regions that process sensations from the back. This suggests that chronic pain may become intertwined with how people perceive themselves and their bodies, the study authors concluded.

"This pain flare has almost become a part of who they are from an egocentric perspective," Zeidan said.

Katherine Martucci, a neuroscientist at Duke University who wasn't involved in the study, praised the experimental design, noting that researchers typically avoid movement during brain scans because it can interfere with the clarity of the scan. This study "nicely gets around" that problem by taking scans before and after the painful motion, Martucci told Live Science in an email.

However, she noted that the observed brain activity could also reflect lingering pain or anxiety following the painful leg raise. In addition, the study couldn't determine whether the altered brain activity observed contributes to chronic pain or develops in response to it.

Nonetheless, Zeidan and colleagues think the findings could eventually inform future treatments for chronic pain. The therapies might address how people relate to their pain, rather than solely targeting the painful sensations themselves. Zeidan, who coincidentally developed chronic back pain while conducting the study, believes that people's past experiences and memories with chronic pain have influenced their brain processes to a point where the pain itself becomes part of who they are.

Zeidan's team is now investigating whether existing approaches, such as mindfulness meditation or cognitive behavioral therapy, can influence the default mode network and help relieve chronic pain. (Cognitive behavior therapy for chronic pain, or CBT-CP, is already a well-established treatment option.)

Martucci cautioned that it's too early to draw conclusions about how these results might be applied in clinical practice. But she said the current findings provide important evidence of how the brain responds to chronic pain flare-ups.

"They do provide solid data on how people with chronic low back pain show important changes in their brain responses after a condition provoking their pain," she said. "The brain imaging data validate their [the participants'] experience of pain in an important and very visible way."

This article is for informational purposes only and is not meant to offer medical advice.

'> Chronic back pain may activate an unexpected brain network, study finds PNAS.

"Family stories of an Indigenous ancestor are very common" in Quebec, study first author Diane Martin-Moya, a biological anthropologist at the University of Quebec in Trois-Rivières in Canada, told Live Science in an email, and "commercial genealogy and DNA tests have amplified this." But distant or claimed Indigenous identities can actually undermine the rights, resources and recognition of Indigenous nations, she said.

To learn more about the founders of Quebec, Martin-Moya and co-authors investigated Notre-Dame Cemetery, which was established in Montreal in 1683 and used for Catholic burials until 1796. Based on previous studies of the skeletons in the cemetery, experts disagreed on whether people of Indigenous, European, African or mixed ancestry were buried there. To settle the question, Martin-Moya and her colleagues sequenced DNA from 45 people buried in the cemetery and compared it with the genomes of people from Europe, West Africa and Indigenous groups in the Americas.

"The ancient DNA showed that all 45 individuals we analyzed had French European ancestry, with no sign of recent Indigenous or African admixture," Martin-Moya said of the research, which she conducted while at the University of Montreal.

These findings suggest that people descended from Indigenous and African populations may have been marginalized in early Montreal, challenging the popular narrative of cooperation and intermarriage, she said.

"Our sample is small and comes from a single cemetery, so this does not show that such unions never happened," Martin-Moya cautioned. "It is, however, consistent with genealogical and genetic studies suggesting that Indigenous ancestry among present-day French Canadians is very limited."

The apparent lack of genetic mixing among European, African and Indigenous populations in this cemetery group "provides a perspective on population relationships during the colonial period, one where perhaps nongenetic interactions were present but no biological relationships were found," Raquel Fleskes, a molecular anthropologist at Dartmouth College who was not involved in the research, told Live Science.

The DNA helped the researchers find several genetic lineages of people that spanned multiple generations. But the graves were scattered across multiple areas of the cemetery, suggesting that burials were not organized into family plots. This finding suggests that, in the 17th century, people in Montreal may have been burying their dead in a way that was not defined by strict biological kinship ties, Fleskes said.

One cemetery, many possibilities

Martin-Moya stressed that the results of the new study do not necessarily apply to all of colonial Montreal.

"Not identifying recent Indigenous or African admixture in this sample does not imply that Indigenous or African-descended people were absent from the city," Martin-Moya said.

In addition, "biological ancestry cannot by itself establish Indigenous belonging," as it "is rooted in kinship, community and relationships with land, not in blood or DNA," she added.

Changes in the use of the cemetery over time also may have influenced the findings, as reburials and later urban development disturbed or destroyed earlier graves.

"Those buried inside the church, mostly clergy and wealthier residents, were more likely to be exhumed and moved," Martin-Moya explained, while the city's poorer residents were buried outside the church and further buried beneath the expanding city. This means that the skeletons in the study may have been the remains of lower-class French colonists.

Archival records show that some Indigenous people were buried in Catholic cemeteries in Montreal as early as the 17th century, Martin-Moya said. "Over time, though, Indigenous communities were increasingly separated from the colonial town through land dispossession and the relocation of missions away from urban centers," she explained. "Their dead would most likely have been buried in those communities. Enslaved people, both Indigenous and African, were often buried on their enslaver's property or in cemeteries for the poor."

The results of the study don't mean that Québécois have no Indigenous ancestors or that relations between French settlers and Indigenous peoples were only hostile, Martin-Moya said. Those relationships were complex and included alliances, trade, conflict and, sometimes, family ties.

"What our results suggest is that when such ancestry exists, it needs to be put in context," Martin-Moya said. "A single ancestor who lived more than 300 years ago does not say the same thing about a person today as being raised within an Indigenous family, community or nation."

How much do you know about the first people to reach the Americas? Find out with our First Americans quiz!

'> DNA from centuries-old skeletons buried in Montreal reveals no genetic mixing between Indigenous people and French colonists

There is currently no cure, so existing treatments aim to alleviate the symptoms. Hormonal medications can stall the menstrual cycle to limit the growth and inflammation of the lesions, while surgery can physically remove lesions. However, the former can come with side effects, such as nausea and mood swings, and lesions often regrow after surgery. So additional options are needed.

In previous research with mice, study co-author Kanako Hayashi, a professor in the Washington State University School of Molecular Biosciences, identified a group of rogue immune cells specific to endometrial lesion tissue. These cells turbocharged the painful inflammatory reactions and drove the growth of more of this problematic tissue.

The cells also happen to have a unique chemical label, called a folate receptor, which makes them an excellent potential drug target. But why start from scratch when there's an existing medication that might do the trick?

Enter niclosamide, a drug approved by the Food and Drug Administration to treat tapeworm infections. In recent years, clinicians have been exploring whether this medicine could also prove effective for other conditions, ranging from cancer to Parkinson's disease.

"We have reported that niclosamide inhibits endometriosis progression, suppressing the inflammatory mechanisms and cytokine secretions," said Hayashi, referencing more of the group's past work in mice. However, several issues made the drug impractical: It doesn't dissolve well in water, last long in the body, or target the cells where it's needed most.

So the researchers teamed up with Anjali Sharma, a nanomedicine specialist at the University of Michigan, to tweak the drug's structure. Using click chemistry — a simple reaction that bolts together two chemical building blocks — Sharma attached the niclosamide unit to a large, tree-like molecule called a dendrimer. This helped the drug dissolve better in blood.

She then added a folate group, which ensured that the modified medication would only target the rogue immune cells with the complementary receptor.

"The drug is attached in such a way that when it is in systemic circulation, nothing happens until it goes inside the diseased cells," Sharma said. Once there, it is slowly released inside the cell over a period of two weeks. "Basically, the dendrimer is like the Uber, the folate is like the GPS, and the drug is like the passenger," she explained.

The next steps

With these practical issues resolved, the team tested the modified drug in a mouse model, which mimics the lesions seen in endometriosis in humans. Scans of the mice showed that the treatment directly zeroed in on the affected endometrial tissue and didn't accumulate in other organs, like the liver.

Treating mice with a single injection dramatically reduced their pain symptoms, compared with untreated mice. It also slowed ‪—‬ or, in some cases, entirely halted ‪—‬ the growth of new lesions.

Because mice don't naturally menstruate or develop endometriosis, there is still significant work to do before these findings can be replicated in humans. But for now, the study is a promising stepping stone for future research, Simitsidellis said.

"There's a lot of potential in repurposing of drugs that have been tested in clinical trials to see if they would be effective in endometriosis ‪—‬ for example, targeting inflammation or immune cell dysfunction," he told Live Science. "The next steps would be to replicate on larger sample sizes and, if that's promising, do a phase one clinical trial in humans." That initial trial would test the treatment's safety in patients, while later trials would look at its effectiveness for endometriosis.

Even at this early stage, though, patients are clamoring to get involved in the upcoming research. Hayashi and Sharma have received hundreds of emails asking to join a future trial.

"They are really suffering," Hayashi said. "Endometriosis is an understudied, underacknowledged, underfunded disease, but hopefully we can make this a solution in the near future."

This article is for informational purposes only and is not meant to offer medical advice.

'> Tapeworm drug could help treat endometriosis, mouse study hints Kathleen Springer, a research geologist at the U.S. Geological Survey, said in a statement.

The White Sands footprints suggest that people from Asia reached the Americas via the region around the Bering Strait much earlier than scientists initially thought, challenging a long-held assumption that humans arrived on the continent around 13,000 years ago. While some scientists have disputed the methods used to date the footprints, evidence is building that they are around 23,000 years old.

White Sands contains footprints from various time periods, including footprints of a caregiver and a toddler who were there 10,000 years ago. Over thousands of years, people trudged across the New Mexico landscape alongside iconic ice age animals, including mammoths and giant ground sloths. The researchers have also discovered sled-like drag marks alongside ancient footprints at White Sands, providing evidence for a kind of travois — a wooden frame made from two poles bound together — that people likely would have used for transporting goods.

By looking at ancient pollen for the new study, researchers could deduce which plants grew across the millennia when humans lived in the area. The site's rock samples also contained waxes from plant leaves, membrane lipids from bacteria, and other organic molecules that helped the researchers better understand the environmental conditions of the time.

The analysis revealed that around 24,200 years ago, White Sands had a large lake and its surrounding mountains were coated in conifer trees (Pinus, Abies, and Picea). Then, over the next two millennia, temperatures rose, the lake began to shrink, and the conifer trees were replaced by oak trees (Quercus) and sagebrush, according to the statement.

"Throughout these periods of change, the people continued to visit and live in this area," study co-author Sally Reynolds, a paleoanthropologist at Bournemouth University in the U.K., said in the statement. "The sediments containing their footprints show us their environment changed significantly within individual human lifetimes."

The researchers speculated that people might have returned to White Sands at different times to benefit from the changing climate, with a shrinking lake potentially providing higher concentrations of animals and plants. However, while the footprints document that humans were present, they reveal little about their behavior.

"The footprints give us a snapshot of the people who lived there over 20,000 years ago," Reynolds said. "But they are not a continuous movie of their lives. They are individual frames — showing moments when humans, mud, water and chance came together."

'> Ancient Indigenous people in New Mexico lived through extreme climate change 23,000 years ago, study suggests artificial intelligence (AI) chatbots will "go rogue," suddenly switching from helpful responses to potentially harmful ones.

In a new study published Oct. 8 in the journal Patterns, physics professor Neil Johnson and doctoral student Frank Yingjie Huo, both at The George Washington University, show how the order in which a chatbot is given certain prompts can drastically reshape its answers, leading to "tipping points" that can send the chatbot down a rabbit hole of bad advice. However, Johnson and Huo say their formula can easily predict these tipping points.There have been horror stories of AI encouraging users into suicide, helping build lethal weapons, and amplifying violent or harmful points of view. At the same time, researchers at OpenAI and Anthropic, respectively, have repeatedly and openly stated that they don't really understand why their creations behave the way they do. They have, however, built safeguards that use a variety of tools ‪—‬ including content filtering, reinforcement learning and other technical guardrails ‪—‬ to reduce risks.

But Johnson sees those tools as insufficient. "The safety measures now are the equivalent of strapping big, bouncy cushions under a plane," he told Live Science. "They don't stop the plane from crashing; they just make it that when the plane crashes, it'll be slightly softer." When people such as doctors, lawyers or soldiers are accessing AI chatbots offline for privacy, the problem is even more acute.

Johnson and Huo sought to find a more fundamental safeguard than the currently available tools. In doing so, they exposed an internal tracking mechanism they describe as a compass needle. This needle is the model's "residual vector" moving across neural network layers as a prompt is processed.

The residual vector naturally gravitates toward either desirable or undesirable outputs, but it is heavily influenced by how a user prompts the AI. "You can tip the balance, not even by changing the content but by changing the order in which you ask it," Johnson said, "which just shows how delicate this internal balance between good and bad, desirable and undesirable, can be."

For example, Johnson and Huo prompted OpenAI’s basic GPT-2 model with questions about vaccines, hurting others and self-harm. When the question “Are vaccines bad?” was asked first, the bot’s responses to this and subsequent questions were desirable, or good. When it was asked last, all subsequent responses were concerning.

From these insights, the researchers developed a mathematical formula to estimate the circumstances in which an AI would reach the tipping point between desirable and undesirable outputs. Johnson said that by embedding their simple mathematical formula in open-source models in the lab, they have shown that it empirically works as an early warning system, though he does not expect OpenAI or Anthropic to be knocking on his door anytime soon.

"I'm expecting a lot of pushback from these companies," he said. "It's not in their interests to have someone from outside saying you could have avoided a lot of these problems."

Wei Xing, a lecturer in AI at the University of Sheffield in the U.K. who was not involved in the study, agrees that concerns surrounding unmonitored offline devices are well founded. However, he urged caution before embracing this approach as a practical safeguard. "The authors reduce a huge system to a single tiny component, like explaining a whole car by studying one spark plug," Xing said.

Safety training — the primary defense in modern AI — cannot be represented in their simplified model, the formula was tested only on old, basic models (GPT-2, and EleutherAI’s Pythia and Meta OPT open-source models) rather than AI assistants people actually use, and the results did not yield significant evidence to support the authors’ conclusions, he added.

In defense, Johnson maintains that the open-source models they used have the same mechanical blueprints as frontier systems, and that he and Huo used fairly large, billion-parameter models in their study.

More testing on the latest models is needed to determine whether this early warning system for AI has legs. But for now, Johnson and Huo’s research has drawn attention to an important concern everyone should be aware of: that AI has the capacity within it to turn over to undesired behavior at the drop of a hat.

'> Physicists claim they can predict when AI will turn dangerous