Removing a type of immune cell from lymph nodes in mice reduced brain inflammation and cell damage in a model of Alzheimer’s-like disease.

Alzheimer’s may begin to unravel the brain when a small group of neurons switches on a receptor it was never meant to use, triggering damage that spreads from synapses to memories. Alzheimer’s disease is often defined by amyloid plaques and tau tangles, but those hallmarks are part of a much wider breakdown. Neurons become overactive, [...]

Children with ADHD showed more erratic pupil responses, a pattern that shifted with medication.

Tough decisions get calculated from a spot right above the eyes involved in impulse control

The post How Your Brain See-Saws between Risk and Reward appeared first on Nautilus.

Authors: Elisa Rigosi, Researcher in Sensory Biology, Department of Biology, Lund University and David O’Carroll, Professor of Sensory Biology, Department of Biology, Lund University

The post Bees view the world in surprisingly different ways appeared first on Mapping Ignorance.

The brain undergoes dramatic changes during puberty and pregnancy, but during menopause, the organ's structure remains remarkably stable, a new study suggests.

The research, published Sept. 8 in the journal Nature Communications, examined the brain's gray matter, which mostly includes the wrinkled outer surface of the organ, called the cerebral cortex. Past studies have found that the volume of gray matter shrinks markedly during puberty and pregnancy, likely reflecting a fine-tuning of neural circuits during those periods.

There's also a gradual decline in gray matter during adulthood that's seen as a normal part of aging, said study co-author Sophie van't Hof, a doctoral student in psychiatry at Amsterdam University Medical Center. However, during the transition leading up to menopause, that gradual loss of gray matter levels off temporarily, the study found.

"This study provides the first direct longitudinal comparison of brain structural changes across all three major female hormonal transitions," said Magdalena Martínez-García, scientific director of maternal health for the Ann S. Bowers Women's Brain Health Initiative, a brain imaging consortium headquartered at the University of California, Santa Barbara.

"I really appreciate the effort that went into finding and curating such an impressive longitudinal dataset of the female brain," Martínez-García, who was not involved in the study, told Live Science in an email.

Declines in puberty and pregnancy

For their analysis, the researchers gathered data from the UK Biobank, a biomedical database that contains information from 500,000 U.K.-based adults. That data includes MRI scans of people's brains, which the team used to study brain changes in menopause.

To look at puberty and pregnancy, the researchers pulled from several brain-scan datasets that had been compiled by Leiden University in the Netherlands.

In all, the study included data from 1,095 brains across the three life stages. They analyzed each participant's brain at two different time points, examining how each person's brain changed over time and how it compared to others' brains.

The youngest cohort included participants who hadn't started menstruating yet, as well as those who'd recently started and those who'd already had periods for an average of 19 months. The pregnancy cohort included 40 who'd had their first pregnancy during the study and 30 who'd had second pregnancies, as well as 40 women who'd never been pregnant, as a point of comparison.

As in previous studies, the researchers observed that both the girls entering puberty and the pregnant women lost gray matter. But scientists don't necessarily see these declines in gray matter at puberty and pregnancy as negative.

It’s a hypothesis, but "we actually see it as something positive," van't Hof said. "We see it as neural fine-tuning."

During puberty, that gray-matter loss is thought to be a normal part of the brain's development into adulthood. Its function in pregnancy is not well understood, van't Hof noted, but the evidence to date doesn't suggest that it contributes to "mommy brain" — the brain fog and forgetfulness some women can experience postpartum.

"I'm not saying that there's no neurobiological basis for this mommy brain, but up until now, we haven't found it," van't Hof said. "But what's really important is that gray matter decline is not equal to cognitive complaints."

Stability in menopause

The analysis included 120 women who entered menopause during the study. At the first time point, these women had not gone a full year without a period, but by the second time point about 3.5 years later, they had. Menopause is defined as the point at which a full year has elapsed since a person's final period.

The researchers compared these women to two other groups: about 50 women (average age 51) who had not had their last period yet and over 670 women (average age 55.5) who had already had their last period.

During late perimenopause — the final stages of the transition to menopause — the brain's gradual decline in gray matter paused, van't Hof said. Then, in postmenopausal women, that gradual decline of gray matter resumed. The exact timing of that pause differed for each woman, but it occurred consistently across the group, van't Hof noted.

The most striking finding was the lessening of the "ongoing age-related decline in brain volume during the transition into and out of menopause, compared with the more stable premenopausal and postmenopausal groups," Martínez-García said. This is an "interesting finding that adds to our understanding of how dynamic the female brain can be across the lifespan."

Related stories

• Neuroscience findings often can't be replicated ‪—‬ and it's a big problem for what we know about the brain
• Is there really a difference between male and female brains? Emerging science is revealing the answer.
• 'Let's just study males and keep it simple': How excluding female animals from research held neuroscience back, and could do so again

Factors such as whether participants had taken hormone replacement therapy for menopause and the number of children they had given birth to did not have a measurable impact on the results, the study authors noted.

In general, complaints of brain fog are widespread just before, during and after menopause, van't Hof said. This could be attributed to declining hormone levels and sleep disruptions.

"We have no clue if there's a neurological basis [for that brain fog], because, again, this is the first study to look at it," she said, adding that more studies are still needed to learn more.

"As with any study, there are some limitations to consider, but overall, I think the methods and conclusions are well supported by the data available," Martínez-García said. Both Martiniz-Garcia and van’t Hof said that they hope other researchers build on these findings to deepen scientists’ understanding of female neurobiology at every stage of life.

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

See how much you know about the most complex organ in the human body with our brain quiz!

It’s easy to see why people might latch onto the idea of a reptilian brain as an explainer, or an explainaway, for complex topics.

Source

In 1983 Benjamin Libet found that brain activity predicts your movements before you are aware of deciding to move. The result has been reproduced many times, and it has been used ever since to argue that free will is an illusion. Three new papers say the measurements were fine but the interpretation was not. Let's take a look.

One of the most popular explanations of human behavior has been that somewhere beneath our rational mind lurks an ancient “lizard brain”—a primitive evolutionary holdover responsible for instinct, emotion, fear, and aggression.

There is just one problem. Neuroscientists have long known that the lizard brain story is wrong. Humans did not evolve a sophisticated new brain by simply stacking it on top of an older reptilian one.

But a new study suggests the enduring lizard brain myth may have inadvertently pointed to something more interesting. Mammalian brains do appear to be organized around two broad computational systems—but not an ancient reptilian brain located beneath a newer, more sophisticated one. Instead, the divide appears to reflect two fundamentally different ways of organizing and processing information.

Published in Science Advances, the research combines anatomical measurements from 182 mammalian species with experiments using artificial neural networks. The researchers found a striking evolutionary trade-off between the neocortex and a collection of structures associated with smell, memory, and the limbic system.

Instead of representing “new” and “old” brains, the researchers say these regions may have evolved different wiring styles optimized for solving different kinds of computational problems.

“Rather than an ‘old’ brain and a ‘new’ brain, our results suggest two systems wired for different kinds of computation,” lead author Dr. Nabil Imam, a researcher at the Georgia Institute of Technology, told The Debrief. “The neocortex is wired to preserve spatial relationships—for example, neighboring points in the visual world are analyzed by neighboring parts of the cortex. The limbic system is more diffusely connected and supports holistic associations across different pieces of information.”

“So, the division between the neocortex and limbic system is about how the two systems are wired,” Dr. Imam added.

This distinction offers a very different picture from the famous lizard brain story.

The lizard brain concept grew from the so-called triune brain theory, which portrays the human brain as having evolved in distinct layers. A primitive “lizard brain” handling basic instincts, a mammalian limbic system producing emotion, and, finally, a newer neocortex responsible for higher thought.

The problem is that neuroscience has long since overturned that evolutionary story. Vertebrate brains did not evolve by progressively stacking newer brain regions on top of older, more primitive ones. Instead, vertebrates share essentially the same broad organizational plan, with existing regions changing in size, connectivity, and function over evolutionary time.

The new study suggests, however, that the mammalian brain may be divided very differently—not by evolutionary age, but by how different neural systems are wired to process information.

Across 182 species from 10 taxonomic groups, animals with an unusually large olfactory system tended to have a smaller-than-expected neocortex. Animals with an expanded neocortex tended to show the opposite pattern.

The nine-banded armadillo provides a particularly dramatic example. Armadillos are largely nocturnal and depend heavily on smell while foraging. As researchers note, the armadillo’s olfactory system was approximately 1.5 times larger than expected for its overall brain size. Its hippocampus—a region central to memory and spatial processing—was about twice its expected size.

Its neocortex, meanwhile, was reduced by a factor of 2.8. Primates such as squirrel monkeys sit closer to the other end of the spectrum. They rely heavily on vision and devote a large portion of their expanded neocortex to processing visual information.

At first glance, that could look like evolution trading smell for sight. But the researchers noticed something more intriguing. The hippocampus grew and shrank alongside the olfactory system, even though memory is obviously not another form of smell. Other structures traditionally grouped into the limbic system, including the amygdala and septum, also tended to change together.

That suggested the important difference might not be what these regions process, but how they are wired to process it.

Two Very Different Ways to Build a Brain

Vision offers a relatively straightforward example. Neighboring points in the visual world are generally processed through neighboring areas of the visual system. Touch operates similarly. Locations beside one another on your body retain spatial relationships as the nervous system processes them. Hearing also uses orderly mappings, including those based on sound frequency.

The result is what neuroscientists call “spatiotopic” organization. In simple terms, the brain preserves relationships between incoming information by arranging it into orderly maps.

However, smell works differently. Odors are represented through combinations of activity distributed across networks rather than being laid out in the same neat spatial fashion.

The researchers suspected that this difference might help explain the anatomical trade-off they had identified across mammals. To test the idea, they turned to artificial neural networks trained to handle vision, touch, hearing, and smell.

They then mapped the networks’ internal models onto artificial two-dimensional surfaces resembling sheets of cortex.

Results showed that networks optimized for vision, touch, and hearing produced smooth, highly ordered maps. On a scale in which 1 represented strong spatial order, the visual network scored 0.90, touch scored 0.86, and hearing scored 0.89.

Yet, the smell network scored just 0.11. Rather than producing a smooth map, information was scattered across a fractured, distributed representation. The researchers even found that imposing localized connectivity on the olfactory model harmed its ability to perform its task.

Researchers then examined memory. Using an artificial network designed to reproduce some relational computations associated with the hippocampus and entorhinal cortex, researchers again saw a fractured, distributed representation resembling the olfactory system rather than vision, hearing or touch.

For Dr. Imam, one of the most surprising results was that artificial networks arrived at an organization resembling real brains despite learning in profoundly different ways.

“Artificial networks are trained by an algorithm that propagates errors through the network, whereas brains are shaped by evolution and through localized changes in synapses,” Imam explained. “The fact that both nevertheless arrive at similar organization suggests that the structure of the information itself—whether visual, auditory, tactile, or olfactory—determines what kind of wiring works best.”

No “Lizard Brain,” But Evolution May Be Trading One Kind of Brainpower for Another

Researchers next wanted to know whether competition between these two wiring styles could reproduce the anatomical patterns seen across real mammals.

They created an evolutionary simulation containing five artificial networks. Vision, hearing, and touch occupied one computational domain based on localized, spatial organization. Smell and hippocampal memory occupied another based on distributed connectivity.

Then an evolutionary algorithm redistributed computational resources between them.

When selection favored vision, resources moved toward the spatially organized networks. When selection favored smell, the distributed networks expanded.

But something interesting occurred to the simulated hippocampal network. Even though researchers weren’t directly selecting for memory, the hippocampal network grew along with the olfactory network because both shared the same broad computational architecture. As resources shifted toward the other system, both contracted.

That closely resembled the pattern found across real mammalian brains.

“It suggests that evolution may not be selecting individual brain regions one at a time, but rather the functions produced by whole patterns of wiring,” Dr. Imam explained. “Because regions that share similar wiring tend to grow or shrink together, selection for one kind of function comes at the expense of another, given that the system must operate with limited energy and space.”

That does not mean an animal with a larger neocortex is simply more intelligent than one with a larger limbic system. Nor does the distributed system represent a primitive emotional brain fighting against a rational one.

Instead, the two architectures appear suited to different computational problems. Evolution may have repeatedly adjusted how much neural real estate mammals devote to each.

Nevertheless, researchers caution that their models are intentionally simplified. Anatomical measurements came from several datasets; some taxonomic groups are better represented than others, and artificial neural networks are not replicas of biological brains.

The evolutionary model is intended to demonstrate that a relatively simple developmental mechanism could produce the observed trade-off, not to reconstruct exactly how mammalian brains evolved.

Still, the research raises another interesting possibility extending beyond the demise of the “lizard brain.” Our brains may arrive in the world with considerably more computational structure already built in than the familiar idea of a blank slate implies.

“The brain may be much less of a blank slate than we often imagine,” Dr. Imam told The Debrief. “Evolution and development build useful assumptions into its wiring before experience-driven learning.”

It is also another example of something scientists are increasingly encountering across very different areas of biology: evolution can produce remarkably sophisticated structures and systems that human engineers are just starting to understand, much less reproduce.

In a recent study covered by The Debrief, researchers discovered that cable bacteria construct microscopic electrical pathways from nickel-rich nanoribbons arranged remarkably like braided electrical wires. The naturally grown structures may achieve extraordinary conductivity while remaining flexible, properties that researchers are now interested in replicating for bio-based electronics.

The mammalian brain represents an enormously more complicated example, but the underlying lesson may be similar. Evolution does not begin with a blank slate each generation. It can build useful solutions into biological architecture itself, leaving subsequent learning along with adaptation to operate within structures refined over immense spans of evolutionary time.

That could also help explain one of the most striking differences between biological intelligence and today’s artificial intelligence. Modern AI systems can require enormous datasets to acquire abilities that biological brains learn from comparatively limited experience.

“That built-in structure may explain why brains can learn efficiently from relatively little experience, whereas most artificial networks require enormous datasets to learn useful functions,” Imam said. “The idea has deep roots in philosophy of mind, but only recently have neuroscience and computer science begun to provide concrete demonstrations of how such built-in structure can aid function.”

The recent study, “Dual computational systems in the development and evolution of mammalian brains,” appeared in Science Advances.

Tim McMillan is a retired law enforcement executive, investigative reporter and co-founder of The Debrief. His writing typically focuses on defense, national security, the Intelligence Community and topics related to psychology. You can follow Tim on Twitter: @LtTimMcMillan.  Tim can be reached by email: tim@thedebrief.org or through encrypted email: LtTimMcMillan@protonmail.com 

After nearly two decades of work, scientists have completed a wiring diagram of the central nervous system of an adult male fruit fly (Drosophila melanogaster).

The post Researchers Unveil Complete Fruit Fly Connectome appeared first on Sci.News: Breaking Science News.

A conversation with neuroscientist and author Antonio Damasio about intelligence, feelings, and robots

The post Does Consciousness Require a Body? appeared first on Nautilus.

LSD, psilocybin, and 2C-B are often classified together as psychedelics—but new brain imaging research in rats shows that each compound produces its own distinct pattern of brain activity.

These differences appeared during both the drugs‘ active effects and in brain scans taken one week later, according to a study published in Nature Communications.

Interest in psychedelic medicine has increased rapidly, with several compounds now being tested in clinical trials for conditions such as depression, PTSD, and addiction. Most previous studies have focused on individual drugs, leaving it unclear how the effects of different psychedelics actually overlap. To address this, researchers at the University of Southern Denmark designed a study to directly compare the effects of different psychedelics side by side.

Different Drugs, Different Fingerprints

Each drug produced its own distinct pattern of brain activity, and only a handful of changes showed up across all three.

“Psychedelic drugs are often discussed as if they work in the same way. But when we look at the brain, the differences are clear,” said Mikael Palner, associate professor at the University of Southern Denmark’s Department of Clinical Research and senior author of the study. “Each drug appears to affect its own networks, and that is new knowledge.”

2C-B and LSD drove the most changes while the drugs were active, but the more striking result showed up after the drugs had worn off. At the one-week mark, 2C-B primarily affected regions of the brain associated with reward, while LSD showed effects in areas involved in habits and motivation. Meanwhile, psilocybin primarily affected regions associated with emotion.

“What is interesting is that the differences do not only appear while the drugs are active. We can also see different traces in the brain afterwards,” said Frederik Gudmundsen, the study’s first author, who completed his PhD at the University of Southern Denmark and now works as a postdoc at Aarhus University’s Translational Neuropsychiatry Unit.

Not Better, Just Different: and Still a Long Way From the Clinic

None of this means one drug is better than another, but it does suggest psychedelics may not be one interchangeable category when it comes to developing them for medical practice.

“If the drugs affect the brain differently, it is also possible that they may eventually prove better suited to different disorders,” Palner said. “We do not know that yet, but our study provides a biological starting point for investigating it.”

Despite these intriguing findings, the research does not determine if these distinct patterns of brain activity from different psychedelic substances apply to human patients. The researchers acknowledge this limitation, noting that the results are based on animal models and that further studies in humans are necessary to determine if the same differences apply.

The authors also disclosed that Mikael Palner holds shares in the psychedelic drug companies Compass Pathways and AtaiBeckley, but neither company was involved in the research.

The study still offers a detailed biological picture of how different psychedelic substances alter brain metabolism and network activity and could help researchers investigate whether specific compounds might eventually prove better suited to particular disorders.

For now, researchers have yet to determine whether LSD, psilocybin, and 2C-B will ultimately have distinct roles in medicine or whether the differences between them are less important in humans.

Austin Burgess is a writer and researcher with a background in sales, marketing, and data analytics. He holds an MBA, a Bachelor of Science in Business Administration, and a data analytics certification. His work focuses on breaking scientific developments, with an emphasis on emerging biology, cognitive neuroscience, and archaeological discoveries.

Cluster headache causes extreme pain, but its origins remain unclear. New research links the disorder to genetics, inflammation, and tobacco smoke exposure. Unlike an ordinary headache, a cluster attack typically erupts without warning and causes excruciating pain around one eye. Episodes can last from 15 minutes to three hours and often return at similar times [...]

Depression in later life may be an early warning from the brain, appearing years before Alzheimer’s begins to affect memory and thinking A new study in JNeurosci found that faster accumulation of tau, a protein closely tied to Alzheimer’s, was associated with worsening depressive symptoms in older adults who remained cognitively healthy. Teodora Markova of [...]

From fireflies to mammals, evolution may have tuned communication to the rhythm of neurons.

Si le cerveau, capable de se réinventer tout au long de la vie, détenait les clés des prochaines avancées médicales ? Entre grandes tables rondes et rencontres en petit comité, la 10e édition de Futurapolis Santé 2026 permettra à tous les curieux de décortiquer ce que la science sait, et ne sait...

A provocative new paper suggests consciousness may not be unique to Earth and could arise in alien life forms far stranger than we can imagine. A new philosophical paper argues that consciousness may not be exclusive to life as we know it. According to Eric Schwitzgebel, a distinguished professor of philosophy at the University of [...]

Whether consciousness arises entirely within the brain or involves processes beyond it has long been debated in scientific and philosophical circles. Historically, most academics have associated consciousness with neurons firing and communicating information; however, precisely how neural activity gives rise to subjective experience remains an open question.

Neuroscientist and consciousness researcher Christof Koch, a former faculty member at institutions including MIT and Caltech, challenges academics to take a closer look at what philosophers call the “hard problem” of consciousness: how the physical processes of the brain could produce subjective experiences in humans.

Earlier this year, Koch presented his arguments at the “Behind and Beyond the Brain” Symposium organized by the Bial Foundation, where he argued that the nature of consciousness, as well as phenomena like near-death experiences, may require a broader scientific framework.

Koch focused on three areas. First is the physical brain itself; second is the question of how we can truly agree on what is “real.” What does blue actually look like to you? What does pain feel like? These questions are difficult to answer scientifically as universal truths.

Third are unexplained experiences that may not fit neatly within a materialistic scientific framework, such as near-death experiences.

Revisiting an old approach 

Looking at older philosophical models might lead researchers toward new understandings or modern ways of approaching consciousness. Koch points to concepts such as idealism and panpsychism.

Idealism holds that consciousness or mind is fundamental to reality—mind comes first, matter second—while panpsychism holds that consciousness is a fundamental feature of the universe.

If mainstream science adopted such a shift, it could profoundly change how we understand ourselves. A paradigm shift of sorts may be coming for humanity, potentially through the integration of these ideas and a move away from strictly materialistic approaches to consciousness.

Koch points to these concepts as potential frameworks in which consciousness remains a fundamental aspect of reality. He also supports the controversial Integrated Information Theory (IIT), which proposes that systems possessing sufficiently integrated information may have some form of subjective experience.

Consciousness in Perspective

For additional perspectives, The Debrief reached out to Julia Mossbridge, a neuroscientist and Sr Distinguished Fellow in AI, Mind and Society at Florida Atlantic University, and co-author of Transcendent Mind: Rethinking the Science of Consciousness (2017), the first American Psychological Association textbook on consciousness to not assume consciousness is reducible to brain activity.

“To many neuroscientists, the brain is starting to seem more like a radio receiver and potentially also a transmitter of consciousness,” Mossbridge said in an email to The Debrief. “The idea that’s losing more ground with every new credible report of so-called ‘anomalous cognition’ is the old one—that the brain creates consciousness like the gallbladder creates bile. Maybe it’s more apt to compare the brain to the heart—it doesn’t create blood, it circulates it. But because you can use a machine to circulate the blood, it’s very clear the heart is important, but in modern times, not essential for circulation.”

Mossbridge points to reports of what she calls “veridical conscious observations” that occur when a patient’s brain shows little or no measurable activity to researchers, or what is described as “brain death,” as proof that consciousness may not be produced entirely by the brain.

These experiences led Mossbridge to consider the brain as a “transformer of consciousness rather than a creator of it.” She compares the relationship to a broken radio: “If you have a disruption in your brain, like a broken radio, you might have a disruption of consciousness.”

To test this hypothesis, Mossbridge says researchers could investigate whether people can perceive and later accurately recall “veridical information” while in deep sleep or under general anesthesia. Although she acknowledges that even positive findings might have another explanation, noting that they “could be explained by basic psychic functioning using some unknown physical mechanism.”

“So if that kind of experiment produces a positive result, and is replicated, you either have to argue that psychic ability is real but is something the brain does nonlocally (like maybe through entanglement) or that consciousness can wander from the body and observe things, or both,” Mossbridge concluded.

“The physical but nonlocal explanation is a bit like a heart pumping the blood, the brain guiding consciousness. The consciousness-wandering explanation is a bit like a heart being fully separated from the blood–and another method is used to circulate consciousness.”

“Either way, the standard model fails,” she added.

Taken together, Koch and Mossbridge’s perspectives point to a provocative possibility: that understanding consciousness may ultimately require science to reconsider some of its most fundamental assumptions about the relationship between mind, brain, and reality.

Chrissy Newton is a PR professional and founder of VOCAB Communications. She hosts the Rebelliously Curious podcast, which can be found on The Debrief’s YouTube Channel. Follow her on X: @ChrissyNewton and at chrissynewton.com.

A University of St. Andrews-led research team has proposed that the red wavelengths of flickering light emitted by early human ancestors’ campfires helped reprogram the human brain to boost social and verbal communication, leading to modern language and storytelling behaviors found only in humans.

The team, which included researchers from Dartmouth College, said the study builds on earlier theories linking fire and language to the extra hours it added to the day.

However, their findings suggest that the biological changes caused by fire use may have enabled complex language as much as fire-associated behavioral changes, accelerating the evolution of verbal communication away from the ape-like systems still used by modern apes toward more complex, “uniquely human” interactions.

Researchers Wondered if Firelight Reprogrammed the Human Brain

Catherine Hobaiter, a Professor of the School of Psychology and Neuroscience at the University of St Andrews and the lead author of a paper detailing the team’s idea, said she has always been fascinated by the origins of language.

“What was the first word?” the professor asked. “The first story?”

Unfortunately, Professor Hobaiter noted, many questions about the origin of humanity’s complex and diverse forms of verbal communication remain unanswered.

Some earlier research has explored a possible link between the first spoken words and the advent of controlled fire use. However, the team notes that most studies have focused primarily on the extra hours of practical light added to the end of each day.

Curious whether other biological mechanisms also contributed to the evolution of language and complex storytelling behavior, Professor Hobaiter and colleagues examined the effects of sitting around a campfire to see whether the emitted light could reprogram the human brain.

Potential Effects of Red Wavelengths and Flickering Lights

First, the team noted that one potential catalyst emitted by firelight that could help reprogram the human brain for complex language is the color of the light wavelengths emitted by campfires. Specifically, Hobaiter and colleagues noted that campfire light emits almost no blue wavelengths but instead mostly in the visible red spectrum.

Many modern studies have focused on the potentially adverse effects of exposure to blue light wavelengths from modern technology on sleep patterns and overall health. Conversely, the paper’s authors described the red wavelengths emitted from fire as ‘uniquely suited’ for human socializing, “allowing an extension to the day without negatively impacting sleep.”

Another component of firelight the study authors suggest could have reprogrammed the human brain for speech is the way a campfire behaves. Unlike a modern, steady light source, the authors noted that firelight “flickers.”

Hobaiter and colleagues said that neurons in the human brain synchronize firing patterns with external flickering lights. For example, flickering lights in movies and TV shows often come with warnings against possible neurological effects on vulnerable viewers. The research team said this mechanism might also help synchronize the behavior of those seated around the campfire, resulting in a much deeper feeling of connection.

Finally, the researchers noted that firelight emits infrared wavelengths, which may have also contributed to helping firelight reprogram the human brain for complex verbal communication.

Are We the Storytelling Ape?

When discussing the potential impact of their proposal, study co-author Nathaniel Dominy, the Charles Hansen Professor of Anthropology at Dartmouth College, said many of the chemical properties have been well researched. However, Professor Dominy also notes that understanding the properties of light that capture our attention and focus, thereby instilling “harmony and cooperation,” has received far less attention.

“Measuring these features is an exciting part of this project,” the study author added.

Professor Hobaiter agreed, while also noting the conundrum scientists face when explaining why humans speak, when “decades of research with other species has shown us that you don’t need language to learn from each other, to organize where and when to forage, to learn cultural knowledge about tools and songs, to co-ordinate hunting, or navigate social politics.”

“While other species share all these skills, there is a fundamental puzzle: we struggle to find evidence of key differences between human and ape communication,” Professor Hobaiter explained. “And yet, we are surrounded by evidence of human distinctiveness. For all their incredible, rich communication and cultures, no other ape is inventing algebra, writing King Lear, or heading out into interstellar space.”

“So, it’s especially exciting to be able to generate testable predictions, to be able to ask if, at the end of the day, we are the storytelling ape,” the professor added.

The paper “Firelight and the Origins of Spoken Language” was published in Proceedings of the Royal Society. 

Christopher Plain has spent the last six years as Associate News Editor and Head Science Reporter at The Debrief. Follow and connect with him on X, learn about his novels at plainfiction.com, or email him at christopher@thedebrief.org.

A fruit fly's brain is roughly the size of a poppy seed — and yet that tiny package contains over 100,000 neurons. A new map charts every single neuron in the male fruit fly brain, as well as the insect's equivalent of a spinal cord, totaling more than 166,000 neurons.

This new map joins a map of a female fruit fly brain that was unveiled in 2024 and covers about 140,000 neurons. These two wiring diagrams, also called "connectomes," can now be compared to see if there are differences between the sexes' brains that help to explain behavioral differences reflected during mating or in aggressive actions, including sex-specific fighting moves.

"It is the first time we can compare both sexes of an animal with complex social behavior," study co-author Gerry Rubin, head of biology and a senior group leader of the Howard Hughes Medical Institute's Janelia Research Campus, said in a statement. "Male and female flies have a lot of differences in their behavior, and neuroscientists want to understand how the brain controls those behaviors. This now allows us to easily home in on the neurons that are causing those differences."

Initially released as a preprint, the new fly brain map was published in the journal Cell and Current Biology Thursday (Sept. 3). The study describing the map was published alongside three other papers, each of which uses the new data to explore a specific aspect of fruit fly neurobiology.

"The fly nervous system performs remarkably sophisticated computations with relatively few neurons and little energy, and its architecture could suggest principles for designing more efficient artificial systems," said Carlos Ribeiro, a principal investigator at the Champalimaud Foundation in Lisbon, Portugal, whose team contributed to the brain map and led one of the related studies.

"This work also provides a technical roadmap for more ambitious connectomics projects in the future, such as those for mice and humans," Ribeiro said in a separate statement from the Champalimaud Foundation.

In the near term, the scientists aim to map the brains of larval zebrafish (Danio rerio) and adult danionin fish (Danionella). In the long run, the goal of this research is to understand how vertebrates' brains enable complex behaviors, and then use that knowledge to help unravel the basis of neurological and psychiatric disorders in humans.

The study led by Ribeiro and other Champalimaud Foundation scientists aimed to map the circuits in the fly brain dedicated to the insect's sense of taste. Fruit flies have taste receptors in many body parts, including their legs, wings, mouthparts and inside of the throat. The researchers identified these taste receptors and traced their connections back to the fly brain. From there, they examined how those circuits interacted with those that govern behaviors such as swallowing or walking. When it comes to eating behaviors, this circuitry helps the fly determine whether a given morsel is safe or harmful and ultimately choose whether to eat it, the researchers concluded.

This diagram of taste processing is a "hypothesis-generation tool," study co-author Inês de Haan Vicente, a research technician in Ribeiro's lab, said in the Champalimaud statement. "Suppose you are interested in how taste controls locomotion. Now you can go to the map and ask: which sensory neurons are connected to the neurons controlling locomotion? Which intermediate neurons should I manipulate? It gives you a place to start."

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The other two papers published alongside the map respectively explore the circuits behind vision processing in the fly brain and sex-specific differences in male and female fly brains. The first showed that visual processing extends deep into the brain, involving more than half of the 11,000 or so types of neurons identified in the map. The latter study found a network of cells that's specific to the male brain and appears to coordinate male-specific behaviors, such as specific aspects of fly courtship and physical aggression. (For example, female flies tend to headbutt while males lunge at their targets.)

While there were some networks specific to each sex, the circuits for sensation and movement are largely shared between males and females, the research found. At times, specific switches within those circuits reroute signals to different destinations in the male and female brain; the consequences of that rerouting will be a focus of future investigations.

See how much you know about the most complex organ in the human body with our brain quiz!