Emily Jacobs wants to know how sex hormones sculpt the brain

When Emily Jacobs embarked on a career studying the brain in the early 2000s, a technique called functional magnetic resonance imaging, or fMRI, was having a moment. “Just like we have super powerful telescopes that can let us quantify the farthest reaches of the known universe, here we have this tool that could allow us to see the entire human brain and as a pulsing, living organ,” says Jacobs, a cognitive neuroscientist at the University of California, Santa Barbara.

By measuring changes in blood flow that serve as a proxy for brain activity, neuroscientists were getting new views of how different situations spur conversations between brain regions, and how the intensity of the conversations changes over time. “I was riding that wave of excitement,” Jacobs says.

But she soon realized there were big questions that weren’t being asked — questions important to half the world’s population. Do the natural hormonal changes that come with menstruation, pregnancy and menopause affect communication across the brain? What about hormonal contraceptives, such as the birth control pill, which are used by hundreds of millions of people globally? And what does it all mean for brain health and behavior?
Big goal
The rise and fall of hormones is a big reason women have historically been excluded from biomedical research, even though hormones in men fluctuate too. The resulting gap in knowledge of female biology has led to inadequate mental, physical and reproductive health care. “Science, and especially neuroscience, has not served the sexes equally,” Jacobs says.

With a range of tools — fMRI, other types of MRI and brain imaging, blood testing, neuropsychological testing, virtual reality and more — Jacobs’ lab is trying to fill in gaps in our basic understanding of how hormones act in the human brain. And she is studying the hormones as a lens for bigger questions about brain changes.

“What’s really special about Emily’s work is that she does it at so many different levels. It’s so multifaceted,” says cognitive neuroscientist Caterina Gratton of Northwestern University in Evanston, Ill. “She has multiple different types of brain measures, from the molecular all the way up to brain systems.”

Standout research
In a series of studies dubbed 28 and Me — for the 28 days of a typical menstrual cycle — Jacobs and colleagues closely monitored the brain of one woman for the duration of her natural menstrual cycle. Every 24 hours over 30 days, this 20-something woman’s brain was scanned, blood hormone levels checked and mood assessed.

As the woman’s estrogen levels peaked during ovulation, regions throughout the brain synced up. And regions in an important hub called the default mode network became tight conversationalists. What’s more, one part of this network rearranged itself to create a new and transient communication clique. After ovulation, when estrogen levels dropped and progesterone levels spiked, gray matter temporarily expanded in a brain structure tied to learning and memory.

When the same woman was examined a year later while on the pill, which quells progesterone, the changes weren’t observed.

The findings, described in 2021 in Current Opinion in Behavioral Sciences, provide strong evidence that the ebb and flow of sex hormones drives changes in the brain on a day-to-day basis, Jacobs and colleagues say. They also saw links between hormone fluctuations and brain changes in a male participant.
What’s next
The observations led cognitive neuroscientist Caitlin Taylor, a postdoc in Jacobs’ lab, to wonder how the brain responds to chronic hormone suppression from oral contraceptive use. The team is launching a large-scale study to attempt to find out.

Initially, Jacobs hesitated to green-light the research. She worried it could be twisted to erode access to contraception. Eventually, she relented, because women “deserve to have science that can serve us,” she says.

Another effort, which Jacobs and Taylor are building, will make data for such large-scale studies widely available. Called the University of California Women’s Brain Initiative, it aims to funnel records from the university system’s eight brain-imaging research centers into an open-access database. When a woman gets her brain scanned at one of the centers, her de-identified brain-imaging data, medical data and information about hormonal contraceptive use will be entered into the database. Once all eight centers are on board, there could be about 10,000 participants annually — way more than a single lab could recruit.

The expected mountain of data should be a boon to researchers asking big and small questions about brain health, Jacobs says. And she hopes it will improve women’s health care.

Christopher Barnes is on a quest for a universal coronavirus vaccine

In January 2020, Caltech biochemist Pamela Bjorkman asked for volunteers to help work out the structures of immune proteins that attack a newly discovered coronavirus. The pathogen had emerged in China and was causing severe pneumonia-like symptoms in the people it infected. Knowing the molecular arrangements of these antibodies would be an important step toward developing drugs to fight the virus.

Christopher Barnes, a postdoc working in Bjorkman’s lab on the structure of HIV and the antibodies that target it, jumped at the chance to solve a new puzzle. “I was like, ‘Oh, I’ll do it!’” Barnes says. At the time he wasn’t aware how urgent the research would become.

Now, we are all too familiar with SARS-CoV-2, which causes COVID-19 and has killed more than 6 million people globally. Studies of the structure of the virus and the antibodies that target it have helped scientists quickly develop vaccines and treatments that have saved tens of millions of lives. But the virus continues to adapt, making changes to the spike protein that it uses to break into cells. That has left researchers scrambling for new drugs and updated vaccines.

Using high-resolution imaging techniques, Barnes is probing coronavirus spike proteins and the antibodies that attack them. His goal: Find a persistent weak spot and exploit it to create a vaccine that works against all coronaviruses.

Standout research
Barnes’ team used cryo-electron microscopy to reveal the structures of eight antibodies that stop the original version of SARS-CoV-2. The technique catches cells, viruses and proteins going about their business by flash freezing them. In this case, the team isolated coronavirus particles entwined with immune system proteins from people with COVID-19.

The antibodies had attached to four spots on the spike protein’s receptor binding domain, or RBD, the team reported in Nature in 2020. This fingerlike region anchors the virus to the cell it will infect. When antibodies bind to the RBD, the virus can no longer connect to the cell.
Barnes’ team also created an antibody classification system based on the RBD location where the immune system proteins tend to latch on. “That’s been really helpful for understanding the types of antibody responses that are elicited by natural infection,” says structural biologist Jason McLellan, who wasn’t involved in the work, and for identifying prime candidates for drug development.

“A major strength of Chris is that he does not limit himself or his research to one technique,” says McLellan, of the University of Texas at Austin. “He quickly adapts and incorporates new technologies to answer important questions in the field.”

Since launching his own lab at Stanford, Barnes and colleagues have determined the structures of six antibodies that attack the original SARS-CoV-2 virus and delta and omicron variants. Those variants are skilled at evading antibodies, including lab-made ones given to patients to treat COVID-19.

The newly identified antibodies, described in the June 14 Immunity, target the spike protein’s N-terminal domain. The structures of the sites where the proteins attach are the same in delta and omicron, hinting that the sites might remain unchanged even in future variants, the team says. Eventually, scientists may be able to mass-produce antibodies that target these sites for use in new therapies.

What’s next
Barnes has now turned his attention to antibodies that can fend off all coronaviruses — from ones that cause the common cold to ones found in livestock and other animals that have the potential to spill over into people.

Barnes and immunologist Davide Robbiani of the University of Lugano in Switzerland identified classes of antibodies that target variants from all four coronavirus families, blocking the viruses’ ability to fuse with cells.

What’s more, the structure of one of the binding sites on the spike protein is the same across the coronavirus family tree, Barnes says. “This is something you wouldn’t want to mutate as you diversify your viral family because this is a critical component of how you enter the cell.”

Two independent teams have identified similarly broad action in the same antibody classes. Taken together, the findings suggest that a universal coronavirus vaccine is possible, Barnes says.

“We’ve all kind of discovered this at the same time,” he says. The teams are now thinking, “Wow, this exists. So let’s try to make a real, true pan-coronavirus vaccine.”

The pandemic shows us how crises derail young adults’ lives for decades

Ninna Ragasa was 24 years old when doctors discovered a mass on the left hemisphere of her brain. Further imaging revealed that Ragasa had an arteriovenous malformation, a tangle of blood vessels that disrupt the flow of oxygen to the brain.

Doctors suggested removing the mass to avoid the possibility of it rupturing, a potentially fatal outcome. Ragasa, a graduate student in interior design at the Pratt Institute in New York City, worried that the brain surgery would hurt her mobility and her career aspirations.

“Being a designer came easily to me,” says Ragasa, who is a friend of mine.

But the procedure went smoothly, and Ragasa returned to her life at Pratt. Then a year or so after the surgery, Ragasa started falling. At first, she blamed her hard-work, hard-party lifestyle and cut back on drinks. But she kept falling. So she switched from spike heels to chunky boots and then to flip flops. Nothing helped. One day Ragasa fell getting off the subway and had to crawl to her mother’s house.

Scans revealed that Ragasa’s brain had swelled after the procedure, causing her to gradually lose mobility along the right side of her body. Ragasa could no longer handle the physical demands of being an art student, such as building models and drawing. So she dropped out of school and found a job that came with medical insurance to pay for her physical therapy treatments. She felt, she says, totally lost.

Many of us get derailed at some point in our lives. We may get sick like Ragasa, divorced, laid off or lose a loved one. Our age when calamity strikes can profoundly influence our response to the event, research suggests, with young adults particularly vulnerable to getting thrown off course. That’s partially because when the rites of passage that mark the transition from childhood to adulthood are delayed or lost, young adults can feel unmoored and increasingly uncertain about the future — a point driven home by this cohort’s plummeting well-being during the ongoing pandemic.
Researchers have not always treated young adulthood as markedly different from other adult years. But it’s now well established that the human brain matures well into one’s 20s (SN: 5/22/19). And social and economic changes in recent generations mean that the once linear path from living in one’s parents’ home to moving out and starting one’s own family has elongated and become considerably more jagged. And for years, climate change has added mounting uncertainty to the already fraught mix (SN: 8/18/21). The pandemic, in other words, did not cause the mental health crisis among young adults, but merely accelerated existing trends.

Ages 18 to 25 constitute an intense time of exploration in love, work and worldview. This age band should be treated as a unique developmental period, distinct from either being a child or a full-fledged adult, psychologist Jeffrey Arnett of Clark University in Worcester, Ma., wrote in a seminal 2000 paper in American Psychologist. “Emerging adulthood is a time of life when many different directions remain possible, when little about the future has been decided for certain, when the scope of independent exploration of life’s possibilities is greater for most people than it will be at any other period of the life course.”

The pandemic has forced us to ask: What happens when that “scope of independent exploration of life’s possibilities” gets stalled or even curtailed?

The evidence so far suggests that the fallout for young adults could be dire. Instead of maturing, this group’s personalities have become more juvenile, I reported last month (SN: 9/28/22). In general, those under age 30 have become less conscientious, less agreeable and more neurotic. Compared with older adults, young adults have also reported higher levels of anxiety, depression and feelings of loneliness during the pandemic.
A survey of roughly 2,600 U.S. adults taken in January 2022, showed that members of this group have distorted the U-curve. This somewhat controversial theory holds that well-being, including happiness and health, are high in early and later life but low in middle age. In this view, despair, once reserved for middle age, has, it seems, become the badge of youth.

“The left part of the ‘U’ has essentially completely flattened,” wrote study coauthor and Harvard University epidemiologist Tyler VanderWeele in Psychology Today. “Young people … report being less happy and less healthy; having less meaning, greater struggles with character, and poor relationships; and [being] less financially stable compared to their older counterparts.”

Decisions made during young adulthood can also have profound knock-on effects. Temporarily delaying going to college at the pandemic’s onset, for instance, could become a permanent decision, thereby radically shifting the trajectory of one’s life.

Some young adults will recover from this event without much trouble, but others may struggle, says personality psychologist Rodica Damian of the University of Houston. “Sometimes when something happens during a critical development period, there is a snowball effect.”

Damian’s comment reminded me of a conversation I had more than a year ago with developmental psychologist Anthony Burrow of Cornell University. Rather presciently, shortly before the pandemic hit, Burrow had begun characterizing a phenomenon he referred to as “derailment.” Derailment, Burrow told me, refers to people’s feeling that their life has been thrown off course. That feeling can lead people to lose their sense of identity, to struggle to answer the question: Who am I?

“Derailment is a subjective sense that who you were cannot be reconciled with who you are,” Burrow says. “That train was heading in one direction on those tracks, but can no longer advance on that track.”

One way to gauge derailment during the pandemic is to ask ourselves: “Am I still the same person as I was pre-pandemic?” Burrow says. “It’s a basic question with profound implications.”

People in the United States who feel derailed struggle with anxiety, depression and reduced feelings of well-being, Burrow and his team reported in 2020 in the Journal of Personality and Social Psychology. Moreover, those feelings of derailment are associated with depressive symptoms a year or more down the road.

But Burrow’s work also points to ways to get our metaphorical trains back on track. In that same study, he found that journaling — having people write a narrative that stitches together their past and present selves — can help them regain that sense of continuity and reestablish goals for the future.

Other research suggests that adopting a more flexible East Asian mindset could help people cope with a life that veers off course. Derailed Japanese individuals, that is, do not show the same drop in well-being observed as Westerners, researchers reported in 2021 in the Journal of Happiness Studies. The researchers suspect that the difference lies in thinking styles. While Westerners tend to believe life should follow a linear course, Japanese people tend to believe life is dialectic, or full of contradictions and in constant flux. Derailments, as such, are to be expected.

Ragasa, who moved to the United States from the Philippines as a child, understands that flux. But losing her identity in her 20s, at a time when she felt physically and emotionally invincible, left her reeling. She eventually moved to Vermont and had a son.

Still, she took years to accept that the old art track she was on was gone forever. “I had to mourn it and let it go,” she says. Now, she says, she has begun the arduous process of finding a new track. “I still feel lost,” she says. “I have to figure out who I am now.”

For the first time, astronomers saw dust in space being pushed by starlight

A pair of stars in our galaxy is revealing how light pushes around matter. It’s the first time anyone has directly seen how the pressure of light from stars changes the flow of dust in space.

Such radiation pressure influences how dust clears from the regions near young stars and guides the formation of gas clouds around dying stars (SN: 9/22/20). The dust pattern surrounding a stellar pair 5,600 light-years away in the Cygnus constellation is providing a rare laboratory to observe the effect in action, astronomer Yinuo Han and colleagues report in the Oct. 13 Nature.

Astronomers have long known that the dust emerging from the star WR 140 and its companion is formed by gas from these two stars colliding and condensing into soot. But images of the pair taken over the course of 16 years show that the dust is accelerating as it travels away from the stars.

Dust initially departs the stars at about 6.5 million kilometers per hour, the researchers report, and over the course of a year accelerates to nearly 10 million km/h. At that speed, the dust could make the trip from our sun to Earth in a mere 15 hours.

The revelation came from comparing the positions of concentric dust shells year to year and deducing a speed. The researchers’ calculations show that the force accelerating the dust is the pressure exerted by light radiated from the stars, says Han, of the University of Cambridge. “Radiation pressure [becomes apparent] only when we put all the images next to each other.”

Not only are those layers of dust feeling light’s push, they also extend out farther than any telescope could see — until this year. Images from the James Webb Space Telescope, or JWST, depict more of the dusty layers around WR 140 and its companion than ever seen before, Han and another team report October 12 in Nature Astronomy.

At first glance, the intricate patterns surrounding the stars resemble a gigantic spider web. But the researchers’ analysis reveals that they are actually enormous, expanding, cone-shaped dust shells. They’re nested inside each other, with a new one forming every eight years as the stars complete another journey around their orbits. In the new images, the shells look like sections of rings because we observe them from the side, Han says.
The patterns don’t completely surround the stars because the distance between the stars changes as they orbit one another. When the stars are far apart, the density of the colliding gas is too low to condense to dust — an effect the researchers expected.

What surprised them is that the gas doesn’t condense well when the stars are closest together either. That suggests there’s a “Goldilocks zone” for dust formation: Dust forms only when the separation between the stars is just right, creating a series of concentric dust shells rippling away from the duo.

“Their Goldilocks zone is a new idea,” says astrophysicist Andy Pollock of the University of Sheffield in England, who was not part of either study. “A similar sort of thing happens in my field of X-rays.”

In his work, Pollock has observed that WR 140 and its partner emit more X-rays as the stars approach each other, but then fewer as they get very close together, suggesting there’s a Goldilocks zone for X-rays coming from the stars as well. “It would be interesting to see if there’s any connection” between the two types of Goldilocks zones, he says. “All of this must somehow fit together.”

Ancient DNA unveils Siberian Neandertals’ small-scale social lives

DNA from a group of Neandertals who lived together and a couple of others who lived not far away has yielded the best genetic peek to date into the social worlds of these ancient hominids.

As early as around 59,000 years ago, Neandertal communities in a mountainous part of Central Asia consisted of small groups of close relatives and adult female newcomers, researchers report October 19 in Nature.

That social scenario comes courtesy of DNA extracted from the teeth and bones of 13 Neandertals found at two caves in the foothills of southern Siberia’s Altai Mountains. Estimates of overall genetic similarity among these Stone Age folks indicate that they formed communities of about 20 individuals, with females often migrating from their home groups to those of their mates, say evolutionary geneticist Laurits Skov of the Max Planck Institute for Evolutionary Anthropology in Leipzig, Germany, and colleagues.

It’s unknown whether Altai Neandertals’ small-scale lifestyle was unusual, perhaps due to living in a sparsely populated area, or mirrored Neandertal practices elsewhere in Asia and Europe. Large numbers of Neandertals in Central Europe transformed a forest into grassland around 125,000 years, suggesting they could scale up communities when needed (SN: 12/15/21).

Skov’s group studied the DNA of 11 Neandertals from Chagyrskaya Cave and two Neandertals from Okladnikov Cave (SN: 1/27/20). The Chagyrskaya individuals included a father and his teenage daughter as well as an adult female and an 8- to 12-year-old boy, who was possibly her nephew or grandson.

In the Chagyrskaya group, mitochondrial DNA, typically inherited from the mother, displayed greater diversity than DNA from the Y chromosome, which is inherited only by males. The enhanced mitochondrial DNA variety suggests that adult females frequently moved into that community while the males stayed put, the researchers suspect.

Meet the BOAT, the brightest gamma-ray burst of all time

The brightest gamma-ray burst ever recorded recently lit up a distant galaxy — and astronomers have nicknamed it the BOAT, for Brightest of All Time.

“We use the boat emoji a lot when we’re talking about it” on the messaging app Slack, says astronomer Jillian Rastinejad of Northwestern University in Evanston, Ill.

Gamma-ray bursts are energetic explosions that go off when a massive star dies and leaves behind a black hole or neutron star (SN: 11/20/19; SN: 8/2/21). The collapse sets off jets of gamma rays zipping away from the poles of the former star. If those jets happen to be pointed right at Earth, astronomers can see them as a gamma-ray burst.
This new burst, officially named GRB 221009A, was probably triggered by a supernova giving birth to a black hole in a galaxy about 2 billion light-years from Earth, researchers announced October 13. Astronomers think it released as much energy as roughly three suns converting all of their mass to pure energy.

NASA’s Neil Gehrels Swift Observatory, a gamma-ray telescope in space, automatically detected the blast October 9 around 10:15 a.m. EDT, and promptly alerted astronomers that something strange was happening.

“At the time, when it went off, it looked kind of weird to us,” says Penn State astrophysicist Jamie Kennea, who is the head of science operations for Swift. The blast’s position in the sky seemed to line up with the plane of the Milky Way. So at first Kennea and colleagues thought it was within our own galaxy, and so unlikely to be something as dramatically energetic as a gamma-ray burst. If a burst like this went off inside the Milky Way, it would be visible to the naked eye, which wasn’t the case.

But soon Kennea learned that NASA’s Fermi Gamma-ray Space Telescope had also seen the flash — and it was one of the brightest things the telescope had ever seen. A fresh look at the Swift data convinced Kennea and colleagues that the flash was the brightest gamma-ray burst seen in the 50 years of observing these rare explosions.

“It’s quite exceptional,” Kennea says. “It stands head and shoulders above the rest.”
After confirmation of the burst’s BOAT bonafides — a term coined by Rastinejad’s adviser, Northwestern astronomer Wen-fai Fong — other astronomers rushed to get a look. Within days, scientists around the world got a glimpse of the blast with telescopes in space and on the ground, in nearly every type of light. Even some radio telescopes typically used as lightning detectors saw a sudden disturbance associated with GRB 221009A, suggesting that the burst stripped electrons from atoms in Earth’s atmosphere.

In the hours and days after the initial explosion, the burst subsided and gave way to a still relatively bright afterglow. Eventually, astronomers expect to see it fade even more, replaced by glowing ripples of material in the supernova remnant.

The extreme brightness was probably at least partially due to GRB 221009A’s relative proximity, Kennea says. A couple billion light-years might seem far, but the average gamma-ray burst is more like 10 billion light-years away. It probably was also just intrinsically bright, though there hasn’t been time to figure out why.

Studying the blast as it changes is “probably going to challenge some of our assumptions of how gamma-ray bursts work,” Kennea says. “I think people who are gamma-ray burst theorists are going to be inundated with so much data that this is going to change theories that they thought were pretty solid.”

GRB 221009A will move behind the sun from Earth’s perspective starting in late November, shielding it temporarily from view. But because its glow is still so bright now, astronomers are hopeful that they’ll still be able to see it when it becomes visible again in February.

“I’m so excited for a few months from now when we have all the beautiful data,” Rastinejad says.

NASA’s DART spacecraft just smashed into an asteroid — on purpose

Mission control rooms rarely celebrate crash landings. But the collision of NASA’s DART spacecraft with an asteroid was a smashing success.

At about 7:15 p.m. EDT on September 26, the spacecraft hurtled into Dimorphos, an asteroid moonlet orbiting a larger space rock named Didymos. The mission’s goal was to bump Dimorphos slightly closer to its parent asteroid, shortening its 12-hour orbit around Didymos by several minutes.

The Double Asteroid Redirection Test, or DART, is the world’s first attempt to change an asteroid’s motion by ramming a space probe into it (SN: 6/30/20). Neither Dimorphos nor Didymos poses a threat to Earth. But seeing how well DART’s maneuver worked will reveal how easy it is to tamper with an asteroid’s trajectory — a strategy that could protect the planet if a large asteroid is ever discovered on a collision course with Earth.

“We don’t know of any large asteroids that would be considered a threat to Earth that are coming any time in the next century,” says DART team member Angela Stickle, a planetary scientist at the Johns Hopkins University Applied Physics Laboratory in Laurel, Md. “The reason that we are doing something like DART is because there are asteroids that we haven’t discovered yet.”
Astronomers have spotted almost all the kilometer-size asteroids in the solar system that could end civilization if they hit Earth, says Jessica Sunshine, a planetary scientist at the University of Maryland in College Park who’s also on the DART team. But when it comes to space rocks around 150 meters wide, like Dimorphos, “we only know where about 40 percent of those are,” Sunshine says. “And that is something that, if it did hit, would certainly take out a city.”

Dimorphos is a safe asteroid to give an experimental nudge, says Mark Boslough, a physicist at Los Alamos National Laboratory in New Mexico who has studied planetary protection but is not involved in DART. “It’s not on a collision course” with Earth, he says, and DART “can’t hit it hard enough to put it on a collision course.” The DART spacecraft weighs only as much as a couple of vending machines, whereas Dimorphos is thought to be nearly as hefty as Egypt’s Great Pyramid of Giza.

After a 10-month voyage, DART met up with Didymos and Dimorphos near their closest approach to Earth, about 11 million kilometers away. Up until the very end of its journey, DART could see only the larger asteroid, Didymos. But about an hour before impact, DART spotted Dimorphos in its field of view. Using its onboard camera, the spacecraft steered itself toward the asteroid moonlet and slammed into it at some 6.1 kilometers per second, or nearly 14,000 miles per hour.
DART’s camera feed went dark after impact. But another probe nearby is expected to have caught the collision on camera. The Light Italian CubeSat for Imaging of Asteroids rode to Dimorphos aboard DART but detached a couple of weeks before impact to watch the event from a safe distance. Its mission was to whiz past Dimorphos about three minutes after DART’s impact to snap pictures of the crash site and the resulting plume of asteroid debris launched into space. The probe is expected to beam images of DART’s demise back to Earth within a couple of days.

“I was absolutely elated, especially as we saw the camera getting closer and just realizing all the science that we’re going to learn,” said Pam Melroy, NASA Deputy Administrator, after the impact. “But the best part was seeing, at the end, that there was no question there was going to be an impact, and to see the team overjoyed with their success.”
DART’s impact is expected to shove Dimorphos into a closer, shorter orbit around Didymos. Telescopes on Earth can clock the timing of that orbit by watching how the amount of light from the double asteroid system changes as Dimorphos passes in front of and behind Didymos.

“It’s really a beautifully conceived experiment,” Boslough says. In the coming weeks, dozens of telescopes across every continent will watch Dimorphos to see how much DART changed its orbit. The Hubble and James Webb space telescopes may also get images.
“It’ll be really interesting to see what comes out,” says Amy Mainzer, a planetary scientist at the University of Arizona in Tucson who is not involved in DART. “Asteroids have a way of surprising us,” she says, because it’s hard to know a space rock’s precise chemical makeup and internal structure based on observations from Earth. So Dimorphos’ motion post-impact may not exactly match researchers’ expectations.

The DART team will compare data on Dimorphos’ new orbit with their computer simulations to see how close those models were to predicting the asteroid’s actual behavior and tweak them accordingly. “If we can get our models to reproduce what actually happened, then you can use those models to [plan for] other scenarios that might show up in the future” — like the discovery of a real killer asteroid, says DART team member Wendy Caldwell, a mathematician and planetary scientist at Los Alamos National Laboratory.

“No matter what happens,” she says, “we will get information that is valuable to the scientific community and to the planetary defense community.”

In Maya society, cacao use was for everyone, not just royals

In ancient Maya civilization, cacao wasn’t just for the elites.

Traces of the sacred plant show up in ceramics from all types of neighborhoods and dwellings in and around a former Maya city, researchers report September 26 in the Proceedings of the National Academy of Sciences. The finding suggests that, contrary to previous thinking, cacao was consumed at every social level of Maya society.

“Now we know that the rituals the elite depict with cacao were likely played out, like Thanksgiving, like any other ritual, by everyone,” says Anabel Ford, an archaeologist at the University of California, Santa Barbara.
Cacao — which chocolate is made from — was sacred to the ancient Maya, consumed in rituals and used as a currency. The cacao tree (Theobroma cacao) itself was linked to Hun Hunahpu, the maize god. Previous research found cacao in ceremonial vessels and elite burials, suggesting that its use was restricted to those at the top.

To explore the extent to which cacao was used in broader Maya society, Ford and colleagues examined 54 ceramic shards dating from A.D. 600 to 900 (SN: 9/27/18). The shards come from jars, mixing bowls, serving plates and vases thought to be drinking vessels. All the pieces were found in residential and ceremonial civic areas of varying size and status from city centers, foothills, upland areas and the valley around the former Maya city of El Pilar, on the present-day border of Guatemala and Belize.

To identify cacao, the researchers searched for theophylline, a compound found in trace amounts in the plant. The team found the compound on more than half of the samples, on all types of ceramics and distributed throughout social contexts.

Future research will move beyond who consumed cacao and explore the role of farmers in managing the critical resource. “A better question is to understand who grew it,” Ford says, because those people probably had greater access to the prized commodity.

A protogalaxy in the Milky Way may be our galaxy’s original nucleus

The Milky Way left its “poor old heart” in and around the constellation Sagittarius, astronomers report. New data from the Gaia spacecraft reveal the full extent of what seems to be the galaxy’s original nucleus — the ancient stellar population that the rest of the Milky Way grew around — which came together more than 12.5 billion years ago.

“People have long speculated that such a vast population [of old stars] should exist in the center of our Milky Way, and Gaia now shows that there they are,” says astronomer Hans-Walter Rix of the Max Planck Institute for Astronomy in Heidelberg, Germany.
The Milky Way’s ancient heart is a round protogalaxy that spans nearly 18,000 light-years and possesses roughly 100 million times the mass of the sun in stars, or about 0.2 percent of the Milky Way’s current stellar mass, Rix and colleagues report in a study posted September 7 at arXiv.org.

“This study really helps to firm up our understanding of this very, very, very young stage in the Milky Way’s life,” says Vasily Belokurov, an astronomer at the University of Cambridge who was not involved in the work. “Not much is really known about this period of the Milky Way’s life,” he says. “We’ve seen glimpses of this population before,” but the new study gives “a bird’s-eye view of the whole structure.”

Most stars in the Milky Way’s central region abound with metals, because the stars originated in a crowded metropolis that earlier stellar generations had enriched with those metals through supernova explosions. But Rix and his colleagues wanted to find the exceptions to the rule, stars so metal-poor they must have been born well before the rest of the galaxy’s stellar denizens came along — what Rix calls “a needle-in-a-haystack exercise.”

His team turned to data from the Gaia spacecraft, which launched in 2013 on a mission to chart the Milky Way (SN: 6/13/22). The astronomers searched about 2 million stars within a broad region around the galaxy’s center, which lies in the constellation Sagittarius, looking for stars with metal-to-hydrogen ratios no more than 3 percent of the sun’s.

The astronomers then examined how those stars move through space, retaining only the ones that don’t dart off into the vast halo of metal-poor stars engulfing the Milky Way’s disk. The end result: a sample of 18,000 ancient stars that represents the kernel around which the entire galaxy blossomed, the researchers say. By accounting for stars obscured by dust, Rix estimates that the protogalaxy is between 50 million and 200 million times as massive as the sun.

“That’s the original core,” Rix says, and it harbors the Milky Way’s oldest stars, which he says probably have ages exceeding 12.5 billion years. The protogalaxy formed when several large clumps of stars and gas conglomerated long ago, before the Milky Way’s first disk — the so-called thick disk — arose (SN: 3/23/22).

The protogalaxy is compact, which means little has disturbed it since its formation. Smaller galaxies have crashed into the Milky Way, augmenting its mass, but “we didn’t have any later mergers that deeply penetrated into the core and shook it up, because then the core would be larger now,” Rix says.

The new data on the protogalaxy even capture the Milky Way’s initial spin-up — its transition from an object that didn’t rotate into one that now does. The oldest stars in the proto–Milky Way barely revolve around the galaxy’s center but dive in and out of it instead, whereas slightly younger stars show more and more movement around the galactic center. “This is the Milky Way trying to become a disk galaxy,” says Belokurov, who saw the same spin-up in research that he and a colleague reported in July.

Today, the Milky Way is a giant galaxy that spins rapidly — each hour our solar system speeds through 900,000 kilometers of space as we race around the galaxy’s center. But the new study shows that the Milky Way got its start as a modest protogalaxy whose stars still shine today, stars that astronomers can now scrutinize for further clues to the galaxy’s birth and early evolution.

Drumming woodpeckers use similar brain regions as songbirds

Songbirds get a lot of love for their dulcet tones, but drummers may start to steal some of that spotlight.

Woodpeckers, which don’t sing but do drum on trees, have brain regions that are similar to those of songbirds, researchers report September 20 in PLOS Biology. The finding is surprising because songbirds use these regions to learn their songs at an early age, yet it’s not clear if woodpeckers learn their drum beats (SN: 9/16/21). Whether woodpeckers do or not, the result suggests a shared evolutionary origin for both singing and drumming.
The ability to learn vocalizations by listening to them, just like humans do when learning to speak, is a rare trait in the animal kingdom. Vocal learners, such as songbirds, hummingbirds and parrots, have independently evolved certain clusters of nerve cells called nuclei in their forebrains that control the ability. Animals that don’t learn vocally are thought to lack these brain features.

While it’s commonly assumed that other birds don’t have these nuclei, “there’s thousands of birds in the world,” says Matthew Fuxjager, a biologist at Brown University in Providence, R.I. “While we say these brain regions only exist in these small groups of species, nobody’s really looked in a lot of these other taxa.”

Fuxjager and his colleagues examined the noggins of several birds that don’t learn vocally to check if they really did lack these brain nuclei. Using molecular probes, the team checked the bird brains for activity of a gene called parvalbumin, a known marker of the vocal learning nuclei. Many of the birds, including penguins and flamingos, came up short, but there was one exception — male and female woodpeckers, which had three spots in their brains with high parvalbumin activity.

Though woodpeckers don’t sing, they do perform a rapid drumming on trees and house gutters to defend their territories or find mates. This drumming is different from the drilling the birds do to find food. When the team found brain nuclei similar to songbirds in woodpeckers, Fuxjager was immediately intrigued. “I thought right away it’s probably related to drumming,” he says.

The researchers subjected downy woodpeckers (Dryobates pubescens) in the wild to audio recordings of drumming from other woodpeckers. This faux territorial invasion sparked an aggressive drumming response from the birds, which were then captured and euthanized to have their recent brain activity analyzed. Sure enough, the same regions identified by earlier lab tests had been activated in the drummers.

The brains of bird vocalists and drummers evolved separately, but the similarity of the analyzed regions hints at a common origin. “It suggests that there are common themes about how you develop these complex behaviors,” says Bradley Colquitt, a biologist at the University of California, Santa Cruz who was not involved in the study. The neural circuitry formed by these nuclei most likely developed from an ancestral circuit controlling movement, Colquitt says.

“Birdsong is basically the brain controlling muscles in a vocal organ called the syrinx,” Fuxjager says. These sophisticated movements are not unlike the swift head-and-neck motions involved in drumming.

Whether drumming is learned like birdsong remains an open question that the team is now exploring. Future work will also look at how woodpeckers’ brains are wired, how these nuclei control drumming and how the brain regions’ role in drumming evolved across woodpecker species, Fuxjager says.

This new study “uncovers another species that we can add to our comparative efforts” to better understand how complex behaviors evolve, Colquitt says. “It is a preview into potentially exciting evolutionary neurobiology.” Now that woodpeckers have joined the band of important musical birds, it looks like the drummers may soon get their chance to shine.