Biology

It’s clear a child’s early experiences can leave a lasting imprint on how their brain forms and functions. Now, a new study reveals how various environmental factors, including financial struggles and neighborhood safety, affect the quality of the brain’s white matter —the wiring that connects different brain regions—and in turn, a child’s cognitive abilities. The work, published today in the Proceedings of the National Academy of Sciences , also points to social factors that can boost resilience in a young brain.

“It’s a really impressive, compelling paper about the long-term consequences of growing up in undersupported environments,” says John Gabrieli, a neuroscientist at the Massachusetts Institute of Technology who was not involved in the study.

White matter consists of nerve fibers facilitating communication between brain regions. They are sheathed in an insulating material called myelin that gives white matter its color. Much of the research to date on how the brain supports cognition has focused on gray matter, tissue mostly made of the cell bodies of neurons that process information, which shows up as gray on brain scans. But complex cognitive tasks are “a symphony of a network” formed by multiple brain areas, Gabrieli says. “And the white matter is what mediates that communication.”

Previous studies have linked poverty and childhood trauma—among other adverse environments—with a lower quality of white matter in children and lower scores on cognitive tests . However, these studies included a small number or participants and only looked at one or a few environmental variables at a time.

For a more complete picture, developmental neuroscientist Sofia Carozza at Brigham and Women’s Hospital and colleagues analyzed data from more than 9000 participants in the Adolescent Brain Cognitive Development (ABCD) Study . Funded by the National Institutes of Health and established in 2015, ABCD is the largest longitudinal study of brain development in a representative group of U.S. children. Surveys of participants and their parents provide data on their home environment, including household income and parents’ level of education. At age 9 or 10, ABCD participants got a form of magnetic resonance imaging that measures the movement of water in the brain. From the strength of this directional signal, researchers can infer how robust and organized the bundles of white matter fibers are, and whether they have signs of deterioration or damage.

The technique offers insight into the health of the brain’s “communication superhighways,” Carozza says. Researchers then tested the kids’ language and math skills 2 and 3 years after the imaging, respectively.

Carozza and her team analyzed the relationship between the quality of 73 white matter tracts across the brain and ABCD data related to a child’s early experiences. That included 10 measures of adversity, such as household financial difficulties and parental substance abuse; and seven protective factors that in some cases might counter adversity, such as parental education and neighborhood safety.

The researchers found that all but one of the variables they examined played some role in shaping the structure of white matter in the brain. (Birth weight was the only exception.) The two largest drivers of deteriorated white matter were exposure to trauma and a measure of social vulnerability, which includes socioeconomic status, housing quality, transportation access, and other neighborhood characteristics . In other words, the more trauma a child had experienced and the more socially vulnerable they were, the lower the quality of white matter in their brain . And this lower quality of white matter was in turn associated with difficulties in language and arithmetic during the follow-up period.

With a study of this size and scope, “we can really start to unpack the puzzle a little bit more carefully,” says Johanna Bick, a developmental psychologist at the University of Houston who was not involved in the new work. The findings suggest “we can’t ignore the social environment,” which is clearly “a mechanism to explain these academic outcomes,” Bick says.

Carozza says she was surprised by how much the social environment, including a child’s neighborhood, influenced white matter architecture. “This points to the broader set of relationships and social experiences that exist beyond a home that can be critical for a child’s development.”

Among the protective factors most strongly associated with better white matter quality were living in a home with two parents and having a high household income. Measures of positive parenting—showing children love, warmth, and kindness—also showed a correlation, as well as living in a trusting community.

The study didn’t include data on the role of peers, an important part of adolescents’ development, Bick says. “So there may even be more social protective factors that could be considered in future work.”

Bick wonders whether results would be similar in kids outside the United States, and how cultural differences, such as community networks in more collectivist societies, might mediate the relationship between the environment and white matter development.

The study points to opportunities to intervene and improve a child’s brain development, Carozza says—for example, by strengthening communities and providing individual support to families. Translating these findings into policy “is not easy,” Gabrieli notes. But “it is motivating to think about … building social policies or practices that would help children in low-income environments not be overwhelmed by these disadvantages.”

Here are our full stories on the Trump administration . Have new story tips, internal Trump administration or science agency emails, or other key documents? Contact us .

Our latest stories

After ‘coding error’ triggers firings, top NIH scientists called back to work

NIH under orders to cancel $2.6 billion in contracts

Trump administration quashes NIH scientific integrity policy

Surprise! White House asks for ‘permanent’ block on NIH’s sudden indirect cost cap

Is the U.S. government quitting on an attempt to cap the National Institutes of Health’s “indirect” costs or just moving the fight to a different stage? Today the Trump administration asked U.S. District Judge Angel Kelley to convert her 5 March preliminary injunction on the attempted cap to a permanent injunction. A coalition of 22 states, university associations, and research advocacy groups had gone to Kelley to stop NIH from implementing its 7 February notice to reduce indirect cost rates to a flat 15%, a change that would have meant billions of dollars less each year to institutions receiving NIH grants.

Today’s request was made with the consent of those plaintiffs and, if granted, would mean there will be no trial before Kelley on the merits of the case. But the government currently has until 14 April to decide whether to appeal Kelley’s injunction to a higher federal court. ( Update: Later on Friday, Kelley issued the permanent injunction and The New York Times reported the administration is likely to appeal . ) Even if it throws in the legal towel, the Trump administration can still try another strategy to reduce the amount of NIH money—typically an additional 50% to 60% of the total spending on direct research—that institutions receive to provide infrastructure and administrative support for the federally funded research done on their campuses. It, for example, could work with the Republican Congress to enact the cap in future budgets. —Jeffrey Mervis

Our previous coverage: Can NIH overturn a court order blocking it from slashing overhead payments? Unlikely, one expert says

State attorneys general sue to restore NIH grants

Sixteen state attorneys general have filed a lawsuit against the Trump administration and the National Institutes of Health over the abrupt terminations of grants and delays in reviewing grant applications. Like a lawsuit filed on 2 March by NIH-funded scientists, a union representing grad students and postdocs and other plaintiffs, the new complaint letter accuses the administration of violating the Administrative Procedure Act, which governs how agencies disperse funds and includes specific procedures for withdrawing them. The lawsuit also says the administration does not legally have the power to withhold money that has been appropriated by Congress.

The AGs say the APA requires the administration and NIH to provide “reasoned” decision-making when deciding to withdraw a grant, and that the agency’s practice of targeting projects that study controversial topics such as transgender issues, vaccine hesitancy, and diversity is arbitrary and capricious. “The agency has failed to acknowledge—let alone provide ‘good reasons for’—any changes in agency policy supposedly justifying the terminations,” the lawsuit reads.

The complaint letter goes on to list the economic impacts that universities in the 16 states have suffered because of delays and terminations. “I won’t allow the Trump Administration to take unlawful actions that play politics with our public health,” Massachusetts Attorney General Andrea Joy Campbell said in a statement. The AGs asked the court to file a preliminary injunction against the administration, which would force NIH to restore the grants, publish notices of funding opportunities, and review grant applications. A ruling in favor of the AGs could affect far more scientists in the states represented in the suit than the similar lawsuit filed yesterday. —Sara Reardon

Our previous coverage: Lawsuit aims to overturn many NIH grant terminations

Trump’s war on universities finds new fronts

The Trump administration’s threats to federal research funding at top universities keep expanding. Earlier this week, Princeton University’s president said in an email to the school that the United States was suspending “several dozen” research grants and that the “full rationale for this action is not yet clear.” Those grants were reportedly from the Department of Defense, NASA, and the Department of Energy but have not been publicly identified so far. White House officials said the move came as part of its antisemitism probe of universities, a justification also used this week to threaten research funding at Harvard and Brown universities. In the latter case, reports that NIH funding had been frozen at Brown were called “rumors” by officials there and have not been confirmed. Biomedical researcher Jeff Flier, former head of Harvard Medical School, noted in a commentary in The New York Times that even though he has also been critical of Harvard policies these actions by the Trump administration represent an “existential threat” to schools.

The New York Times : I Led Harvard’s Medical School, and I Fear for What’s to Come

Oops, you’re not fired

Yesterday Science reported on how the National Institutes of Health was trying to rehire some top neuroscientists eliminated in the reduction in force enacted on Tuesday by the Department of Health and Human Services. Turns out other scientists and staff at the Food and Drug Administration and the Centers for Disease Control and Prevention were also mistakenly let go or HHS subsequently said they were needed. CDC, for example, planned to reinstate people at a program overseeing blood levels of lead in children, The Wall Street Journal reported . (But new questions then arose about whether the program would be restored .) HHS Secretary Robert F. Kennedy Jr. acknowledged his agency and the administration’s Department of Government Efficiency made mistakes and had expected that. “That was always the plan,” Kennedy told reporters Thursday. “Part of the DOGE—we talked about this from the beginning—is we’re going to do 80% cuts, but 20% of those are going to have to be reinstalled, because we’ll make mistakes.”

Our previous coverage: After ‘coding error’ triggers firings, top NIH scientists called back to work

Headlines elsewhere

The Wall Street Journal : Ousted Vaccine Chief Says RFK Jr.’s Team Sought Data to Justify Anti-Science Stance

NBC News: CDC's IVF team gutted even as Trump calls himself the 'fertilization president'

STAT : Federal advisory panel on ethical, legal issues in human health research disbanded

STAT : HHS deputy secretary pick O’Neill discloses history of work with vaccine developers

Large-bodied animals can maintain territories up to hundreds of square kilometers in size, and they defend these vast domains however they can, from leaving behind their scent to getting physically aggressive. But there are tiny, equally brave critters that protect much smaller areas, too. Researchers have now discovered that a type of moth caterpillar defends one of the smallest territories ever seen : the tip of a leaf barely 1 centimeter wide.

The two-lined hooktip moth ( Falcaria bilineata ) lays its eggs on the twigs and leaves of birch trees across North America. When these eggs hatch, the caterpillars—known as warty birch caterpillars—usually head to the tips of nearby leaves. At less than 2 millimeters long, the newborn bugs are extremely vulnerable. But for years, researchers have noticed that warty birch caterpillars vibrate on their leaves, perhaps a sign of the insects’ territoriality.

To test this idea in the lab, researchers at Carleton University analyzed how a warty birch caterpillar reacted when another caterpillar of the same species was added to its leaf. When an intruder arrived, the resident caterpillar started vibrating more insistently, producing the sounds by striking against the leaf and also wriggling and scraping its body. As the intruder approached the resident caterpillar’s perch on the leaf tip, the resident began vibrating nearly 25 times per minute, a 14-fold increase in the caterpillar’s signaling rate, researchers report in the Journal of Experimental Biology .

Most of the time, this buzzy display seemed to work: In 71% of the cases, the residents kept their territory. But if the intruder prevailed, the resident caterpillar made a daring escape, jumping down from the leaf with a silk thread. The team believes the caterpillars claim territory on leaf tips because the tips’ springiness may amplify the footfalls of approaching predators and the caterpillars’ own vibrations—while also providing a great escape route, just in case.

In the swampy forests of Indonesian New Guinea, “food brigades” of soldiers are guarding bulldozers as they clear vegetation for future rice fields. The operation is part of an initiative announced late last year by Indonesian President Prabowo Subianto to create 1 million hectares of new rice farms in the Merauke Regency, a region at the far eastern end of Indonesia’s sprawling archipelago. The country’s 281 million people, who will consume more than 30 million tons of rice this year, need more production, the government asserts. “Food is a matter of our nation’s survival,” Subianto said in February.

But many soil scientists and agricultural researchers predict the effort could become the latest in a series of disastrous farming megaprojects launched by Indonesia’s leaders over the past few decades. Merauke’s soils and relatively dry climate are poorly suited to growing rice, they say. They fear the project, covering an area the size of Jamaica, could lead to dry, degraded landscapes that are vulnerable to wildfires—and harm Merauke’s Indigenous people. So far, however, government officials have had “their eyes and ears closed to all criticism from scientists,” says anthropologist Laksmi Adriani of Yayasan Pusaka Bentala Rakyat, a nonprofit that advocates for Indigenous rights.

The rice project is rooted in a pledge by Subianto, a former general who took office in October 2024, to make Indonesia self-sufficient in food production within 4 years. In particular, his administration is trying to compensate for the loss of farmland to development on Java, Indonesia’s most populated island, by rapidly adding 3 million hectares of cropland across the nation. In New Guinea, Indonesia’s military is helping a firm owned by the brother of Subianto’s agriculture minister clear the land; it’s not clear who the farmers would be.

To many researchers, Subianto’s initiative is reminiscent of past failed megaprojects. In the 1990s, they note, then-President Soeharto moved to convert 1 million hectares of wet peatland forests in Central Kalimantan on the island of Borneo to rice paddies. But draining the wetlands exposed soils rich in the mineral pyrite to air, enabling chemical reactions that produced sulfuric acid. The soils became too acidic to support economically viable rice farming, says Dwi Andreas, a soil scientist at Bogor Agricultural University. Then, beginning in the late 1990s, many of the cleared areas were abandoned. Many of the dry, shrub-covered plots then burned, as a result of both El Niño–induced drought and intentional fires set by firms eager to plant oil palm plantations. The smoke threatened the health of millions in Indonesia and neighboring countries and released billions of tons of planet-warming carbon.

A similar failure has unfolded in North Sumatra, where in 2020 then-President Joko Widodo rapidly expanded onion and potato farming as part of a food sovereignty project. Even before the project started, soil scientist Budiman Minasny of the University of Sydney warned that region’s hard and acidic soils, which originated from the Toba supervolcano eruption some 75,000 years ago, were unsuitable for agriculture. Farmers have now abandoned 90% of the fields, local media recently reported.

The government now risks repeating these mistakes, researchers say. Officials haven’t said exactly where they plan to grow rice in 4.6-million-hectare Merauke, but early signs suggest they are targeting vulnerable soils. Using satellite imagery, landscape ecologist David Gaveau of TreeMap, a company that monitors land-use change in Southeast Asia, found that workers have recently cleared 4200 hectares near a village called Wanam. It lies along a 135-kilometer-long “food estate road” being built by Indonesia’s Ministry of Defense. Geologic maps show the road slices into “older swamp deposits,” according to a scientist at the National Research and Innovation Agency who asked to remain anonymous.

That’s worrying, scientists say, because it means that, as on Borneo in the 1990s, the cleared soils could become acidic. So far, however, the government has not released any technical review of Merauke’s soils or whether they will support rice, says soil scientist Wirastuti Widyatmanti of Gadjah Mada University.

Indonesian Minister of Agriculture Amran Sulaiman has said the government will, if necessary, plant new rice varieties to deal with acidic soils. But Andreas is skeptical. In Central Kalimantan, he tested 12 rice varieties in soils similar to Merauke’s, and all fared poorly. He suspects rice farmers would need to add large quantities of costly lime fertilizer to their paddies to neutralize soil acidity. As a result, “farmers will get no profit at all,” Andreas predicts. And if paddies are abandoned, Gaveau says the region’s relatively dry climate means “more fires will likely come in the future.”

This isn’t the first time the Indonesian government has tried to expand rice farming in Merauke. In 2010, then-President Susilo Bambang Yudhoyono launched an effort to clear tens of thousands of hectares of land for rice. That project also failed, Adriani notes. It destroyed forests that Indigenous Papuans relied on for hunting and gathering, and—far from bringing abundance—led to an increase in childhood malnutrition. Now, she fears Subianto’s rice initiative will only make matters worse.

Some of the world’s deadliest toxins are found in marine creatures such as the puffer fish and the blue-ringed octopus. For many, there is no antidote. So when U.S. Department of Defense (DOD) officials in 2019 confronted their Chinese counterparts with concerns about experiments with marine neurotoxins being conducted in China’s military labs, they were hoping for reassurance. Prior discussions had included “good dialogue” on how to keep such research from taking a nefarious turn, says a former DOD official involved in the sensitive talks.

But the neurotoxin queries hit a nerve. “We got completely slammed with disinformation,” including assertions that the United States was operating its own bioweapons programs, the former official says. China broke off talks, and then in 2020 Chinese officials alleged that the U.S. Army had released the COVID-19 virus in Asia as a bioweapon—a charge the U.S. vehemently denied.

The bitter breakdown highlighted what many see as enduring weaknesses in the Biological Weapons Convention (BWC), a landmark arms control treaty that this year marks its 50th anniversary. Architects of the BWC , which has been ratified by China, the U.S., and 186 other countries, hoped it would eliminate weapons “repugnant to the conscience of mankind.” But the convention will need much stronger teeth if it is to keep humanity safe, said researchers who gathered last week at a meeting in Washington, D.C., sponsored by the U.S. National Academies of Sciences, Engineering and Medicine to review the convention’s first 5 decades.

One major flaw, speakers said, is that the BWC lacks a mechanism to verify compliance—or even meaningful transparency measures. If international monitors can’t gain access to labs, or glean clues to what is happening there, it’s hard to judge when dual-use research—peaceful science that can have military applications—crosses a line. Adding to the urgency are rapid advances in the life sciences including synthetic biology and gene editing, enhanced by artificial intelligence (AI). They could lead to “weapons that are nastier than what’s found in nature—more transmissible and more deadly. Or resistant to existing vaccines or drugs,” says Jaime Yassif, who leads the biosecurity program at the nonprofit Nuclear Threat Initiative (NTI).

BWC working groups and nonprofits have been exploring a variety of approaches to strengthening the pact. Monitors could use AI to sniff out suspicious signals in trade data, scientific articles, and satellite imagery, for example, while companies that sell DNA sequences could use sophisticated screens to weed out those that might be used to construct weapons. Drug companies could be coaxed to stand in as proving grounds for inspections should treaty parties adopt site visits as a way to force violators to move or shut down work.

But efforts to strengthen the BWC face stiff headwinds. In December 2024, a treaty meeting ended in acrimony after Russia derailed consensus on measures for international cooperation and assistance in implementing the BWC and for the provision of science advice to treaty members. In his closing statement , Italy’s top negotiator, Leonardo Bencini, lamented the impasse. “If a biological weapon were to be used tomorrow, we would be caught completely unprepared. The world would look at us and would ask: ‘What have you done to prevent this?’”

The first international agreement to ban an entire category of weapons of mass destruction, the BWC has led to the closure of more than 20 offensive bioweapons programs since it entered into force on 26 March 1975, including the clandestine weaponization of everything from deadly human pathogens such as anthrax and smallpox to rinderpest, a virus lethal to cattle, and stem rust fungi against wheat and rye. “It’s important to remember that before the BWC, the U.S. had one of the largest biological weapons programs in the world. Leaders chose to walk away from that capability,” says Gigi Kwik Gronvall, a biosecurity expert at the Johns Hopkins University Center for Health Security.

Still, although bioweapons are unwieldy—they can be tricky to deploy and sicken the aggressor’s own troops or civilians—they remain appealing because they are cheap and terrifying. In an April 2024 nonproliferation report, the U.S. Department of State decried what it views as worrisome dual-use research in China and Iran. And it concluded that two nations—North Korea and Russia—currently have programs to develop and stockpile offensive bioweapons. Unclassified details are sketchy, but “there’s no uncertainty in that assessment,” says Andrew Weber, a senior fellow at the Council on Strategic Risks who led threat reduction programs for the U.S. government, including dismantling a Soviet anthrax facility in Kazakhstan in the 1990s. The public report, he says, is “the visible tip of an underwater mountain of intelligence.”

According to the report, Russia has spent millions of dollars renovating Soviet-era bioweapons labs of its 48th Central Scientific Research Institute. In October 2024, The Washington Post highlighted satellite images of the ongoing refurbishment at Sergiyev Posad-6, the institute’s virus lab near Moscow. Before the Soviet Union collapsed, researchers there weaponized smallpox, Ebola, and other pathogens. The new imagery indicates a “massive buildup,” including the installation of a high-level containment lab, that “rang a lot of alarms,” Yassif says. Russia has insisted it is modernizing the labs to develop defenses against bioweapons. Arms control analysts also believe Russia is helping North Korea evade sanctions to acquire biotech equipment.

The ranks of potential violators is expanding, from nations to terrorist groups, as new technologies make it easier to manipulate life. “Emerging technologies might lower the barrier to entry,” says Bonnie Jenkins, who served as undersecretary of state for arms control and international security affairs in former President Joe Biden’s administration.

Potential acts of subterfuge also remain a major worry. One nightmare scenario Weber envisions is Russia unleashing a pathogen via the Port of Rotterdam in the Netherlands, Europe’s largest, then claiming it was an accidental lab release from nearby Erasmus University.

To reduce risk, NTI last year launched the International Biosecurity and Biosafety Initiative for Science to safeguard biotechnology from misuse. The initiative has begun to offer free screening software to DNA synthesis companies to help them avoid selling genes for, say, new bacterial toxins. The screening tool can pick up dangerous new proteins designed by AI, Microsoft’s Bruce Wittmann and colleagues reported in December 2024 on bioRxiv. But novel sequences generated by a pioneering technique that creates proteins from noncanonical amino acids—beyond the 20 protein building blocks found in nature—might slip past. Such genetic code expansion is “the risk I’m shouting about right now,” says Katarzyna Adamala, a synthetic biologist at the University of Minnesota Twin Cities.

In unpublished work, Adamala and colleagues sent the sequence of a harmless protein, a luciferase, to a collaborator at a DNA synthesis company and asked him to alter his screening database to flag it as a sequence of concern. Then, they sent a version of the sequence that coded for a luciferase built in part from noncanonical amino acids, which passed the screen. They repeated that with a couple other benign sequences, then with pathogenic sequences without ordering the DNA. All evaded the screen. “We were able to fly under the radar,” she says, suggesting “we need to change how screening works.”

BWC backers hope that in talks scheduled for coming months treaty parties will hammer out a mechanism for triggering inspections. “You don’t need inspections to be perfect. You just need them to raise the cost of cheating,” says Christopher Park, an arms control expert who last week retired from the U.S. Department of State. “Moving, hiding, or destroying material can destroy a bioagent,” adds Sonia Ben Ouaghram-Gormley, a bioweapons expert at George Mason University. “Even if a program resumes later, you’ve delayed it. In biology, that’s a big win.”

Any progress, however, will come only after treaty parties move past the ill will generated by last year’s meeting. And U.S. President Donald Trump’s new administration has not yet articulated a stance on the BWC. The general mood in nonproliferation circles, Jenkins says, is that “political will is still lacking” to make significant changes.

For now, the taboo that bioweapons represent to much of humanity may be the strongest safeguard against their use.