A custom brain implant lifted a woman’s severe depression

A personalized brain implant eased the crushing symptoms of a woman’s severe depression, allowing her to once again see the beauty of the world. “It’s like my lens on the world changed,” said Sarah, the research volunteer who requested to be identified by her first name only.

The technology, described October 4 in Nature Medicine, brings researchers closer to understanding how to detect and change brain activity in ultraprecise ways (SN: 2/10/19).

The device was bespoke; it was built specifically for Sarah’s brain. The details of the new system may not work as a treatment for many other people, says Alik Widge, a psychiatrist and neural engineer at the University of Minnesota in Minneapolis. Still, the research is “a really significant piece of work,” he says, because it points out a way to study how brain activity goes awry in depression.

Researchers at the University of California, San Francisco implanted temporary thin wire electrodes into Sarah’s brain. The 36-year-old woman had suffered from severe depression for years. These electrodes allowed researchers to monitor the brain activity that corresponded to Sarah’s depression symptoms — a pattern that the researchers could use as a biomarker, a signpost of trouble to come. In Sarah’s case, a particular sign emerged: a fast brain wave called a gamma wave in her amygdala, a brain structure known to be involved in emotions.
With this biomarker in hand, the researchers then figured out where to stimulate the brain to interrupt Sarah’s distressing symptoms. A region called the ventral capsule/ventral striatum, or VC/VS, seemed to be the key. That’s not surprising; previous research suggests the region is involved with feeling good and other emotions. When researchers applied tiny jolts of electrical current to this region, Sarah’s mood improved. “We could learn the road map of Sarah’s brain in a way that we could really improve her depression symptoms,” Katherine Scangos of UCSF said in a Sept. 30 news briefing.

During this mapping phase of the experiment, Sarah felt joy when the right spot was stimulated. “I laughed out loud,” she said in the briefing. “This was the first time I had spontaneously laughed and smiled where it wasn’t faked or forced in five years.”

Surgeons then implanted a more permanent device into Sarah’s brain last June. Scientists programmed the device to detect when gamma signals were high in Sarah’s amygdala, and respond with a tiny jolt to her VC/VS. This happened about 300 times a day. The stimulation was calibrated so Sarah didn’t feel any zaps, but she said they left her feeling a little more energetic.

The research paper describes Sarah’s improvements as the technology did its work in her head over two months; it’s unclear how long the benefits might last, though she’s now had the device implanted for over a year. “As time has gone on, it’s been this virtuous cycle, a spiral upwards,” Sarah said. “Everything has gotten easier and easier and easier.”

The approach used by the UCSF researchers required a lot of sophisticated imaging and machine learning technology. That complexity may prevent it from being a wider treatment, cautions Helen Mayberg, a neurologist at Icahn School of Medicine at Mount Sinai in New York City.

Still, the results — which add to a variety of ways to detect and change problematic brain activity — contain valuable information about how depression takes hold of a brain, and how brain stimulation can change that, says Mayberg, whose research has helped build and refine the field of deep brain stimulation for mood disorders. “What we all want to know is, ‘How does this work?’”

A child’s partial skull adds to the mystery of how Homo naledi treated the dead

A child’s partial skull found in a remote section of a South African cave system has fueled suspicion that an ancient hominid known as Homo naledi deliberately disposed of its dead in caves.

An international team led by paleoanthropologist Lee Berger of University of the Witwatersrand, Johannesburg pieced together 28 skull fragments and six teeth from a child’s skull discovered in a narrow opening located about 12 meters from an underground chamber where cave explorers first found H. naledi fossils (SN: 9/10/15). Features of the child’s skull qualify it as H. naledi, a species with an orange-sized brain and skeletal characteristics of both present-day people and Homo species from around 2 million years ago.

“The case is building for deliberate, ritualized body disposal in caves by Homo naledi,” Berger said at a November 4 news conference held in Johannesburg. While that argument is controversial, there is no evidence that the child’s skull was washed into the tiny space or dragged there by predators or scavengers (SN: 4/19/16).

Berger’s group describes the find in two papers published November 4 in PaleoAnthropology. In one, Juliet Brophy, a paleoanthropologist at Louisiana State University in Baton Rouge and colleagues describe the youngster’s skull. In the other, paleoanthropologist Marina Elliott of Canada’s Simon Fraser University in Burnaby and colleagues detail new explorations in South Africa’s Rising Star cave system.

Researchers nicknamed the new find Leti, short for a word in a local South African language that means “the lost one.” Leti likely dates to the same time as other H. naledi fossils, between 335,000 and 236,000 years ago (SN: 5/9/17). Berger’s team suspects Leti died at about age 4 to 6 years based on the rate at which children grow today. But that’s a rough approximation as the scientists can’t yet say how fast H. naledi kids grew.

‘Flashes of Creation’ recounts the Big Bang theory’s origin story

The Big Bang wasn’t always a sure bet. For several decades in the 20th century, researchers wrestled with interpreting cosmic origins, or if there even was a beginning at all. At the forefront of that debate stood physicists George Gamow and Fred Hoyle: One advocated for an expanding universe that sprouted from a hot, dense state; the other for a cosmos that is eternal and unchanging. Both pioneered contemporary cosmology, laid the groundwork for our understanding of where atoms come from and brought science to the masses.

In Flashes of Creation, physicist Paul Halpern recounts Gamow’s and Hoyle’s interwoven stories. The book bills itself as a “joint biography,” but that is a disservice. While Gamow and Hoyle are the central characters, the book is a meticulously researched history of the Big Bang as an idea: from theoretical predictions in the 1920s, to the discovery of its microwave afterglow in 1964, and beyond to the realization in the late 1990s that the expansion of the universe is accelerating.

Although the development of cosmology was the work of far more than just two scientists, Halpern would be hard-pressed to pick two better mascots. George Gamow was an aficionado of puns and pranks and had a keen sense of how to explain science with charm and whimsy (SN: 8/28/18). The fiercely stubborn Fred Hoyle had a darker, more cynical wit, with an artistic side that showed through in science fiction novels and even the libretto of an opera. Both wrote popular science books — Gamow’s Mr Tompkins series, which explores modern physics through the titular character’s dreams, are a milestone of the genre — and took to the airwaves to broadcast the latest scientific thinking into people’s homes.
“Gamow and Hoyle were adventurous loners who cared far more about cosmic mysteries than social conventions,” Halpern writes. “Each, in his own way, was a polymath, a rebel, and a master of science communication.”

While the Big Bang is now entrenched in the modern zeitgeist, it wasn’t always so. The idea can be traced to Georges Lemaître, a physicist and priest who proposed in 1927 that the universe is expanding. A few years later, he suggested that perhaps the cosmos began with all of its matter in a single point — the “primeval atom,” he called it. In the 1940s, Gamow latched on to the idea as way to explain how all the atomic elements came to be, forged in the “fireball” that would have filled the cosmos in its earliest moments. Hoyle balked at the notion of a moment of creation, convinced that the universe has always existed — and always will exist — in pretty much the same state we find it today. He even coined the term “Big Bang” as a put-down during a 1949 BBC radio broadcast. The elements, Hoyle argued, were forged in stars.

As far as the elements go, both were right. “One wrote the beginning of the story of element creation,” Halpern writes, “and the other wrote the ending.” We now know that hydrogen and helium nuclei emerged in overwhelming abundance during the first few minutes following the Big Bang. Stars took care of the rest.

Halpern treats Gamow and Hoyle with reverence and compassion. Re-created scenes provide insight into how both approached science and life. We learn how Gamow, ever the scientist, roped in physicist Niels Bohr to test ideas about why movie heroes always drew their gun faster than villains — a test that involved staging a mock attack with toy pistols. We sit in with Hoyle and colleagues while they discuss a horror film, Dead of Night, whose circular timeline inspired their ideas about an eternal universe.
And Halpern doesn’t shy away from darker moments, inviting readers to know these scientists as flawed human beings. Gamow’s devil-may-care attitude wore on his colleagues, and his excessive drinking took its toll. Hoyle, in his waning decades, embraced outlandish ideas, suggesting that epidemics come from space and that a dinosaur fossil had been tampered with to show an evolutionary link to birds. And he went to his grave in 2001 still railing against the Big Bang.

Capturing the history of the Big Bang theory is no easy task, but Halpern pulls it off. The biggest mark against the book, in fact, may be its scope. To pull in all the other characters and side plots that drove 20th century cosmology, Gamow and Hoyle sometimes get forgotten about for long stretches. A bit more editing could have sharpened the book’s focus.

But to anyone interested in how the idea of the Big Bang grew — or how any scientific paradigm changes — Flashes of Creation is a treat and a worthy tribute to two scientific mavericks.

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Earth’s lower atmosphere is rising due to climate change

Global temperatures are rising and so, it seems, is part of the sky.

Atmosphere readings collected by weather balloons in the Northern Hemisphere over the last 40 years reveal that climate change is pushing the upper boundary of the troposphere — the slice of sky closest to the ground — steadily upward at a rate of 50 to 60 meters per decade, researchers report November 5 in Science Advances.

Temperature is the driving force behind this change, says Jane Liu, an environmental scientist at the University of Toronto. The troposphere varies in height around the world, reaching as high as 20 kilometers in the tropics and as low as seven kilometers near the poles. During the year, the upper boundary of the troposphere — called the tropopause — naturally rises and falls with the seasons as air expands in the heat and contracts in the cold. But as greenhouse gases trap more and more heat in the atmosphere, the troposphere is expanding higher into the atmosphere (SN: 10/26/21).

Liu and her colleagues found that the tropopause rose an average of about 200 meters in height from 1980 to 2020. Nearly all weather occurs in the troposphere, but it’s unlikely that this shift will have on a big effect on weather, the researchers say. Still, this research is an important reminder of the impact of climate change on our world, Liu says.

“We see signs of global warming around us, in retreating glaciers and rising sea levels,” she says. “Now, we see it in the height of the troposphere.”

What the Perseverance rover’s quiet landing reveals about meteor strikes on Mars

The lander was listening. On February 18, NASA’s InSight lander on Mars turned its attention to the landing site for another mission, Perseverance, hoping to detect its arrival on the planet.

But InSight heard nothing.

Tungsten blocks ejected by Perseverance during entry landed hard enough to create craters on the Martian surface. Collisions like these — whether from space missions or meteor strikes — send shock waves through the ground. Yet in the first experiment of its kind on another world, InSight failed to pick up any seismic waves from the blocks’ impacts, researchers report October 28 in Nature Communications.

As a result, researchers think that less than 3 percent of the energy from the impacts made its way into the Martian surface. The intensity of impact-generated rumblings varies from planet to planet and is “really important for understanding how the ground will change from a big impact event,” says Ben Fernando, a geophysicist at the University of Oxford.
But getting these measurements is tricky. Scientists need sensitive instruments placed relatively near an impact site. Knowing when and where a meteor will strike is nearly impossible, especially on another world.

Enter Perseverance: a hurtling space object set to hit Mars at an exact time and place (SN: 2/17/21). To help with its entry, Perseverance dropped about 78 kilograms of tungsten as the rover landed about 3,450 kilometers from InSight. The timing and weight of the drop provided a “once-in-a-mission opportunity” to study the immediate seismic effects of an impact from space, Fernando says.

The team had no idea whether InSight would be able to detect the blocks’ impacts or not, but the quiet arrival speaks volumes. “It lets us put an upper limit on how much energy from the tungsten blocks turned into seismic energy,” Fernando says. “We’ve never been able to get that number for Mars before.”