Chronic stress can also alter the prefrontal cortex, the brain’s executive control center, and the amygdala, the fear and anxiety hub. Too many glucocorticoids for too long can impair the connections both within the prefrontal cortex and between it and the amygdala. As a result, the prefrontal cortex loses its ability to control the amygdala, leaving the fear and anxiety center to run unchecked. This pattern of brain activity (too much action in the amygdala and not enough communication with the prefrontal cortex) is common in people who have post-traumatic stress disorder (PTSD), another condition that spiked during the pandemic, particularly among frontline health-care workers.
The social isolation brought on by the pandemic was also likely detrimental to the brain’s structure and function. Loneliness has been linked to reduced volume in the hippocampus and amygdala, as well as decreased connectivity in the prefrontal cortex. Perhaps unsurprisingly, people who lived alone during the pandemic experienced higher rates of depression and anxiety.
Finally, damage to these brain areas affects people not only emotionally but cognitively as well. Many psychologists have attributed pandemic brain fog to chronic stress’s impact on the prefrontal cortex, where it can impair concentration and working memory.
So that’s the bad news. The pandemic hit our brains hard. These negative changes ultimately come down to a stress-induced decrease in neuroplasticity—a loss of cells and synapses instead of the growth of new ones. But don’t despair; there’s some good news. For many people, the brain can spontaneously recover its plasticity once the stress goes away. If life begins to return to normal, so might our brains.
“In a lot of cases, the changes that occur with chronic stress actually abate over time,” says James Herman, a professor of psychiatry and behavioral neuroscience at the University of Cincinnati. “At the level of the brain, you can see a reversal of a lot of these negative effects.”
In other words, as your routine returns to its pre-pandemic state, your brain should too. The stress hormones will recede as vaccinations continue and the anxiety about dying from a new virus (or killing someone else) subsides. And as you venture out into the world again, all the little things that used to make you happy or challenged you in a good way will do so again, helping your brain to repair the lost connections that those behaviors had once built. For example, just as social isolation is bad for the brain, social interaction is especially good for it. People with larger social networks have more volume and connections in the prefrontal cortex, amygdala, and other brain regions.
Even if you don’t feel like socializing again just yet, maybe push yourself a little anyway. Don’t do anything that feels unsafe, but there is an aspect of “fake it till you make it” in treating some mental illness. In clinical speak, it’s called behavioral activation, which emphasizes getting out and doing things even if you don’t want to. At first, you might not experience the same feelings of joy or fun you used to get from going to a bar or a backyard barbecue, but if you stick with it, these activities will often start to feel easier and can help lift feelings of depression.
Rebecca Price, an associate professor of psychiatry and psychology at the University of Pittsburgh, says behavioral activation might work by enriching your environment, which scientists know leads to the growth of new brain cells, at least in animal models. “Your brain is going to react to the environment that you present to it, so if you are in a deprived, not-enriched environment because you’ve been stuck at home alone, that will probably cause some decreases in the pathways that are available,” she says. “If you create for yourself a more enriched environment where you have more possible inputs and interactions and stimuli, then [your brain] will respond to that.” So get off your couch and go check out a museum, a botanical garden, or an outdoor concert. Your brain will thank you.
Exercise can help too. Chronic stress depletes levels of an important chemical called brain-derived neurotrophic factor (BDNF), which helps promote neuroplasticity. Without BDNF, the brain is less able to repair or replace the cells and connections that are lost to chronic stress. Exercise increases levels of BDNF, especially in the hippocampus and prefrontal cortex, which at least partially explains why exercise can boost both cognition and mood.
Not only does BDNF help new synapses grow, but it may help produce new neurons in the hippocampus, too. For decades, scientists thought that neurogenesis in humans stopped after adolescence, but recent research has shown signs of neuron growth well into old age (though the issue is still hotly contested). Regardless of whether it works through neurogenesis or not, exercise has been shown time and again to improve people’s mood, attention, and cognition; some therapists even prescribe it to treat depression and anxiety. Time to get out there and start sweating.
Turn to treatment
There’s a lot of variation in how people’s brains recover from stress and trauma, and not everyone will bounce back from the pandemic so easily.
“Some people just seem to be more vulnerable to getting into a chronic state where they get stuck in something like depression or anxiety,” says Price. In these situations, therapy or medication might be required.
Some scientists now think that psychotherapy for depression and anxiety works at least in part by changing brain activity, and that getting the brain to fire in new patterns is a first step to getting it to wire in new patterns. A review paper that assessed psychotherapy for different anxiety disorders found that the treatment was most effective in people who displayed more activity in the prefrontal cortex after several weeks of therapy than they did beforehand—particularly when the area was exerting control over the brain’s fear center.
Other researchers are trying to change people’s brain activity using video games. Adam Gazzaley, a professor of neurology at the University of California, San Francisco, developed the first brain-training game to receive FDA approval for its ability to treat ADHD in kids. The game has also been shown to improve attention span in adults. What’s more, EEG studies revealed greater functional connectivity involving the prefrontal cortex, suggesting a boost in neuroplasticity in the region.
Now Gazzaley wants to use the game to treat people with pandemic brain fog. “We think in terms of covid recovery there’s an incredible opportunity here,” he says. “I believe that attention as a system can help across the breadth of [mental health] conditions and symptoms that people are suffering, especially due to covid.”
Meet the people who warn the world about new covid variants
In March 2020, when the WHO declared a pandemic, the public sequence database GISAID held 524 covid sequences. Over the next month scientists uploaded 6,000 more. By the end of May, the total was over 35,000. (In contrast, global scientists added 40,000 flu sequences to GISAID in all of 2019.)
“Without a name, forget about it—we cannot understand what other people are saying,” says Anderson Brito, a postdoc in genomic epidemiology at the Yale School of Public Health, who contributes to the Pango effort.
As the number of covid sequences spiraled, researchers trying to study them were forced to create entirely new infrastructure and standards on the fly. A universal naming system has been one of the most important elements of this effort: without it, scientists would struggle to talk to each other about how the virus’s descendants are traveling and changing—either to flag up a question or, even more critically, to sound the alarm.
Where Pango came from
In April 2020, a handful of prominent virologists in the UK and Australia proposed a system of letters and numbers for naming lineages, or new branches, of the covid family. It had a logic, and a hierarchy, even though the names it generated—like B.1.1.7—were a bit of a mouthful.
One of the authors on the paper was Áine O’Toole, a PhD candidate at the University of Edinburgh. Soon she’d become the primary person actually doing that sorting and classifying, eventually combing through hundreds of thousands of sequences by hand.
She says: “Very early on, it was just who was available to curate the sequences. That ended up being my job for a good bit. I guess I never understood quite the scale we were going to get to.”
She quickly set about building software to assign new genomes to the right lineages. Not long after that, another researcher, postdoc Emily Scher, built a machine-learning algorithm to speed things up even more.
They named the software Pangolin, a tongue-in-cheek reference to a debate about the animal origin of covid. (The whole system is now simply known as Pango.)
The naming system, along with the software to implement it, quickly became a global essential. Although the WHO has recently started using Greek letters for variants that seem especially concerning, like delta, those nicknames are for the public and the media. Delta actually refers to a growing family of variants, which scientists call by their more precise Pango names: B.1.617.2, AY.1, AY.2, and AY.3.
“When alpha emerged in the UK, Pango made it very easy for us to look for those mutations in our genomes to see if we had that lineage in our country too,” says Jolly. “Ever since then, Pango has been used as the baseline for reporting and surveillance of variants in India.”
Because Pango offers a rational, orderly approach to what would otherwise be chaos, it may forever change the way scientists name viral strains—allowing experts from all over the world to work together with a shared vocabulary. Brito says: “Most likely, this will be a format we’ll use for tracking any other new virus.”
Many of the foundational tools for tracking covid genomes have been developed and maintained by early-career scientists like O’Toole and Scher over the last year and a half. As the need for worldwide covid collaboration exploded, scientists rushed to support it with ad hoc infrastructure like Pango. Much of that work fell to tech-savvy young researchers in their 20s and 30s. They used informal networks and tools that were open source—meaning they were free to use, and anyone could volunteer to add tweaks and improvements.
“The people on the cutting edge of new technologies tend to be grad students and postdocs,” says Angie Hinrichs, a bioinformatician at UC Santa Cruz who joined the project earlier this year. For example, O’Toole and Scher work in the lab of Andrew Rambaut, a genomic epidemiologist who posted the first public covid sequences online after receiving them from Chinese scientists. “They just happened to be perfectly placed to provide these tools that became absolutely critical,” Hinrichs says.
It hasn’t been easy. For most of 2020, O’Toole took on the bulk of the responsibility for identifying and naming new lineages by herself. The university was shuttered, but she and another of Rambaut’s PhD students, Verity Hill, got permission to come into the office. Her commute, walking 40 minutes to school from the apartment where she lived alone, gave her some sense of normalcy.
Every few weeks, O’Toole would download the entire covid repository from the GISAID database, which had grown exponentially each time. Then she would hunt around for groups of genomes with mutations that looked similar, or things that looked odd and might have been mislabeled.
When she got particularly stuck, Hill, Rambaut, and other members of the lab would pitch in to discuss the designations. But the grunt work fell on her.
Deciding when descendants of the virus deserve a new family name can be as much art as science. It was a painstaking process, sifting through an unheard-of number of genomes and asking time and again: Is this a new variant of covid or not?
“It was pretty tedious,” she says. “But it was always really humbling. Imagine going through 20,000 sequences from 100 different places in the world. I saw sequences from places I’d never even heard of.”
As time went on, O’Toole struggled to keep up with the volume of new genomes to sort and name.
In June 2020, there were over 57,000 sequences stored in the GISAID database, and O’Toole had sorted them into 39 variants. By November 2020, a month after she was supposed to turn in her thesis, O’Toole took her last solo run through the data. It took her 10 days to go through all the sequences, which by then numbered 200,000. (Although covid has overshadowed her research on other viruses, she’s putting a chapter on Pango in her thesis.)
Fortunately, the Pango software is built to be collaborative, and others have stepped up. An online community—the one that Jolly turned to when she noticed the variant sweeping across India—sprouted and grew. This year, O’Toole’s work has been much more hands-off. New lineages are now designated mostly when epidemiologists around the world contact O’Toole and the rest of the team through Twitter, email, or GitHub— her preferred method.
“Now it’s more reactionary,” says O’Toole. “If a group of researchers somewhere in the world is working on some data and they believe they’ve identified a new lineage, they can put in a request.”
The deluge of data has continued. This past spring, the team held a “pangothon,” a sort of hackathon in which they sorted 800,000 sequences into around 1,200 lineages.
“We gave ourselves three solid days,” says O’Toole. “It took two weeks.”
Since then, the Pango team has recruited a few more volunteers, like UCSC researcher Hindriks and Yale researcher Brito, who both got involved initially by adding their two cents on Twitter and the GitHub page. A postdoc at the University of Cambridge, Chris Ruis, has turned his attention to helping O’Toole clear out the backlog of GitHub requests.
O’Toole recently asked them to formally join the organization as part of the newly created Pango Network Lineage Designation Committee, which discusses and makes decisions about variant names. Another committee, which includes lab leader Rambaut, makes higher-level decisions.
“We’ve got a website, and an email that’s not just my email,” O’Toole says. “It’s become a lot more formalized, and I think that will really help it scale.”
A few cracks around the edges have started to show as the data has grown. As of today, there are nearly 2.5 million covid sequences in GISAID, which the Pango team has split into 1,300 branches. Each branch corresponds to a variant. Of those, eight are ones to watch, according to the WHO.
With so much to process, the software is starting to buckle. Things are getting mislabeled. Many strains look similar, because the virus evolves the most advantageous mutations over and over again.
As a stopgap measure, the team has built new software that uses a different sorting method and can catch things that Pango may miss.
Disability rights advocates are worried about discrimination in AI hiring tools
Making hiring technology accessible means ensuring both that a candidate can use the technology and that the skills it measures don’t unfairly exclude candidates with disabilities, says Alexandra Givens, the CEO of the Center for Democracy and Technology, an organization focused on civil rights in the digital age.
AI-powered hiring tools often fail to include people with disabilities when generating their training data, she says. Such people have long been excluded from the workforce, so algorithms modeled after a company’s previous hires won’t reflect their potential.
Even if the models could account for outliers, the way a disability presents itself varies widely from person to person. Two people with autism, for example, could have very different strengths and challenges.
“As we automate these systems, and employers push to what’s fastest and most efficient, they’re losing the chance for people to actually show their qualifications and their ability to do the job,” Givens says. “And that is a huge loss.”
A hands-off approach
Government regulators are finding it difficult to monitor AI hiring tools. In December 2020, 11 senators wrote a letter to the US Equal Employment Opportunity Commission expressing concerns about the use of hiring technologies after the covid-19 pandemic. The letter inquired about the agency’s authority to investigate whether these tools discriminate, particularly against those with disabilities.
The EEOC responded with a letter in January that was leaked to MIT Technology Review. In the letter, the commission indicated that it cannot investigate AI hiring tools without a specific claim of discrimination. The letter also outlined concerns about the industry’s hesitance to share data and said that variation between different companies’ software would prevent the EEOC from instituting any broad policies.
“I was surprised and disappointed when I saw the response,” says Roland Behm, a lawyer and advocate for people with behavioral health issues. “The whole tenor of that letter seemed to make the EEOC seem like more of a passive bystander rather than an enforcement agency.”
The agency typically starts an investigation once an individual files a claim of discrimination. With AI hiring technology, though, most candidates don’t know why they were rejected for the job. “I believe a reason that we haven’t seen more enforcement action or private litigation in this area is due to the fact that candidates don’t know that they’re being graded or assessed by a computer,” says Keith Sonderling, an EEOC commissioner.
Sonderling says he believes that artificial intelligence will improve the hiring process, and he hopes the agency will issue guidance for employers on how best to implement it. He says he welcomes oversight from Congress.
We just got our best-ever look at the inside of Mars
NASA’s InSight robotic lander has just given us our first look deep inside a planet other than Earth.
More than two years after its launch, seismic data that InSight collected has given researchers hints into how Mars was formed, how it has evolved over 4.6 billion years, and how it differs from Earth. A set of three new studies, published in Science this week, suggests that Mars has a thicker crust than expected, as well as a molten liquid core that is bigger than we thought.
In the early days of the solar system, Mars and Earth were pretty much alike, each with a blanket of ocean covering the surface. But over the following 4 billion years, Earth became temperate and perfect for life, while Mars lost its atmosphere and water and became the barren wasteland we know today. Finding out more about what Mars is like inside might help us work out why the two planets had such very different fates.
“By going from [a] cartoon understanding of what the inside of Mars looks like to putting real numbers on it,” said Mark Panning, project scientist for the InSight mission, during a NASA press conference, “we are able to really expand the family tree of understanding how these rocky planets form and how they’re similar and how they’re different.”
Since InSight landed on Mars in 2018, its seismometer, which sits on the surface of the planet, has picked up more than a thousand distinct quakes. Most are so small they would be unnoticeable to someone standing on Mars’s surface. But a few were big enough to help the team get the first true glimpse of what’s happening underneath.
Marsquakes create seismic waves that the seismometer detects. Researchers created a 3D map of Mars using data from two different kinds of seismic waves: shear and pressure waves. Shear waves, which can only pass through solids, are reflected off the planet’s surface.
Pressure waves are faster and can pass through solids, liquids, and gases. Measuring the differences between the times that these waves arrived allowed the researchers to locate quakes and gave clues to the interior’s composition.
One team, led by Simon Stähler, a seismologist at ETH Zurich, used data generated by 11 bigger quakes to study the planet’s core. From the way the seismic waves reflected off the core, they concluded it’s made from liquid nickel-iron, and that it’s far larger than had been previously estimated (between 2,230 and 2320 miles wide) and probably less dense.