Contributors

Daniel Blumstein grew up in the suburbs of Philadelphia , escaping to the nearby wilderness to backpack , canoe , and mountaineer surrounded by plants and animals .
Shortly after beginning college at the University of Colorado Boulder , in 1982 , he realized that it was possible to make a career out of studying animal behavior .
Thereafter , it was an easy decision for him to double major in environmental conservation and environmental , population , and organismic biology .
After graduating , while cycling around the world , Blumstein happened upon a group of golden marmots ( @ @ @ @ @ @ @ that live in burrows—in Khunjerab National Park in Pakistan , kicking off a decades-long interest in marmots that persists to this day .
He completed a PhD in animal behavior at the University of California , Davis in 1994 , and eventually landed a faculty position at the University of California , Los Angeles .
As an ethologist , he studies social and antipredator behaviors in many animals , including all 15 species of marmots .
When asked why he chose these charismatic rodents , Blumstein has a quick answer : “ They @ @ @ @ @ @ @ address , ” making them easy to mark and trap for study over long periods of time .
Marmots also use an intricate series of verbal calls to signal danger , making them an ideal species in which to study the evolution of fear .
In “ Opinion : What Animals Can Teach Us About Fear ” in this issue , Blumstein shares insights he ’ s gleaned into the human emotion from more than 35 years of watching animals behave .
For Genna Reed , it was the lack of her own @ @ @ @ @ @ @ first made her interested in the environment .
As an undergraduate in biology at Lehigh University in Pennsylvania , and later as a master ’ s student majoring in environmental policy design at the same institution , Reed spent summers analyzing water samples from the nearby Hackensack Meadowlands , a series of sprawling wetlands subjected to decades of environmental abuse by industrial development .
The recognition that corporations could shirk responsibility for actions that polluted the environment—and the toll those decisions exacted on local ecosystems and human communities—made her realize that “ as @ @ @ @ @ @ @ in the lab , I wanted to help bridge the work to the policy and help protect people ’ s health , ” Reed says .
After stints at the Environmental Protection Agency and the public interest organization Food & Water Watch , Reed joined the Union of Concerned Scientists in 2015 , where she is now the lead science and policy analyst for the organization ’ s Center for Science and Democracy .
Reed works to combat scientific misinformation , an endeavor made even more essential during the COVID-19 pandemic .
The @ @ @ @ @ @ @ an accompanying “ infodemic ” —an overabundance of information , some of it false , that sows confusion and distrust .
“ During a pandemic , that is incredibly dangerous , ” Reed says .
“ There are lives at stake.
” In this issue , she shares how scientists can leverage their knowledge to help the public make informed choices and how the onus falls on each person to advocate for sound science in federal decision-making .
Paul J. Zak may be the director of the Center for Neuroeconomics at Claremont Graduate @ @ @ @ @ @ @ be a mistake to paint him as just an economist .
While Zak does hold bachelor ’ s degrees in mathematics and economics from San Diego State University and a PhD in economics from the University of Pennsylvania , he is also a certified phlebotomist and a self-taught neuroscientist .
Zak views economics as a lens through which to study the mechanisms behind human choices , he says .
“ Economics ultimately is about decisions , and so decisions are a wonderful fulcrum to understand the variations [ in behavior ] across individuals.
@ @ @ @ @ @ @ research focuses has been oxytocin , a hormone and neuropeptide .
Little research existed in the early 2000s on the role of this “ love hormone ” in humans .
Zak suspected oxytocin might be involved in trust , generosity , and charitable giving , aspects of our social selves that are “ important for humans economically and socially.
” He first showed that changes in oxytocin could be measured in blood rather than spinal taps .
By combining multiple streams of physiological data—cardiac rhythms , nervous system activity , and skin conductance @ @ @ @ @ @ @ and other signaling molecules—Zak developed a new measure called “ immersion , ” which can predict a person ’ s likelihood of donating to a charitable cause with 82 percent accuracy .
In this issue , he shares more about the experiments that led him to launch the company Immersion Neuroscience to help clients better predict people ’ s behavior .

DAVI
Daniel Blumstein grew up in the suburbs of Philadelphia, escaping to the nearby wilderness to backpack, canoe, and mountaineer surrounded by plants and animals. Shortly after beginning college at the University of Colorado Boulder, in 1982, he realized that it was possible to make a career out of studying animal behavior. Thereafter, it was an easy decision for him to double major in environmental conservation and environmental, population, and organismic biology. After graduating, while cycling around the world, Blumstein happened upon a group of golden marmots (Marmota caudata)—cat-sized, semi-social rodents that live in burrows—in Khunjerab National Park in Pakistan, kicking off a decades-long interest in marmots that persists to this day.
He completed a PhD in animal behavior at the University of California, Davis in 1994, and eventually landed a faculty position at the University of California, Los Angeles. As an ethologist, he studies social and antipredator behaviors in many animals, including all 15 species of marmots. When asked why he chose these charismatic rodents, Blumstein has a quick answer: “They’re diurnal and they have an address,” making them easy to mark and trap for study over long periods of time. Marmots also use an intricate series of verbal calls to signal danger, making them an ideal species in which to study the evolution of fear. In “Opinion: What Animals Can Teach Us About Fear” in this issue, Blumstein shares insights he’s gleaned into the human emotion from more than 35 years of watching animals behave.
JA-REI WANG
For Genna Reed, it was the lack of her own backyard growing up in New Jersey that first made her interested in the environment. As an undergraduate in biology at Lehigh University in Pennsylvania, and later as a master’s student majoring in environmental policy design at the same institution, Reed spent summers analyzing water samples from the nearby Hackensack Meadowlands, a series of sprawling wetlands subjected to decades of environmental abuse by industrial development. The recognition that corporations could shirk responsibility for actions that polluted the environment—and the toll those decisions exacted on local ecosystems and human communities—made her realize that “as much as I loved doing the work in the lab, I wanted to help bridge the work to the policy and help protect people’s health,” Reed says.
After stints at the Environmental Protection Agency and the public interest organization Food & Water Watch, Reed joined the Union of Concerned Scientists in 2015, where she is now the lead science and policy analyst for the organization’s Center for Science and Democracy. Reed works to combat scientific misinformation, an endeavor made even more essential during the COVID-19 pandemic. The coronavirus, she explains, has created an accompanying “infodemic”—an overabundance of information, some of it false, that sows confusion and distrust. “During a pandemic, that is incredibly dangerous,” Reed says. “There are lives at stake.” In this issue, she shares how scientists can leverage their knowledge to help the public make informed choices and how the onus falls on each person to advocate for sound science in federal decision-making.
PAUL J. ZAK
Paul J. Zak may be the director of the Center for Neuroeconomics at Claremont Graduate University in California, but it would be a mistake to paint him as just an economist. While Zak does hold bachelor’s degrees in mathematics and economics from San Diego State University and a PhD in economics from the University of Pennsylvania, he is also a certified phlebotomist and a self-taught neuroscientist. Zak views economics as a lens through which to study the mechanisms behind human choices, he says. “Economics ultimately is about decisions, and so decisions are a wonderful fulcrum to understand the variations [in behavior] across individuals.”
One of Zak’s main research focuses has been oxytocin, a hormone and neuropeptide. Little research existed in the early 2000s on the role of this “love hormone” in humans. Zak suspected oxytocin might be involved in trust, generosity, and charitable giving, aspects of our social selves that are “important for humans economically and socially.” He first showed that changes in oxytocin could be measured in blood rather than spinal taps. By combining multiple streams of physiological data—cardiac rhythms, nervous system activity, and skin conductance, in addition to levels of oxytocin and other signaling molecules—Zak developed a new measure called “immersion,” which can predict a person’s likelihood of donating to a charitable cause with 82 percent accuracy. In this issue, he shares more about the experiments that led him to launch the company Immersion Neuroscience to help clients better predict people’s behavior.


thescientist--2020-10-01--The Rise of BCI Enables Advances in Neuroscience

ABOVE : Neurosity ’ s Notion headset , released in 2019 , is one of a handful of consumer brain-computer interface devices that scientists are adapting for their EEG research .
STEVE GONG Conor Russomanno hadn ’ t stopped wondering about the effects of the multiple concussions he ’ d suffered playing football and rugby at Columbia University .
In 2011 , less than a year after his last severe hit , he had passed a neurologist ’ s standardized test of cognition , but he still wasn ’ t himself , at least not all the time .
“ @ @ @ @ @ @ @ than it was before , ” he says .
“ I was really , really amped and self-motivated and confident on certain days , and then I would hit these extreme lows on other days.
” The following year , as Russomanno was pursuing a master ’ s degree in design in New York City , a friend offered to sell him a MindFlex—a cutting-edge toy from Mattel that allowed users to make a ball hovering on an air jet rise and fall by concentrating on it—and pointed him to an online tutorial @ @ @ @ @ @ @ to create a brain-computer interface ( BCI ) .
Russomanno jumped at the opportunity to figure out what was going on inside his brain .
He deconstructed the toy and fitted it to a baseball cap with its single electroencephalogram ( EEG ) electrode resting on his forehead .
He added a Bluetooth transmitter on the brim that allowed the device to communicate with his smartphone and built an app into which he could enter his activities and moods .
Then Russomanno wore the hat one day while walking around New York City @ @ @ @ @ @ @ if I [ could ] quantitatively track my habits and routines and stitch them to my emotions and internal states , ” he explains .
Russomanno ’ s device was just a prototype , and one day ’ s worth of data was not enough to answer the questions he had about his own mind .
But his tinkering opened his eyes to the potential of BCI and the technology it ’ s based on .
Around that time , his grandmother was diagnosed with a rare form of dementia , and a @ @ @ @ @ @ @ injury .
Russomanno realized that portable EEG devices that feed information about brain activity into a computer , if done well , could have all sorts of applications , including monitoring brain health and assisting people with disabilities ; the technology could “ be applied in so many ways beyond my personal curiosity.
” There were already a handful of mobile EEG devices on the market and several more on the way , driven partly by neuroscientists ’ desire to make the technology more practical for use in healthcare and other settings , @ @ @ @ @ @ @ s interest in developing EEG-based consumer BCI applications .
Accordingly , companies selling the devices typically fell into one of two groups : those targeting researchers , with high-quality but extremely expensive equipment , and those targeting tech developers with low-cost hardware , usually with only a few electrodes and sometimes with fees to access the raw data .
Russomanno saw an opportunity to democratize a technology that , at the time , was largely limited to big companies and well-funded labs .
In December 2013 , he and Joel Murphy , his @ @ @ @ @ @ @ Design , launched a Kickstarter campaign that promised to deliver an open-source , reasonably priced BCI device that could amplify and convert analog EEG signals into digital data to be streamed wirelessly to a computer .
In less than two months , 947 backers pledged more than $ 215,000 .
In early 2014 , Russomanno and Murphy founded a company , OpenBCI ; they started shipping their first product—a small box that amplified the analog brain signals from up to eight EEG electrodes and sent the translated digital data to a computer—by the @ @ @ @ @ @ @ couldn ’ t have been better .
The consumer BCI industry was just beginning to blossom .
In September 2014 , Toronto-based InteraXon launched Muse , one of the first EEG-based devices truly targeted at consumers : a headband with four electrodes that communicated with smartphone or computer apps , designed to improve mindfulness and meditation by giving users auditory feedback on their cognitive state .
A few years later , Paris and San Francisco–based Rythm ( now called Dreem ) launched the Dreem headband with six electrodes and apps to help consumers @ @ @ @ @ @ @ electrode headsets—and the hardware and software needed to process their recorded neural activity—have come on the market .
From health and wellness to gaming and virtual reality , the BCI market—which Brandessence Market Research valued in 2019 at $ 980 million and predicted would double in value in the next 15 years—is mainly driven by consumer demand .
But the BCI industry also has an eye toward research , and with neuroscientists striving to make EEG mobile , consumer BCI wearables may be just what the field needs .
“ The consumer market @ @ @ @ @ @ @ t exist .
.
.
devices that open doors for researchers , ” says Olav Krigolson , a University of Victoria neuroscientist .
“ It ’ s a new emerging technology and researchers are slowly figuring out the things you can do with it.
” Although EEG took a back seat in neuroscience with the advent of magnetic resonance imaging ( MRI ) in the 1970s and ’ 80s , the technology has been making a comeback in recent years , says Krigolson , thanks in no small part to the fact that @ @ @ @ @ @ @ .
The first “ mobile ” EEG setups involved packing traditional equipment into backpacks , an approach that was cumbersome and produced noisy data .
In the late 2000s and early 2010s , at least half a dozen companies sprang up to offer more-practical setups .
These products were expensive , with price points in the thousands or tens of thousands of dollars .
The equipment was designed with researchers , not consumers , in mind .
But soon , the first low-cost devices began to hit the market .
In 2009 , @ @ @ @ @ @ @ , which had 14 electrodes—still far fewer than the 32 or 64 of a traditional EEG cap—and cost researchers just $ 750 .
That same year , NeuroSky released MindSet , a pair of consumer-targeted headphones with an arm that positioned a sin-gle electrode on the forehead—for $ 199 .
( MindFlex and another EEG-based toy—Uncle Milton ’ s Force Trainer , which similarly allowed users to control a ball by concentrating while hearing instructions from Yoda—were also released in 2009 and used chips sold by NeuroSky . )
And in 2014 , @ @ @ @ @ @ @ and a price of $ 150 , it became the first consumer product to make real inroads into research .
Researchers were initially skeptical about the quality of the EEG data that Muse and other low-cost devices could yield .
Krigolson , for example , worried that the noise generated from muscle movements and other sources would wash out any signal that the device recorded from the brain .
“ Picking up muscle activity is very easy ; it ’ s orders of magnitude bigger ” than the neural signal , he notes @ @ @ @ @ @ @ , who have no financial ties to InteraXon , put it to the test a few years ago , they found that Muse did yield data of sufficient quality to detect event-related potentials ( ERPs ) —patterns of neural activity in response to a stimulus .
Enthused , Krigolson and his colleagues designed a protocol to detect cognitive fatigue and successfully tested it first on hospital workers and miners , and then on themselves during a week-long expedition to the Mars Habitat at the Hawaii Space Exploration Analog and Simulation .
Other researchers @ @ @ @ @ @ @ website , InteraXon lists nearly 200 publications on diverse topics including pain and post-traumatic stress disorder ( PTSD ) that have used data collected by the headband .
“ People have been using Muse for research for a long time now , as a recording device , as a therapeutic device , and everything in between , ” says Subash Padmanaban , a research engineer at the company .
Still , the data from Muse and other mobile devices are not as pristine as data retrieved from research-grade equipment , notes Anthony Ries @ @ @ @ @ @ @ Army Research Laboratory who was part of a team that compared research-targeted mobile EEG technologies with conventional EEG systems .
“ Generally , there is a tradeoff between data quality and mobility , ” he tells The Scientist by email .
Thea Radüntz of the Federal Institute for Occupational Safety and Health in Berlin , Germany , agrees .
She has compared devices from EMOTIV , NeuroSky , and others , and found that EEG setups with fewer electrodes often produce messier data and limit researchers ’ ability to triangulate the source of @ @ @ @ @ @ @ for many applications , just one or a few electrodes may be sufficient .
Strong , brain-wide responses , for example , are “ pretty easy to record with one of these mobile systems , ” says Scott Burwell , a neuroscientist currently wrapping up a postdoc at the University of Minnesota who has used Muse and an EMOTIV headset for his research .
“ And in the clinical setting especially , people are just interested in registering that brain response , and you can do that with relatively few channels.
” New @ @ @ @ @ @ @ tinker The consumer BCI industry continues to grow , with established companies launching upgraded and novel products and a handful of new competitors entering the market with low-priced devices .
While the BCI-enabling products primarily focus on consumer applications , these companies are also paying mind to research applications of the technology .
In 2019 , Neurosity launched Notion , a headset with eight electrodes that sells for $ 899 , with raw data freely available to users .
Like Muse , Notion comes with neurofeedback software , but instead of encouraging a @ @ @ @ @ @ @ to maximize focus and productivity , with the primary market so far being software coders , says Neurosity cofounder Alex Castillo .
Notion has an on-board computer so that the data can be stored and later retrieved directly , and thus does not have to be streamed , something Castillo argues is critical for data fidelity and security .
The device also comes preloaded with an app that can learn to interpret the user ’ s imagined motor commands , for applications in gaming and artificial reality/virtual reality ( AR/VR ) .
Castillo @ @ @ @ @ @ @ health and wellness applications is never far from his mind .
His brother has epilepsy , and at the end of 2019 , researchers published a study that suggested it may be possible to predict an epileptic seizure up to one hour before it starts using EEG data and machine learning .
“ Maybe people who suffer from epilepsy can use this technology and predict this is going to happen and maybe not go for a drive , ” he speculates .
“ Our device , it is for consumers , but it @ @ @ @ @ @ @ so you can use it for research , because we ’ re also looking to the future and this new generation of neuroscientists [ who ] are going to use it to develop their own research.
” This July , another new competitor , NextMind , began presales of its $ 399 headset .
This device also uses eight electrodes but specifically targets the visual cortex , located at the back of the brain .
The company has developed software it calls the NextMind engine , which ascertains visual attention and translates that @ @ @ @ @ @ @ particularly in the gaming and AR/VR industries , to get creative .
“ We are basically offering the platform to the industry such that the industry will be able to build on top of it , ” says NextMind founder Sid Kouider .
NextMind does not currently offer access to raw data , but Kouider says the team would consider doing so in the future .
“ By addressing this broader market we expand the potential of neuro-technology , ” he writes in an email , adding that it “ should help us @ @ @ @ @ @ @ far ” and thereby benefit research .
While these latest devices have yet to undergo stringent tests by independent labs , they ’ re already being adopted by researchers .
Kouider says that most buyers so far are developers , but some are academic researchers or consumers .
And the University of Minnesota ’ s Burwell was all too happy to try out Notion after Neurosity cofounder and CEO AJ Keller , formerly of OpenBCI , reached out to him .
Burwell is launching a company based on software he ’ s developing @ @ @ @ @ @ @ , and had been using Muse to monitor patients ’ brain activity .
But now he says he ’ s leaning toward taking his work forward with Notion .
He says Muse has done well for him , but it has some limitations—if wearers move their heads or scrunch their foreheads , for example , the electrical activity of the facial muscles can “ swamp out the EEG signals.
” Notion sits on the crown of the head , where there are fewer muscles to interfere .
Burwell is now on the list @ @ @ @ @ @ @ which began shipping this summer , and Neurosity has written support letters for Burwell ’ s grant applications for research using their equipment .
“ Up until maybe five years ago , this stuff wasn ’ t ready for prime time yet , ” says Burwell .
Even now , many neuroscientists remain cautious , largely sticking to EEG setups designed for researchers .
But consumer-oriented technology is starting to prove itself , and Burwell says he expects that as it continues to improve , the research community will come to accept at @ @ @ @ @ @ @ research tools .
“ We ’ re kind of at a really critical period here .
”

ABOVE: Neurosity’s Notion headset, released in 2019, is one of a handful of consumer brain-computer interface devices that scientists are adapting for their EEG research.
STEVE GONG
Conor Russomanno hadn’t stopped wondering about the effects of the multiple concussions he’d suffered playing football and rugby at Columbia University. In 2011, less than a year after his last severe hit, he had passed a neurologist’s standardized test of cognition, but he still wasn’t himself, at least not all the time. “My mind [was] definitely different than it was before,” he says. “I was really, really amped and self-motivated and confident on certain days, and then I would hit these extreme lows on other days.”
The following year, as Russomanno was pursuing a master’s degree in design in New York City, a friend offered to sell him a MindFlex—a cutting-edge toy from Mattel that allowed users to make a ball hovering on an air jet rise and fall by concentrating on it—and pointed him to an online tutorial on how he could hack the toy to create a brain-computer interface (BCI). Russomanno jumped at the opportunity to figure out what was going on inside his brain.
He deconstructed the toy and fitted it to a baseball cap with its single electroencephalogram (EEG) electrode resting on his forehead. He added a Bluetooth transmitter on the brim that allowed the device to communicate with his smartphone and built an app into which he could enter his activities and moods. Then Russomanno wore the hat one day while walking around New York City. “I wanted to start seeing if I [could] quantitatively track my habits and routines and stitch them to my emotions and internal states,” he explains.
The consumer market is creating these devices that didn’t exist . . . devices that open doors for researchers. —Olav Krigolson, University of Victoria
Russomanno’s device was just a prototype, and one day’s worth of data was not enough to answer the questions he had about his own mind. But his tinkering opened his eyes to the potential of BCI and the technology it’s based on. Around that time, his grandmother was diagnosed with a rare form of dementia, and a close friend suffered a temporarily paralyzing neck injury. Russomanno realized that portable EEG devices that feed information about brain activity into a computer, if done well, could have all sorts of applications, including monitoring brain health and assisting people with disabilities; the technology could “be applied in so many ways beyond my personal curiosity.”
There were already a handful of mobile EEG devices on the market and several more on the way, driven partly by neuroscientists’ desire to make the technology more practical for use in healthcare and other settings, and partly by the tech industry’s interest in developing EEG-based consumer BCI applications. Accordingly, companies selling the devices typically fell into one of two groups: those targeting researchers, with high-quality but extremely expensive equipment, and those targeting tech developers with low-cost hardware, usually with only a few electrodes and sometimes with fees to access the raw data. Russomanno saw an opportunity to democratize a technology that, at the time, was largely limited to big companies and well-funded labs.
In December 2013, he and Joel Murphy, his physical computing professor at Parsons School of Design, launched a Kickstarter campaign that promised to deliver an open-source, reasonably priced BCI device that could amplify and convert analog EEG signals into digital data to be streamed wirelessly to a computer. In less than two months, 947 backers pledged more than $215,000. In early 2014, Russomanno and Murphy founded a company, OpenBCI; they started shipping their first product—a small box that amplified the analog brain signals from up to eight EEG electrodes and sent the translated digital data to a computer—by the end of the year.
MEDITATION EEG: The original Muse headset, released in 2014, was one of the first consumer devices to make inroads into the research community. © MUSE BY INTERAXON INC.
The timing couldn’t have been better. The consumer BCI industry was just beginning to blossom. In September 2014, Toronto-based InteraXon launched Muse, one of the first EEG-based devices truly targeted at consumers: a headband with four electrodes that communicated with smartphone or computer apps, designed to improve mindfulness and meditation by giving users auditory feedback on their cognitive state. A few years later, Paris and San Francisco–based Rythm (now called Dreem) launched the Dreem headband with six electrodes and apps to help consumers sleep. Since then, several new electrode headsets—and the hardware and software needed to process their recorded neural activity—have come on the market.
From health and wellness to gaming and virtual reality, the BCI market—which Brandessence Market Research valued in 2019 at $980 million and predicted would double in value in the next 15 years—is mainly driven by consumer demand. But the BCI industry also has an eye toward research, and with neuroscientists striving to make EEG mobile, consumer BCI wearables may be just what the field needs.
“The consumer market is creating these devices that didn’t exist . . . devices that open doors for researchers,” says Olav Krigolson, a University of Victoria neuroscientist. “It’s a new emerging technology and researchers are slowly figuring out the things you can do with it.”
Neuroscientists seek mobile EEG technology
Although EEG took a back seat in neuroscience with the advent of magnetic resonance imaging (MRI) in the 1970s and ’80s, the technology has been making a comeback in recent years, says Krigolson, thanks in no small part to the fact that it can be taken on the go. The first “mobile” EEG setups involved packing traditional equipment into backpacks, an approach that was cumbersome and produced noisy data. In the late 2000s and early 2010s, at least half a dozen companies sprang up to offer more-practical setups. These products were expensive, with price points in the thousands or tens of thousands of dollars. The equipment was designed with researchers, not consumers, in mind.
But soon, the first low-cost devices began to hit the market. In 2009, San Francisco–based EMOTIV launched its first headset, which had 14 electrodes—still far fewer than the 32 or 64 of a traditional EEG cap—and cost researchers just $750. That same year, NeuroSky released MindSet, a pair of consumer-targeted headphones with an arm that positioned a single electrode on the forehead—for $199. (MindFlex and another EEG-based toy—Uncle Milton’s Force Trainer, which similarly allowed users to control a ball by concentrating while hearing instructions from Yoda—were also released in 2009 and used chips sold by NeuroSky.) And in 2014, InteraXon launched Muse. With four electrodes and a price of $150, it became the first consumer product to make real inroads into research.
Researchers were initially skeptical about the quality of the EEG data that Muse and other low-cost devices could yield. Krigolson, for example, worried that the noise generated from muscle movements and other sources would wash out any signal that the device recorded from the brain. “Picking up muscle activity is very easy; it’s orders of magnitude bigger” than the neural signal, he notes. But when Krigolson and his colleagues, who have no financial ties to InteraXon, put it to the test a few years ago, they found that Muse did yield data of sufficient quality to detect event-related potentials (ERPs)—patterns of neural activity in response to a stimulus.
Enthused, Krigolson and his colleagues designed a protocol to detect cognitive fatigue and successfully tested it first on hospital workers and miners, and then on themselves during a week-long expedition to the Mars Habitat at the Hawaii Space Exploration Analog and Simulation. Other researchers also started using Muse; on its website, InteraXon lists nearly 200 publications on diverse topics including pain and post-traumatic stress disorder (PTSD) that have used data collected by the headband. “People have been using Muse for research for a long time now, as a recording device, as a therapeutic device, and everything in between,” says Subash Padmanaban, a research engineer at the company.
SINGULAR ELECTRODE: NeuroSky’s MindSet headset, released in 2009, was one of the first consumer BCI products on the market. Its underlying technology was used in two toys that year that allowed users to hover a ball over a stream of air by concentrating. NEUROSKY, INC.
Still, the data from Muse and other mobile devices are not as pristine as data retrieved from research-grade equipment, notes Anthony Ries, a research psychologist at the US Army Research Laboratory who was part of a team that compared research-targeted mobile EEG technologies with conventional EEG systems. “Generally, there is a tradeoff between data quality and mobility,” he tells The Scientist by email. Thea Radüntz of the Federal Institute for Occupational Safety and Health in Berlin, Germany, agrees. She has compared devices from EMOTIV, NeuroSky, and others, and found that EEG setups with fewer electrodes often produce messier data and limit researchers’ ability to triangulate the source of the electrical activity being recorded.
But for many applications, just one or a few electrodes may be sufficient. Strong, brain-wide responses, for example, are “pretty easy to record with one of these mobile systems,” says Scott Burwell, a neuroscientist currently wrapping up a postdoc at the University of Minnesota who has used Muse and an EMOTIV headset for his research. “And in the clinical setting especially, people are just interested in registering that brain response, and you can do that with relatively few channels.”
New BCI products invite developers and researchers to tinker
The consumer BCI industry continues to grow, with established companies launching upgraded and novel products and a handful of new competitors entering the market with low-priced devices. While the BCI-enabling products primarily focus on consumer applications, these companies are also paying mind to research applications of the technology.
In 2019, Neurosity launched Notion, a headset with eight electrodes that sells for $899, with raw data freely available to users. Like Muse, Notion comes with neurofeedback software, but instead of encouraging a meditative state, it’s used to maximize focus and productivity, with the primary market so far being software coders, says Neurosity cofounder Alex Castillo. Notion has an on-board computer so that the data can be stored and later retrieved directly, and thus does not have to be streamed, something Castillo argues is critical for data fidelity and security. The device also comes preloaded with an app that can learn to interpret the user’s imagined motor commands, for applications in gaming and artificial reality/virtual reality (AR/VR).
Castillo says that Notion’s potential in health and wellness applications is never far from his mind. His brother has epilepsy, and at the end of 2019, researchers published a study that suggested it may be possible to predict an epileptic seizure up to one hour before it starts using EEG data and machine learning. “Maybe people who suffer from epilepsy can use this technology and predict this is going to happen and maybe not go for a drive,” he speculates. “Our device, it is for consumers, but it is clinical grade. We made it so you can use it for research, because we’re also looking to the future and this new generation of neuroscientists [who] are going to use it to develop their own research.”
For many applications, just one or a few electrodes may be sufficient.
This July, another new competitor, NextMind, began presales of its $399 headset. This device also uses eight electrodes but specifically targets the visual cortex, located at the back of the brain. The company has developed software it calls the NextMind engine, which ascertains visual attention and translates that into digital commands, allowing developers, particularly in the gaming and AR/VR industries, to get creative. “We are basically offering the platform to the industry such that the industry will be able to build on top of it,” says NextMind founder Sid Kouider. NextMind does not currently offer access to raw data, but Kouider says the team would consider doing so in the future. “By addressing this broader market we expand the potential of neuro-technology,” he writes in an email, adding that it “should help us to reach a scale never achieved so far” and thereby benefit research.
While these latest devices have yet to undergo stringent tests by independent labs, they’re already being adopted by researchers. Kouider says that most buyers so far are developers, but some are academic researchers or consumers. And the University of Minnesota’s Burwell was all too happy to try out Notion after Neurosity cofounder and CEO AJ Keller, formerly of OpenBCI, reached out to him.
Burwell is launching a company based on software he’s developing to detect neural biomarkers of drug craving, and had been using Muse to monitor patients’ brain activity. But now he says he’s leaning toward taking his work forward with Notion. He says Muse has done well for him, but it has some limitations—if wearers move their heads or scrunch their foreheads, for example, the electrical activity of the facial muscles can “swamp out the EEG signals.” Notion sits on the crown of the head, where there are fewer muscles to interfere. Burwell is now on the list to receive the Notion 2 headset, which began shipping this summer, and Neurosity has written support letters for Burwell’s grant applications for research using their equipment.
“Up until maybe five years ago, this stuff wasn’t ready for prime time yet,” says Burwell. Even now, many neuroscientists remain cautious, largely sticking to EEG setups designed for researchers. But consumer-oriented technology is starting to prove itself, and Burwell says he expects that as it continues to improve, the research community will come to accept at least some of these devices as valid research tools. “We’re kind of at a really critical period here.”


thescientist--2020-10-01--The Brain's Immune Cells Stand Sentinel Against Viral Invasion

ABOVE : T cells ( red ) in the olfactory bulb of mice engage with antigens on vesicular stomatitis virus , leading to cell signaling ( green ) that ultimately prevents neuronal death .
E.A .
MOSEMAN ET AL.
, SCI IMMUNOL , 5 : EABB1817 , 2020 Failure to smell fresh cut grass or a poo-laden diaper is , at least these days , a potential sign of COVID-19 infection .
“ People say things smell funny or they can ’ t smell at all , ” says Harvard University neurobiologist Sandeep Datta .
Reading about people ’ s @ @ @ @ @ @ @ SARS-CoV-2 , the virus that causes COVID-19 , might be having this effect .
One possibility was that the virus attacks cells that line and support olfactory neurons in the nose .
Alternatively , SARS-CoV-2 could be directly targeting the neurons themselves .
Datta ’ s and other researchers ’ work—which so far includes genetic and cellular analyses in humans , rodents , and monkeys—suggests that mammalian olfactory neurons don ’ t have the right cell receptors for the virus to get inside them , meaning that the lack of smell most likely @ @ @ @ @ @ @ cells .
But not everyone is convinced by the data ; some researchers continue to argue that SARS-CoV-2 can infect neurons in the nose and ultimately invade the brain this way .
If the virus were able to enter olfactory neurons , it ’ s in theory a “ very short route , ” along a single neuron , from nose to brain , notes pathologist Debby van Riel of Erasmus Medical Center in the Netherlands .
Van Riel , who began studying influenza ’ s ability to attack nerve fibers involved in @ @ @ @ @ @ @ s not convinced SARS-CoV-2 can infect olfactory neurons .
But the discussion has reminded scientists how little they know about viral invasion through the nose .
That ’ s why , she says , she was fascinated to read about recent experiments by Duke University immunologist Ashley Moseman and colleagues that tracked immune responses in mice that had had vesicular stomatitis virus ( VSV ) squirted up their noses .
VSV is known to infect olfactory neurons in mice .
The team was interested in what Moseman calls a “ sneaky front door @ @ @ @ @ @ @ nerve fibers that project from the nasal cavity and connect with neurons deeper in the brain .
Mice that get the virus don ’ t die from the infection , even if it enters the brain , and they don ’ t suffer significant brain damage , either .
Interested in how the mice avoided this damage , Moseman and his colleagues decided to tag VSV particles with fluorescent markers , then inject them into the mice ’ s noses to see if the team could uncover how the immune system responded to @ @ @ @ @ @ @ that VSV was infecting neuronal fibers in the nose and also neurons farther up in the olfactory bulb leading to the brain .
“ VSV gets into neurons in the nose and actually kills those neurons , ” says study coauthor Dorian McGavern , a viral immunologist at the National Institute of Neurological Disorders and Stroke .
“ But those neurons can grow back .
They can replenish the system and restore sense of smell.
” Neurons farther up in the brain can ’ t be regenerated , yet , oddly , they @ @ @ @ @ @ @ infection .
Probing further , Moseman , McGavern , and their colleagues revealed how those neurons that sat deeper in the brain were spared .
Microglia , the primary immune cells of the brain , were gobbling up bits of the virus from infected neurons in the olfactory bulb .
Although not getting infected themselves , the microglia were projecting those viral bits , like flags , on their cell surfaces , attracting killer T cells in the blood to come to the brain and mount an immune defense against the microglia , @ @ @ @ @ @ @ which also display viral bits on their surfaces .
The interaction between the microglia and the killer T cells led the T cells to release cytokines that triggered the elimination of the virus from infected neurons without killing those neurons in the process , the team found .
“ Microglia are playing an absolutely critical role here in protecting neurons within the brain , ” McGavern says .
What ’ s not yet clear is if the killer T cells do , in fact , kill the virus-flaunting microglia or whether the two @ @ @ @ @ @ @ other way to spur T cells to release the virus-eradicating cytokines .
“ It ’ s possible that microglia sort of take that hit on behalf of everybody , ” Moseman says , “ and in doing so T cells avoid going to try to engage with neurons , which don ’ t replenish themselves very well.
” Microglia are replaceable , he speculates , so losing them might be less consequential than the irreversible damage of neuronal death .
The work offers a glimpse at how the body and brain respond to @ @ @ @ @ @ @ the nose , van Riel says .
“ If you know the way the body can handle an infection without causing severe [ brain ] damage , it could lead to new insights , which could lead to therapeutic strategies.
” However , scientists still don ’ t yet have a good grasp of which viruses can enter the central nervous system this way .
That may change as more researchers investigate whether or not SARS-CoV-2 can .
The work might even suggest that each and every virus elicits a unique immune response @ @ @ @ @ @ @ .
“ I think we ’ re only seeing the tip of the iceberg .
”

ABOVE: T cells (red) in the olfactory bulb of mice engage with antigens on vesicular stomatitis virus, leading to cell signaling (green) that ultimately prevents neuronal death.
E.A. MOSEMAN ET AL., SCI IMMUNOL, 5:EABB1817, 2020
Failure to smell fresh cut grass or a poo-laden diaper is, at least these days, a potential sign of COVID-19 infection. “People say things smell funny or they can’t smell at all,” says Harvard University neurobiologist Sandeep Datta. Reading about people’s experiences of anosmia, Datta wondered how SARS-CoV-2, the virus that causes COVID-19, might be having this effect. One possibility was that the virus attacks cells that line and support olfactory neurons in the nose. Alternatively, SARS-CoV-2 could be directly targeting the neurons themselves.
Datta’s and other researchers’ work—which so far includes genetic and cellular analyses in humans, rodents, and monkeys—suggests that mammalian olfactory neurons don’t have the right cell receptors for the virus to get inside them, meaning that the lack of smell most likely comes from the infection of olfactory support cells. But not everyone is convinced by the data; some researchers continue to argue that SARS-CoV-2 can infect neurons in the nose and ultimately invade the brain this way.
Microglia were gobbling up bits of the virus from infected neurons in the olfactory bulb.
If the virus were able to enter olfactory neurons, it’s in theory a “very short route,” along a single neuron, from nose to brain, notes pathologist Debby van Riel of Erasmus Medical Center in the Netherlands. Van Riel, who began studying influenza’s ability to attack nerve fibers involved in olfaction decades ago, says she’s not convinced SARS-CoV-2 can infect olfactory neurons. But the discussion has reminded scientists how little they know about viral invasion through the nose. That’s why, she says, she was fascinated to read about recent experiments by Duke University immunologist Ashley Moseman and colleagues that tracked immune responses in mice that had had vesicular stomatitis virus (VSV) squirted up their noses.
VSV is known to infect olfactory neurons in mice. The team was interested in what Moseman calls a “sneaky front door” for this virus to travel via nerve fibers that project from the nasal cavity and connect with neurons deeper in the brain. Mice that get the virus don’t die from the infection, even if it enters the brain, and they don’t suffer significant brain damage, either. Interested in how the mice avoided this damage, Moseman and his colleagues decided to tag VSV particles with fluorescent markers, then inject them into the mice’s noses to see if the team could uncover how the immune system responded to the infection.
The fluorescent imaging showed that VSV was infecting neuronal fibers in the nose and also neurons farther up in the olfactory bulb leading to the brain. “VSV gets into neurons in the nose and actually kills those neurons,” says study coauthor Dorian McGavern, a viral immunologist at the National Institute of Neurological Disorders and Stroke. “But those neurons can grow back. They can replenish the system and restore sense of smell.” Neurons farther up in the brain can’t be regenerated, yet, oddly, they didn’t appear to die after infection.
NEURONAL ROUTE: Six days after infection, virus (green) appears in nerve fibers that project into the olfactory bulb (OB) of mice, meaning the virus has spread from the nose into the brain. SCI IMMUNOL, 5:EABB1817, 2020
Probing further, Moseman, McGavern, and their colleagues revealed how those neurons that sat deeper in the brain were spared. Microglia, the primary immune cells of the brain, were gobbling up bits of the virus from infected neurons in the olfactory bulb. Although not getting infected themselves, the microglia were projecting those viral bits, like flags, on their cell surfaces, attracting killer T cells in the blood to come to the brain and mount an immune defense against the microglia, rather than against the infected neurons, which also display viral bits on their surfaces. The interaction between the microglia and the killer T cells led the T cells to release cytokines that triggered the elimination of the virus from infected neurons without killing those neurons in the process, the team found. “Microglia are playing an absolutely critical role here in protecting neurons within the brain,” McGavern says.
What’s not yet clear is if the killer T cells do, in fact, kill the virus-flaunting
microglia or whether the two types of immune cells interact in some other way to spur T cells to release the virus-eradicating cytokines. “It’s possible that microglia sort of take that hit on behalf of everybody,” Moseman says, “and in doing so T cells avoid going to try to engage with neurons, which don’t replenish themselves very well.” Microglia are replaceable, he speculates, so losing them might be less consequential than the irreversible damage of neuronal death.
The work offers a glimpse at how the body and brain respond to invasion of viruses such as VSV through the nose, van Riel says. “If you know the way the body can handle an infection without causing severe [brain] damage, it could lead to new insights, which could lead to therapeutic strategies.” However, scientists still don’t yet have a good grasp of which viruses can enter the central nervous system this way. That may change as more researchers investigate whether or not SARS-CoV-2 can. The work might even suggest that each and every virus elicits a unique immune response in the brain, van Riel notes. “I think we’re only seeing the tip of the iceberg.”


thescientist--2020-10-01--Neural Connections Bolstered in Monkeys That Lift Weights

The paper I.S .
Glover , S.N .
Baker , “ Cortical , corticospinal , and reticulospinal contributions to strength training , ” J Neurosci , 40:5820–32 , 2020 .
Of the two major neural highways that carry messages about movement down the spinal cord , one—the reticulospinal tract—is decidedly less fashionable , according to neuroscientist Stuart Baker of Newcastle University in the UK .
In contrast to the corticospinal tract ( CST ) , which evolved more recently and helps control complex , uniquely human movements such as playing the piano , the reticulospinal tract ( RST ) is @ @ @ @ @ @ @ as posture and walking , Baker says .
But he suspects that the RST plays a bigger role in our movements than researchers currently appreciate .
To test for the RST ’ s possible contribution to strength training , Baker ’ s PhD student Isabel Glover , now a postdoc at University College London , taught two macaque monkeys to grasp and pull a handle attached to a pulley with their right paws .
Feeding the monkeys fruit , nuts , or bits of chocolate as rewards for successful reps , she gradually @ @ @ @ @ @ @ of the pulley .
After a couple of months , the animals were able to pull their own body weight .
Prior to the weight training , the researchers had implanted electrodes in the monkeys ’ brain stems and arm muscles .
This allowed the scientists to stimulate the CST or the RST and measure the electrical response in the muscles .
Glover did this as the monkeys pulled an unweighted lever each morning before training began .
Then she and Baker looked at how the neural connections changed over the course of @ @ @ @ @ @ @ uptick in the muscles ’ response to RST stimulation as weight training continued .
By the end of training , responses had increased by about 50 percent .
The team continued to track the strength of the neural connections for two weeks after training was complete and found that the increased connectivity persisted .
The muscles ’ responses to CST stimulation did not show the same steady increase during training , however , and in one monkey , CST connectivity appeared to decrease .
After the training , the monkeys were killed , @ @ @ @ @ @ @ Baker and Glover found further evidence of the RST ’ s role in weight training : the connections on the trained ( right ) side were stronger than on the untrained ( left ) side , as evidenced by greater electrical responses of neurons in the spinal cord to stimulation of the brain stem .
“ It ’ s as if the volume was turned up on the trained side , ” Baker says .
There was no difference between the two sides for the CST .
“ The most interesting [ part @ @ @ @ @ @ @ result , ” says Timothy Carroll , a neuroscientist at the University of Queensland in Australia who was not involved in the research .
“ It ’ s a level of analysis that just hasn ’ t been attempted for this type of exercise before.
” He agrees with Baker that the RST is “ underappreciated , ” noting that “ there is a really strong overemphasis on the cortex in controlling movement.
” The new study , he adds , “ is a nice example that there ’ s probably a lot @ @ @ @ @ @ @ probably the spinal cord ” during movement .
In the future , Baker is interested in understanding how increased connectivity of the RST relates to how the body heals after injury and how to help accelerate the process .
For example , a study he published with colleagues earlier this year found that noninvasive brain stimulation could speed the recovery of hand function in stroke patients .
“ We ’ re very interested in using targeted stimulation of the RST to improve recovery after damage , ” he says .

ABOVE: © ISTOCK.COM, koto_feja
EDITOR’S CHOICE IN NEUROSCIENCE
The paper
I.S. Glover, S.N. Baker, “Cortical, corticospinal, and reticulospinal contributions to strength training,” J Neurosci, 40:5820–32, 2020.
Of the two major neural highways that carry messages about movement down the spinal cord, one—the reticulospinal tract—is decidedly less fashionable, according to neuroscientist Stuart Baker of Newcastle University in the UK. In contrast to the corticospinal tract (CST), which evolved more recently and helps control complex, uniquely human movements such as playing the piano, the reticulospinal tract (RST) is associated with “boring” functions such as posture and walking, Baker says. But he suspects that the RST plays a bigger role in our movements than researchers currently appreciate.
To test for the RST’s possible contribution to strength training, Baker’s PhD student Isabel Glover, now a postdoc at University College London, taught two macaque monkeys to grasp and pull a handle attached to a pulley with their right paws. Feeding the monkeys fruit, nuts, or bits of chocolate as rewards for successful reps, she gradually increased the weight on the other end of the pulley. After a couple of months, the animals were able to pull their own body weight.
PDF LIFT, AND LOWER: Over the course of two months, researchers trained macaque monkeys to lift more and more weight, until they were able to do the equivalent of a one-armed pull-up. When the researchers stimulated a bundle of nerves in the spinal cord known as the reticulospinal tract (RST), they saw increases in the resulting neuronal electrical signals in the monkeys’ arm muscles as training progressed, while they did not see the same consistent upward trend in the muscles’ responses to stimulation of the corticospinal tract (CST). The results suggest that RST connectivity may play a critical role in muscle strengthening. WEB © Kelly Finan
Prior to the weight training, the researchers had implanted electrodes in the monkeys’ brain stems and arm muscles. This allowed the scientists to stimulate the CST or the RST and measure the electrical response in the muscles. Glover did this as the monkeys pulled an unweighted lever each morning before training began. Then she and Baker looked at how the neural connections changed over the course of the experiment.
They found a marked uptick in the muscles’ response to RST stimulation as weight training continued. By the end of training, responses had increased by about 50 percent. The team continued to track the strength of the neural connections for two weeks after training was complete and found that the increased connectivity persisted. The muscles’ responses to CST stimulation did not show the same steady increase during training, however, and in one monkey, CST connectivity appeared to decrease. After the training, the monkeys were killed, and looking inside their spinal cords, Baker and Glover found further evidence of the RST’s role in weight training: the connections on the trained (right) side were stronger than on the untrained (left) side, as evidenced by greater electrical responses of neurons in the spinal cord to stimulation of the brain stem. “It’s as if the volume was turned up on the trained side,” Baker says. There was no difference between the two sides for the CST.
“The most interesting [part] to me was the spinal cord result,” says Timothy Carroll, a neuroscientist at the University of Queensland in Australia who was not involved in the research. “It’s a level of analysis that just hasn’t been attempted for this type of exercise before.” He agrees with Baker that the RST is “underappreciated,” noting that “there is a really strong overemphasis on the cortex in controlling movement.” The new study, he adds, “is a nice example that there’s probably a lot going on in the brain stem and probably the spinal cord” during movement.
In the future, Baker is interested in understanding how increased connectivity of the RST relates to how the body heals after injury and how to help accelerate the process. For example, a study he published with colleagues earlier this year found that noninvasive brain stimulation could speed the recovery of hand function in stroke patients. “We’re very interested in using targeted stimulation of the RST to improve recovery after damage,” he says.


thescientist--2020-10-01--Opinion: What Animals Can Teach Us About Fear

Humans have many unique behaviors among animals .
For instance , we have a formal language that permits unparalleled communication about things that exist in the past , present , and future .
We can be especially jealous and can feel schadenfreude .
Yet we share at least one fundamental emotion with many other species : fear .
That primordial emotion , as I describe in my latest book , The Nature of Fear , binds us to our past .
We are the descendants of a long lineage of successful individuals who got their risk assessments right .
While @ @ @ @ @ @ @ hominin ancestors to understand why we act as we do , I suggest that we go much farther back in time and beyond our branch on the tree of life .
All animals , past and present , must assess life-threatening predation risks and make decisions to avoid or otherwise manage those risks .
It ’ s a delicate balance : being too fearful is costly if caution means that you miss out on acquiring food , mates , or other important resources .
Being too brazen could end very poorly indeed .
@ @ @ @ @ @ @ trade-offs right , and because of this , leave relatively more offspring .
Despite some differences in the precise neurochemicals that modulate fear , the neurophysiological mechanisms associated with fear in humans are readily seen across vertebrates .
Controlled laboratory studies in rodents and humans have identified identical regions of the brain and “ fear circuits.
” But to really understand our fears we have to get outside to study how animals assess and manage predation risk in the wild .
This is because context influences all decisions .
If you ’ re @ @ @ @ @ @ @ take more risks lest you starve .
And , if you ’ re dominant and can steal food from others at will , perhaps it ’ s OK to be a bit more cautious .
My students and I have spent more than 35 years studying the antipredator and social behavior in giant clams , fishes , skinks and other lizards , as well as in several species of birds and mammals .
I ’ ve studied and researched antipredator behavior in marmots and wallabies in depth .
We ’ ve even explored @ @ @ @ @ @ @ close their leaves when threatened .
One of the main lessons I ’ ve learned is that risk is ubiquitous , and that it ’ s impossible to completely eliminate it .
Fear is a natural emotion and a potent motivator .
Indeed , humans share with many animals a tendency to overestimate risk ( it ’ s better to be safe than sorry ! )
.
This makes us vulnerable to politicians with malevolent intentions who make compelling advertisements that efficiently tap into our well-honed neurophysiological fear systems .
Once they stoke @ @ @ @ @ @ @ their proposed policies will guarantee our safety .
But think for a moment before you support such fearmongers .
Ultimately , we must learn to manage our risks .
Trustworthy politicians lead us down a path of efficient risk management and recognize that uncertainty is both natural and ubiquitous .
In The Nature of Fear , I describe how natural expressions of this emotion influence the structure of ecological communities , and I review studies that show how the removal of predators changes entire ecosystems .
We know this , in part , @ @ @ @ @ @ @ predators to locations where they have been extirpated .
To manage predatory risks , animals modify their activity patterns , habitat selection , and their diet .
Fear of predators can also reduce an individual ’ s reproductive success .
All of these fear-induced modifications can have a profound influence on both the environment and the distribution and abundance of many species .
Fear , it turns out , is an essential ingredient in healthy ecosystems and helps maintain biodiversity .
I find it comforting to know that my fear comes from a @ @ @ @ @ @ @ human and nonhuman .
It is an inherited treasure , a powerful ally .
Yet , it is also an annoying and sometimes intolerable companion .
It is a compass that , when calibrated properly , guides us away from danger and toward opportunity .
Coopted and mutated , it can lead us down destructive paths that often endanger our own humanity .
Daniel T. Blumstein is an ethologist and conservation biologist .
He is a professor in the Department of Ecology and Evolutionary Biology , as well as a professor in the @ @ @ @ @ @ @ at the University of California , Los Angeles .
Read an excerpt of The Nature of Fear .

ABOVE: © ISTOCK.COM, KeithFLS
Humans have many unique behaviors among animals. For instance, we have a formal language that permits unparalleled communication about things that exist in the past, present, and future. We can be especially jealous and can feel schadenfreude. Yet we share at least one fundamental emotion with many other species: fear. That primordial emotion, as I describe in my latest book, The Nature of Fear, binds us to our past. We are the descendants of a long lineage of successful individuals who got their risk assessments right.
While many evolutionary psychologists focus solely on our hominin ancestors to understand why we act as we do, I suggest that we go much farther back in time and beyond our branch on the tree of life. All animals, past and present, must assess life-threatening predation risks and make decisions to avoid or otherwise manage those risks. It’s a delicate balance: being too fearful is costly if caution means that you miss out on acquiring food, mates, or other important resources. Being too brazen could end very poorly indeed. Successful individuals are those that get these trade-offs right, and because of this, leave relatively more offspring.
Despite some differences in the precise neurochemicals that modulate fear, the neurophysiological mechanisms associated with fear in humans are readily seen across vertebrates. Controlled laboratory studies in rodents and humans have identified identical regions of the brain and “fear circuits.”
But to really understand our fears we have to get outside to study how animals assess and manage predation risk in the wild. This is because context influences all decisions. If you’re hungry, it’s wise to take more risks lest you starve. And, if you’re dominant and can steal food from others at will, perhaps it’s OK to be a bit more cautious.
My students and I have spent more than 35 years studying the antipredator and social behavior in giant clams, fishes, skinks and other lizards, as well as in several species of birds and mammals. I’ve studied and researched antipredator behavior in marmots and wallabies in depth. We’ve even explored antipredator behavior in plant species that rapidly close their leaves when threatened.
One of the main lessons I’ve learned is that risk is ubiquitous, and that it’s impossible to completely eliminate it. Fear is a natural emotion and a potent motivator. Indeed, humans share with many animals a tendency to overestimate risk (it’s better to be safe than sorry!). This makes us vulnerable to politicians with malevolent intentions who make compelling advertisements that efficiently tap into our well-honed neurophysiological fear systems. Once they stoke our fear, they tell us that their proposed policies will guarantee our safety. But think for a moment before you support such fearmongers. Ultimately, we must learn to manage our risks. Trustworthy politicians lead us down a path of efficient risk management and recognize that uncertainty is both natural and ubiquitous.
In The Nature of Fear, I describe how natural expressions of this emotion influence the structure of ecological communities, and I review studies that show how the removal of predators changes entire ecosystems. We know this, in part, because of remarkable experiments where we restore predators to locations where they have been extirpated. To manage predatory risks, animals modify their activity patterns, habitat selection, and their diet. Fear of predators can also reduce an individual’s reproductive success. All of these fear-induced modifications can have a profound influence on both the environment and the distribution and abundance of many species. Fear, it turns out, is an essential ingredient in healthy ecosystems and helps maintain biodiversity.
I find it comforting to know that my fear comes from a long line of my ancestors, both human and nonhuman. It is an inherited treasure, a powerful ally. Yet, it is also an annoying and sometimes intolerable companion. It is a compass that, when calibrated properly, guides us away from danger and toward opportunity. Coopted and mutated, it can lead us down destructive paths that often endanger our own humanity.
Daniel T. Blumstein is an ethologist and conservation biologist. He is a professor in the Department of Ecology and Evolutionary Biology, as well as a professor in the Institute of the Environment and Sustainability, at the University of California, Los Angeles. Read an excerpt of The Nature of Fear.


thescientist--2020-10-01--Infographic: Measurements that Predict People's Behavior

Immersion is a neurological state of attention and emotional resonance that predicts what people will do after an experience , @ @ @ @ @ greater accuracy .
We identified it by comparing neural activity in people who took an @ @ @ @ @ those who did not .
Participants viewed a video about “ Big ” Ben Bowen @ @ @ @ @ aggressive brain tumor at age two and was featured in a fundraising campaign from St. @ @ @ @ @ Hospital .
As participants watched Bowen ’ s story , we measured attention and emotional @ @ @ @ @ measured by electroencephalography ( EEG ) as well as multiple signals from the peripheral nervous @ @ @ @ @ blood from participants before and after they viewed the video to measure changes in oxytocin @ @ @ @ @ hormone ( ACTH ) .
One-half of the hundreds of people who viewed the video @ @ @ @ @ .
Our analysis predicted who would donate with 82 percent accuracy .

Immersion is a neurological state of attention and emotional resonance that predicts what people will do after an experience, often with 80 percent or greater accuracy. We identified it by comparing neural activity in people who took an action after an experience versus those who did not.
Participants viewed a video about “Big” Ben Bowen, who suffered from an aggressive brain tumor at age two and was featured in a fundraising campaign from St. Jude Children’s Research Hospital. As participants watched Bowen’s story, we measured attention and emotional responses using brain activity as measured by electroencephalography (EEG) as well as multiple signals from the peripheral nervous system. We also drew blood from participants before and after they viewed the video to measure changes in oxytocin, cortisol, and adrenocorticotropic hormone (ACTH). One-half of the hundreds of people who viewed the video donated money to St. Jude. Our analysis predicted who would donate with 82 percent accuracy.
Read the full story.


Ten Minute Sabbatical

7 .
Cerebrum ’ s convoluted surface 8 .
Drill a hole in the skull of 9 .
Unit for @ @ @ @ @ s shock 10 .
Hypoesthesia 11 .
German physician Carl , who researched encephalopathy 13 @ @ @ @ @ labs 15 .
One of 100 in a googol 17 .
Tiny bit of a @ @ @ @ @ , as a trait 22 .
Brachia 23 .
When light speed is constant 24 @ @ @ @ @ above species

ACROSS 7. Cerebrum’s convoluted surface
8. Drill a hole in the skull of
9. Unit for measuring an electric eel’s shock
10. Hypoesthesia
11. German physician Carl, who researched encephalopathy
13. Maze runners in many labs
15. One of 100 in a googol
17. Tiny bit of a chemical compound
19. Nonheritable, as a trait
22. Brachia
23. When light speed is constant
24. Groups below families and above species


thescientist--2020-10-01--Timeline: When Bad Research Changes Public Health Strategy

Surgisphere Corporation had a busy few months in 2020 , overseeing the launch of a new website , the publication @ @ @ @ @ and outcomes in COVID-19 patients , and eventually a collapse of its reputation .

ABOVE: © ISTOCK.COM, BORISLAV; © ISTOCK.COM, EDEVARDE_MOREIRA; WIKIMEDIA, THE WORLD HEALTH ORGANIZATION
Surgisphere Corporation had a busy few months in 2020, overseeing the launch of a new website, the publication of high-impact papers on treatments and outcomes in COVID-19 patients, and eventually a collapse of its reputation.
Read the full story.


thescientist--2020-10-01--Non-Concussive Head Hits Influence the Brain’s Microstructure

ABOVE : Functional MRI scans show higher connectivity in the brains of rugby players in the off-season ( top row ) compared with non-contact athletes ( bottom row ) .
© NEUROLOGY , 95 : e402–12 , 2020 The paper K.Y .
Manning et al.
, “ Longitudinal changes of brain microstructure and function in nonconcussed female rugby players , ” Neurology , 95 : e402–12 , 2020 .
Conversations about injuries in high-impact sports , such as football , hockey , and rugby , typically center around concussions , brain injuries that can affect memory , cognition , and @ @ @ @ @ @ @ a concussion , and even repeated , seemingly harmless impacts can alter the microstructure of white matter , myelinated neurons located deep in the brain , researchers reported in Neurology in July .
The study followed 104 female collegiate athletes in rugby , swimming , and rowing .
Athletes wore headband sensors to measure the force of collisions during practices and games .
None of the hits experienced by any athlete caused a concussion .
Still , MRI and other imaging techniques showed differences in the white matter of rugby players who suffered @ @ @ @ @ @ @ of swimmers and rowers who didn ’ t suffer head hits .
The differences were most noticeable in the corpus callosum , a nerve bundle that facilitates communication between the brain hemispheres , says study coauthor Ravi Menon , a neuroscientist at Robarts Research Institute in Canada .
Specifically , imaging during and after the athletes ’ competitive seasons showed altered axon placement and increased functional connectivity among white matter neurons in the brains of the rugby players .
Such neural rewiring , previous research suggests , could be a way for the @ @ @ @ @ @ @ Following athletes in the off-season is novel , says Pashtun Shahim , a physician at the National Institutes of Health Clinical Center who was not involved with the work .
But , he cautions , “ whether these changes in functional connectivity or white matter integrity are transient or persist over a long time is unclear.
” Blood biomarkers that can be tracked noninvasively over longer periods of time , Shahim suggests , would be a more practical way to identify potential axon disruption in college athletes .

ABOVE: Functional MRI scans show higher connectivity in the brains of rugby players in the off-season (top row) compared with non-contact athletes (bottom row).
© NEUROLOGY, 95:e402–12, 2020
EDITOR’S CHOICE IN NEUROSCIENCE
The paper
K.Y. Manning et al., “Longitudinal changes of brain microstructure and function in nonconcussed female rugby players,” Neurology, 95:e402–12, 2020.
Conversations about injuries in high-impact sports, such as football, hockey, and rugby, typically center around concussions, brain injuries that can affect memory, cognition, and balance. But not every collision yields a concussion, and even repeated, seemingly harmless impacts can alter the microstructure of white matter, myelinated neurons located deep in the brain, researchers reported in Neurology in July.
The study followed 104 female collegiate athletes in rugby, swimming, and rowing. Athletes wore headband sensors to measure the force of collisions during practices and games. None of the hits experienced by any athlete caused a concussion. Still, MRI and other imaging techniques showed differences in the white matter of rugby players who suffered low-impact collisions compared with the white matter of swimmers and rowers who didn’t suffer head hits. The differences were most noticeable in the corpus callosum, a nerve bundle that facilitates communication between the brain hemispheres, says study coauthor Ravi Menon, a neuroscientist at Robarts Research Institute in Canada.
Specifically, imaging during and after the athletes’ competitive seasons showed altered axon placement and increased functional connectivity among white matter neurons in the brains of the rugby players. Such neural rewiring, previous research suggests, could be a way for the brain to compensate for an injury.
Following athletes in the off-season is novel, says Pashtun Shahim, a physician at the National Institutes of Health Clinical Center who was not involved with the work. But, he cautions, “whether these changes in functional connectivity or white matter integrity are transient or persist over a long time is unclear.” Blood biomarkers that can be tracked noninvasively over longer periods of time, Shahim suggests, would be a more practical way to identify potential axon disruption in college athletes.


thescientist--2020-10-01--Clues to the Origin and Function of the Brain’s Alpha Waves

ABOVE : Patterns of neural activity known as alpha waves , often recorded via electroencephalography , may stem from the visual cortex .
© ISTOCK.COM , undefined undefined Groups of neurons firing in sync produce predictable and measurable brainwave patterns , including the alpha rhythm , which dominates when we ’ re relaxed and our eyes are closed .
While researchers have long suspected the alphas originate in a brain region called the thalamus , the waves ’ definitive source and function remain elusive , says Roger Traub , a mathematical neurologist with IBM .
Experimenting with slices of rat @ @ @ @ @ @ @ inserted electrodes into a piece of visual cortex and used drugs to chemically induce a stable alpha rhythm .
This rhythm , the team found , emanated from pyramidal neurons in the fourth layer of the visual cortex .
People think that because there aren ’ t many pyramidal neurons in that fourth layer , they aren ’ t important , but those neurons appear to generate alpha waves , Traub says .
Comparing a model of neurons ’ electrical firing to the team ’ s experimental data , he confirmed the cortex @ @ @ @ @ @ @ .
The waves form when pyramidal neurons fire in sync , and the model suggested that the period of the resulting oscillation ( the time it takes to complete one cycle ) was determined by synaptic excitation , as opposed to the synaptic inhibition common in other brain waves .
When excited , pyramidal cell activity oscillates at a different frequency ( the number of waves per second ) than nearby sensory neurons , possibly interrupting the flow of information throughout the cortex .
The findings are “ very convincing , ” says @ @ @ @ @ @ @ who was not involved in the study .
He questions , however , whether the result will translate into humans .
The alpha frequency in a rodent , for example , may be different than in a human .
“ It ’ s a very questionable assumption ” that the frequencies in different animals are the same , Klimesch says

ABOVE: Patterns of neural activity known as alpha waves, often recorded via electroencephalography, may stem from the visual cortex.
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EDITOR’S CHOICE IN NEUROSCIENCE
The paper
R.D. Traub et al., “Layer 4 pyramidal neuron dendritic bursting underlies a post-stimulus visual cortical alpha rhythm,” Commun Biol, 3:230, 2020.
Groups of neurons firing in sync produce predictable and measurable brainwave patterns, including the alpha rhythm, which dominates when we’re relaxed and our eyes are closed. While researchers have long suspected the alphas originate in a brain region called the thalamus, the waves’ definitive source and function remain elusive, says Roger Traub, a mathematical neurologist with IBM.
Experimenting with slices of rat brain tissue, Traub’s colleagues inserted electrodes into a piece of visual cortex and used drugs to chemically induce a stable alpha rhythm. This rhythm, the team found, emanated from pyramidal neurons in the fourth layer of the visual cortex. People think that because there aren’t many pyramidal neurons in that fourth layer, they aren’t important, but those neurons appear to generate alpha waves, Traub says.
Comparing a model of neurons’ electrical firing to the team’s experimental data, he confirmed the cortex as the source of the alpha waves. The waves form when pyramidal neurons fire in sync, and the model suggested that the period of the resulting oscillation (the time it takes to complete one cycle) was determined by synaptic excitation, as opposed to the synaptic inhibition common in other brain waves. When excited, pyramidal cell activity oscillates at a different frequency (the number of waves per second) than nearby sensory neurons, possibly interrupting the flow of information throughout the cortex.
The findings are “very convincing,” says University of Salzburg neuroscientist Wolfgang Klimesch, who was not involved in the study. He questions, however, whether the result will translate into humans. The alpha frequency in a rodent, for example, may be different than in a human. “It’s a very questionable assumption” that the frequencies in different animals are the same, Klimesch says.


thescientist--2020-10-01--Curiosity and Hunger Are Driven by the Same Brain Regions

ABOVE : Edward Poynter ’ s Orpheus and Eurydice depicts the mythical Greek hero just before his curiosity gets the better of him .
WIKIMEDIA In Greek mythology , Orpheus descends to the underworld and persuades Hades to allow him to take his dead wife , Eurydice , back to the realm of the living .
Hades agrees , but tells Orpheus that he must not look back until he has exited the underworld .
Despite the warning , Orpheus glances behind him on his way out to check whether Eurydice is indeed following him—and loses her forever .
The @ @ @ @ @ @ @ curiosity , a drive to seek certain kinds of knowledge even when doing so is risky—and even if the information serves no practical purpose at the time .
In fact , the way people pursue information they ’ re curious about can resemble the drive to attain more tangible rewards such as food—a parallel that hasn ’ t been lost on scientists .
To investigate the apparent similarity between curiosity and hunger , researchers led by Kou Murayama of the University of Reading in the UK recently devised an experiment to compare how @ @ @ @ @ @ @ knowledge , and the risks people are willing to take to satisfy those desires .
Beginning in 2016 , the team recruited 32 volunteers and instructed them not to eat for at least two hours before coming into the lab .
After they arrived , the volunteers ’ fingers were hooked up to electrodes that could deliver a weak current , and researchers calibrated the level of electricity to what each participant reported was uncomfortable , but not painful .
Then , still hooked up to the electrodes , the volunteers were asked @ @ @ @ @ @ @ photo of a food item or a video of a magician performing a trick , followed by a visual depiction of their odds of “ winning ” that round ( which ranged from 1:6 to 5:6 ) .
If they accepted the gamble and won , based on a random , computer-generated outcome , they ’ d receive tokens that gave them a better chance of getting the pictured food or the explanation for the magic trick at the end of the experiment .
If they lost , they ’ d instead get @ @ @ @ @ @ @ an electric shock at the end of their session .
On being presented with their odds of winning , participants reported how desirable they found either the food or the explanation of the magic trick , and whether they were willing to accept the gamble .
Not surprisingly , the chances of winning and the desirability that participants assigned the food or magic reveal each correlated with their likelihood of accepting the gamble .
But the category of the reward—food or satiated curiosity—was not a statistically significant predictor of participants ’ decisions .
@ @ @ @ @ @ @ were similar in how they affected the participants ’ risk-taking .
The research team suspected that the neural processes underlying the risk-taking would also be similar for the two types of motivation .
“ There is a body of literature suggesting that , as far as the neurobiological mechanisms [ go ] , they seem to be similar to a certain extent , ” says cognitive neuroscientist Johnny King Lau , a postdoc at the University of Reading and the study ’ s first author .
To test this hypothesis for their risk-taking @ @ @ @ @ @ @ similar to the first , this time with a different set of subjects making their decisions inside an MRI machine as their brains were scanned .
The patterns of blood flow revealed by the scan indicated that the brain regions involved in the two motivations were indeed the same .
When participants viewed either the food or the curiosity-inducing stimulus—which , in this functional MRI ( fMRI ) experiment , could be either a magic trick or a trivia question—a region deep in the brain called the nucleus accumbens became more active , @ @ @ @ @ @ @ solution as highly desirable .
If the subjects then decided to accept the gamble , three areas known to be involved in reward processing—the nucleus accumbens , the bilateral caudate nucleus , and the ventral tegmental area—lit up more than they did if participants decided not to take the chance .
The experiment showed that curiosity , like the desire for tangible reward , induces people to take risks , “ and it seems to have [ a ] very similar underlying mechanism in the brain , ” Lau says .
“ This @ @ @ @ @ @ @ how curiosity can act as a motivational drive , ” says Andrew Lutas , a neuroscientist at Beth Israel Deaconess Medical Center who studies neural circuitry in rodents and was not involved in the work .
The fact that similar brain regions are involved in both hunger and curiosity means that discoveries made in animals about food-related reward circuits in the brain are also likely to be relevant to curiosity and other drives that are difficult to study in model organisms , he adds .
Researchers have typically measured human curiosity by asking @ @ @ @ @ @ @ pay for a piece of information , or having them tell researchers how desirable the information was to them , notes Ming Hsu , a neuroeconomist at the University of California , Berkeley , who also was not involved in the study .
“ To show this with electric shock I thought was very creative , very novel , ” he says .
“ And it really , I think , underscores the point of just how valuable curiosity is that people are not just willing to pay , say , a few @ @ @ @ @ @ @ ] also willing to take the risk ” of an electric shock .
While the research team ’ s fMRI scans implicate the same brain regions in processing hunger and curiosity , the images don ’ t have the resolution to identify the specific circuitry involved , Hsu notes , so a question for future studies will be “ whether the same neurons are firing the same way with respect to curiosity and food.
” Another unanswered question , he says , is what makes some facts uninteresting to people , while other @ @ @ @ @ @ @ .
“ We can measure the amount of curiosity that people express , ” he says .
“ But what we don ’ t know is , why are people curious about some information but not others ?
”

ABOVE: Edward Poynter’s Orpheus and Eurydice depicts the mythical Greek hero just before his curiosity gets the better of him.
WIKIMEDIA
In Greek mythology, Orpheus descends to the underworld and persuades Hades to allow him to take his dead wife, Eurydice, back to the realm of the living. Hades agrees, but tells Orpheus that he must not look back until he has exited the underworld. Despite the warning, Orpheus glances behind him on his way out to check whether Eurydice is indeed following him—and loses her forever.
The story hints at a dark side to curiosity, a drive to seek certain kinds of knowledge even when doing so is risky—and even if the information serves no practical purpose at the time. In fact, the way people pursue information they’re curious about can resemble the drive to attain more tangible rewards such as food—a parallel that hasn’t been lost on scientists. To investigate the apparent similarity between curiosity and hunger, researchers led by Kou Murayama of the University of Reading in the UK recently devised an experiment to compare how the brain processes desires for food and knowledge, and the risks people are willing to take to satisfy those desires.
Similar brain regions are involved in both hunger and curiosity.
Beginning in 2016, the team recruited 32 volunteers and instructed them not to eat for at least two hours before coming into the lab. After they arrived, the volunteers’ fingers were hooked up to electrodes that could deliver a weak current, and researchers calibrated the level of electricity to what each participant reported was uncomfortable, but not painful. Then, still hooked up to the electrodes, the volunteers were asked to gamble: they viewed either a photo of a food item or a video of a magician performing a trick, followed by a visual depiction of their odds of “winning” that round (which ranged from 1:6 to 5:6). If they accepted the gamble and won, based on a random, computer-generated outcome, they’d receive tokens that gave them a better chance of getting the pictured food or the explanation for the magic trick at the end of the experiment. If they lost, they’d instead get tokens that increased their chances of getting an electric shock at the end of their session. On being presented with their odds of winning, participants reported how desirable they found either the food or the explanation of the magic trick, and whether they were willing to accept the gamble.
Not surprisingly, the chances of winning and the desirability that participants assigned the food or magic reveal each correlated with their likelihood of accepting the gamble. But the category of the reward—food or satiated curiosity—was not a statistically significant predictor of participants’ decisions. Behaviorally, at least, the drives were similar in how they affected the participants’ risk-taking.
ANDRZEJ KRAUZE
The research team suspected that the neural processes underlying the risk-taking would also be similar for the two types of motivation. “There is a body of literature suggesting that, as far as the neurobiological mechanisms [go], they seem to be similar to a certain extent,” says cognitive neuroscientist Johnny King Lau, a postdoc at the University of Reading and the study’s first author. To test this hypothesis for their risk-taking scenario, the researchers ran an experiment similar to the first, this time with a different set of subjects making their decisions inside an MRI machine as their brains were scanned.
The patterns of blood flow revealed by the scan indicated that the brain regions involved in the two motivations were indeed the same. When participants viewed either the food or the curiosity-inducing stimulus—which, in this functional MRI (fMRI) experiment, could be either a magic trick or a trivia question—a region deep in the brain called the nucleus accumbens became more active, particularly if they rated the food or solution as highly desirable. If the subjects then decided to accept the gamble, three areas known to be involved in reward processing—the nucleus accumbens, the bilateral caudate nucleus, and the ventral tegmental area—lit up more than they did if participants decided not to take the chance. The experiment showed that curiosity, like the desire for tangible reward, induces people to take risks, “and it seems to have [a] very similar underlying mechanism in the brain,” Lau says.
People are not just willing to pay, say, a few cents for it, but are also willing to take the risk of an electric shock. —Ming Hsu University of California, Berkeley
“This study is particularly interesting because it investigates how curiosity can act as a motivational drive,” says Andrew Lutas, a neuroscientist at Beth Israel Deaconess Medical Center who studies neural circuitry in rodents and was not involved in the work. The fact that similar brain regions are involved in both hunger and curiosity means that discoveries made in animals about food-related reward circuits in the brain are also likely to be relevant to curiosity and other drives that are difficult to study in model organisms, he adds.
Researchers have typically measured human curiosity by asking subjects how much money they’d pay for a piece of information, or having them tell researchers how desirable the information was to them, notes Ming Hsu, a neuroeconomist at the University of California, Berkeley, who also was not involved in the study. “To show this with electric shock I thought was very creative, very novel,” he says. “And it really, I think, underscores the point of just how valuable curiosity is that people are not just willing to pay, say, a few cents for it, but [are] also willing to take the risk” of an electric shock.
While the research team’s fMRI scans implicate the same brain regions in processing hunger and curiosity, the images don’t have the resolution to identify the specific circuitry involved, Hsu notes, so a question for future studies will be “whether the same neurons are firing the same way with respect to curiosity and food.” Another unanswered question, he says, is what makes some facts uninteresting to people, while other tidbits—say, celebrity gossip—are irresistible to many. “We can measure the amount of curiosity that people express,” he says. “But what we don’t know is, why are people curious about some information but not others?”


thescientist--2020-10-01--Infographic: How Cytokines Flow into and out of the Brain

The meninges ’ innermost layer , the pia mater , lines the perimeter of the brain , separating neural tissue from the surrounding fluid and tissue .
But gaps in the thin , fibrous tissue allow blood vessels to extend deep into the brain .
Along blood vessels in the brain , a tightly packed layer of endothelial cells , along with projections , or “ feet , ” from astrocytes collectively make up the blood-brain barrier , which prevents blood from entering the organ .
But CSF that sits in the space between the pia mater and upper layers @ @ @ @ @ @ @ endothelium-lined blood vessels .
As arteries pulse with each beat from the heart , CSF pushes into the astrocyte feet through AQP4 water channels .
This CSF can carry signals from the immune system such as cytokines IL-17 , IL-4 , and interferon gamma that may also talk directly with neurons .
Once in the brain , the CSF mixes with extracellular fluid from neuronal tissue , sweeping up cellular waste excreted along with any toxins , pathogen-derived antigens , and debris formed as part of normal neural rewiring .
This fluid is @ @ @ @ @ @ @ astrocyte feet into the perivascular space , where it can interact with gamma delta T cells .
Those T cells may then respond by releasing cytokines such as IL-17 that can move right back into the brain , although this has yet to be shown .

The meninges’ innermost layer, the pia mater, lines the perimeter of the brain, separating neural tissue from the surrounding fluid and tissue. But gaps in the thin, fibrous tissue allow blood vessels to extend deep into the brain.
Along blood vessels in the brain, a tightly packed layer of endothelial cells, along with projections, or “feet,” from astrocytes collectively make up the blood-brain barrier, which prevents blood from entering the organ. But CSF that sits in the space between the pia mater and upper layers of the meninges flows down around the endothelium-lined blood vessels.
As arteries pulse with each beat from the heart, CSF pushes into the astrocyte feet through AQP4 water channels. This CSF can carry signals from the immune system such as cytokines IL-17, IL-4, and interferon gamma that may also talk directly with neurons.