Floating out of your body and looking down on it. The story of your life flashing by before your eyes. Seeing a bright light at the end of a dark tunnel. These are just two of the most common experiences that people report after a near-death experience (NDE). For some people, NDEs are a transformative spiritual or mystical experience. But what's the source of the phenomena? That's a question that fascinates Dr. Christof Koch is president and chief scientist of the Allen Institute for Brain Science who studies the neuroscience of consciousness. In Scientific American, Koch surveys the science of near-death experiences and what they can tell us about how our brains work under extreme duress. From Scientific American
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Modern death requires irreversible loss of brain function. When the brain is starved of blood flow (ischemia) and oxygen (anoxia), the patient faints in a fraction of a minute and his or her electroencephalogram, or EEG, becomes isoelectric—in other words, flat. This implies that large-scale, spatially distributed electrical activity within the cortex, the outermost layer of the brain, has broken down. Like a town that loses power one neighborhood at a time, local regions of the brain go offline one after another. The mind, whose substrate is whichever neurons remain capable of generating electrical activity, does what it always does: it tells a story shaped by the person’s experience, memory and cultural expectations.
Given these power outages, this experience may produce the rather strange and idiosyncratic stories that make up the corpus of NDE reports.
An array of scientific evidence suggest that in some cases, the bacteria in your gut–your microbiome–could be tied to neurological and psychological disorders and differences, from anxiety and autism to Parkinson's and schizophrenia. The journal Science published a survey of the field and the Cambridge, Massachusetts start-up Holobiome that hopes to use insight into this "psychobiome" to develop treatments for depression, insomnia, and other conditions with a neurological side to them. From Science:
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For example, many people with irritable bowel syndrome are also depressed, people on the autism spectrum tend to have digestive problems, and people with Parkinson’s are prone to constipation.
Researchers have also noticed an increase in depression in people taking antibiotics—but not antiviral or antifungal medications that leave gut bacteria unharmed. Last year, Jeroen Raes, a microbiologist at the Catholic University of Leuven, and colleagues analyzed the health records of two groups—one Belgian, one Dutch—of more then 1000 people participating in surveys of their types of gut bacteria. People with depression had deficits of the same two bacterial species, the authors reported in April 2019 in Nature Microbiology.
Researchers see ways in which gut microbes could influence the brain. Some may secrete messenger molecules that travel though the blood to the brain. Other bacteria may stimulate the vagus nerve, which runs from the base of the brain to the organs in the abdomen. Bacterial molecules might relay signals to the vagus through recently discovered “neuropod” cells that sit in the lining of the gut, sensing its biochemical milieu, including microbial compounds.
"I feel so brain dead I can't even speak." Find out what happens when two editors from Popular Science quit their six-cup-a-day coffee habit for two weeks.
From the YouTube description:
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Caffeine is the most widely used psychoactive drug on the planet. Like all good things in this world, it should be consumed in moderation—but PopSci editors Jess Boddy and Claire Maldarelli were definitely not following that unwritten rule, guzzling between six and ten cups of coffee per day. That put them at risk for disrupted sleep, heart palpitations, unusual nervousness, and more. So they decided to detox. Will their torturous 14-day cut regulate their sleep patterns and teach them to respect caffeine for the powerful drug that it is? Find out on this week's episode of Test Dummy.
Telepathy. ESP. The ability to communicate thoughts, feelings, or experiences without using our known sensory channels is a timeless superpower. Soon, advances in neuroscience, molecular biology, and computer science will make some kinds of synthetic telepathy possible. Meanwhile though, methods to treat brain disorders through magnetic stimulation of brain circuits could enable crude (or eventually not-so-crude) mind control. National Institutes of Health neuroscientist R. Douglas Fields -- author of Electric Brain: How the New Science of Brainwaves Reads Minds, Tells Us How We Learn, and Helps Us Change for the Better -- wrote a brief essay for Scientific American surveying the present, past, and possible future of this strange field. From Scientific American:
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Neuroscientist Marcel Just and colleagues at Carnegie Mellon University are using fMRI brain imaging to decipher what a person is thinking. By using machine learning to analyze complex patterns of activity in a person’s brain when they think of a specific number or object, read a sentence, experience a particular emotion or learn a new type of information, the researchers can read minds and know the person’s specific thoughts and emotions. “Nothing is more private than a thought,” Just says, but that privacy is no longer sacrosanct....
...The prospect of “mind control” frightens many, and brain stimulation to modify behavior and treat mental illness has a sordid history. In the 1970s neuropsychologist Robert Heath at Tulane University inserted electrodes into a homosexual man’s brain to “cure” him of his homosexual nature by stimulating his brain’s pleasure center.
With unfortunate frequency, elderly patients go to the hospital for a surgery or other treatment and quickly become confused, bewildered, and sometimes agitated or totally disoriented. This is called delirium and while it apparently affects between 10 and 50 percent of patients over 65, it's only recently been studied in depth. Sharon K. Inouye, director of Harvard's Aging Brain Center, is leading the charge to understand delirium, its impact on patients' longterm cognitive faculties, and how to prevent it. From Scientific American:
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[Delirium] is the phenomenon, sadly familiar to many families, of Grandpa never being quite the same after an operation...
The consequences of delirium, if it lasts more than a few days and especially if it is followed by cognitive decline, are enormous. “It’s a house of cards,” Inouye says. “Patients start getting treated with medications for agitation or disruptive behavior, and those medications lead to complications. Or they are very sedated, and that leads to complications.” Delirious patients may choke on their food or pills and die of aspiration pneumonia. They may wind up in bed for long periods and suffer fatal blood clots. Once up, they are prone to falling. It’s a downward spiral and a costly one. Delirium adds more than $183 billion a year to U.S. health care costs, outstripping congestive heart failure.
Fortunately, basic steps can be taken to prevent delirium or shorten its course, such as making sure the patient is well hydrated, has access to eyeglasses and hearing aids if he or she uses them, gets out of bed and walks as soon as possible, has adequate sleep, and is socially engaged by hospital staff and loved ones.
Professional musician Dagmar Turner had brain surgery at King's College Hospital, London to remove a benign tumor.
Every year, the nonprofit Neural Correlate Society, an organization "that promotes scientific research into the neural correlates of perception and cognition," holds a competition for the Best Illusion of the Year. This year's winner is the above "Dual Axis Illusion" created by Frank Force (USA).
"This spinning shape appears to defy logic by rotating around both the horizontal and vertical axis at the same time!" reads the description. "To make things even more confusing, the direction of rotation is also ambiguous. Some visual cues in the video will help viewers change their perception."
Below, second prize winner "Change the Color" by Haruaki Fukuda (Japan) and third prize winner "The Rotating Circles Illusion" by Ryan E.B. Mruczek and Gideon Paul Caplovitz (USA).
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For some children with severe epilepsy, the best treatment may be a very rare surgical procedure in which a large portion -- even half -- of the child's brain is removed or disconnected. Amazingly, many of these individuals can relearn motor, language, and cognitive skills. How? The brain reorganizes itself and builds new connections. To better understand this incredible process, and hopefully inform new interventions and rehabilitation, Caltech neuroscientists conducted brain scans on six adults "all of whom received the surgeries as children and now have relatively normal cognitive abilities." From Caltech:
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"Despite missing an entire brain hemisphere, we found all the same major brain networks that you find in healthy brains with two hemispheres," says Dorit Kliemann, lead author of the new report and a postdoctoral scholar who works in the laboratory of Ralph Adolphs (PhD '93), the Bren Professor of Psychology, Neuroscience, and Biology, and the director of the Caltech Brain Imaging Center.
The brain scans also revealed an increased number of connections between the brain networks in the patients compared to healthy individuals. For example, the regions in the patients' brains that control the function of walking appeared to be communicating more with the regions that control talking than what is typically observed.
"It appears that the networks are collaborating more," says Kliemann. "The networks themselves do not look abnormal in these patients, but the level of connections between the networks is increased in all six patients...."
Says Kliemann, "It's truly amazing what these patients can do.
Cecil Castellucci (previously
) is a polymath artist: YA novelist, comics writer, librettist, rock star; her latest book, Girl on Film
, is an extraordinary memoir of her life in the arts, attending New York's School for the Performing Arts (AKA "The Fame School") and being raised by her parents, who are accomplished scientists.
In 1964, a German experiment asked people to randomly tap their fingers -- whenever they wanted -- while having their brain's electrical activity monitored. The scientists discovered something nifty: The Bereitschaftspotential, a little burst of electrical activity the subjects' brains gave off in the milliseconds just before the finger-tap. Neuroscientists were fascinated: We now had a glimpse of the brain's crucial planning activities.
In the 80s, things got super weird. The American physiologist Benjamin Libet repeated the experiment and observed the Bereitschaftspotential occurring about 350 milliseconds before the subject decided to move their fingers. In other words, your brain and body were deciding to move your finger before you yourself were aware of your intent to do so. Free will was an illusion.
Armchair philosophers went to town on this, as you can imagine: Consciousness is an illusion! We're well and truly just self-deluding bags of meat! etc etc.
Then in 2012, Aaron Schurger -- a scientist at Paris' National Institute of Health and Medical Research -- proposed a different explanation for the Bereitschaftspotential. As he knew from his research, the brain is constantly a hive of activity and electrophysiological noise, and like any natural phenomenon with tons of little jittering components, it produces wave-like crests of activity.
So maybe the Bereitschaftspotential was just that. Maybe it was just the product of a noisy brain. A couple of top neuroscientists wondered if the original 1964 finger-tap experiment had been misinterpreted, and its correlations misunderstood. Since the decision to tap your finger randomly isn't terribly consequential, maybe the subjects were unconsciously timing their fingertaps with the Bereitschaftspotential. Read the rest
The esteemed research institute and medical school Johns Hopkins Medicine is starting the Center for Psychedelic and Consciousness Research thanks to $17 million in private donations. The generous funders include Boing Boing pal and author Tim Ferriss, WordPress founder Matt Mullenweg, TOMS shoes founder Blake Mycoskie, and investor Craig Nerenberg. Psychedelics have tremendous unlocked therapeutic potential for the likes of severe depression, PTSD, obsessive-compulsive disorder, and alcoholism, What a wonderful, important, and worthy cause these individuals chose to support. From Johns Hopkins Medical:
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In 2000, the psychedelic research group at Johns Hopkins was the first to achieve regulatory approval in the U.S. to reinitiate research with psychedelics in healthy volunteers who had never used a psychedelic. Their 2006 publication on the safety and enduring positive effects of a single dose of psilocybin sparked a renewal of psychedelic research worldwide.
Since then, the researchers have published studies in more than 60 peer-reviewed journal articles. Their research has demonstrated therapeutic benefits for people who suffer from conditions including nicotine addiction and depression and anxiety caused by life-threatening diseases such as cancer. It has paved the way for current studies on treatment of major depressive disorder. These researchers have also expanded the field of psychedelic research by publishing safety guidelines that have helped gain approval for psychedelic studies at other universities around the world and by developing new ways of measuring mystical, emotional, and meditative experiences while under the influence of psychedelics.
The group's findings on both the promise and the risks of psilocybin in particular helped create a path forward for the chemical's potential medical approval and reclassification from a Schedule I drug, the most restrictive federal government category, to a more appropriate level.
On Slate Star Codex (previously), Scott Alexander breaks down Invisible Designers: Brain Evolution Through the Lens of Parasite Manipulation, Marco Del Giudice's Quarterly Review of Biology paper that examines the measures that parasites take to influence their hosts' behaviors, and the countermeasures that hosts evolve to combat them.
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Scientists have used laser light to activate neurons in a mouse's brain so the rodents "sees" non-existent lines. The technique, called optogenetics, switches on and off neurons that have been previously genetically engineered to be light-sensitive. According to Science News, "the results, described online July 18 in Science, represent the first time scientists have created a specific visual perception with laboratory trickery." In this case, the mice had been trained to drink water from a spout upon seeing the lines. From Science News:
When optogenetics first debuted about 15 years ago, everyone was hoping to achieve this level of precise control over perception, and the behaviors that follow, says Karl Deisseroth, a neuroscientist and psychiatrist who pioneered the technique. “It’s exciting to get to this point,” says Deisseroth, a Howard Hughes Medical Institute investigator at Stanford University....
Similar approaches could let scientists create other sorts of perceptions, such as smells, touches and tastes, Deisseroth says.
Previously: "Scientists remote control a mouse with a wireless LED brain implant"
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More than 100 hours of MIR scanning has generated an image of a whole human brain with unprecedented level of detail. Massachusetts General Hospital researchers and their colleagues used a 7 Tesla MRI machine, recently approved by the FDA, to scan the donated brain from a 58-year-old-woman. The image shows detail down to .1 millimeter. From Science News:
Before the scan began, researchers built a custom spheroid case of urethane that held the brain still and allowed interfering air bubbles to escape. Sturdily encased, the brain then went into a powerful MRI machine called a 7 Tesla, or 7T, and stayed there for almost five days of scanning...
Researchers can’t get the same kind of resolution on brains of living people. For starters, people couldn’t tolerate a 100-hour scan. And even tiny movements, such as those that come from breathing and blood flow, would blur the images...
These (new kinds of) detailed brain images could hold clues for researchers trying to pinpoint hard-to-see brain abnormalities involved in disorders such as comas and psychiatric conditions such as depression.
"7 Tesla MRI of the ex vivo human brain at 100 micron resolution" (bioRxiv.org)
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A new study suggests that humans can subconsciously sense Earth's magnetic field. While this capability, called magnetoreception, is well known in birds and fish, there is now evidence that our brains are also sensitive to magnetic fields. The researchers from Caltech and the University of Tokyo measured the brainwaves of 26 participants who were exposed to magnetic fields that could be manipulated. Interestingly, the brainwaves were not affected by upward-pointing fields. From Science News:
Participants in this study, who all hailed from the Northern Hemisphere, should perceive downward-pointing magnetic fields as natural, whereas upward fields would constitute an anomaly, the researchers argue. Magnetoreceptive animals are known to shut off their internal compasses when encountering weird fields, such as those caused by lightning, which might lead the animals astray. Northern-born humans may similarly take their magnetic sense “offline” when faced with strange, upward-pointing fields...
Even accounting for which magnetic changes the brain picks up, researchers still don’t know what our minds might use that information for, (Caltech neurobiologist and geophysicist Joseph) Kirschvink says. Another lingering mystery is how, exactly, our brains detect Earth’s magnetic field. According to the researchers, the brain wave patterns uncovered in this study may be explained by sensory cells containing a magnetic mineral called magnetite, which has been found in magnetoreceptive trout as well as in the human brain.
"Transduction of the Geomagnetic Field as Evidenced from Alpha-band Activity in the Human Brain" (eNeuro)
"Evidence for a Human Geomagnetic Sense" (Caltech) Read the rest
"Consciousness is what allows us to be aware of both our surroundings and our own inner state." In the first of a three part video series, "Kruzgesagt - In a Nutshell" examines "how unaware things come aware." Stay tuned for theories of consciousness that of course may be as much about philosophy as they are neuroscience.
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Scientists Lior Appelbaum and David Zada in Israel publish new proof that sleep serves to help our brains repair damage. Read the rest