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Chris Hadfield
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How psychedelics work: Fire the conductor, let the orchestra play

Michael Pollan explains what goes on during the mental fireworks of a psychedelic experience.

MICHAEL POLLAN: So how do these psychedelics work? Well, the honest answer is: We don't entirely know. But we know a few things. One is, they fit a certain receptor site -- the serotonin 52A receptor -- and they look a lot like serotonin, if you look at the molecular models of them. And in fact, LSD fits that receptor site even better than serotonin does, and it stays there longer, and that's why the LSD trip can last 12 hours.

What happens after that, we don't really know. It's an agonist to that receptor, so it increases its activity. And this, the neuroscientists say, "leads to a cascade of effects," which is shorthand for "don't really know what happens next." But one thing we do know, or we think we know, is that it appears that one particular brain network is deactivated or quieted, and that is the default mode network. This was discovered not very long ago by a researcher in England named Robin Carhart-Harris, who was dosing people with psilocybin and LSD and then sliding them into an MRI machine to take an FMRI, a Functional Magnetic Resonance Image. And the expectation, I think, was that people would see an excitation of many, many different networks in the brain. That's what the kind of mental firework foretold. But he was very surprised to discover that one particular network was down-regulated, and that was this default mode network.

So what is that? Well, it's a tightly linked set of structures connecting the prefrontal cortex to the posterior cingulate cortex to deeper, older centers of emotion and memory. It appears to be involved in things like self reflection, theory of mind (the ability to impute mental states to others), mental time travel (the ability to project forward in time and back) which is central to creating an identity, right? You don't have an identity without a memory. And the so-called autobiographical memory, the function by which we construct the story of who we are by taking the things that happen to us and folding them into that narrative, and that appears to take place in the posterior cingulate cortex.

So to the extent the ego can be said to have a location in the brain, it appears to be this, the default mode network. It's active when you're doing nothing, when your mind is wandering. It can be very self critical. It's where self talk takes place. And that goes quiet. And when that goes quiet, the brain is sort of, as one of the neuroscientists put it, let off the leash because those ego functions, that self idea, is a regulator of all mental activity. And the brain is a hierarchical system and the default mode network appears to be at the top; it's kind of the orchestra conductor or corporate executive. And you take that out of the picture, and suddenly you have this uprising from other parts of the brain, and you have networks that don't ordinarily communicate with one another suddenly striking up conversations. So you might have the visual cortex talking to the auditory system and suddenly you're seeing music. Or it becomes palpable. You can feel it or smell it -- synesthesia. So you have this temporary rewiring of the brain in the absence of the control of the regulator.

And this appears to have a beneficial effect in terms of jogging the brain out of bad patterns. Many of the disorders that psychedelics appear to treat well are manifestations of a stuck brain, a brain that is locked in loops, a mind that's telling itself destructive stories, like 'I can't get through the day without a cigarette. I'm unworthy of love. My work is shit.' These kinds of evidence of habitual thinking in a really negative loop are relieved. And it may be that an overactive ego is what punishes us. And that relief from that dictator is exactly what some people need to free themselves from habits -- mental habits and behavioral habits. That, at least, is the theory. I think there's a lot more we need to learn, but it's a very provocative theory. And then if we have a tool for behavior change, that's a huge deal. I mean, I know, having worked on food for many years, that changing people's food habits as adults is almost impossible. We are creatures of habit in many, many ways. And the older we get, the worse it gets. So if we have something that can kind of lubricate cognition, that can shake the snow globe, as another researcher put it, this might be very helpful in helping people escape these traps.

  • If your ego had a "location" in the brain, it would be the default mode network, where much of your self-critical mind chatter happens. Taking psychedelics down-regulates this brain network.
  • Researchers describe the effect of psychedelics as "letting the brain off its leash", or firing the conductor to let the orchestra play. Without the default mode network acting as a dictator, areas of the brain that don't normally interact meet, producing phenomena like hallucinations and synesthesia.
  • An overactive ego may be what punishes those of us plagued with anxiety, addiction and mental health disorders. Psychedelics can have a beneficial effect by temporarily killing the ego, jogging the brain out of negative thinking patterns.

A new hydrogel might be strong enough for knee replacements

Duke University researchers might have solved a half-century old problem.

Photo by Alexander Hassenstein/Getty Images
Technology & Innovation
  • Duke University researchers created a hydrogel that appears to be as strong and flexible as human cartilage.
  • The blend of three polymers provides enough flexibility and durability to mimic the knee.
  • The next step is to test this hydrogel in sheep; human use can take at least three years.
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Predicting PTSD symptoms becomes possible with a new test

An algorithm may allow doctors to assess PTSD candidates for early intervention after traumatic ER visits.

Image source: camillo jimenez/Unsplash
Technology & Innovation
  • 10-15% of people visiting emergency rooms eventually develop symptoms of long-lasting PTSD.
  • Early treatment is available but there's been no way to tell who needs it.
  • Using clinical data already being collected, machine learning can identify who's at risk.

The psychological scars a traumatic experience can leave behind may have a more profound effect on a person than the original traumatic experience. Long after an acute emergency is resolved, victims of post-traumatic stress disorder (PTSD) continue to suffer its consequences.

In the U.S. some 30 million patients are annually treated in emergency departments (EDs) for a range of traumatic injuries. Add to that urgent admissions to the ED with the onset of COVID-19 symptoms. Health experts predict that some 10 percent to 15 percent of these people will develop long-lasting PTSD within a year of the initial incident. While there are interventions that can help individuals avoid PTSD, there's been no reliable way to identify those most likely to need it.

That may now have changed. A multi-disciplinary team of researchers has developed a method for predicting who is most likely to develop PTSD after a traumatic emergency-room experience. Their study is published in the journal Nature Medicine.

70 data points and machine learning

nurse wrapping patient's arm

Image source: Creators Collective/Unsplash

Study lead author Katharina Schultebraucks of Columbia University's Department Vagelos College of Physicians and Surgeons says:

"For many trauma patients, the ED visit is often their sole contact with the health care system. The time immediately after a traumatic injury is a critical window for identifying people at risk for PTSD and arranging appropriate follow-up treatment. The earlier we can treat those at risk, the better the likely outcomes."

The new PTSD test uses machine learning and 70 clinical data points plus a clinical stress-level assessment to develop a PTSD score for an individual that identifies their risk of acquiring the condition.

Among the 70 data points are stress hormone levels, inflammatory signals, high blood pressure, and an anxiety-level assessment. Says Schultebraucks, "We selected measures that are routinely collected in the ED and logged in the electronic medical record, plus answers to a few short questions about the psychological stress response. The idea was to create a tool that would be universally available and would add little burden to ED personnel."

Researchers used data from adult trauma survivors in Atlanta, Georgia (377 individuals) and New York City (221 individuals) to test their system.

Of this cohort, 90 percent of those predicted to be at high risk developed long-lasting PTSD symptoms within a year of the initial traumatic event — just 5 percent of people who never developed PTSD symptoms had been erroneously identified as being at risk.

On the other side of the coin, 29 percent of individuals were 'false negatives," tagged by the algorithm as not being at risk of PTSD, but then developing symptoms.

Going forward

person leaning their head on another's shoulder

Image source: Külli Kittus/Unsplash

Schultebraucks looks forward to more testing as the researchers continue to refine their algorithm and to instill confidence in the approach among ED clinicians: "Because previous models for predicting PTSD risk have not been validated in independent samples like our model, they haven't been adopted in clinical practice." She expects that, "Testing and validation of our model in larger samples will be necessary for the algorithm to be ready-to-use in the general population."

"Currently only 7% of level-1 trauma centers routinely screen for PTSD," notes Schultebraucks. "We hope that the algorithm will provide ED clinicians with a rapid, automatic readout that they could use for discharge planning and the prevention of PTSD." She envisions the algorithm being implemented in the future as a feature of electronic medical records.

The researchers also plan to test their algorithm at predicting PTSD in people whose traumatic experiences come in the form of health events such as heart attacks and strokes, as opposed to visits to the emergency department.

Hints of the 4th dimension have been detected by physicists

What would it be like to experience the 4th dimension?

Two different experiments show hints of a 4th spatial dimension. Credit: Zilberberg Group / ETH Zürich
Technology & Innovation

Physicists have understood at least theoretically, that there may be higher dimensions, besides our normal three. The first clue came in 1905 when Einstein developed his theory of special relativity. Of course, by dimensions we’re talking about length, width, and height. Generally speaking, when we talk about a fourth dimension, it’s considered space-time. But here, physicists mean a spatial dimension beyond the normal three, not a parallel universe, as such dimensions are mistaken for in popular sci-fi shows.

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How often do vaccine trials hit paydirt?

Vaccines find more success in development than any other kind of drug, but have been relatively neglected in recent decades.

Pedro Vilela/Getty Images
Surprising Science

Vaccines are more likely to get through clinical trials than any other type of drug — but have been given relatively little pharmaceutical industry support during the last two decades, according to a new study by MIT scholars.

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