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The Exact Number of Computers Needed to Simulate the Human Brain is Almost Inconceivable

Yes, conceivably. And if/when we achieve the levels of technology necessary for simulation, the universe will become our playground.

David Eagleman: The big picture in modern neuroscience is that you are the sum total of all the pieces and parts of your brain. It’s a vastly complicated network of neurons, almost 100 billion neurons, each of which has 10,000 connections to its neighbors. So we’re talking a thousand trillion neurons. It’s a system of such complexity that it bankrupts our language. But, fundamentally it’s only three pounds and we’ve got it cornered and it’s right there and it’s a physical system. 

The computational hypothesis of brain function suggests that the physical wetware isn’t the stuff that matters. It’s what are the algorithms that are running on top of the wetware. In other words: What is the brain actually doing? What’s it implementing software-wise that matters? Hypothetically we should be able to take the physical stuff of the brain and reproduce what it’s doing. In other words, reproduce its software on other substrates. So we could take your brain and reproduce it out of beer cans and tennis balls and it would still run just fine. And if we said hey, "How are you feeling in there?" This beer can/tennis ball machine would say "Oh, I’m feeling fine. It’s a little cold, whatever."

It’s also hypothetically a possibility that we could copy your brain and reproduce it in silica, which means on a computer at zeroes and ones, actually run the simulation of your brain. The challenges of reproducing a brain can’t be underestimated. It would take something like a zettabyte of computational capacity to run a simulation of a human brain. And that is the entire computational capacity of our planet right now.

There’s a lot of debate about whether we’ll get to a simulation of the human brain in 50 years or 500 years, but those would probably be the bounds. It’s going to happen somewhere in there. It opens up the whole universe for us because, you know, these meat puppets that we come to the table with aren’t any good for interstellar travel. But if we could, you know, put you on a flash drive or whatever the equivalent of that is a century from now and launch you into outer space and your consciousness could be there, that could get us to other solar systems and other galaxies. We will really be entering an era of post-humanism or trans-humanism at that point.

Now because it seems like a possibility that we could download and simulate — not in our lifetimes, but soon — that has opened up a question from many people, which is how would we know if we’re already living in a simulation? Maybe we are the products of a civilization that came a billion years before us and we’re already living in The Matrix. And this is a position that philosophers are taking seriously.

In fact, Rene Descartes, the French philosopher, had a version of this when he asked how would I know if I’m just a brain in a vat and I’m being stimulated by scientists to make me think that I’m hearing, and seeing, and feeling and so on. And his conclusion, like others that have followed him, is that you actually can’t know. Really it would be almost impossible to know because all of this feels real to you. And so Descartes’ solution to this was to say you know, I might not ever be able to really know, but there’s somebody who’s asking the question and therefore I exist. There’s some "I" at the center of all this that’s thinking about this. And so that was a solution for him but it doesn’t solve the bigger question of how would we know if we’re already in the simulation and we may well be.

 

David Eagleman is the host of The Brain on PBS, as well as the author of the book of the same name. In this video, he tackles several fascinating subjects concerning your brain. If the brain is merely the hardware, could we emulate its software somewhere else? Could we simulate your version of consciousness on a man-made computer? Yes, says Eagleman, although it's not going to happen anytime soon. But when it does, and we're able to move beyond our flesh, deep space travel goes from being impossible to possible.

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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