Archive for August, 2018

Aug 28 2018

New Neuron Type Discovered in Humans

Published by under Neuroscience

Human brains are perhaps the most complex known structures in the universe (known to us), and while we have discovered a tremendous amount of information about them, there is still much to discover. Recently neuroscientists have discovered a new neuron (brain cell) type, so far discovered only in humans – the rosehip neuron.

Neurons are highly specialized cells in the brain and other parts of the nervous system. They have a general structure that includes a soma, which is the cell body, and projections called dendrites and axons. Generally dendrites are short and numerous and receive electrochemical signals from other neurons. Axons tend to be long and few (often only one) and carry signals away from the soma to other cells. Neurons are therefore a basic component of the nervous system circuit.

Neurons also tend to be either excitatory (increasing the firing of the neuron they synapse on) or inhibitory (decreasing the firing of the neuron they synapse on). Different neuron types are identified by their general shape and their neurochemistry – are they excitatory or inhibitory and what neurotransmitter do they use. The most common neuron type in the cortex is the pyramidal cell, which has a pyramid-shaped soma, a dense bush of dendrites, and one long axon. Pyramidal cells are excitatory and tend to use glutamate as their neurotransmitter.

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Aug 27 2018

Programmable Matter

Published by under Technology

I have been reading a lot recently about material science and one thing that has struck me is that we still mostly build our civilization out of traditional materials – concrete, steel, wood, ceramics, paper, leather, and plant fibers, for example.  Perhaps the most common modern material is plastic. Look around your home – other than various types of plastic, most of the stuff will be made out of materials we have been using for hundreds or even thousands of years. The notable exception is electronics which often use more recently discovered rare earths.

This is not to say that we don’t have a lot of high-tech new materials, they are just mostly too expensive to find in the average home in abundance, so we sill use a lot of wood, metal, rock, and natural fibers. This is why material scientists are always looking for the next plastic, a truly modern material that is inexpensive, easily manufactured, with properties that make it ideal for many applications.  Perhaps carbon nanofibers (or nanomaterials more broadly) will be that material, and it has tremendous potential, but we’re not there yet.

Scientists report on a new type of material that I don’t think we will be building our homes out of anytime soon, but does potentially open the door to new applications – programmable matter. The material is liquid crystal elastomers (LCEs), which they are able to program into a specific shape using specific wavelengths of light. The material can then oscillate between two different shapes at different temperatures:

To solve this, the researchers installed a light-activated trigger to LCE networks that can set a desired molecular alignment in advance by exposing the object to particular wavelengths of light. The trigger then remains inactive until exposed to the corresponding heat stimuli. For example, a hand-folded origami swan programmed in this fashion will remain folded at room temperature. When heated to 200 degrees Fahrenheit, however, the swan relaxes into a flat sheet. Later, as it cools back to room temperature, it will gradually regain its pre-programmed swan shape.

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Aug 24 2018

Transitional Turtles

Facts matter. While that should be obvious, and skeptics have been pushing that world view for decades, it seems that the central importance of objective facts to both democracy and any intellectual pursuit might be more apparent recently. You tend to notice the importance of something more when you lose it, and the recently popular political tactics of “fake news,” “alternative facts,” and “truth isn’t truth,” have certainly focused attention.

But attacking objective reality in order to promote an ideology or preferred belief system is nothing new, even if it has become more obvious and odorous. Sure, everyone has their narrative and philosophy by which they organize their understanding of reality. This narrative influences how we perceive reality, which facts we accept and remember, and which ones we find reasons to dismiss. The question is a matter of degree – how much do we allow facts to influence our beliefs vs our beliefs to influence the perception of facts?

The main virtue of science is that it systematically puts facts above beliefs, and constantly hits beliefs over the head with facts. Other contexts, not so much. And there are times when ideology becomes so dominant that facts become irrelevant. Belief in creationism is one of those contexts – the creationist culture traffics almost entirely in “alternative facts.” People consuming the creationist literature and culture are effectively being gaslighted – presented with an alternate reality as if it is true. There are countless examples of this, but one of my favorites is the creationist claim that there are no transitional fossils. For example:

Contrary to the impression given by evolutionary books and magazines, evidence of transition is rare and limited to variation within kinds. Sensationalistic claims of ‘evolutionary ancestors’ make it into the newspapers; retractions and more sober evaluations of new fossils do not.

Add some outdated or out-of-context quotes, and a complete misinterpretation of evolutionary theory and the fossil record, and you create an alternate reality. The real reality, as I have discussed many times before, is that there are tons of transitional fossils, supporting the fact that life on earth has changed over time through a pattern of common descent. Here is one more to throw onto the pile – the evolution of the turtle.

Turtles are reptiles, but they have some unique features as a group. They have a beaky mouth with no teeth, a top shell made from fused ribs and vertebra, and a bottom shell. They also lack holes above their eyes used for the insertion of jaw muscles. So – common descent predicts that turtles must be related to other reptiles, which means we should find fossils of turtle ancestors that have some turtle features but not all – a transitional turtle.

But keep in mind, evolution is not a ladder but a bush. There will not be a straight line from the last common ancestor between turtles and other reptiles and modern turtles. There will be a bush of diversity, with different features appearing at different times, and even disappearing, and individual groups with relatively primitive features surviving late in the fossil record. As scientists discover a puzzle piece here and there, a confusing picture will emerge in terms of the specific details of evolutionary history. But the big picture will be clear – a transition over evolutionary time from the common ancestor to modern turtles.

So – in 2008 scientists discovered several turtle fossils 220 million years old that only have a shell on the bottom, not the top, and a beaky mouth. They had some but not all of the turtle unique features. Then, in 2015, they discovered a 240 million year old turtle (Pappochelys rosinae) with just the beginnings of a bottom shell. And now, in 2018, scientists report the finding of an older turtle ancestor, 230 million years old (Eorhynchochelys sinensis), that has no shell but still has the beaky mouth. The ribs are starting to expand into the upper shell or carapace, but only partly. These latter two specimens also still have the skull holes of other reptiles, showing their relationship to other modern reptiles.

The presence of the beaky jaw is early for the turtle line, showing that some later turtle species may have lost the beak. We are looking at a diverse group, only one line of which lead to modern turtles.

These fossils do not represent a straight line, as I said, but they show the existence of turtle relatives over evolutionary time progressively acquiring the classic turtle features. These are stunning transitional fossils that absolutely confirm the predictions of the common descent part of evolutionary theory. The fiction that there are few or no transitional fossils is demonstrable nonsense, but that will not stop creationists in their alternative universe from continuing to make this false claim.

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Aug 23 2018

The Superconductivity Hubbub

A recent paper, published to arXiv, claims to have a method for making a superconducting material at ambient temperatures and pressures. The authors, Dev Kumar Thapa, Anshu Pandey, are from the Indian Institute of Science, and have garnered a lot of attention for their paper. However, recently there was published another paper on arXiv by Brian Skinner from MIT. Skinner noticed a suspicious pattern of repeating noise in two sets of data from the Thapa-Pandey paper. This could be a signature of fabricated data.

Scientific American has a good summary of the whole story, but that’s the quickie version. Skinner did not make any accusations, just published his analysis with a question to the original authors to explain the repeating pattern. Thapa and Pandey have responded only to say their results are being replicated. The rest of the physics community is not satisfied with this response, and are calling for them to send their material to outside labs for completely independent testing.

Another wrinkle to the story is that Pratap Raychaudhuri, a physicist at the Tata Institute of Fundamental Research in India, floated a hypothesis that perhaps the noise is not noise, but a signal resulting from “the natural rotation of particles within a magnetic field.” If that’s the case, then the pattern should replicate. So we are still left with the need to independently replicate the experiments.

The stakes here are high because so-called room temperature superconductivity is one of the holy grails of material science. Superconductivity means that electricity can flow through the medium without resistance, and therefore with no loss of power. A room temperature superconductor could therefore transform electronics, the power grid, and anything using super powerful magnets (like MagLev trains and MRI scans).

The current dominant theory as to how superconductivity works in certain materials two electron can come together to form what’s called a Cooper pair. This pair of electrons can then travel long distances in the material without resistance. However, Cooper pains can only exist at very low temperatures. So the quest has been to find materials that will allow Cooper pairs to exist at higher and higher temperatures.

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Aug 21 2018

Teleology and Conspiracy Thinking

I hate the headline of the Independent article about this new study – “Scientists discover the reason people believe in conspiracy theories.” No, they didn’t. What they potentially found was an additional factor that predicts conspiracy thinking, meaning that it correlates with it.  A much better headline would be – “Scientists find that believing in final causes correlates with conspiratorial thinking,” or something like that.

I understand the need to make headlines eye-catching, but you can do that without misrepresenting the science. The body of the article itself, while it does a decent job of explaining teleology, also misrepresents the implications of the study in a typical way – it fails to put it into the context of existing research.

Mainstream science reporting often follows a typical narrative – we essentially knew nothing, then scientists made this breakthrough discovery, and now we fully understand “the” cause of whatever.

The real scientific narrative is often quite different – we know something about this complex phenomenon, but there is still much that is not known, and now scientists have added one more piece to the puzzle. This is actually, in my opinion, a far more compelling narrative, but you have to tell the whole story of the scientific question, not just the one study.

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Aug 20 2018

Bullshit Research

Published by under Neuroscience

I am not talking about dubious research, but rather research into the phenomenon of bullshit (BS) itself. BS has an operational definition or paradigm within psychological research – it is the extent to which subject rate as highly meaningful statements which are crafted to be vacuous, unconcerned about the truth, and lacking in any unambiguous meaning. Think just about anything Deepak Chopra says. Such statements are also called “pseudoprofound” when they are BS and try to sound profound or philosophical.

“Intuition expresses visible choices.”

“Meditation makes the entire nervous system go into a field of coherence.”

“Experiential truth belongs to the expansion of abstract beauty.”

One of those quotes is from Chopra, the other two from the Chopra simulator.

A recent study extends the research on BS a bit, but first gives a brief summary of what existing research has found:

Recently, some psychological research has focused on individual differences in the extent to which people perceive bullshit as meaningful. These studies have shown that people who rate bullshit sentences as highly meaningful have more religious and supernatural beliefs, are less reflective, intelligent, and numerate, more prone to ontological confusions and conspiratorial ideation, endorse free market policies more, and have more favorable views of Republican presidential candidates in US politics. The aim of this study is to develop the academic field of bullshit further.

Given the relatively few number of references in the paper, it’s probably best to consider these conclusions preliminary. While many of these features make sense, like being prone to believing in the paranormal and conspiracies, I would want to see some independent replication before making any firm conclusion.

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Aug 17 2018

Death by Herbalism

“It’s dressed-up quackery isn’t it?” magistrate Daniel Reiss said.

“That’s one view, your honour,” the prosecutor replied.

That is a good summary of pretty much all alternative medicine. Practitioners have gotten very good at dressing it up, enough to even fool academics who aren’t paying close attention. But in the end, it’s all quackery.

The quote above refers to a recent case of a Sydney Chinese herbalist, Yun Sen Luo, who was arrested and charged with manslaughter in the death of 56 year old client he was treating. He advised the diabetic woman to go off her diabetes medication, ultimately resulting in her death. The charge is gross negligence.

The success of alternative medicine over the last few decades has been in convincing the world that what they offer is a genuine alternative to real medicine. They have rebranded it as complementary, and the integrative, but it’s all the same – using unproven, fanciful, or even disproven treatments instead of real medicine. They justify the substitution by appealing to nature, distracting with hand-waving pseudoscientific jargon, appealing to antiquity, or straight-up lying. In the extreme they weave complex conspiracy theories about the medical establishment to scare people away from real medicine.

This case is just one example, but it’s not atypical. The core problem is that we have a practitioner who is practicing medicine without a license, and without the requisite medical knowledge, training, and experience. The con is that if you simply call what you do “alternative” you can get away with it (until you kill someone – and even then, sometimes).

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Aug 16 2018

Drug-Induced Near Death Experience

There is no question that people occasionally have strange experiences, sometimes very strange. There is a tendency to interpret such experiences as external, reflecting something happening in the world, rather than internal, reflecting something happening in our brains.

Neuroscience, however, has provided us a powerful tool for understanding some of these experiences. They are a window into how our brains construct our experience of reality, and what we experience when that process breaks down or is altered by drugs, trauma, electrical stimulation, oxygen deprivation, or other stressors.

A recent study looking at the hallucinogen DMT (N,N-Dimethyltryptamine) adds an interesting insight into our collective knowledge of these altered states of consciousness. The researchers studied 13 healthy volunteers, who were given placebo, and then in a separate session a week later DMT, and extensively questioned about their experiences. The researchers specifically wanted to test the possibility that a DMT-induced hallucination would be similar to reported near-death experiences.

In short they found that the DMT experiences were extremely similar to near-death experiences (NDE), but let’s look at the details.

They gave the subjects an established NDE scale, which assesses for 16 features reported by those who experience an NDE. A score of 7 or higher is considered to be a genuine NDE. All 13 subjects scored 7 or higher on this scale when given DMT. Ten of the 16 features were statistically more likely during DMT than placebo. And the total scores were similar to a historical control group of reported NDEs. So again – DMT produced an experience that was very similar to reported NDEs.

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Aug 14 2018

Phantom and Prosthetic Limbs

One of the goals of prosthetic technology (replacement limbs for amputees) is to make the user feel like the prosthetic is part of their body – that they own it and control it (called embodiment). It is more difficult to control a limb that does not feel like part of your body, and users need to visually look at a prosthetic to see where it is. This is true of passive prosthetics as well as robotic ones.

I have written previously about researcher attempts to provide sensory feedback to robotic limbs. A new study adds to this growing knowledge about how embodiment works and how to hack the brain to make it happen.

The key to embodiment seems to be multimodal sensory feedback. If the brain sees and feels the same action, that is all that is necessary for the “ownership module” to kick in – that part of the brain that makes you feel as if you own the various parts of your body. The most primitive manifestation of this is the rubber hand illusion. If you have a rubber hand protruding from your sleeve as if it is your real hand, and you see the rubber hand touched while your real hand is touched (and therefore you feel it), this will create the temporary illusion that the rubber hand is your real hand. Obviously this is not practical for everyday use of a prosthetic.

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Aug 13 2018

Dunning Kruger Effect and Anti-Vaccine Attitudes

One of the persistent themes of this blog is that expertise matters. This is not to say the experts are always right (sometimes they disagree with each-other), and there is also a range of expertise, and different kinds of experts can have different biases and blind spots. But all things considered, someone who has formal expertise on a specific topic is likely to know much more about that topic than someone who has read about it on the internet.

Further, most people underestimate the amount of knowledge that exists on a topic, and therefore the vast gulf of knowledge that exists between them and the experts. In fact, the more someone knows about a topic the more they understand how much is known, and the more humble they tend to be with respect to their own knowledge. The flip side of this – people who know little tend to overestimate their relative knowledge – is an established psychological phenomenon known as the Dunning-Kruger effect.

Operationally Dunning and Kruger found in their study that the lower someone performed on a test of knowledge, the greater the gap between their perceived knowledge and performance and their actual performance. At around the 80th percentile and above, people tend to underestimate their relative knowledge. Below that point they tend to increasingly overestimate it, and everyone thinks they are above 50%.

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