Video: Optogenitics is Nature's Method of the Year

Long-time readers will remember a guest post by my friend Hugh Pastoll about optogenetics. I didn't catch it at the time, but Nature declared optogentics its 'Method of the Year' for 2010. An explanatory video below (direct link):



(Video found via Ed Yong).

Guest post: Neuroscience through Optogenetics

A guest post from Hugh Pastoll, my good friend and long-time intellectual sparring partner. Hugh's introduction follows, and then his article. 

Michael and I met while studying PPE at the University of Cape Town. Like him, I’ve completely changed direction since then and am now doing a PhD in Computational Neuroscience at the University of Edinburgh.

As part of my postgraduate studies I’ve been fortunate enough to use an exciting new and truly revolutionary technology known as optogenetics. Optogenetics permits fine-grained control of brain activity with light, dramatically increasing the range of interesting experiments we can do. Since it is likely that it will soon become the technology of choice for investigating brain function, Michael has invited me to give a short primer on optogenetics in general and channelrhodopsins in particular.

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As a computational neuroscientist I am ultimately motivated by understanding how neural activity determines behavior. Frustratingly, for a long time even attempting to answer this sort of question has been pretty much impossible. This has been a major barrier to understanding how brains work… until recently.

To see why we have been stuck, imagine that I want to test the hypothesis that some pattern of neural activity causes a particular behavior. In order to test this hypothesis I’d need to conduct an experiment where I manipulated the animal’s neural activity and observed its behavior (simply noticing that the pattern and behavior both occur when I give the animal a stimulus only establishes correlation, not causality). Now, we’ve been able to control neural activity for quite a while - the sticking point was that we weren’t able to do it with the millisecond fidelity, neuron type specificity and sub-cubic-millimeter spatial precision we need to test most of our important hypotheses.

To illustrate, say I hypothesize that synchronized firing of excitatory neurons in the subthalamic nucleus at 20 Hz is responsible for akinesia (deficit in movement initiation). Testing this typical hypothesis would require me to synchronize only sub-thalamic excitatory neurons without changing their overall firing rate or affecting activity in nearby brain areas while the animal is behaving. I can’t think of any way we would have to able to accomplish this with drugs, electrical stimulation or any other standard technique for controlling neural activity.

Thanks to the recent development of optogenetics, though, such control is not only possible, but relatively easy. I can’t really exaggerate how completely cool this is - it is going to allow the field of computational neuroscience to hit its stride and start delivering the kinds of insights we need to understand what’s really going on in the brain.

So how does optogenetics work? To understand this, you need to know how ion channels control action potentials in neurons. Very briefly, ion channels are specialized protein channels that, when open, conduct ions (charged molecules) across cell membranes. The brief rise in membrane potential during an action potential is due to positive ions rapidly moving from the outside to the inside of a cell. Channelrhodopsins are ion channels that open when you shine blue light on them! This means we can force the membrane potential of a neuron to become more positive and generate an action potential. This is the ‘opto’ part of optogenetics.

Channelrhodopsin-2 (ChR2 - the most useful original kind) was first described in a species of green algae called Chlamydomonas reinhardtii in 2002 and found to work in mammalian neurons. Since then, genetic engineers have found that strategically mutating different amino acids changes the kinetics of the channel (how quickly it opens and closes). So, now there are different versions that allow different types of control. The fastest type (named ChETA ) opens in about 2 milliseconds and closes after about 5ms; fast enough to pulse blue light at 200 Hz and have the neuron fire at virtually every pulse. Another type (ChR2-C128S) usually takes minutes to close but shuts off very quickly if you shine green light on it. This means it can act as a kind of bi-stable on-off neuron switch. With such fine-grained control we can manipulate neuron spiking in pretty much any way we like.

Now for the ‘genetic’ part of optogenetics: Different kinds of neurons make different kinds of proteins. Since channelrhodopsin is a protein, we can use the cellular machinery that determines whether a protein is expressed in a neuron to restrict channelrhodopsin expression to a specific type of neuron.
This allows us to make one type of neuron in an area fire, without directly disrupting the normal activity of other types in the same area, giving us the neuron sub-type specificity we need for our experiments.

Furthermore, we can restrict channelrhodopsin expression to a very small area of the brain. Since we know that genes code for proteins, if only cells in one area have the channelrhodopsin gene only those cells in that area will respond to light. We can accomplish this by infecting a group of neurons with a non-replicating retrovirus that carries the channelrhodopsin gene. This gene will then be integrated into the genome of the infected neurons and expressed, introducing channelrhodopsins with spatial specificity.

However, although this combination of temporal, neuron sub-type and spatial specificity will enable a wide range of experiments, even more is possible. Another class of membrane proteins, known as halorhodopsins, have the opposite effect to channelrhodopsins. Halorhodopsins are not passive channels - they actively pump negative ions into a cell when illuminated with yellow light, making it more negative and stopping it from firing. Additionally, proteins that pump positive hydrogen ions out of cells to make their interior more negative have been described recently. These proteins are more effective than some types of halorhodopsins at preventing neurons from firing and different types respond to a different light colors – allowing researchers to pick colors that don't interfere with other rhodopsins the animal may also be expressing.

With such powerful optogenetic tools at our disposal we can imagine performing complex experiments, orchestrating neural activity with an array of different color intra-cranial LEDs. Although such experiments will be technically challenging, at the moment it feels like we are only limited by our imagination.

Selected references:
Nagel, G. et al. (2002) "Channelrhodopsin-2, a directly light-gated cation-selective membrane channel," PNAS, doi:10.1073/pnas.193619210.
Boyden, E. et al. (2005) "Millisecond-timescale genetically targeted optical control of neural activity," Nature Neuroscience, doi:10.1038/nn1525
Berndt, A. et al. (2008) "Bi-stable neural state switches," Nature Neuroscience, doi:10.1038/nn.2247
Gradinaru, V. et al. (2009) "Optical deconstruction of Parkinsonian neural circuitry," Science, doi:10.1126/science.1167093
Chow, B. et al. (2010) "High-performance genetically targetable optical neural silencing by light-driven proton pumps," Nature, doi:10.1038/nature08652
Gunaydin, L. et al. (2010) "Ultrafast optogenetic control," Nature Neuroscience, doi:10.1038/nn.2495

Encephalon #76

The 76th edition of Encephalon is out over at Neuroskeptic. Posts to check out: The Neurocritic asks whether neuroscience tells us torture doesn't work, Neurophilosophy on how vegetative and minimally conscious pantiens can learn, and Crime and Consequences on the silliness of neurolaw.

Lazy Linking

"The Durban Boredom Festival"

• So a friend, my fiancée and I went to a local psychic fair recently. I was planning to write about it... but it was a horrid experience, so I never got round it it. Luckily, Angela (the aforementioned fiancée) has written a great account of what went down at the fair and trust me, short as it is, her post contains everything you'll possibly want to know about it. Overall conclusion: way too much incense, rampant woo, boring as hell, complete ripoff.

"The latest verdict on using brain imaging for lie detection"

• BPS Research Digest reports on using fMRI et. al. to spot lying. Short version: it doesn't work. (At least not yet).

"Offensive Play: How different are dogfighting and football?"

• Malcolm Gladwell's latest New Yorker piece in which he compares the morality of dogfighting - almost universally reviled - with that of American football. It turns out that, like with boxing, a football career often results in an Alzheimers-like condition called chronic traumatic encephalopathy. Amazingly, new resarch using accelerometers has revealed players regularly suffer hits to the head of up to 90gs. Not surprisingly this is a Bad Thing that does severe damage to the brain over the long run. Gladwell suggests this may make football morally comparable to dogfighting: the injuries and suffering of the players are an inherent and ineradicable feature of the game.
• As a big rugby fan I couldn't help wondering what the situation is like for my favorite Saturday diversion. Do rugby players also suffer as much damage? Obviously, only research could settle the issue (and some may already exist, I don't know). From the armchair, it's difficult to tell: on the one hand, there are many fewer hits to the head in rugby but, on the other, the players don't wear helmets or much protective gear. My (rather bland) guess, for the little that's worth, is that brain trauma is not as common in rugby as it is in football or boxing, but significantly more prevalent than in the general populace. I'm not going to stop watching though, that's for sure.

"Psychology: A Reality Check" (paywall, I think)

• A great Nature editorial calling for evidence-based clinical psychology in the United States. I'd say it's also much needed elsewhere, the training of psychologists is often criminally devoid of science or even critical thinking. 
• "Clinical psychology at least has its roots in experimentation, but it is drifting away from science. Concerns about cost–benefit issues are growing, especially in the United States. According to a damning report [pdf] published last week an alarmingly high proportion of practitioners consider scientific evidence to be less important than their personal — that is, subjective — clinical experience."
  
• "The irony is that, during the past 20 years, science has made great strides in directions that could support clinical psychology — in neuroimaging, for example, as well as molecular and behavioural genetics, and cognitive neuroscience. Numerous psychological interventions have been proved to be both effective and relatively cheap. Yet many psychologists continue to use unproven therapies that have no clear outcome measures — including, in extreme cases, such highly suspect regimens as 'dolphin-assisted therapy'."

"How We Lost Our Diversity"

• Interesting piece by the excellent Ann Gibbons about new research on the causes of human genetic homogeneity (relative to other primates).
• "Modern humans are a lot alike - at least at the genetic level - compared with other primates. If you compare any two people from far-flung corners of the globe, their genomes will be much more similar than those of any pair of chimpanzees, gorillas, or other apes from different populations. Now, evolutionary geneticists have shown that our ancestors lost much of their genetic diversity in two dramatic bottlenecks that sharply squeezed down the population of modern humans as they moved out of Africa between 60,000 and 50,000 years ago."
• See also: John Hawks' fairly critical analysis of the same study.

"Analogies to apes lead us on the wrong track"

• Razib Khan over at Gene Expression on how Ardi drives home the message that drawing analogies between humans and the other extant apes can be misleading. Six million years is a long time, and there's no reason to think our common ancestor with the chimps and bonobos was particularly chimp-like. Somewhat counterintuitively, the opposite might even be true.

"Dear Penn and Teller: Bullshit!"

• I've only recently remembered that I have Season 6 of Penn & Teller's Bullshit so I'm only watching it now. And like Massimo Pigliucci in the above post, I just hated their episode (6-06) on environmentalism. Libertarians so obviously have blinkers on when it comes to global warming that it positively amazes me that they're not more self-critical. It also reminds us all, of course, that being vigilant about our own biases is important.  

"Islam: A Shifting Focus"

• One of the most widespread misconceptions about Islam is that most of its faithful are Arabs. In actual fact, Asian Muslims vastly outnumber Muslims from other parts of the world, making up 61.9% of the global number of 1.57 billion believers.
• "A new survey of the world’s Muslim population, by the Pew Research Center based in Washington, DC, will help those who are keen to break that link [i.e. the perception that most Muslims are Arabs]. It estimates the total number of Muslims in the world at 1.57 billion, or about 23% of a global population of 6.8 billion. Almost two-thirds of Muslims live in Asia, with Indonesia providing the biggest contingent (203m), followed by Pakistan (174m) and India (160m)."
• "Perhaps more surprising will be the finding that the European country with the highest Muslim population is not France or Germany, but Russia, where 16.5m adherents of Islam make up nearly 12% of the total national population. Compared with other surveys, the report gives a lowish estimate for the number of Muslims in France (3.6m), as it does for the United States (2.5m); in both those countries, secular principles make it impossible to ask religious questions on a census."

Carnival of Evolution 16

• A superb edition of the Carnival of Evolution - there are many worthwhile posts to check out. My pieces on foxes and on chameleons were featured. 

New Scientist's Top 10 Brain Articles of 2008

New Scientist magazine has a interesting list of their Top 10 Brain Articles of 2008. My picks:

• "Brains apart: The real difference between the sexes" by Hannah Hoag,
  
• "How primate porn reveals what we really want" by Helen Phillips, and
  
• "The subconscious mind: Your unsung hero" by Kate Douglas

Goodbye HM

Patient HM, one of the most important subjects in neuroscience research for over 50 years, has passed away.

Mouse Party

Mouse Party is an awesome little animation that teaches the basics of the neuroscience of addiction. The animation is part of a set of educational resources on the science of addiction, which is itself one part of the broader Learn.Genetics site. (There is also Teach.Genetics website, but it's still in beta). By the way, the Inside a Cell animation, part of the Amazing Cells suite of materials, is pretty cool too.

All these resources were created by the NIH-funded Genetic Science Learning Center at the University of Utah.

(Hat tip: Hugh).

Neuroscience denial is the new wedge

New Scientist magazine has a great article out on how the Discovery Institute, the Seattle based "think"-tank infamous for promoting intelligent design creationism, has a new wedge: neuroscience. While the Institute has long focused on evolution, its overarching aim and its real ideology has always been to overturn materialism, as the opening paragraphs of the Wedge document (pdf) made clear:

The proposition that human beings are created in the image of God is one of the bedrock principles on which Western civilization was built. Its influence can be detected in most, if not all, of the West’s greatest achievements...

Yet a little over a century ago, this cardinal idea came under wholesale attack by intellectuals drawing on the discoveries of modern science. Debunking the traditional conceptions of both God and man, thinkers such as Charles Darwin, Karl Marx, and Sigmund Freud portrayed humans not as moral and spiritual beings, but as animals or machines who inhabited a universe ruled by purely impersonal forces and whose behavior and very thoughts were dictated by the unbending forces of biology, chemistry, and environment. This materialistic conception of reality eventually infected virtually every area of our culture, from politics and economics to literature and art.

Perhaps as a result of a string of recent setbacks on the evolution front (like Kitzmiller vs. Dover), it seems the Institute is switching tactics and is trying to resuscitate Cartesian dualism. The 17th century French philosopher and mathematician Rene Descartes, you will remember, argued in the Meditations on First Philosophy and elsewhere that there were two kinds of substances: matter, which made up the body, and a nonmaterial soul which accounted for the mind and consciousness. (The mind and the body were supposed to interact via the pineal gland). It goes without saying that there are innumerable problems with this view and long before the advent of modern neuroscience numerous philosophers contended dualism is untenable. Indeed, as far as I can see, dualism is dead in modern professional philosophy. Of course, neurology and neuroscience have closed the case on dualism: the evidence is now overwhelming that the mind is what the brain does (in Pinker's felicitous phrase).

The problem for the religious, though, is that materialism is manifestly incompatible with traditional religious notions like personal immortality and a divinely ordered universe. (See Richards, 2000 for example). A successful science of the mind and brain, therefore, indirectly undermines religion by reducing the area of the unexplained, thus eliminating gaps where Gods might otherwise reside. It's as if neuroscientists are saying of skyhooks, like LaPlace is reputed to have done: 'I have no need for that hypothesis'. In the perverse logic of the intelligent design movement, therefore, dualism must be resurrected and defended from attack.

While I have no doubt Discovery Institute fools will fail (once more), our understanding of how the mind and brain work is far less complete than our understanding of evolution and is thus more open to attack. Vigilance is necessary: neuroscience denial is the new wedge and we should parry the thin edge.

(See also: Steven Novella's response to the New Scientist piece).

Encephalon #55

The 55th edition of Encephalon is out at Neuroscientifically Challenged. Highlights: Neuroanthropology on exaggerated claims of neuroplasticity on All in the Mind; Cognitive Daily on teenage sexual behavior and sex education; Sharp Brains on some of the psychological effects of video games; and The Mouse Trap on the 8 basic adaptive problems animals face.

Encephalon #53: Out of Africa

Welcome to the 53rd edition of Encephalon, the premier blog carnival for cognitive science, psychology, neuroscience and other mindy / brainy -ology's. If I'm not mistaken, this is the very first Encephalon to be hosted from Africa. (Yay for globalization!). Cue a gratuitous stereotype-reinforcing picture of Africa:


With that safely out of the way, we can proceed with the fun...

First out of the blocks is Mo the Neurophilosoph[er] with the longest blog post I've ever seen (it's very good too). The post is a detailed history of the renowned neurosurgeon Wilder Penfield and the invention of the Montreal Procedure.

Doctor Spurt of Effortless Incitement is recently big into chimps, he's got two great posts on our closest cousins. The first is on the surprising finding that chimps use self-distraction to counteract impulsivity and the second covers a cool PNAS paper on stress reduction via consolation.

Scicurious of Neurotic Physiology submitted a post related to my own research interests (bless her heart): she has the lowdown on a PLoS ONE paper that found culture influences how we process faces.

Chris of Ouroboros (as in the mythical serpent eating its own tail) has a post sure to get Aubrey de Grey excited: he covers a paper that found a way of counteracting age-related decline in neurological function. (In mice, alas).

Vaughn of Mind Hacks visited London's red light district recently. For research purposes. No, really.

Neuronism is a new blog that looks promising (check it out!). The author submitted two posts: the first covers the widely-reported Nature Neuroscience paper about predicting hits or misses in basketball from 'thin slices' and the second is about grid cells.

David of deadpopstar has a really odd name for his blog; which certainly doesn't explain why he knows a lot about Cochlear implants. (That, I suspect, may have something to do with his Ph.d...). Anyway, his post is about a couple of papers on ways of improving the implants.

Jake of Pure Pedantry is a veritable research blogging machine. (I'm not jealous of his work ethic or anything...). His latest piece is on an example of encoding diversity, namely, orthogonal encoding. I'm not at all sure I understand what's going on, but it looks pretty darn important.

Next is posts by two of the Neuroanthropology authors, Greg and Paul. The former disputes the notion that the difference in the variance in math ability between men and women has biological roots, and the latter produced a useful post listing some of the web's best neuroscience resources.

Jennifer Gibson, writing for Brain Blogger, has a fascinating piece about the new theory that the visual system generates images that predict one tenth of a second into the future. Crucially, the theory, dubbed "perceiving the present", seemingly explains how optical illusions arise.

Brain Stimulant, appropriately enough, submitted a post on transcranial magnetic stimulation as a treatment for Asperger's syndrome.

Finally, a trifecta of posts from Sharp Brains: Laurie Bartels with a list of resources related to neuroplasticity and neurogenesis, Adrian Preda on how the brain benefits from exercise, and Alvaro with a roundup of cognitive health news.

That's it! The next edition of the carnival will be hosted by the most excellent Neurophilosophy on September 15th. If you would like to contribute, send an email to {encephalon}{dot}{host}{at}{gmail}{dot}{com}.

Neuropod podcast

Nature Neuroscience's monthly podcast, Neuropod, is just superb and I highly recommend it to anyone interested in neuroscience, cognitive science or psychology. Perhaps the coolest thing about Neuropod is that it mostly consists of interviews with the actual authors of notable recent papers. This month's edition is particularly good, it features interviews with the authors of:

1. The awesome recent Nature article that tracked the development of altruism in children and how it may be related to parochialism
   
2. A fascinating essay in Nature on the role of imprinted genes in mental illnesses such as autism and schizophrenia
3. A Nature Neuroscience paper, with very promising future applications, on the role of the neurotransmitter GABA in obesity in mice, and
   
4. An awesome Nature Reviews Neuroscience piece (coauthored by Teller and James Randi!) on how magicians can help neuroscience research (and possibly vice versa).

As I said, just awesome. Check it out!

Neurons: Animated Cellular and Molecular Concepts

University of Toronto researchers have created a fantastic animated introduction to the cellular and molecular biology of the neuron. The introduction is divided into eight thematic chapters (e.g. "Anatomy of a Neuron", "Action Potential"), that explains the basics of neuroscience using interactive text and accompanied animations. Highly recommended.

By the way, the Society for Neuroscience's "Brain Facts" booklet (downloadable for free as a pdf) is also a useful introductory resource.

(Via Science's Random Samples).

Encephalon #49

The 49th edition of Encephalon is out at Neuroscientifically Challenged. Pieces to check out: The Neurocritic on rigor and fMRI in Science; Neurophilosophy on functional recovery after stroke; and Mind Hacks on the recent backlash against fMRI. (Yes, I don't like a lot of current cognitive neuroscience: too often all one can conclude from a study is that "x happens in the brain!" [insert love, perception, fear, desire or any other mental trait for x]. The brain is really, really, really complicated, one method with many limitations is never going to give us anything remotely resembling the complete picture).

This is your brain on nonsense

Remember that idiotic NYT editorial from November last year that claimed fMRI scans of swing voters' brains could be used to read their minds? Well, the same company that pulled off that stunt is back with an equally egregious piece in The Atlantic. Slate's Daniel Engber is suitably skeptical, accusing the company of "neuropunditry":

The neuropundits are more like tarot readers than scientists: They claim to read specific mental states from patterns of blood flow and brain activity, but the narratives they invent are arbitrary, equivocal, and inconsistent. And whenever the imaging data happen to contradict reality, they change their interpretation without a second thought.

Indeed. Another example of cognitive neuroscience gone badly awry...

Video: Why a scared expression brings a survival advantage

A new paper in Nature Neuroscience (which I haven't read, because I can't access it) argues facial expressions have an adaptive value. Specifically, the study found that the fear expression enhances sight and air-intake, while the expression of disgust reduces air intake. Check out the great New Scientist video (embedded below or click here) that admirably explains the study's results.



(See also: New Scientists' article and ScienceNOW's take).

PsyBlog on Mind-Myths

The most excellent PsyBlog has just finished a series of ten articles on Mind-Myths: those persistent fables about our minds that many of "the folk" subscribe to. My favorite myth busting pieces: we don't use only 10% of our brain, the placebo effect cannot affect cancer and hemispheric specialization in the brain is much more complex and you might think.

I highly recommend PsyBlog by the way, it's certainly one of the best psychology blogs on the web. Check it out!

Video: Jill Bolte Taylor at TED

Jill Bolte Taylor, an Indiana University School of Medicine neuroanatomist, gave a fascinating talk at TED in February. (The video is embedded below, here is the direct link). While I certainly think the video is worth watching (otherwise I wouldn't feature it here), I have a couple of serious reservations. It's clear from the video that Taylor's experience was an intensely emotional one and, let's be frank, science and intense emotions don't go so well together. It certainly made me worry when she started going on about "nirvana", it annoyed me that she dramatically oversimplified the very nuanced, complicated and still emerging picture of hemispherical specialization in the brain, and it frustrated me generally that she seems to let her emotions get in the way of her science. (To be clear: emotions are important and I have no problem with them being expressed, even at TED. But we should try our best not to let our emotions influence our intellectual positions - that's what I'm criticizing Taylor for, not the sheer fact of being emotional).



See also: Wired's article on Taylor's TEDTalk.

Lazy Linking: Wallace, Wikis and more

Some interesting articles to tide my readers over while I work on a conference paper (and not on blogging)...

There is a fantastic article in the NYT blogs about Alfred Russell Wallace (co-discoverer of natural selection, the mechanism of evolution). Olivia Judson, the author and an evolutionary biologist, laments that Wallace does not receive more recognition.

I am a longtime fan of Wikipedia and its founder Jimmy Wales. (I was extremely skeptical of Wikipedia - for elitist reasons - and always urged my students not to consult it until I read, of all things, a positive Economist article sometime during 2005 and decided to see for myself. I had to change my mind about a lot of things as a result). Anyway, as most of you will know, Wikipedia is a wiki, a type of software that allows collaborative editing that has been pretty controversial, especially since the fact that it can be edited by anyone immediately makes people suspect it is unreliable. So I was more than a little surprised (and now we come to the actual link!) that an august traditional media publication is giving (a very watered down) wiki model a try. Scientific American announced that (appropriately enough) they're conducting an experiment to see whether allowing readers to shape an article improves it. Again appropriately, the article in question is on "Science 2.0", or how blogs, wikis, and other Web 2.0 technologies are (possibly) going to revolutionize science. Now if only they were brave enough to allow people to edit the article themselves... (The article all on its own, by the way, would have been worth a link).

Francisco Ayala has an interesting editorial in PNAS in which he discusses the new National Academy of Sciences publication "Science, Evolution and Creation" (available as a pdf once you sign in). The publication is a significantly revised version of "Science and Creationsim: A View from the National Academy of Sciences".

The Neurocritic has a good blog entry on the fMRI study of ESP I also reported on.

There is a particularly interesting guest on this week's episode of Point of Inquiry: Aubrey de Grey, a controversial gerontologist committed to fighting aging in all its forms. (He was also a speaker at the TED conference). The reason I find him so fascinating is that I genuinely can't make up my mind about whether he's doing genuine (and good) science, or whether he's a crackpot. He certainly makes bold claims that raises some skeptical red flags - but he seems very scientifically minded. There is a MIT Technology Review article subtitled "Aubrey de Grey thinks he knows how to defeat aging. He's brilliant, but is he nuts?" that might help you make up your mind.

Lastly, Furious Seasons has a post about the effectiveness of current anti-depression therapies.

ESP vs. fMRI

Two Harvard psychologists, Samuel Moulton and John Lindsley, have a study in the Journal of Cognitive Neuroscience which provides yet more evidence against extra-sensory perception. Moulton and Lindsley reasoned that if psi exists it must occur in the brain and thus neuroimaging should be able to detect it. Using several modalities aimed at detecting the existence of different psi abilities (clairvoyance, telepathy and precognition) the authors conclude that, since "the brains of our participants... reacted to psi and non-psi stimuli in a statistically indistinguishable manner", the study provides "the strongest evidence yet obtained against the existence of paranormal mental phenomena".

This probably goes without saying, but I sincerely doubt any true believers will be convinced by this evidence. The contentious issue will no doubt be whether psi abilities would have to be a product of the brain - cue dualist nonsense.

(See also: ScienceDaily's report, Deric Bownds's Mindblog and Scienceblog).

Your brain on politics: the bad and the better

The bad

A disturbingly bad article, entitled "This is Your Brain on Politics", appeared recently in the New York Times. It presented purported "research" about the brains of swing voters in the 2008 US Presidential Elections but, unfortunately, the article does little but illustrate the dangers of circumventing the peer-review process and the shocking state of science journalism in the mainstream media. Luckily, the NYT published an angry letter by a group of cognitive neuroscientists condemning the article and the blogosphere responded forcefully, among the blogs that attacked the piece were: Bad Science, Neurocritic, Mindhacks, Brainethics and Natural Rationality. Subsequently, Nature published an editorial also condemning the article and even Slate joined in.

The better

Thankfully there has also been some better recent research concerning 'the brain on politics' and good media coverage thereof to boot. The subject of last week's edition of ABC Radio National's fantastic radio show/podcast, All in the Mind, was "The Political Brain" and the show discussed, among other things, an interesting study in Nature Neuroscience entitled "Neurocognitive correlates of liberalism and conservatism" (see also the supplementary materials). The study, led by NYU assistant professor of psychology David Amodio, evoked considerable interest and was widely discussed by the science blogging community. (See links below). I suspect the study has been somewhat misunderstood, so, despite it being stale by web standards, I'll look at it in some detail.

The hypothesis the authors defend is that political orientation (conservative vs. liberal) is "associated with individual differences in a basic neurocognitive mechanism involved broadly in self-regulation" (Amodio et. al., 2007: 1246). They go about testing this proposition in a somewhat tortuous way: previous research had shown that conservatives are "more structured and persistent in their judgments and approaches to decision-making" whereas liberals "report higher tolerance of ambiguity and complexity, and greater openness to new experiences". Other research showed that psychological differences between liberals and conservatives "map onto the... self-regulatory process of conflict monitoring" (the system that detects a mismatch between habitual responses and the response required in the current situation) which in turn has been "associated with neurocognitive activity in the anterior cingulate cortext"(ACC). So, to test whether liberals and conservatives differ in their patterns of self-regulation, the authors measured the acitivity of the ACC in a situation requiring conflict-monitoring.

Amodio et. al. conducted this test by using an electroencephalogram to record the ACC activity in 43 subjects who were asked to complete a go/no-go association task (Nosek & Banaji, 2001). For the task, participants were placed in a sound-proof room, in front of a computer screen in the center of which either an "M" or a "W" appeared. Half the subjects were instructed to "go" (i.e. hit a key) when they saw an "M" and do nothing ("no-go") when they saw a "W", while the other half were asked to do the opposite. The task consisted of 500 trails, 80% of which consisted of the "go" stimulus and 20% of the "no-go" stimulus. This meant that for half the subjects "M" became a habitual response (which needed to be inhibited when they saw a "W") and for the other half "W" became habitual (which needed to be inhibited when they saw an "M"). Additionally, before the task was administered, subjects reported their political attitudes confidentially on a scale ranging from -5 (very liberal) to +5 (very conservative).

The results were very suggestive. Firstly, however, it is important to note that there are in fact two types of finding in this study: the behavioral findings (which the authors do not focus on) and the cognitive neuroscience findings (which the authors emphasized and most of the subsequent discussion revolved around). The behavioral finding - which is interesting all by itself - is that liberals were more accurate than conservatives on the no-go trails (r(41) = 0.30, P less than 0.05) which "suggests that a more conservative orientation is related to greater persistence in a habitual response pattern, despite signals that this response pattern should change".

The neurocognitive findings were (among other things) that the response-locked error-related negativity (ERN) - a measure of conflict between a habitual tendency and an alternative - was strongly correlated (r(41) = 0.59, P less than 0.001) with political attitudes:

Additionally, liberalism was strongly associated with greater conflict-related neural activity when a habitual response had to be inhibited:

Subsequently, localization analysis was performed, which confirmed that the above mentioned ERN activity originated from the ACC. Amodio et. al. conclude that "taken together, our results are consistent with the view that political orientation, in part, reflects individual differences in the functioning of a general mechanisms related to cognitive control and self regulation".

A couple of observations. The study is clearly preliminary and a good deal of the reporting of it in the lay press went far beyond the evidence. The authors, however, obviously cannot be blamed for this - they were careful not to stray from the evidence in their paper. Furthermore, only 43 subjects took part in the study and, worse, only 7 of those self-reported as conservative. The findings would have to be replicated by a different team in a different part in the US with a larger number of participants before too much stock can be placed in them. For now this can be filed under "interesting and suggestive but preliminary". We'll have to wait and see how the literature develops.

Links

• Coverage of the Amodio paper on other blogs: NeuroLogica, Cognitive Daily, Natural Rationality, Crooked Timber, Mixing Memory, and Neurocritic.
• News coverage: Scientific American.
  

Bibliography

Amodio, D.A., Jost, J.T., Master, S.L., Yee, C.M. (2007). Neurocognitive correlates of liberalism and conservatism. Nature Neuroscience, 10, 1246-1247. DOI: 10.1038/nn1979

Nosek, B. A., & Banaji, M. R. (2001) "The go/no-go association task," Social Cognition, 19(6): 161-176.