Author: vaughanbell

Encephalon 52 raises its hand

The 52nd edition of the Encephalon psychology and neuroscience writing carnival has just arrived, this time hosted by the excellent Ouroboros.

A couple of my favourites include a post on the latest science of ‘grandmother cells‘ at the combining cognits blog (the new name for the excellent ‘Memoirs of a Postgrad’) and another on neuroimaging and social attachment style on the new-to-me but engaging Neurotic Physiology.

There’s plenty more article in this fortnight’s edition, so have a look and see what sparks your curiosity.

Link to Encephalon 52.

Tweaking with Sherlock Holmes

I just found this fascinating aside on Sherlock Holmes in a 1973 paper on amphetamine psychosis, suggesting that the cocaine-using Holmes displayed the classic repetitive behaviour often seen in frequent users of dopamine-acting stimulants.

The paper discusses what was known about the pharmacology of amphetamine in the early 1970s and how it relates to psychosis, but starts with an excellent description of the effects of chronic speed use.

One of these constellations involves an intense feeling of curiosity, often manifested by repetitious, stereotyped examining, searching, and sorting behaviors. This repetitious activity has been variously called “punding”, “hung-up activity”, “obsessive-compulsive tendencies”, and “knick-knacking” (by inhabitants of the Haight-Ashbury scene).

Its characteristic feature is engagement in tasks that primarily involve small bits or minutiae and a marked enhancement of perceptual acuity directed toward these minute objects. At times there are perceptuo-motor compulsions, manifested as repetitious stringing of beads or as acts of arranging, sorting, and lining up pebbles, rocks, or other small objects. Most of the so-called “speed art” is replete with complicated syntheses of a multitude of minute details, often depicting universal themes or mandalas. Speed users are frequently observed taking apart such objects as television sets, watches, radios, and phonographs.

Subsequently, the parts may be analyzed, arranged, sorted, filed, and cataloged and, rarely, put back together. Many patients report a sense of satisfaction associated with this compulsive-like conduct. Perhaps the best-known example of searching and examining behavior is that of Sherlock Holmes, whose cocaine habit was described by Dr. Watson:

Finally he thrust the sharp point home, pressed down the tiny piston, and sank back into the velvet-lined arm-chair with a long sigh of satisfaction. Three times a day for many months I had witnessed this performance…

‚ÄúIt is cocaine,‚Äù he [Holmes] said, ‚Äúa seven-per-cent solution… I suppose that its influence is physically a bad one. I find it, however, so transcendently stimulating and clarifying to the mind that its secondary action is a matter of small moment…

‚ÄúMy mind,‚Äù he said, ‚Äúrebels at stagnation. Give me problems, give me work, give me the most abstruse cryptogram, or the most intricate analysis, and I am in my own proper atmosphere. I can dispense then with artificial stimulants. But I abhor the dull routine of existence. I crave for mental exaltation. That is why I have chosen my own particular profession, or rather created it, for I am the only one in the world…

“To the trained eye there is as much difference between the black ash of a Trichinopoly and the white fluff of a bird’s-eye as there is between a cabbage and a potato.” “You have an extraordinary genius for minutiae,” I [Watson] remarked (The Sign of the Four, pp. 610-612).

Holmes’s description of his “grooving on” puzzles and cryptograms and his penchant for magnificent synthesis of details to solve a given case are quite analogous to the amphetamine addict’s intense curiosity and preoccupation with minutiae. Even at a low point in the drug-use cycle, these persons will seek out stimulating mechanical or intellectual puzzles. This compulsion for analysis is widely recognized in the “speed scene.”

Of course, cocaine wasn’t the only drug Holmes dabbled in, as he was also a user of opium and tabacco, but it’s interesting that the author of the paper makes a link between Holmes’ cocaine use, and both his investigative style and ‘knick-knacking’ between cases.

Link to full text of paper.
Link to PubMed entry.

Psycho killer – Qu’est-ce que c’est?

Bad Science has an excellent article about the almost unreported news that homicides by people with mental illness have dropped dramatically in England and Wales, despite the fact that murders by people without mental illness have increased.

Right now I’m looking at a press release on a story which seems pretty important to me: people with serious mental illnesses are committing fewer murders than ever before, by a truly enormous margin. Homicides in this group increased from around 40 a year in the 1950s to 100 a year in the 1970s, in line with a similar increase in the general population. But while murders by people like you have continued to increase, and roughly trebled (0.6 per 100,000 of population in the 1950s, and almost 2 per 100,000 now), murders by people with serious mental illnesses, despite the hype and the fear, the public pronouncements and the headlines, have come down massively since the 1970s, to fewer than 20 a year today.

Ben laments the fact that even a hint of a connection between mental illness and murder makes front page news, stigmatising those with mental disorders and unnecessarily increasing prejudice, while news based on thorough research showing that these fears are unreasonable and unfounded barely raises a byline.

Indeed, it’s rare that positive mental illness news is made ‘sexy’ by the media. The nearest we get is when celebrities admit that they’ve suffered depression. Eating and anxiety disorders are occasionally discussed but it’s rare that psychosis is ever discussed in terms of recovery and by celebrities who have experienced it.

By the way, the picture is of bluesman and ex-Fleetwood Mac guitarist Peter Green who spent some tough years in psychiatric hospital, apparently diagnosed with schizophrenia, but is still as rock n’ roll as ever – recording and touring with some of his best material.

Link to Bad Science on ‘The news you didn‚Äôt read’.
Link to full-text of study.

Neurowar of words

Wired Science covers a recent US military report on military threats from the latest developments in neuroscience as well as how brain research could be ‘weaponised’ to enhance soldiers’ capabilities or disable enemy fighters.

It’s a bit difficult to judge the quality of the report, as unlike the recent in-depth report from the JASON Pentagon advisory panel, they’re charging people to download it.

From the Wired summary, it seems to cover similar ground although is perhaps a little more wide-ranging and focuses on policy and foresight rather than the nuts and bolts of brain science.

It apparently covers four main areas: mind reading; cognitive enhancement; mind control and brain-machine interfaces. As you can probably tell from the list, there’s likely to be a fair amount of speculation going on there.

It’s also interesting that the US military are really promoting their ‘military neuroscience’ angle, which is not to say that it is not a research priority. Whole wings of military research are now devoted to ‘human research’, as illustrated by the extensive science portfolio of the US Army’s Research Lab.

Nevertheless, the discussions about drug-based enhancements have so far been largely reiterating what soldiers have already done for millennia – using drugs to reduce fatigue, increase confidence and cope with trauma.

Drugs have been used for soldiering as long as there have been wars and the low-tech still prevails – from the use of coca leaves by Inca warriors to the use of the khat by modern-day Sudanese militias.

If anyone does happen to stumble across an unrestricted copy of the report online, do let me know as it’d be great to be able to link to the original.

Link to Wired Science article ‘Uncle Sam Wants Your Brain’.
Link to online shop for report.

Knitting delusions from thoughts

An insightful excerpt from psychologist Peter Chadwick’s chapter from an excellent new academic book on the science of persecutory delusions. Chadwick is a clinical psychologist and leading psychosis researcher who has experienced madness first hand.

When looking at Hopper’s forlorn paintings one has the feeling that no moment in life need be wasted. Hopper captures a barman putting a glass or cup on a shelf; a women looking at her nails, another woman lost in thought in a cafe. Little things, things one wouldn’t normally notice or think about, let alone render on canvas, are there to be appreciated.

Some of the experiential moments which built the network of emotionally charged ideas that mediated my own psychosis were trivial in themselves. A remark from my mother; an insult from a bully at school; a strange expression on a shop assistant’s face. But all were eventually collected up, knitted together and turned into a delusional web of thoughts and feelings that in the end drove me to multiple suicide attempts that very nearly succeeded in killing me.

In madness, no moment of one’s existence seems to be wasted; it is if one’s whole life, and the depths of one’s very being in selective perspective, have been made magically clear in their awful and portentous significance. One’s past comes hauntingly back, in a kind of near-death experience while one is physically fully alive. ‘This is what’s it’s all been leading up to!’ I remember often thinking in the blazing hot, mad hot summer of 1979.

Chadwick also wrote a powerful 2006 article that recounted his experience of madness – weaving his insights as a scientifically inclined psychologist and his considerable literary powers into a piece that stands out as unusually powerful amid the typically arid academic literature.

Link to more details on the book.
Link to article ‘Schizophrenia From the Inside’.

2008-08-15 Spike activity

Quick links from the past week in mind and brain news:

Sharp Brains has a thoughtful piece on the hoped-for demise of dementia.

Peter Donnelly gives an excellent TED talk on how juries are fooled by statistics.

Channel N finds an interesting video lecture on the conditioned fear response and combat resilience in the armed forces.

Apparently we’re a ‘Top 100‘ Mental Health and Psychology Blog.

The Frontal Cortex has an interesting summary of a study on basketball pros and the mirror system. A nice complement to a study on ballet dancers and capoeira experts.

Is being gay in your biology? All in the Mind investigates.

The Situationist has an interesting piece on “The Psychology of Barack Obama as the Antichrist”. Cor blimey!

An interesting project to visualise sound to help deaf people interact with sound is covered by BBC News – with video of it in action.

Wired Science picks up on a new study that finds that placebos work better in children.

Cool! Artwork that displays separate images under different lighting conditions – with videos.

Furious Seasons has an excellent investigative piece on the fact that the FDA seem to be validating new psychiatric diagnoses off their own backs.

The most conceptually confused headline of the year? “Nature Or Nurture: Are You Who Your Brain Chemistry Says You Are?” Actually a study on addiction.

Is psychoanalysis equivalent to a spiritual practice? A commonly made link between psychoanalysis and religion is explored rather deftly in an article for The Immanent Frame.

The BPS Research Digest has an interesting piece on disaster psychology and why so many people perish needlessly in emergencies.

More from the Hot Spanish Psychologist. ¬°Vaya chica!

Not Exactly Rocket Science covers a fascinating study showing that referees have a tendency to award more points to competitors wearing red.

YouTribe

Anthropologist Michael Wesch gave a thoughtful and engaging talk on ‘An anthropological introduction to YouTube’ to the Library of Congress earlier this year and, rather appropriately, it’s available online as a video on the popular video sharing site.

Wesh runs a digital ethnography project which looks at how cultures form and operate on the net.

The project’s blog is also full of fascinating insights and is well worth checking out if you thought anthropology was only ever about people who don’t have electricity.

Link to talk ‘An anthropological introduction to YouTube’.

‘Anti-torture’ candidate to run for APA presidency

Despite the American Psychological Association revising their ethics policy twice in the debate over American psychologists’ participation in war-on-terror interrogations, significant unrest still remains over the fact the APA has yet to actually enforce its reluctantly implemented ban.

The Boston Globe has an op-ed article by psychologist and APA critic Stephen Soldz who notes that an anti-torture candidate has been put forward for the APA presidency in an attempt to force the Association’s hand.

The new candidate is psychologist Steven Reisner who even has a campaign website – an innovation for presidential elections which are usually wildly underwhelming.

According to the Globe piece, Reisner received the most votes of the five candidates in the nomination phase. If the momentum carries forward, APA’s careful tiptoeing to avoid offending the US military may backfire if the most political president for years takes the helm.

Interestingly, both Soldz and Reisner are psychoanalysts, a group who have been leading the campaign against psychologists’ role in US military interrogations and who have consistently opposed the ‘war-on-terror’ since it began.

Freud himself was particularly interested in the tension between individual drives and governmental control. In Civilization and its Discontents he suggested government was an inevitable result of the need to control the unacceptable desires we all have.

He was particularly interested in how common individual neuroses get expressed socially as we project our own fears onto specific groups deemed to be ‘outsiders’, often with barbarous and disastrous consequences.

Link to Boston Globe op-ed.

Hypnosis addiction: the scourge of the Victorian lady

I’m currently reading the wonderful but very long book The Discovery of the Unconscious which I shall post more about later.

However, I noticed this little gem about hypnosis in the late 1800s which just smacks of the current hand-wringing over the non-existent (or rather can’t-existent) ‘internet addiction’.

The problems described are so obviously not addiction, and, in fact, like the internet, there’s no specific activity to be addicted to that is defined by the term ‘hypnosis’. After all hypnosis is just where you concentrate and someone makes suggestions – can you be addicted to concentration and listening? Obviously not.

Nevertheless, the concerns got framed in the language of addiction as a placemarker for a fear of the unknown and as a fig leaf for other social problems (from p118):

Deleuze and the early mesmerists also described the evils resulting from too frequent or too prolonged hypnotic sessions. Such subjects gradually became addicted to hypnosis: not only did their need for frequent hypnotization increase, but they became dependent on their particular magnetizer, and this dependency could often take on a sexual slant. This well-known fact was rediscovered by Charcot, who gave an account of a woman who had been hypnotized five times within three weeks and who could think of nothing but her hypnotist, until she ran away from her home to live with him. Her husband took her back, but she fell into severe hysterical disturbances that necessitated her admission to a hospital.

Link to Wikipedia page on The Discovery of the Unconscious.

Interrupting Napoleon on the genetics of mental illness

Today’s Nature has got an interesting letter on psychiatric genetics suggesting an interesting approach to studying the genetics of mental illness.

It’s from neuroscientists John McGrath and Jean-Paul Selten and comments on an earlier Nature article which we discussed previously.

Napoleon Bonaparte advised: “Never interrupt your enemy when he is making a mistake.” Those of us who assess the contribution of non-heritable risk factors to neuropsychiatric illness would like to politely interrupt this battle to remind opponents that environmental risk factors have now overtaken genetic factors with respect to both effect size and the proportion of the population that is affected.

For schizophrenia, for example, factors relating to urban birth, cannabis use and migrant status are well replicated and have relatively large effects ‚Äî in contrast to the scant evidence that remains after decades of genetics research. Although the ‘heritability index’ for schizophrenia is large (about 85%), this metric encompasses the neglected contribution of gene‚Äìenvironment interactions, as well as the high-profile genetic component. This key point is largely forgotten in the heat of the battle.

It has been convincingly argued (A. Caspi and T. E. Moffitt Nature Rev. Neurosci. 7, 583‚Äì590; 2006) that the power to detect genuine genetic-susceptibility loci would be substantially increased if we could stratify samples according to environmental risk factors. Let’s have more funding to help fine-map the wide range of non-heritable risk factors associated with disabling disorders such as schizophrenia and depression, and discover how they act. These clues are too valuable to overlook.

It’s an interesting point and is relevant to the fact that heritability must be one of the most misinterpreted statistics in genetics.

If a study reports that schizophrenia has a heritability of 85%, many people interpret it to mean that 85% of the risk of developing schizophrenia comes from genetics and this is something to do with the condition itself.

In fact, what it shows is that 85% of the risk of schizophrenia in the samples taken so far is estimated to come from genetics, but crucially this estimate is dependent on the environment in quite subtle ways.

The letter above mentions gene-environment interactions: where exactly the same genes can produce different heritability depending on the environment.

Imagine that everyone lived in a virtually identical environment and we all had almost exactly the same life experiences. The only possible difference in the prevalence of mental disorder would have to come from genetics, because the environment is virtually the same for everyone. In this case, heritability would be close to 100%.

Alternatively, if the environment was widely different for everyone, much more of the difference would come from experience and so the heritability estimate would be less.

In other words, the estimate of heritability depends partly on the variability in the environment experienced by the people being studied.

I was told by a genetics researcher that studies on the genetics of intelligence in school children tend to show that IQ is more heritable in the UK than the US, because in the UK we have a National Curriculum – a specified education programme that every child follows.

This means that UK children have a more similar learning environment, whereas in the US the curriculum is decided state-by-state meaning there’s much more variability in experience. Hence, IQ is less heritable in US school children.

I’ve not found the the studies on IQ in school children, so I’m not sure how it stands at the moment, but it serves as a good illustration of how heritability estimates can be environment dependent.

Actually, this week’s Nature has two other letters on the same topic, and additional feature articles on autism and neural synchrony, as well as a couple brain-relevant book reviews.

Link to contents of this week’s Nature.
pdf of Nature Reviews Genetics paper on twin studies and heritability.

FBI’s Most Wanted neuroscientist on imitation

Aafia Siddiqui was the FBI’s Most Wanted Woman for several years and is currently in US custody in New York, awaiting trial on charges that she is a terrorist and member of Al-Qaeda.

She is also a neuroscientist and co-authored a scientific paper in 2005 on the cognitive science of imitation learning.

Before her recent capture, which some sources claim may have actually happened five years ago in Pakistan, Siddiqui completed a PhD entitled ‘Separating the components of imitation’ at Brandeis University in the US.

Before that, she completed a Masters degree in neuroscience, also on imitation learning, and her 2005 paper is based on her work for this degree.

The paper describes three experiments that attempt to understand how our learning of seen actions is affected by delays, memory interference and visual interference.

Each experiment involved a pale red disc that followed an ‘invisible track’ on a computer monitor. The sort of track is illustrated in the diagram of the left, although in the actual experiment the participants just saw the disc.

In Siddiqui’s experiment, one group of participants used a trackpad to ensure that the cursor was within the disc at all times (a classic pursuit-tracking task), while another group had to wait until the disc had followed the route before trying to reproduce it from memory.

To look at the effect of complexity on imitation learning, some routes had only three straight lines, while others had up to seven.

Furthermore, some routes were repeated, while others appeared only once. This allowed the researchers to compare learning for identical routes (specific learning) with learning for the general task (skill learning).

The results showed that, unsurprisingly, participants were better at reproducing the simpler routes. What was more surprisingly though, was that practice-related improvement was only seen when participants watched the whole movement before starting, and then only on routes that were repeated.

Intriguingly, when interviewed after the experiment, the participants had no idea some routes were presented more than once, suggesting that this learning occurred without any conscious involvement.

A further experiment showed that delays of up to 6 seconds barely affected performance and that interfering with short-term memory by getting participants to do maths problems only made them a little worse.

Finally, the researchers ran an experiment where the disc appeared only at the beginning and end of each straight line, or when it was turning a corner. This had virtually no impact on performance. Participants were almost equally as good with much less information.

The research helps us understand the limits of learning when we need to copy a certain action sequence, be this tying shoelaces, swinging a golf club or learning tai chi.

The study suggests that for short action sequences we may be better off waiting until we watch the whole thing before attempting it ourselves.

Link to PubMed entry for paper.
Link to library record for Siddiqui’s PhD thesis.

The common language of pride and shame

Wired Science covers an elegant study that suggests that spontaneous expressions of pride and shame are innate behaviours that are not significantly influenced by culture.

The researchers came up with the ingenious idea of comparing how judo wrestlers from the 2004 Olympics and blind judo wrestlers from the 2004 Paralympics celebrated and commiserated their matches.

This allowed a cross cultural comparison, but it also allowed a comparison with blind athletes who have never seen another person in the same position to copy their behaviour.

The new research, however, distilled from high-resolution, high-speed photographic sequences of sighted and blind judo competitors at the 2004 Olympics and Paralympics, suggests that most nonverbal responses to wins and losses are almost universal.

No cultural differences were observed among competitors from different countries and, aside from the shaking of the fists after a loss, sighted and blind athletes displayed remarkably similar nonverbal behavior.

In other words, it made virtually no difference what culture each individual came from, or even whether the person had seen another wrestler at the end of a match or not – the expression of pride was indistinguishable, suggesting that this may be a common expression that we all share.

There was a slight effect of culture on the expression of shame – as the researchers note “it was less pronounced among individuals from highly individualistic, self-expression-valuing cultures, primarily in North America and West Eurasia”.

However, as there was no difference within cultures between sighted and blind individuals, they further suggest that both pride and shame are likely to be innate, but that shame display may be intentionally inhibited by some sighted individuals in accordance with cultural norms.

Link to Wired Science on elegant study.
Link to full text of paper.

George Lakoff and the linguistics wars

George Lakoff is famous for being one of the founding fathers of cognitive linguistics, for battling Noam Chomsky, and for arguing that using the right metaphors is the key to winning a political debate.

He’s profiled in an article for the Chronical Review which serves as a fantastic introduction to the man, his work and his controversial foray into politics.

Lakoff is particularly interesting because he advised the US Democratic party on the use of language and in ‘framing’ debates – meaning they are described with metaphors that automatically conjure up positive ideas and concepts that are favourable to the policy under discussion.

Whether you share Lakoff’s politics or not, the story of how he became prized by the party and then embroiled in a backlash over whether this was just gloss and glitter rather than anything of political substance is interesting.

The roots of the cognitive revolution in the social sciences are numerous and wide-ranging, but Lakoff traces his own story to Berkeley in 1975, when he attended a series of lectures that prompted him to embrace a theory of the mind that is fully embodied. Lakoff came to believe that reason is shaped by the sensory-motor system of the brain and the body. That idea ran counter to the longstanding belief — Lakoff traces it back 2,500 years to Plato — that reason is disembodied and that one can make a meaningful distinction between mind and body.

One of the most influential lectures Lakoff heard that summer was delivered by Charles J. Fillmore, now an emeritus professor of linguistics at the university, who was developing the idea of “frame semantics” ‚Äî the theory that words automatically bring to mind bundles of ideas, narratives, emotions, and images. He called those related concepts “frames,” and he posited that they are strengthened when certain words and phrases are repeated. That suggested that language arises from neural circuitry linking many distinct areas of the brain. In other words, language can’t be studied independently of the brain and body. Lakoff concluded that linguistics must take into account cognitive science.

The field of cognitive linguistics was born, and Lakoff became one of its most prominent champions. But it wasn’t until the mid-1990s that he began thinking through some of the political implications of framing. Startled by the Republican takeover of the House of Representatives in 1994, Lakoff set about looking for conceptual coherence in what he saw as the seemingly arbitrary positions that defined modern conservatism. What thread connected a pro-life stance with opposition to many social programs, or a hostility toward taxes with support of the death penalty? Lakoff concluded that conservatives and liberals are divided by distinct worldviews based on the metaphor of the nation as a family.

The fact that throughout Lakoff was trying to apply the cognitive science of language to a practical problem makes for an interesting tension between science, speculation and ambition.

Link to article ‘Who Framed George Lakoff?’.

Mainlining the active ingredients of cannabis

I’ve uploaded a fascinating video clip where a TV presenter is intravenously injected with the active ingredients of cannabis as part of the BBC documentary Should I Smoke Dope?

It’s part of an experiment to compare the effects of intravenous THC and cannabidiol combined, with intravenous THC on its own. The mix of both gives the presenter a pleasant giggly high while THC on its own causes her to become desolate and paranoid.

Both are these are known to be key psychoactive ingredients in cannabis but the video is interesting as it is a reflection of the fact that THC has been most linked to an increased risk of developing psychosis while cannabidiol seems to have an antipsychotic effect.

As we discussed earlier this year, one study found that cannabis smokers who had higher levels of cannabidiol in hair samples had the lowest levels of psychosis-like experiences.

Another study we covered reported that, at least in the UK, ‘skunk’ has virtually no cannabidiol, while hash, although variable, was more likely to contain high cannabidiol levels.

And if you’re after a more balanced view on the link between cannabis and psychosis than you normally get in the media, I’ve also uploaded a clip from the same programme where psychiatrist and leading cannabis researcher Robin Murray discusses the findings from the latest research.

If you want to check out the whole documentary, where BBC reporter Nicky Taylor gets stoned for 30 days in a row while investigating the science, culture and legal status of cannabis, it’s available as a torrent or in six parts on YouTube (1, 2, 3, 4, 5, 6).

Link to video of IV cannabidiol and THC experiment.
Link to video of psychiatrist Robin Murray on cannabis and psychosis.

Parapsychology in a nutshell

Today’s featured article on Wikipedia is a rather splendid article on parapsychology – the scientific study of the supposed paranormal phenomena of the mind.

Academic parapsychology is notable for the exceptional quality of the experiments it conducts and the inconclusive nature of its findings – at least to mainstream science.

Large reviews of many studies (meta-analyses) tend to find that ‘psi’ effects are statistically significant but of small effect. The disagreement comes in over whether this small effect is a genuine reflection of paranormal ability or just an artefact of research – such as negative findings being published less often.

The history and process are fascinating though, with some of the great luminaries of psychology, such as William James, having been interested in experimental studies of psychic powers.

Link to Wikipedia page on ‘parapsychology’.

Cannibalism, prions and encephalopathy (oh my!)

Cannabalism gave Western medicine its first understanding of prion diseases as an epidemic of the neurological disorder swept the South Fore tribe in Papua New Guinea. Neurophilosophy has written a remarkably lucid article on the history and neuroscience of how prion diseases, of which ‘mad cow disease’ is one, affect the brain.

The piece starts with some archive footage of a tribe member with the devastating disorder and continues to describe how this class of diseases are probably caused by misfolded proteins that can trigger the same misfolding in other proteins leading to a chain reaction of neural damage.

The Fore tribe had a tradition of ritually consuming the brain and body of deceased relatives, which likely lead to the outbreak.

The word kuru means “shaking death” in the Fore language, and describes the characteristic symptoms of the disease. Because it affects mainly the cerebellum, a part of the brain involved in the co-ordination of movement, the first symptoms to manifest themselves in those infected with the disease would typically be an unsteady gait and tremors. As the disease progresses, victims become unable to stand or eat, and eventually die between 6-12 months after the symptoms first appear.

Kuru belongs to a class of progressive neurodegenerative diseases called the transmissible spongiform encephalopathies (TSEs), which also includes variant Creutzfeldt-Jakob Disease (vCJD) and bovine spongiform encephalopathy (BSE, more popularly known as “Mad Cow Disease”). TSEs are fatal and infectious; in humans, they are relatively rare, and can arise sporadically, by infection, or because of genetic mutations. They are unusual in that the infectious agent which transmits the diseases is believed to a misfolded protein. (Hence, the TSEs are also referred to as the prion diseases, “prion” being a shortened form of the term “proteinaceous infectious particle”).

Prion diseases are a complicated area and you probably won’t find a better written introduction that captures both the science and the intrigue of these relatively new disorders.

Link to article ‘Cannibalism and the shaking death’.