Being Human

The latest edition of the Journal of Neuroscience has a fantastic collection of articles by leading neuroscientists who look back on the last 40 years of discoveries in brain research.

The collection is to celebrate the 40th anniversary of the Society for Neuroscience. As the articles make clear, the last four decades have seen a huge expansion in our knowledge of how the brain works and the Society asked leading lights in the field to reflect on this scientific revolution.

Memory and Brain Systems: 1969–2009 by Larry R. Squire [link]

Neurotransmitters, Receptors, and Second Messengers Galore in 40 Years by Solomon H. Snyder [link]

Four Decades of Neurodegenerative Disease Research: How Far We Have Come! by Anne B. Young [link]

A Paradigm Shift in Functional Brain Imaging by Marcus E. Raichle [link]

The Development of Developmental Neuroscience by Carol Mason [link]

The Biology of Memory: A Forty-Year Perspective by Eric R. Kandel [link]

Strictly speaking, they're not all retrospectives. For example, while Larry Squire gives a whistle-stop tour through the last 40 years of the cognitive neuroscience of memory (and you'll probably not read a better brief article in this area), Marcus Raichle takes the opportunity to look forward and is clearly enthusiastic about the 'default network' which he is co-credited with discovering.

They're all academic articles, so are not the most accessible if you're not familiar with the scientific literature, but as brief guides to some of the major areas of neuroscience they're fantastic and freely available online.

Science News has a brilliant special issue on the 'science of slumber' that tackles sleep disorders, the mental impact of sleep deprivation, how sleep differs across species and the still mysterious question of why we need to sleep.

I found the article on two seemingly straightforward sleep disorders, insomnia and narcolepsy, the most interesting. They seem straightforward because they appear as a lack and an excess of sleep, but as the piece makes clear, they are still quite mysterious.

Insomnia is particularly interesting because having trouble sleeping happens to everyone at some point, so in itself, it's not abnormal - meaning that research into what triggers it is unlikely to find anything striking.

Instead research has shifted to try and understand what prevents insomnia from resolving naturally so it becomes a chronic condition:

Sleeplessness may be brought on by traumatic events such as a death in the family, an illness such as cancer or anything else distressing, causing a person to lie awake at night with a racing mind. For a subset of people, though, insomnia has no prompting signal — a condition called primary insomnia.

Regardless of the trigger (or lack thereof), temporary insomnia has a nasty way of becoming a habit. Poor sleep habits can become ingrained. When trouble sleeping persists for three or four nights a week over several months, insomnia is considered chronic.

It may turn out that untangling the prompting signals of insomnia, as many sleep researchers attempt, is a fool’s errand, says Michael Perlis, director of the University of Pennsylvania’s Behavioral Sleep Medicine Program in Philadelphia. “The whole zeitgeist has changed,” he says. Most sleep researchers now agree that “once insomnia goes chronic, it stays that way,” regardless of the prompting signal, Perlis says. So rather than focusing on the immediate trigger for insomnia, many scientists are trying to figure out why it becomes chronic and how to prevent that from happening.

I also liked the short piece that briefly compares the amount of type of sleep between lots of different animals. It seems dolphins don't have REM sleep. I wonder if that means that they lack or have very limited dreams?

Anyway, a great collection of articles and all freely available online.

Link to SciNews 'Science of Slumber' collection.

There's a comprehensive and compelling introduction to neuroanthropology over at the blog of the same name that outlines why we can't fully understand the brain or culture while thinking of them as separate entities.

The Neuroanthropology blog is run by two of the main researchers in the field and this recent article was written to launch their recent conference 'The Encultured Brain'.

The article is in-depth but accessible and clearly lays out the main ideas in the field, looking at the benefits to both brain science and cultural studies in a combined approach and noting where narrow thinking has dimmed our view of human nature.

The potential gains are enormous: a robust account of brains in the wild, an understanding of how we come to possess our distinctive capacities and the degree to which these might be malleable across our entire species. The applications of this sort of research are myriad in diverse areas such as education, cross-cultural communication, developmental psychology, design, therapy, and information technology, to name just a few. But the first step is the one taken here – by coming together, we can achieve significant advances in understanding how our very humanity relies on the intricate interplay of brain and culture.

Link to 'Why Neuroanthropology? Why Now?'

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

Slate has a brilliant article on the links between face structure and aggression and whether we can see criminality in the face. Contains the wonderful euphemism 'muscular unreasonableness'.

Video games are good for the brain, according to an article from The Boston Globe that reviews evidence for the cognitive benefits of computer games.

The BPS Research Digest has an awesome review of the state of brain scan 'lie detection' research. Punchline: scientifically interesting, practically useless still.

There's a brilliant article on doing cognitive neuroscience experiments with patients during neurosurgery in this week's Nature. Stupidly locked behind a paywall but has been touched by the irony fairy and given the rubbing-salt-in-the-wounds title 'Opening up brain surgery'.

PsyBlog has as excellent piece on 'how rewards can backfire and reduce motivation'.

The tragedy of the commons is really a farce, according to an excellent piece from The New York Times TiernyLab blog that tackles the myth behind the phrase and the latest economics nobel.

Not Exactly Rocket Science covers new research on how the placebo effect affects pain signalling in the spine.

The sound of something getting closer increases the sensitivity of the visual cortex – before you're even conscious of hearing it, according to new research covered by New Scientist.

Neurotopia is live blogging the annual Society of Neuroscience gathering of the tribes and has a list of other bloggers covering the proceedings.

An experiment on the neurobiology of fizz, is covered by a carbonated Science News.

Time magazine has a piece on the debates over whether dementia should be considered a terminal illness and new evidence that challenges the traditional view that the brain decline itself isn't fatal.

There's an great piece on placebo side-effects on the increasingly excellent Neuroskeptic.

The New York Times travels into the science of the ear and hearing.

Is Alzheimer's like a strange form of brain cancer? asks Disover Magazine.

APS Observer has an interesting piece on an antique piece on psychology equipment called the 'memory drum'.

New research on Galileo's work in the science of perception is covered by the wonderful Advances in the History of Psychology.

The Times has a breathless piece on the dawn of 'brain to brain communication' which includes "sending messages formed by one person’s brain signals though an internet connection to another person’s brain many miles away". RFC1149 is that you?

The world's largest scientific conference, the Society for Neuroscience meeting, starts tomorrow in Chicago. Tens of thousands of researchers from all areas of neuroscience will meet to discuss all aspects of the brain. The conference always has a full programme of social events, as well as the usual scientific programme (I am still filled with regret about missing the 'Hippocampus Poetry Slam' the last time I went). If you are in Chigaco this year, one particular event you might want to check out is the Neuroethics Social, hosted by Martha Farah from the University of Pennslyvania

Neuroethics Social
Time & Date: Tuesday Oct 20, 6:30-8:00
Location: Room N139, convention center
Guests: J.T. Cacioppo J.D. Haynes J. Illes S. Laureys H.S. Mayberg E.A. Phelps R.A. Poldrack B.J. Sahakian
"Interested in the ethical, legal or policy implications of neuroscience? Come to the neuroethics social hour and meet others with the same interests. And don't miss the short but spirited debate, between two leading neuroimaging researchers, on the proposition that "brain imaging is already capable of (something worthy of the term) 'mind reading'."

Martha is the academic director of the Center for Neuroscience & Society at U. of Pennsylvania and for the last few years has been running a 'Neuroscience Bootcamp' for professionals and graduate students in fields such as law, ethics and education who feel they need a crash course in modern neuroscience.

An interesting case study from a 2002 edition of The Lancet of a man who suffered paralysis from drinking too much Earl Grey tea owing to the toxic effects of huge doses of bergamot oil - taken from orange rind and used as flavour:

A 44-year-old man presented in May, 2001, with muscle cramps. He had no medical history of note, but volunteered the fact that he had been drinking up to 4 L of black tea per day over the past 25 years. His preferred brand was GoldTeefix (Tekanne, Salzburg, Austria). Since this type of tea had given him occasional gastric pain, he changed to Earl Grey (Twinings & Company, London, UK), which he thought would be less harmful to his stomach. 1 week after the change, he noticed repeated muscle cramps for some seconds in his right foot. The longer he drank Earl Grey tea, the more intense the muscle cramps became. After 3 weeks, they also occurred in the left foot...

Earl Grey tea is composed of black tea and the essence of bergamot oil, an extract from the rind of bergamot orange (Citrus aurantium ssp bergamia), which has a pleasant, refreshing scent. Bergamot oil contains bergapten (5-methoxypsoralen), bergamottin (5-geranyloxypsoralen), and citropten (5,7-dimethoxycoumarin), which can be found in grapefruit juice, celery, parsnips, and Seville orange juice. Bergamot oil is a well-known UVA-induced photosensitiser with a strong phototoxic effect, and is used therapeutically in psoriasis, vitiligo, mycosis fungoides, and cutaneous lymphoma. Because of this side-effect, bergamot oil has been widely banned as an ingredient in cosmetics and tanning products. Bergamot oil also has a hepatotoxic effect and may cause contact-allergy. The adverse effects of bergamot oil in this patient are explained by the effect of bergapten as a largely selective axolemmal potassium channel blocker, reducing potassium permeability at the nodes of Ranvier in a time-dependent manner. This may lead to hyperexcitability of the axonal membrane and phasic alterations of potassium currents, causing fasciculations and muscle cramps.

In other words, it disrupts the way chemical flow through the membrane of the nerve fibre, causing the neurons that connect to the muscles to malfunction.

Link to DOI entry for the case study.

Not Exactly Rocket Science covers a fantastic study on how the structure of the brain changes as illiterate adults learn to read and write. The research was conducted on rather a novel group of participants. Most were ex-members of guerilla forces in Colombia that had recently put down their weapons to re-integrate in society.

Colombia has a sizeable program to rehabilitate ex-paramilitary 'reinsertados' that includes social support and education, as many have never attended school. As the researchers note, this sets up an interesting natural experiment:

After decades spent fighting, members of the guerrilla forces have begun re-integrating into mainstream Colombian society, introducing a sizeable population of illiterate adults who have no formal education. Upon putting down their weapons and returning to society, some had the opportunity to learn to read for the first time in their early twenties, providing the perfect natural situation for experiments investigating structural brain differences associated with the acquisition of literacy in the absence of other types of schooling or maturational development.

The researchers, led by neuroscientist Manuel Carreiras, recruited a group of ex-paramilitaries who could read less than five simple words on a Spanish reading and writing test, and compared them to a similar group who learnt to read and write from an early age.

The research team use MRI scans to compare differences in brain structure between the two groups to allow an insight into how brain anatomy changes to accommodate reading and writing.

While it is possible to do this with children, it is almost impossible to separate out which are the brain changes due specifically to acquiring literacy and which are just part of the massive changes that constantly take place as children develop.

The images above show the areas of the brain (in orange) where the structure was significantly different between literate and illiterate adults.

Rather neatly, these are also areas that have been identified in brain activation studies of reading and writing, and are known to be associated with visual perception, processing word sounds and dealing with the meaning of words.

Subsequent analyses showed that pathways the angular gyrus, a key language area, across each hemisphere were less developed in illiterate adults and were less active when the participants were asked to name objects.

A brilliantly innovative study, a good write-up from Not Exactly Rocket Science and perfectly timed for my arrival in Colombia.

Link to NERS on guerilla reading.
Link to summary of scientific paper.

In the celebrations of the fifty-year forty-year anniversary of the moon landing, we've probably all seen this iconic photo of Buzz Aldrin's footprint on the lunar surface:

Looking at it again yesterday, I realised that there was something that disturbed me about it. The footprint looks wrong somehow. Our world-knowledge tells us that footprints press into the surface they are made on, yet this footprint looks like it rises out. What gives?

The effect is due to a well known visual phenomenon whereby our brains use shading to infer the percepion of shape (in the book, Hack #22). We are wired to assume that light comes from above, so things with shading underneath, like the ridges of the footprint, are seen as sticking out towards us. Things with shading on the top are seen as sticking in, away from us.

You can make the moon-footprint look 'right' by turning the photograph the other way up. This is the opposite to the way it is normally shown, but gells with our natural inclination to assume light comes from the top of the photo:

Perhaps the unnatural look of this photo is one source of moonlanding-denial conspiracy theories?

There's a chance Mind Hacks posts might be a bit sporadic over the next week as I'm returning to beautiful Colombia to work with the fantastic psychologists and psychiatrists in Hospital Universitario San Vicente de Paúl in Medellín.

I'm at the airport in London, but due to my bargain basement plane tickets I won't arrive in Medellín for another 30 hours and then have to find somewhere to live.

After the jet lag has cleared and I find a reliable internet connection, normal service will be resumed, but in the meantime I'll post when I can.

By the way, the picture is the entrance to the psychiatric ward in Hospital San Vicente de Paúl, which like the rest of the hospital, is remarkably beautiful.

Consciousness and the 'myth of the self' are tackled in an interesting discussion with philosopher Thomas Metzinger on this week's edition of ABC Radio National All in the Mind.

Metzinger is one of a relatively new breed of philosopher who actually gets his hands dirty with the business of experimental cognitive science and has co-authored some of the recent widely discussed studies that induced 'out of body experiences' in the lab.

The interview focuses on the material from his new book, Ego Tunnel, which seems to be getting quite a bit of attention recently.

I've not read it but it was reviewed very positively by Metapsychology, probably the best mind and brain book review site on the net. Nevertheless, I do have to agree with a point in the somewhat snarky New Scientist review that contrary to what the blurb says, this is neither a new nor radical approach and is accepted by most philosophers of mind.

The interview is fascinating though, not least because Metzinger is very articulate, but also because he gets wonderfully side-tracked into discussing his own experiences with altering his consciousness and how this relates to this work in understanding the mind.

I also recommend the extended discussions on the All in Mind blog where he explains his original look at an ethics of consciousness and discusses alien or anarchic hand syndrome.

Link to AITM discussion with Metzinger.
Link to AITM blog post with mp3s of extra discussions.

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

Cutting-edge technology has renewed the search for a better lie detector. Some show promise, but they have yet to be tested in court. Excellent piece from law publication ABA Journal.

Newsweek has some remarkable brain images with the low-down on what they mean.

Monitoring your pulse during a gambling task can lead to better decisions, according to a study covered by Frontal Cortex.

Prospect Magazine ponders the relevance of neuroscience discoveries to left and right wing political assumptions about human nature.

Is it possible to visualise sensory impossibilities? asks The Splintered Mind.

The New York Times has a piece on 'How Nonsense Sharpens the Intellect' which should be called how reading a short story by Kafka improves implicit learning on a pattern detection task.

The XMRV virus is detected in two thirds of patients with chronic fatigue syndrome, according to a great write-up by Not Exactly Rocket Science. Although as chronic fatigue is both a common post-viral symptom and also not tied to any one condition, whether this 'explains' chronic fatigue, as some media reports have claimed, is another matter,

Scientific American updates on one of our earlier posts on the development of a 'cocaine vaccine'. Let's hope they never need eye surgery, where cocaine is used medically. Also, great coverage from Neuroskeoptic.

Cut! The Neurocritic reviews the neurocinema hype.

The LA Times has a piece on the difficulties with assessing and treating 'mild traumatic brain injuries' on the sports field and battlefield.

There's a useful summary of talks on the anthropology of psychiatry over at Somatosphere.

The Guardian has a good Chris French piece on the waking nightmare of sleep paralysis.

The placebo effect works for high definition TVs too, according to research covered by New Scientist.

The Independent has a piece on arachnophobia.

fMRI willy waving or next step in neuroimaging technology? Clearly both. Medill Reports covers the University of Illinois at Chicago's prototype 9.4 Tesla MRI machine.

Nature has an excellent piece on the greatest hits and misses of new genetics technique genome wide association studies, including a discussion of the recent research on schizophrenia.

The latest Nature NeuroPod podcast has just been released and covers the use of the hot new genetics technique genome-wide association studies in neuroscience, sections on colour-blindness and stroke, and a recent study on learning in patients in coma-like states.

The discussion of genome-wide association studies (GWAS) is interesting in light of some headline studies that have come along recently on schizophrenia, autism and Alzheimer's disease. There's also a fantastic article in this week's Nature that discusses the successes and failures of the technique, including in recent studies on the genetics of schizophrenia.

Perhaps the most interesting section is the discussion on how patients in a coma-like 'persistent vegetative state' (PVS) can show conditioned learning where they can associate different sensations. Not all unconscious patient could show learning, but the ones that did showed much better recovery from their severe brain damage.

Link to NeuroPod page.
mp3 of this edition.

There are a couple of excellent posts on Neurophilosophy covering recent studies that demonstrate the powerful effect of vision on the perception of physical sensations in our body.

The first covers an interesting study that found that looking directly at your hand reduces laser-induced pain compared to a condition where you are only looking at a visual substitute created with a mirror reflection of the other hand (akin to a mirror box set up).

The second post discusses the possibilities of taking advantage of the 'rubber hand illusion' to allow us to feel like we're physically inhabiting virtual bodies.

Numerous experiments have shown that we look at a rubber hand being touched simultaneously and in the same way as our real hand, the sensation seems to be located in the fake.

This new experiment attempted something similar but in virtual reality, demonstrating that a synchronised 'touch' could be perceived as arising from an avatar hand in a 3D computer generated environment.

While the same research team had demonstrated this effect before this new study showed how the effect could transfer, albeit more weakly, to a virtual arm controlled by a brain-computer interface driven solely from EEG readings.

Both of these studies demonstrate how vision is integrated with tactile information from the body to create our sense of body image, ownership and sensation and both get a great write-up from Neurophilosophy.

Link to Neurophilosophy post visual pain reduction.
Link to Neurophilosophy on the 'virtual hand illusion'.

This clip, from the US version of comedy show The Office, shows Jim training co-worker Dwight to expect a sweet everytime he reboots his computer.

From Vodpod.

Psychologists everywhere will recognise this an an application of classical conditioning. The 'scientist' Jim has heard of is, of course, Ivan Pavlov.

Thanks to Russ Fazio for showing us this clip during his keynote at the recent BPS Social Psychology Section conference.

There's a curious case published in the medical journal Epilepsy and Behavior of a young man who had his epilepsy triggered by the sight of stairs. This would cause seizures that would trigger "repetitive hugging and affectionate kissing of one of the people around him".

Our patient is currently 24 years old. He is a right-handed male with a history of right temporal lobe epilepsy. He had his first seizure when he was 10 years old. His seizures usually started with an aura of a “feeling” inside his body or abdomen. This feeling, described at times as pain or nausea, lasted a few seconds or a few minutes. His eyes would then widen, he would become confused, and he would look around right and left as if wondering. The seizure would last 1 to 2 minutes with altered consciousness, spitting, and often repetitive hugging and affectionate kissing of one of the people around him.

At times this was followed by head and eye deviation to the left and, sometimes, rotation of the whole body to the left side. Occasionally, he would walk around for a few seconds. These seizures were often precipitated by looking at stairs, whether or not he was walking up the stairs. He learned to avoid looking at stairs to avoid having seizures. He also noted that looking down a flight of stairs did not precipitate his seizures.

I am constantly amazed by both how seizures can be triggered by very specific experiences (such as seeing a certain thing, or hearing a specific sound) and how they can lead to very selective actions.

This is by no means a typical effect of epilepsy but it does raise the interesting question of how these very narrow experiences lead to destabilising brain states which trigger a seizure.

I have heard anecdotal reports from several clinicians that they've met patients who can 'think their way out' of a seizure by deliberately focusing their thoughts on a specific topic, presumably which reduces the destabilising effect of their original 'trigger experience'.

I've not seen this discussed in the medical literature though, so if you know of any articles that do tackle it, I'd love to hear about them.

Link to PubMed entry for stair triggered epilepsy case.

New Scientist has a fantastic issue on 'strange journeys of the mind' that has three great articles on the twilight zone of sleep, simulating psychopathology with hypnosis and laboratory-induced out-of-body experiences.

The piece on the hypnotic simulation of brain disturbances is fantastic, not least because it features two researchers I work with, Peter Halligan and David Oakley, who have done some of the seminal work in the area.

Essentially, the approach views hypnosis as a tool that allows researchers, with the co-operation of the participant, to temporarily alter mental states in a completely safe and reversible way.

Importantly, these alterations, such as blindness or paralysis, seem like they're happening 'on their own' - which helps us understand conditions like conversion disorder, where these sorts of symptoms appear without any neurological damage but without the patient seeming to have any control over them.

The other article which blew me away was on recent studies suggesting that sleep and alertness are not two distinct states of consciousness and in some people with a dementia-like brain disorder the boundaries between sleep and wakefulness completely break down.

That this can happen contradicts the way we usually think about sleep, but it came as no surprise to Mark Mahowald, medical director of the Minnesota Regional Sleep Disorders Center in Minneapolis, who has long contested the dogma that sleep and wakefulness are discrete and distinct states. "There is now overwhelming evidence that the primary states of being are not mutually exclusive," he says. The blurring of sleep and wakefulness is very clear in status dissociatus, but he believes it can happen to us all. If he is right, we will have to rethink our understanding of what sleep is and what it is for. Maybe wakefulness is not the all-or-nothing phenomenon we thought it was either.

Finally, the piece on out of body experiences covers the work of Swiss researchers who have been studying these states in people with brain disorder, and managing to induce them in volunteers in a number of inventive ways.

Three awesome articles, all worth your time, all open-access. Three cheers New Scientist.

Link to article on sleep states.
Link to article on hypnotic simulations.
Link to article on out-of-body experiences.

Electrical readings from seven patients who died in hospital suggest that the brain undergoes a surge of activity at the moment of death, according to a study just published in the Journal of Palliative Medicine.

Palliative care is a medical approach that aims to make dying patients as comfortable as possible. As part of this, doctors from George Washington University Medical Centre's intensive care unit were using standard alertness monitors for seven patients that include EEG measurements of the frontal lobes.

The monitors are commercial devices designed to help anaesthetists monitor how 'awake' patients are, and they combine the electrical readings from the brain into a single signal that reflects alertness.

For each of the seven patients, the researchers noticed that at the point where blood pressure dropped to zero there was a surge in brain activity. The graph on the right is from one of the patients and shows a typical activity burst.

This is not the first time these have been noticed, but previous reports were single cases and the electrical surges were explained away as due to electrical interference from other sources. In these new cases, the doctors could be pretty confident that previously suggested sources of interference weren't present.

Instead, they suggest that the surge was due to 'anoxic depolarisation' - a process where the lack of oxygen destabilises the electrical balance of the neurons leading to one last cascade of activity.

Now, this is just a case series and the neuroelectrical measures aren't the best. The researchers encourage more systematic research with appropriate tools, but they do suggest an intriguing hypothesis with regard to 'near death experiences':

We speculate that in those patients who suffer cardiac arrest who are successfully revived, they may recall the images and memories triggered by this cascade. We offer this as a potential explanation for the clarity in which many patients have "out of body experiences" when successfully revived from a near death event.

One of the difficulties, of course, is that although 'near death experiences' are a well-known phenomenon, we only know about them from people who weren't really dying (or even from people who were never actually 'near death' as one of my favourite studies attests).

Nevertheless, neuroscience studies on the dying are likely to be of increasing interest especially as the debate about what counts as death become more prominent.

Link to DOI entry and summary of study.

In what sounds like a plot from an animated sci-fi film, I've just found a remarkable study where Japanese researchers put a Yoga Master in a brain scanner and fired lasers at him because he claimed not to be able to feel pain while meditating.

It turns out that he showed significantly less brain activity in areas typically activated by pain when meditating.

Intracerebral pain processing in a Yoga Master who claims not to feel pain during meditation.

Eur J Pain. 2005 Oct;9(5):581-9.

Kakigi R, Nakata H, Inui K, Hiroe N, Nagata O, Honda M, Tanaka S, Sadato N, Kawakami M.

We recorded magnetoencephalography (MEG) and functional magnetic resonance imaging (fMRI) following noxious laser stimulation in a Yoga Master who claims not to feel pain when meditating. As for background MEG activity, the power of alpha frequency bands peaking at around 10 Hz was much increased during meditation over occipital, parietal and temporal regions, when compared with the non-meditative state, which might mean the subject was very relaxed, though he did not fall asleep, during meditation.

Primary pain-related cortical activities recorded from primary (SI) and secondary somatosensory cortices (SII) by MEG were very weak or absent during meditation. As for fMRI recording, there were remarkable changes in levels of activity in the thalamus, SII-insula (mainly the insula) and cingulate cortex between meditation and non-meditation. Activities in all three regions were increased during non-meditation, similar to results in normal subjects. In contrast, activities in all three regions were weaker during meditation, and the level was lower than the baseline in the thalamus.

Recent neuroimaging and electrophysiological studies have clarified that the emotional aspect of pain perception mainly involves the insula and cingulate cortex. Though we cannot clearly explain this unusual condition in the Yoga Master, a change of multiple regions relating to pain perception could be responsible, since pain is a complex sensory and emotional experience.

I have an image of scientists shielding their eyes as lasers fail to penetrate the force field of the Yoga Master who serenely hovers a few inches above the ground, although I suspect that's because I've read too many manga comics

Link to PubMed entry for study,

RadioLab has a brilliant short podcast on the psychological role of blinks, based on a study that found that when watching a film our blinks are remarkably synchronised.

The programme dispels the myth that blinking serves only to keep our eyes wet as apparently studies have shown that we don't blink any more or less in different humidities.

Instead, it explores a fascinating new study that found that blinks became synchronised when watching a film of another person, but not when watching landscapes or listening to stories.

Interestingly, blinks seems to be controlled so they occur at the start and end of meaning actions.

This is from the study abstract:

Synchronized blinks occurred during scenes that required less attention such as at the conclusion of an action, during the absence of the main character, during a long shot and during repeated presentations of a similar scene. In contrast, blink synchronization was not observed when subjects viewed a background video or when they listened to a story read aloud. The results suggest that humans share a mechanism for controlling the timing of blinks that searches for an implicit timing that is appropriate to minimize the chance of losing critical information while viewing a stream of visual events.

Blinking helps us comprehend the world. I find that quite amazing.

We know that blinking is also tied to some quite fundamental functions of the brain. For example, the higher the amount of spontaneous blinking you do, the higher the amount of dopamine you produce in the striatum, a deep brain area.

This is also links to your ability to stop unwanted actions, with a recent study linking higher blink rates to slower stop times.

As always the RadioLab programme is gripping audio velvet. I really recommend some headphones and 15 minutes of undisturbed time to lose yourself.

Link to RadioLab short podcast 'Blink'.
Link to full text of blink synchronisation study.

Earlier this year we covered a study on REM sleep behaviour disorder (RBD) where normal sleep paralysis breaks down and sleepers act out their dreams. The Journal of Forensic Science has just published a study on the dark side of the disorder, where affected sleepers experience nightmares and can unknowingly damage themselves or their partners in fits of dream world violence.

The researchers examined all the published cases on violence in REM sleep behaviour disorder with potential for a lethal outcome and found they fall into three groups: choking or headlock attacks, throwing someone or throwing yourself through a window, and diving from the bed.

Some of the descriptions are pretty intense:

A 63-year-old man with RBD and delayed-onset Shy-Drager Syndrome reported "a progressive 10-year history of abnormal behavior during sleep. He would at various times choke, kick, punch, and spit on his wife while he was asleep. In addition, complex behaviors such as getting out of bed and running into walls while asleep were reported by family members. This behavior occurred while the patient was dreaming, usually of being attacked.

A 67-year-old man had a 3-year history of progressive stiffness and slowing of his left side. Five years before the onset of these symptoms, he began having vivid dreams together with violent movements during sleep. Once he dreamed of being trapped in a house on fire, and he almost jumped out of the window, if not for his wife awakening and restraining him.

A 25-year-old woman with multiple sclerosis "presented with a 6-month history of sudden awakenings from fearful, often vivid…dreams and with terrified screams or violent behavior such as kicking, running to the door or to the window, crying and falling out of bed. If awakened, she always recalled a fighting dream. Once she repetitively banged her head against the floor, inducing a large facial hematoma. On that occasion, she was dreaming that a man was knocking her against the wall.

The idea that someone could be violent during sleep without any awareness was initially treated with suspicion but it has since been confirmed in sleep labs where patient are video-taped and wired up to an EEG to confirm they are in REM sleep.

There have now been numerous legal cases where 'sleepwalking violence' has been used as a defence for murders or attempted murders, and at least one case where it led to a successful acquittal.

Link to summary of RBD lethal violence study.