The shadows of the moon

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?

Colombia bound

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 Pa√∫l in Medell√≠n.

I’m at the airport in London, but due to my bargain basement plane tickets I won’t arrive in Medell√≠n 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 Pa√∫l, which like the rest of the hospital, is remarkably beautiful.

A shadow of your former self

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.

2009-10-09 Spike activity

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

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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.

NeuroPod on learning in coma-like states

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.

Feeling the body in a new light

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’.

Pavlov, Office Style

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.

Stairway to loving

Photo by Flickr user larry&flo. Click for sourceThere’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.

Strange journeys of the mind

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.

Spike at the end of the tunnel

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.

Strung out on lasers

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,

Blink outside the box

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.

Night terrors and night terrorists

Photo by Flickr user Jon Haynes Photography. Click for sourceEarlier 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‚Ķdreams 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.

One nagging thing…

Photo by Flickr user jcoterhals. Click for sourceThe BPS Research Digest has a fantastic feature where they’ve invited some of the world’s leading psychologists to discuss one nagging thing they still don’t understand about themselves.

Some take the challenge as a query about themselves as human beings, others about them personally, and the answers are a wonderful mix of the scientific and personal, the profound and ephemeral.

This is one of the many highlights, from social psychologist Norbert Schwartz, cursing his inability to detect his own biases:

One nagging thing I don‚Äôt understand about myself is why I‚Äôm still fooled by incidental feelings. Some 25 years ago Jerry Clore and I studied how gloomy weather makes one‚Äôs whole life look bad — unless one becomes aware of the weather and attributes one‚Äôs gloomy mood to the gloomy sky, which eliminates the influence. You‚Äôd think I learned that lesson and now know how to deal with gloomy skies. I don‚Äôt, they still get me. The same is true for other subjective experiences, like the processing fluency resulting from print fonts [pdf] ‚Äì I still fall prey to their influence. Why does insight into how such influences work not help us notice them when they occur? What makes the immediate experience so powerful that I fail to apply my own theorizing until some blogger asks a question that brings it to mind?

In fact, there are several pieces where psychologists gently bemoan their inability to apply their research findings to their own life, giving the series a slightly wistful feel.

Link to BPS Research Digest ‘One nagging thing…’ series.

Rubbish in the margin

One of the most influential and controversial papers in psychiatry was from a 1976 study published in The Lancet that found that people with schizophrenia had larger fluid filled ventricles in the brain.

Yesterday, I looked up the original paper in London’s Institute of Psychiatry library and was amazed to see that the controversy seems ingrained into the paper copy, which has been ripped, repaired, damaged and defaced.

In the early days of scientific psychiatry, during the 1800s, many famous German psychiatrists expended a great deal of effort examining the post-mortem brains of patients with schizophrenia (also known at that time as dementia praecox) attempting to demonstrate Wilhelm Griesinger’s theory that “all mental illness is disease of the brain.”

Despite numerous studies, they were unable to replicate the success of studies on dementia, which they linked to specific changes in the brain. So for generations, schizophrenia came to be defined as a condition in which the brain was structurally normal.

This fact was often highlighted by the antipsychiatry movement to suggest that ‘mental illness’ was nothing more than a difference in human experience and there was no medical evidence supporting the work of psychiatrists.

But the fact was also cited by many psychiatrists resistant to the relatively new wave of medications that had appeared on the scene. The drugs were claimed to ‘fix’ the brain with the assumption that the discovery of clear evidence for brain differences would just be a matter of time.

Enter Eve Johnstone and her colleagues at Northwick Park Hospital in London, who, in the midst of this politically charged environment, completed a study that compared CAT brain scans of 18 patients with schizophrenia to a group of healthy control participants. Alongside the scans, the researchers also tested the participants’ mental abilities with psychological tests.

The results were striking. They found the size of the ventricles, the fluid filled spaces in the brain, was, on average, larger in patients with schizophrenia and that it was correlated with the degree of difficulty with tests of memory, concentration and problem solving.

This caused enormous interest and controversy at the time. The paper copy from London’s Institute of Psychiatry library clearly reflects this, as it has been read so many times (and possibly ripped out) that it is virtually in tatters and has been reattached with sticky tape in an otherwise pristine copy of the journal.

There are a few annotations on the page, including the word “Rubbish” written in the margin!

Although seminal, the study has been rightly criticised and one of the major difficulties with these sorts of studies is that because patients are normally taking antipsychotic medication, it’s hard to distinguish where the effect is linked to schizophrenia or the treatment.

While some medication is thought to also thought to affect brain structure, a study on patients that have never taken medication seem to suggest some differences in ventricle size, on average, are still apparent.

The ‘on average’ bit is important though, as these differences are not present in everyone with the diagnosis. They’re just an average difference when you compare a group of people with and without schizophrenia. Furthermore, we’re still not quite sure of its significance.

So the topic is still as controversial as when Johnstone’s study first appeared in 1976, although the argument has shifted from whether differences in the structure of the brain are associated with schizophrenia, to whether they are telling us anything useful.

Link to scan of article from Institute of Psychiatry library.
Link to PubMed entry for same.

Lightning-induced robotic speech

Photo by Flickr user swamysk. Click for sourceI just found a curious case study of a man who developed ‘robotic speech’ after being hit by lightning. Rather than the “I am a Dalek!” style mechanical sound it seems to be more like the very. deliberate. and. exact. speech synthesis style, somewhat like Data from Star Trek the Next Generation

Lightning-induced robotic speech

Neurology. 1994 May;44(5):991-2.

To the Editor

Because of a recently observed case, I was intrigued by the communication of Cherington et al[1] concerning lightning encephalopathy. The authors referred to evidence by Critchley[2] that the cerebellum can be selectively injured in lightning-struck patients, Two of their there patients had signs of cerebellar dysfunction. MRI in one of their patients evidenced superior cerebellar atrophy.

The force of a lightning strike threw a 20-year-old roofer to the ground from the truck in which he was standing. Panicked, he immediately began to run. A numbness and weakness of his arms and back cleared after several days, but the more striking abnormality was a profound alteration of his speech, which he described as having become robotic. Each syllable was clearly enunciated with a slight pause between syllables, so that while the flow of his speech was slowed, he was able to communicate well. His speech was actually easier to comprehend than that of some normal persons. His brother had indeed complained that the patient’s premorbid speech had been too rapid and word-jumbled; that speech was transformed to robotic speech, with fine diction and super-clear enunciation. Each morning, his speech was “normal” until shortly after he began to talk, when it reverted to the robotic pattern for the remainder of the day. The neurologic examination was normal except for right upper extremity hypalgesia. Brain MRI was normal.

I considered his robotic-speech problem to be most like the “scanning speech” of cerebellar disease. I have found no references to similar cases, but the reports of selective cerebellar injury by lightning strike[1-3] lead-me to suspect that robotic speech maybe a more common sequel than has been recognized.

Gordan J. Gilbeft, MD
St. Petersbutg, FL

1. Cherington M, Yarnell P, Hallmark D. MRI in lightning encephalopathy. Neurology 1993; 43(7):1437-8
2. Critchley M. Neurological effects of lightning and electricity. Lancet 1934;1:68–72
3. Morocutti C, Spadaro M, Amabile G. TRH treatment in cerebellar ataxia following a lighting stroke. Ital J Neurol Sci 1989;10:531.

The original authors reply and seemed somewhat baffled, saying that it could equally arise from the shock of the experience rather than damage to the brain.

Link to PubMed entry for case study.