Category: Inside the Brain

Wired magazine has just published a must-read article on the hyping of neuroimaging technology by companies wanting to sell brain scans on the deceptive premise that they can tell you something about your mood and personality, the effectiveness of adverts or whether you’re being truthful.

Here at Mind Hacks, we’ve covered several highlights in the ongoing parade of brain scan powered bullshit in the past (FKF Applied Research I’m looking at you) but this new article, by psychiatrist Daniel Carlat, is an engaging guide that tackles many of these issues in one go.

Neuroimaging studies that measure brain function are almost always done on large numbers of people and the results are usually only reliable when average differences between groups are compared. This makes it difficult to make sensible judgements about any one individual.

Brain scanning is also often reported as if it is revealing exactly which parts of the brain do what, but it typically only reports associations.

For example, an experiment might find that fear is associated with amygdala activation. But it’s impossible to say the reverse, that every time the amygdala is activated, the person is fearful.

Here’s an analogy. On average, people from New York may be more impatient than people from other cities.

If you predicted that all people from New York were impatient on the basis of this, you’d be grossly mistaken so many times that it would make your prediction invalid.

In fact, taking the average attributes of populations and applying them to individuals is stereotyping, and we avoid it because it is so often wrong as to cause us to misjudge people.

Alternatively, if you met an impatient person and therefore concluded that they must live in New York, you’d be equally inaccurate.

But this is essentially what these commercial brain scan companies are doing, but they are selling it as if it is reliably telling us about an individual person or an individual product because people tend to be blinded by the fact it just seems more scientific. After all, it’s neuroscience right?

Scientists and responsible clinicians will know about these shortcomings and make sure they don’t oversell their findings, but commercial companies are not selling you the data, they’re selling you a way of make you feel better about your insecurities, whether they be commercial concerns or health worries.

Interestingly, the Amen Clinic comes in for criticism which seems to specialise in pushing and overinterpreting SPECT scans to patients.

These guys were the subject of a similarly critical article in Salon the other week and were pulled up the the Neurocritic blog last year for suggesting political candidates should be brain scanned to see what sort of people they are.

If you want to be immune to this sort of nonsense, the Wired article looks at some of the current commercial offerings and how they’re trying to sell you short.

Link to article ‘Brain Scans as Mind Readers? Don’t Believe the Hype’.

Science News has an article on one of the most important future topics in neuroscience – epigenetics, the science of how information coded in the genes is used when the brain does its work.

Almost every cell in the body has a copy of the DNA, and therefore has the capability to express any protein.

But you wouldn’t want proteins that are used for digesting food produced in the brain, so the body has various ways of regulating which proteins get expressed at any one time. This is epigenetics.

If DNA is like a blueprint, epigenetics is the committee of civil engineers that coordinate the construction site.

We’ve known from twin studies and molecular genetic research that genes and the environment both influence cognition and behaviour, but these studies only give statistical associations. What they don’t tell us is how this happens.

In a sense, epigenetics is the scientific glue that allows us to understand how genes influence learning and behaviour, but also how learning and behaviour influences the expression of genes.

In other words, its goal is to explain how the environment combines with genetic information in the brain.

Needless to say, much epigenetic research is focusing on mental illness, the classic example of how genetic risk, experience and environment combine with sometimes disastrous consequences.

One of the most interesting aspects is that there is growing evidence that epigenetic information can be inherited. So your experiences may actually cause changes to gene regulation that are then passed on to offspring.

Link to Science New article on epigenetics.
Link to abstract of good review article on epigenetics and cognition.

Neurophilosophy has a fascinating article on the recent archaeological discovery of numerous ancient Incan skulls of which over 1 in 6 showed signs of trepanation – an ancient form of brain surgery where a hole was drilled in the skull.

What’s surprising is just how common it was. 66 skulls from Incan burial sites had a total of 109 trepanation holes. Some, like the one pictured, obviously needed a significant amount of skill and practice to complete.

And with this many examples, the archaeologists could make some fascinating inferences about the purpose and success of these operations:

Andrushko and Verano argue that the Incas performed trepanation primarily to treat head injuries incurred during battle, because the holes are most often found at the front of the skull to the left, consistent with injuries caused by a right-handed opponent during face-to-face combat, and because adult males are overrepresented in the sample. The procedure was evidently used to treat mastoiditis (an infection of the region of the temporal bone behind the ear) as well.

The authors also show that the success rate of the procedure improved with time, as the Inca empire progressed and made advances in medicine. The earliest specimens, dated to around 1,000 A.D., showed no signs of bone growth around the perforations, suggesting that the procedure was often fatal. But specimens dating to around 400 years later suggest a survival rate of around 90%.

Link to Neurophilosophy article on prehistoric Inca neurosurgery.

Phantom limbs are a well-known phenomenon where sensations and feelings are still experienced from a missing limb. In rare cases after brain injury, an additional phantom limb can appear – causing the sensation of a phantom third hand, arm or leg.

The drawings on the left are from two case studies of people with these ‘supernumerary phantom limbs’ recently published in the journal Neurology. They show an artist’s impression of the body sensations of two patients who suffered brain stem strokes.

Both patients had the experience of having a third arm and a third leg, although the male patients had the leg ‘appear’ along the midline of the body, while the female patient seemed to experience it ‘superimposed’ upon an existing leg.

One distressing element for the female patient was that although the patient could ‘move’ the phantom arm voluntarily, “she described occasional loss of control and feeling strangulated by the phantom arm around the neck”.

Two earlier case studies from neuropsychologist Peter Halligan and colleagues reported similarly disembodied extra limbs, but this time after damage to the right hemisphere of the brain.

As is more common after right hemisphere damage, these tended to have a delusional quality, so they weren’t just sensations – the patients genuinely believe their additional limbs existed.

One gentleman believed that he had a third arm in the middle of his body, and another believed that he had a third hand.

In this last case, the patient reported actually ‘seeing’ the additional limb, similar to this case study of a gentleman who believed he had a third leg protruding from his left knee after suffering a stroke that affected the thalamus:

He consistently maintained that the phantom leg was attached to his knee with a “bone plate” that “had no flesh on it”. However, he reported that the phantom limb itself looked normal and had a shinbone and a foot. It usually “appeared” in the morning when he was helped to put on his trousers. The patient stated that the phantom limb prevented him from turning over in bed, but did not adversely affect him otherwise.

When asked about how he knew about this leg he said that he could see it (despite his severe visual impairment) and feel it with his hand. He believed that the phantom limb belonged to him, although he readily accepted that it was not “normal” to have three legs. Initially he reported that the “leg” was growing from his own knee, but then reasoned that (given its size) he would have noticed it before the stroke.

At other times he believed the leg was attached to him by the nursing staff, but could not explain why. The patient was aware of phantom limb phenomena as his wife was an amputee. He was also aware that a stroke may affect perception and cognition. He did not believe either issue applied in his case.

The experience of a ‘supernumerary phantom limb’ is usually the result of a brain injury and typically resolves over time.

Phantom limbs are thought to arise because the somatosensory cortex, the part of the brain that represents the body’s sensations and feelings, reorganises so that the area previously used to represent the limb is partially ‘re-used’ for other functions, meaning the sensations sometimes get activated when these other functions are active.

Nevertheless, supernumerary phantom limbs are still mysterious, largely due to the small number of cases and diverse brain areas involved.

There is some suspicion that they might be caused because of disrupted communication between parietal lobes, which are known to represent body image, and the sensory feedback from the nerves in the body.

Link to abstract of Neurology case studies.
Link to full text of 1993 case study.
Link to full text of 1995 study.

I’m thoroughly digging the brain section of the Radiology Picture of the Day website. As you might expect, it’s a wonderfully geeky place where radiologists post an image every day, often brain CTs or MRIs, with a little gem of wisdom with each one.

One of the most interesting is the pictured CT scan with a ‘ring artefact’. I’ve contrast enhanced the image so you can see the circle or ring near the centre a little more clearly.

It’s a known imaging problem caused by poor calibration of the scanner.

However, the Radiology Picture of the Day entry notes that these were given special significance by the quacktastic German physician Ryke Geerd Hamer who claimed that his ‘New Medicine’ could cure 98% of all cancers.

He gave these rings the rather immodest name ‘Hamer Foci’ and if they appeared in the brain, apparently this meant cancer was elsewhere in the body.

For Hamer, cancer was simply the body’s reaction to a psychological conflict, and presumably this was what he thought the CT scanner was picking up.

This is despite the fact that CT scans only picture large scale structure on which psychological changes make no recognisable impact.

A curious case of neuroimaging apophenia.

Link to ‘Ring Artefact with Pseudomedical Interpretation’.

To coincide with stroke awareness month, a new report from the US Government’s Center for Disease and Control and Prevention has highlighted that less than half of people surveyed could identify the potentially life-saving early warning signs of stroke.

A stroke, known medically as a cerebrovascular accident, is where the blood supply to the brain is interrupted because of blockage or damage to an essential blood vessel.

It can be fatal, and more often leads to significant brain damage, but this can be limited or a life potentially saved if it is detected and treated as soon as possible.

The following are warning signs of stroke. If someone you know experiences any of these, call an ambulance or get them medical care as soon as possible.

Sudden numbness or weakness of the face, arm or leg, especially on one side of the body

Sudden confusion, trouble speaking or understanding

Sudden trouble seeing in one or both eyes

Sudden trouble walking, dizziness, loss of balance or coordination

Sudden, severe headache with no known cause

To reduce your chances of having a stroke, you need to look after your cardiovascular health.

Essentially, healthy body, healthy brain – so alcohol, smoking, excess fatty food, little exercise and head injury will increase the chances of blood supply problems in the brain.

Link to CDC report on stroke awareness.
Link to write-up from Yahoo! News.

The Telegraph has an article and video on the Harvard ‘baby brain lab’ and some of its recent discoveries which are helping us understand how the mind and brain develops through the earliest months of life.

The research team is otherwise known as the Laboratory for Developmental Studies and is headed up by developmental psychologist Elizabeth Spelke who’s interviewed on the video.

You would think babies are difficult to test with behavioural experiments because they are can’t even stick to simple procedures, so developmental psychologists have created a task that takes advantage of the fact that infants stare at things when they’re new or interesting, but get bored and stop looking at the things they’ve seen before.

Let’s say you wanted to test whether newborn babies can tell the difference between familiar and unfamiliar people when they see their faces from different angles.

You show a picture of a person’s face, facing directly forward, until the infant becomes bored and starts looking away.

Then you flash up two new pictures both taken at the same angle, one of the original person and one of a new person. You then measure how long the infant looks at each face.

Because infants look at new or different things for longer, they would spend more time looking at the unfamiliar face if they can genuinely tell the difference. If they both seem the same to the infant, they should look at both equally, on average.

In fact, this was a recent study done on 1 and 2-day old babies, and it turns out they can tell the difference between a familiar face and a new face when the change in viewing angle isn’t too great.

Variations on this simple procedure have taught us a great deal about what babies can perceive, understand or expect, as well as how their brains function when they’re doing these tasks.

What is often most surprising is what babies can do within their first few days or birth – such as recognise faces, as in the study above – but the debate about how much these sorts of skills are due to innate knowledge, or innate rapid learning mechanisms, are still raging:

Newborns have no idea what they look like, yet they enter the world equipped with a basic understand of what a face is. They know that the pink blob in the middle of a face is a tongue, and that they can poke out their own tiny tongue in just the same way. This was crucial ammunition for an intellectual war that still rages over whether we emerge from the womb as general-purpose learning machines that soak up details of our environments, or, as Spelke believes, born ‘precocious’, so we can immediately do things that are key to survival (just as newly-hatched chicks and fish can immediately do things such as navigate, or find and recognise food).
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Spelke has crossed swords with Professor Mark Johnson of Birkbeck’s Centre for Brain and Cognitive Development in London, whose studies of infant brains stretch back nearly two decades. He points out that the four and six month olds at Spelkeland have hundreds of hours of experience in categorising the world, which challenges Spelke’s ‘core knowledge’ theory. He believes that we enter the world with ‘soft biases to attend to different aspects of the environment, and to learn about the world in particular ways’.

His colleague, Prof Annette Karmiloff-Smith, who once worked with Piaget, praises some of the Spelkeland work (‘Liz has done some great behavioural experiments’) but adds, ‘Paradoxically, although she studies babies, in my view she doesn’t raise questions about infants’ capacity for learning, which may account for their extraordinary abilities without the need for them to be born with pre-specified knowledge.’

Link to article ‘Harvard’s baby brain research lab’ (via 3QD).
Link to video of Spelke interview.

This is an excerpt from quite possibly the geekiest forensic pathology article I have ever read. Three pathologists discuss the physics of how a Mexican coin ended up in the brain of a dead shooting victim.

They speculate he may have been holding it in his hand while shielding his head and the bullet impacted on the coin and both ended up deep in the brain. Oh, but with maths.

The images on the left are an artist’s reconstruction of the position of the man when shot and the path of the bullet, and a photo of the coin in the dead man’s brain.

Items that become accessory or secondary projectiles usually possess a minimal amount of energy, producing superficial or insignificant wounds. The secondary projectile in this case, a coin, gained sufficient kinetic energy to penetrate the scalp, skull, and brain. We believe the coin was being held by the decedent in his left hand next to his head at the time of the shooting. The bullet passed through the hand, producing the described injury and picking up the coin as a secondary projectile before entering the head.

The coin, a 1970 Mexican 50-centavo piece, was 25 mm in diameter with a weight of 6.4 g. In comparison, the diameter of a 1970 U.S. quarter dollar coin is 24.3 mm with a weight of 5.6 g. Both coins contain a mixture of copper and nickel, and the U.S. coin is coated with silver. The mixture of nickel and copper is relatively soft and permits deformation, as seen in this case. The primary projectile, a .380-caliber automatic Colt pistol 9- √ó 17-mm Winchester Silvertip bullet, weighs 5.1 g, with a rated muzzle velocity of 304 m/second (1000 feet/second). The mass of the conjoined projectile more than doubled with addition of the coin, yet retained sufficient velocity to produce the described lethal injury.

We attempted to see if this would be theoretically possible using some simple physical principles. Under ideal conditions, this event represents a form of an inelastic collision. We assumed that there was conservation of momentum between the oncoming bullet and the departing conjoined bullet-coin mass that subsequently penetrated the skull and brain. If momentum is conserved during this collision, then the mass of the bullet multiplied by its velocity would equal the mass of the conjoined bullet and 50-centavo coin multiplied by their departing velocity. The velocity of the bullet just prior to striking the coin is unknown and could not be determined.

For our calculations, we used the known muzzle velocity of this ammunition, understanding the limitations of such an assumption. We also calculated the kinetic energy and momentum of the oncoming bullet and exiting conjoined bullet-coin before and after collision. The results indicate two things: as expected in an inelastic collision, the kinetic energy of the conjoined bullet and coin is much less than that of the oncoming bullet, and the velocity of the conjoined projectile drops by greater than a factor of two. No doubt some of this loss in kinetic energy resulted from the energy expended in deforming the Mexican coin. The calculated loss in velocity of the bullet postcollision slows this projectile (i.e., the conjoined bullet/coin) to <150 meters per second (<450 feet/second). However, this velocity would still be well in excess of the minimal velocity needed to penetrate skin and bone, which has been reported to be about 66 meters per second (200 feet/second).

Forensic pathology has this morbid deadpan geekiness about it which just makes it so interesting to read.

You can just see them in the pathology room, arguing about what happened and sketching calculations on the back of envelopes.

Link to PubMed entry for article.

In the wake of the Nature survey that found that 20% of scientists admit to using brain enhancing drugs, Wired has just published an article detailing what drugs their scientist readers use to keep on keepin’ on.

Although the drugs issue is obviously the headline-grabber, the publication also has a great feature on cognitive enhancement that largely covers tips, tricks and techniques to boost your mental skills that aren’t drug-related.

The article itself is anecdotally interesting, but has a curious tone throughout:

Surprisingly large numbers of people appear to be using brain-enhancing drugs to work harder, longer and better. They’re popping pills normally prescribed for narcolepsy or attention-deficit disorder to improve their performance at work and school.

“We aren’t the teen clubbers popping uppers to get through a hard day running a cash register after binge drinking,” wrote a Ph.D. research scientist who regularly takes a wakefulness drug called Provigil, normally prescribed for narcolepsy. “We are responsible humans.”

Whenever people talk about using drugs, they’re always keen to distance themselves from that sort of drug user. You know, the ones that aren’t responsible.

This belies the fact that most people use most drugs with few problems. Even teen clubbers popping uppers.

While all drugs have risks and illicit street drugs increase the health risks and definitely have an impact on body and brain function, it’s only a minority of drug users who have problems that interfere with their daily lives.

For example, a recent study found that 4% of Australian workers use the (fairly nasty) drug methamphetamine. The figure rises to over 11% for 18-29 year olds. That more than 1 in 10.

While the study found that using methamphetamine significantly increases chances of a range of health problems, it’s still the minority of users that report significant problems. This is the typical pattern for studies on drug use.

In other words, drugs are bad for you but most people manage the risks. A small minority, of course, don’t, and die instantly or suffer long-term consequences.

The benefit and using and abusing prescription drugs for ‘brain doping’ is largely in the fact that you can be sure of the purity of the product and that probably (depending on how you acquire them) you’re not funding a vicious criminal network.

At the end of the day though, the process is the same, whether you’re using legal drugs, illegal drugs, for recreation or for performance.

Just make sure you’re educated about the risks and know the consequences. Just like everything else in life.

Link to Wired.com Readers’ Brain-Enhancing Drug Regimens.
Link to Wired ‘Give Your Intellect a Boost’ techniques.

This month’s Trends in Cognitive Sciences has a fantastic review article on the neuroscience of meditation – focusing on how the contemplative practice alters and sharpens the brain’s attention systems.

The full article is available online as a pdf, and discusses what cognitive science studies have told us about the short and long-term impact of meditation on the mind and brain.

Meditation is now being quite extensively studied by cognitive science owing to the clear effects it has on the brain, and on the increasing evidence for its benefit in mental health.

A recent review of ‘mindfulness’ meditation-based therapy found that although research is in its early stages and not all possibilities have been ruled out, there’s good evidence from the existing RCTs that it’s particularly good in preventing relapse in severe depression.

The Trends article, which largely focused on the neuroscience research, makes the distinction between two types of meditation: ‘focused attention’ meditation – that involves focusing on a particular thing and refocusing if you become distracted by thoughts or sensations; and ‘open monitoring’ meditation which involves nonreactively monitoring the content of experience and acting as almost a detached observer to feelings and mental events.

This is an excerpt where the authors discuss the experimental evidence for the long-term ‘open monitoring’ or OM meditation:

Long-term practice of OM meditation is also thought to result in enduring changes in mental and brain function. Specifically, because OM meditation fosters nonreactive awareness of the stream of experience without deliberate selection of a primary object, intensive practice can be expected to reduce the elaborative thinking that would be stimulated by evaluating or interpreting a selected object. In line with this idea, Slagter et al. recently found that three months of intensive OM meditation reduced elaborative processing of the first of two target stimuli (T1 and T2) presented in a rapid stream of distracters…

Because participants were not engaged in formal meditation during task performance, these results provide support for the idea that one effect of an intensive training in OM meditation might be reduction in the propensity to ‘get stuck’ on a target, as reflected in less elaborate stimulus processing and the development of efficient mechanisms to engage and then disengage from target stimuli in response to task demands. From the description in Box 2,we anticipate a similar improvement in the capacity to disengage from aversive emotional stimuli following OM training, enabling greater emotional flexibility.

Moreover, the article includes many other studies that have reported interesting effects. For example, highly experienced focused attention meditators need minimal effort to sustain attentional focus, while even short courses on meditation can improve attention and decrease stress.

Most of the techniques are taken from Buddhist meditation practices and I’m sure Buddhists are cracking a wry smile as cognitive science is just starting to catch on to what they’ve been noting for thousands of years.

As for the neuroscience, I’m sure the remarkably science-savvy Dalai Lama is fascinated as he’s held a number of conferences with leading researchers to discuss the the intersection between Buddhist practice and cognitive science.

Link to abstract of article.
pdf of full-text.

It is now quite widely known that cannabis use is linked to a small but significant increase in the chance of developing psychosis, but it is less widely known that one of the ingredients in cannabis actually has antipsychotic effects.

Unlike THC, it’s lesser known cousin cannabidiol is not responsible for the cannabis ‘high’ but it is naturally present in the plant.

There is accumulating evidence that cannabidiol has an antipsychotic effect, potentially damping down the psychosis-promoting effects of THC.

The amount of this substance varies in street cannabis, with some strains having more cannabidiol than others, and ‘skunk’ having the least of all – it being mostly eliminated by selective breeding for high THC content.

An ingenious new study looked at levels of cannabidiol consumption in groups of cannabis smokers by testing hair samples, and found that the groups who had the lowest cannabidiol levels had the most psychosis-like experiences.

In contrast, those with the most cannabidiol levels had the least psychosis-like experiences – equal to a comparison group with no detectable cannabis compounds who were presumably non-smokers.

One caveat is that the participants were all recruited from a study on ketamine users (a substance known to raise the risk of psychosis), so the study will have to be repeated on people who solely use cannabis to be sure the effect isn’t a specific interaction between the two drugs.

However, the results seem to tie up with what we already know about how THC and cannabidiol work, so may reflect a genuine effect.

As any visitor to Amsterdam will tell you, cannabis breeders often try to maximise THC content to grow a plant with more ‘bang for the gram’.

As cannabidiol seems to have no effect on the high itself, perhaps we might see breeders also trying to maximise the cannabidiol content in future, potentially reducing the risk to smokers’ mental health.

UPDATE: A reader who prefers to remain anonymous sent in the following interesting comment:

Cannabidiol is in fact bred for in cannabis product, but is mainly done for taste. There are mentions within the cannabis breeding literature (i.e. seed catalogues) on breeds which lack psychosis (often defined as “low paranoid strains”), and these correspond to the “tasty” breeds to a great extent.

Probably ‘lacking psychosis’ would be considered controversial by the scientific community, but it’s interesting that the growing and smoking community make the distinction between high and low ‘paranoid strains’. It’d be interested to see whether these stand up to scientific investigation.

Link to abstract of scientific study.

The New York Times has a fantastic article on the remarkable artistic talent seemingly released in some people with fronto-temporal dementia (FTD) – a condition where frontal and temporal lobes start deteriorating.

Dementia is any condition where the brain or brain function deteriorates quicker than would be expected through normal ageing.

This can occur because of still poorly understood Alzheimer’s-like changes involving abnormal protein accumulation in the brain, or often, because the blood vessels start dying and deteriorating, leading to the death of the brain areas they serve.

A mix of both is not uncommon but the damage to the brain is often uneven and patchy, meaning that while mental function generally declines, specific skills and abilities can be impaired while others are left relatively intact.

Some brain areas are particularly involved in controlling or inhibiting others, meaning if these areas are damaged, the areas they ‘control’ can suddenly begin to work overtime (its like if you damaged the break on a car, often it would speed up when you didn’t want it to).

In fact, if these systems break down due to brain damage, we can regain reflexes we had when we were first born – such as automatically grasping things put in the hand – but which the brain inhibits as it matures.

The NYT article discusses a recent case study published in the medical journal Brain that suggests that this same process may release brain circuits leading to new artistic talents and skills.

From 1997 until her death 10 years later, Dr. Adams underwent periodic brain scans that gave her physicians remarkable insights to the changes in her brain.

“In 2000, she suddenly had a little trouble finding words,” her husband said. “Although she was gifted in mathematics, she could no longer add single digit numbers. She was aware of what was happening to her. She would stamp her foot in frustration.”

By then, the circuits in Dr. Adams’s brain had reorganized. Her left frontal language areas showed atrophy. Meanwhile, areas in the back of her brain on the right side, devoted to visual and spatial processing, appeared to have thickened.

When artists suffer damage to the right posterior brain, they lose the ability to be creative, Dr. Miller said. Dr. Adams’s story is the opposite. Her case and others suggest that artists in general exhibit more right posterior brain dominance. In a healthy brain, these areas help integrate multisensory perception. Colors, sounds, touch and space are intertwined in novel ways. But these posterior regions are usually inhibited by the dominant frontal cortex, he said. When they are released, creativity emerges.

The art of Anne Adams, the subject of the case study, can be seen on two websites and the NYT article contains a couple of striking pieces.

Link to NYT article ‘A Disease That Allowed Torrents of Creativity’.
Link to PubMed abstract of scientific study.

The Boston Globe has an interesting article on the concept of ‘brain death’. The criteria for brain death are being contested and it’s become a hot issue, partly because the US allows organs from consenting donors to be removed when brain death has been diagnosed.

The ‘dead donor rule’ stipulates that it’s only possible to remove organs in cases where a person has died, and this can either be after cardiac death, where the heart and lungs stop functioning, or after brain death, where the brain suffers irreversible damage which causes coma where the patient is kept alive solely by life support.

Most organs donated from the deceased come from people who have been diagnosed as brain dead. Organs remain viable for only about an hour or two after a person’s last heartbeat. Brain dead patients are ideal candidates for organ donation, then, because they are kept on ventilators, which means their heart and lungs continue to work, ensuring that a steady flow of oxygen-rich blood keeps their organs healthy. Surgeons remove the donor’s organs, then shut off the ventilator. The patient’s heart eventually stops.

Yet a small but vocal minority in the medical community has always insisted that some brain dead patients may not be dead. For instance, one study documented some kind of brain activity in up to 20 percent of people declared brain dead, suggesting to some critics that doctors sometimes misdiagnose the condition. Although some neurologists contend the claim, University of Wisconsin medical ethicist Dr. Norman Fost points to research showing that many “brain dead” patients have a functioning hypothalamus, a structure at the base of the brain that governs certain bodily functions, such as blood pressure and appetite.

It’s an challenging that speaks directly to our idea of what divides life and death. There is no question that any of the patients will recover, regardless of any residual activity detected in their brain.

But it prompts the question of what sort of brain activity we consider human enough to constitute life.

Of course, the issue is compounded by the importance of life-saving organ donation operations, for which suitable organs are almost always in short-supply.

Link to Boston Globe article ‘Fatal flaw’.

Wired Science have got a great short film that follows a two people who have deep brain stimulation devices implanted in their brains to treat tremors.

Tremor is a symptom of Parkinson’s disease and this was one of the earliest targets for early DBS trials.

The film follows someone who has exactly this difficulty, plus someone who has a different form a tremor disorder, known as essential tremor, through the process of the operation.

While most people assume brain surgery is all pre-planned beforehand, for many treatments for cognitive or behavioural functions, the surgeons need to wake up the patient after they’ve open their skull to make sure they’re targeting the right place (and avoiding damaging essential functions).

In this case, they wake the patients up during neurosurgery so they can test out their movements while stimulating different areas of the brain, in a trial and error style.

Wired Science also has a shorter film online about the post-mortem dissection of a brain of a patient who had Alzheimer’s disease that’s also well worth having a look at.

Link to video of deep brain stimulation neurosurgery.
Link to video on ‘The Brain of an Alzheimer’s Patient’.

A case of a man with unstoppable hiccups has just been published online in the medical literature. Rather unusually, it turned out they were caused by early stage Parkinson’s disease.

Parkinson’s disease is most commonly associated with movement difficulties and the public most associate it with tremor or shaking.

However, it can have a wide range of other effects (more recently, problems with cognitive functions and mental health have been recognised), although this seems to be the first time hiccups have been reported as an early symptom.

The case study is reported in the journal Parkinsonism and Related Disorders:

The patient was a 62-year-old male who had been suffering from intractable hiccups for more than 6 months. The initial intermittent nature of hiccups became continuous over time. When he was quiet, the hiccups were more prominent, although his symptoms tended to decrease when he was speaking.

The hiccups frequently interrupted his speech particularly towards the end of a sentence. The hiccups tended to disappear when he was asleep. Hiccup frequency increased with emotional stress such as anxiety and anger. The patient was depressed and socially isolated due to the embarrassment caused by his continuous hiccups.

It’s a curious case, but the paper also contains a fascinating paragraph on the causes of hiccups. One cause can be with (unsurprisingly) the organs in the chest, but another can be disruption to part of the brainstem called the medulla.

The causes of hiccup can be divided into ‘peripheral’ and ‘central’. A wide variety of peripheral conditions can cause hiccup including: gastroesophageal pathologies, renal failure, malignancies, medications, abdominal surgery and even myocardial infarction.

Central causes can result from structural or functional disorders of the medulla or various other supraspinal neural elements such as multiple sclerosis, medulla oblongata cavernoma, brainstem tumors, basilar artery aneurysm, cerebellar hemangioblastoma, dorsal and lateral medullary infarctions…

The antidopaminergic agent chlorpromazine is the only drug approved for the treatment of intractable hiccups.

I never knew there was an approved drug for difficult to control hiccups, let alone chlorpromazine, the first antipsychotic drug to be developed and widely used in the 1950s.

However, stranger treatments have been discussed in the medical literature.

Perhaps some of the finest moments in hiccup medicine have come from the small but determined literature on the use of digital rectal massage (translation: finger up the arse) as a treatment.

The abstract of 1990 article from the Journal of Internal Medicine is fantastic simply for its deadpan delivery. Needless to say, it was honoured with an IgNobel award.

Link to PubMed entry for case study.