Category: Inside the Brain

A brain scanning technology called MEG is being used to track the function of unborn babies’ brains as they grow inside the womb until after they’ve been born.

The full name for MEG is magnetoencephalography and it works by reading the magnetic fields created by the electrical signalling in the brain.

One of the advantages is that it can be used at various angles, doesn’t require the person to be in a cramped space, and is less sensitive to movement, so is ideally suited to scanning babies.

This includes unborn babies and with a bit of modification, as illustrated in the picture, researchers can pick up signals from the fetal brain in response to flashes or light or sounds.

We discussed the use of fMRI to scan the fetal brain previously, but this is a remarkable study that scanned the brains of babies inside the womb, every two weeks from week 27 until delivery, and then once after they were born.

Clearly, unborn babies are not the best at doing tasks set by experimenters, but there are various tests that just require the individual to experience changes in what’s presented to them.

One is called the auditory oddball task, where a series of tones are played that can either be similar (‘beep beep beep’) or can have include an ‘oddball’ (‘beep beep boop’). The brain is very good at picking out differences and the oddball is known to reliably trigger brain signals related to detecting changes.

This was the exact task used with the babies and the researchers looked to see if they could pick out a brain reaction to the ‘oddball’.

They found that they could detect this response 83% of the time in unborn babies, and that the reaction to the ‘oddball’ increased in speed throughout pregnancy. The newly born babies showed the response every time without fail.

This is an impressive finding as it shows how the brain development of the unborn child can be tracked over time with a brain scanner.

In a recent review article that discusses the development of this technology, the same group of researchers suggest that these and similar techniques could help track how different conditions in the mother affect the developing brain and even how the brain begins to develop its understanding of speech sounds before birth.

Link to PubMed entry for MEG study of developing fetus.
Link to PubMed entry for review article on fetal MEG.

Neuroskeptic covers a fascinating case of a man born with a genetic mutation meaning he had a severe lifelong deficiency of both serotonin and dopamine.

The case report concerns a gentleman with sepiapterin reductase deficiency, a genetic condition which prevents the production of the enzyme sepiapterin reductase which is essential in the synthesis of both dopamine and serotonin.

The most widely recognised symptoms of the condition, linked to the deficiency in dopamine which has an important role in controlling movement, are problems coordinating both conscious movements and the unconscious control of muscles that allows simple actions. Unconscious control requires that the brain signals one muscle to contract while releasing the complementary muscle, and problems with this process cause spasticity.

The effects the condition on serotonin, often stereotyped as the ‘happy chemical’, are less well known, but in this case it was clear that the patient wasn’t depressed but did some other difficulties:

These included increased appetite – he ate constantly, and was moderately obese – mild cognitive impairment, and disrupted sleep:

“The patient reported sleep problems since childhood. He would sleep 1 or 2 times every day since childhood and was awake during more than 2 hours most nights since adolescence. At the time of the first interview, the night sleep was irregular with a sleep onset at 22:00 and offset between 02:00 and 03:00. He often needed 1 or 2 spontaneous, long (2- to 5-h) naps during the daytime.”

After doctors did a genetic test and diagnosed SRD, they treated him with 5HTP, a precursor to serotonin. The patient’s sleep cycle immediately normalized, his appetite was reduced and his concentration and cognitive function improved (although that may have been because he was less tired)…

Overall, though, the biggest finding here was a non-finding: this patient wasn’t depressed, despite having much reduced serotonin levels. This is further evidence that serotonin isn’t the “happy chemical” in any simple sense.

This is another piece of evidence against the common myth that depression is “caused by low serotonin” although Neuroskeptic speculates whether the link between disrupted sleep and depression may indicate an effect of serotonin dysfnction.

Link to Neuroskeptic on ‘Life Without Serotonin’.
Link to summary of scientific paper.

This morning’s edition of BBC Radio 4’s brilliant In Our Time was dedicated to the infant brain and has a wide ranging discussion about how ideas about the early development of the child developed into the modern age of neuroscience.

The streamed version will be available on the website permanently, but if you want to download the podcast you only have a week to do so from this page.

Melvyn Bragg and guests Usha Goswami, Annette Karmiloff-Smith and Denis Mareschal discuss what new research reveals about the infant brain.

For obvious reasons, what happens in the minds of very young, pre-verbal children is elusive. But over the last century, the psychology of early childhood has become a major subject of study.

Some scientists and researchers have argued that children develop skills only gradually, others that many of our mental attributes are innate.

Sigmund Freud concluded that infants didn’t differentiate themselves from their environment.

The pioneering Swiss child psychologist Jean Piaget thought babies’ perception of the world began as a ‘blooming, buzzing confusion’ of colour, light and sound, before they developed a more sophisticated worldview, first through the senses and later through symbol.

More recent scholars such as the leading American theoretical linguist Noam Chomsky have argued that the fundamentals of language are there from birth. Chomsky has famously argued that all humans have an innate, universally applicable grammar.

Over the last ten to twenty years, new research has shed fresh light on important aspects of the infant brain which have long been shrouded in mystery or mired in dispute, from the way we start to learn to speak to the earliest understanding that other people have their own minds.

Link to In Our Time ‘The Infant Brain’ (thanks Petra!)

The March edition of The Psychologist has just appeared online and has two freely available articles: one article investigates whether women really suffer a reduction in mental sharpness during pregnancy, and another interviews baby psychologist Alison Gopnik about her work.

This idea that pregnancy causes a slight reduction in mental sharpness, sometimes known as ‘baby brain’ or ‘pregnesia’, is widespread but the results from scientific studies are mixed, and at best show only a negligible effect:

We’ve seen that whilst many women report experiencing cognitive difficulties during pregnancy, objective evidence for a link between pregnancy and cognitive decline has been inconsistent. This begs the question: does the memory deficit, if it exists, matter? Is there sufficient cause for women to worry about it? On the other hand, if there is no deficit, should we be doing more to combat what amounts to a pervasive sexist myth?

Crawley says that even if there is a real deficit, it’s nothing to worry about. ‘In a previous study of mine, before I gave women the standard questionnaire comparing their cognition now to before they were pregnant, I asked them to tell me about the kinds of changes they’d noticed about themselves since they’d become pregnant. Out of 198 women, only three spontaneously mentioned cognitive changes, so I don’t think they’re very salient.’

The interview with Alison Gopnik, is, as always, thoroughly engaging and largely riffs on themes from her new book The Philosophical Baby.

Link to Psychologist article ‘The Maternal Brain’.
Link to interview with Alison Gopnik.

Full disclosure: I’m an unpaid associate editor and occasional columnist for The Psychologist and I worked as a baby early in my career.

Sleep is a nightmare for neuroscientists but a new study using electrodes implanted deep within the brains of people going about their daily lives has revealed that the brain falls asleep from the inside out, contrary to what was expected.

Most neuropsychology studies require people to complete tasks while the brain is being monitored and the technologies that allow passive recording either only measure activity on the brain surface (EEG, MEG) or are too uncomfortable to measure realistic sleep (fMRI, PET). This is one of the reasons human sleep has been difficult to study and why we still understand little about it.

A new study just published online in the Proceedings of the National Academy of Sciences used the innovative technique of recording from semi-permanent electrodes implanted in the brains of 13 people undergoing assessment for difficult-to-treat epilepsy. These electrodes stay in for several weeks, meaning the researchers had access to brain activity as people continued their lives and, of course, as they drifted off to sleep.

Certain types of epilepsy don’t respond to normal treatment and neurosurgery to remove a small part of the brain that triggers the seizures is known to be an effective treatment in many cases. However, this is only feasible when it’s possible to locate where the seizures originate.

In rarer cases still, a standard EEG or brief surgical test doesn’t give a good idea of where this might be, so surgeons can insert depth electrodes into the most likely areas. These remain in place and record any unusual activity directly from locations across the brain.

The researchers, led by neuroscientist Michel Magnin from the University of Lyon, asked the patients if they could also use this data to help understand what happened during sleep onset.

They found that as people drifted off to sleep, the deep brain area the thalamus wound down several minutes before the cortex.

This is surprising because the thalamus has traditionally been considered a structure that regulates alertness and ‘relays’ information to the rest of the brain from the body and the spinal cord.

It was often assumed that it would ‘shut down’ the cortex first, because this is often considered to be where our ‘higher’ conscious functions like abstract thought and complex perception lie, while continuing with its minimal vigilance functions. A bit like a neural ‘standby’ setting.

Instead, what seems to happen is that the thalamus ‘disconnects’ itself and leaves the cortex freewheeling before it finally settles down into inactivity.

Indeed, freewheeling is, perhaps, a good description here. The researchers found lots of uneven activity in the upper brain areas as they were left to drift off.

Interestingly, sleep onset is one of the times when we are most likely to experience hallucinations. In fact, they are so common as to have been given their own name – hypnagogic hallucinations – while this drifting off period is known as hypnagogia.

Although they didn’t specifically ask about the whimsical thoughts and unusual perceptions that typically occur in this state, the researchers speculate that this pattern of freewheeling close-down might explain why hallucinations are so common at this time.

Link to PubMed entry for study.

The Times has just released its monthly science magazine, Eureka, with a special issue on the brain and all the articles freely available online.

There doesn’t seem to be a way to link to a whole issue, but inside you’ll find an excellent piece on the use of transcranial magnetic stimulation (TMS) to temporarily switch off bits of the working brain, a profile of neurosurgeon Huma Sethi, an article on commercial brain-computer interfaces, a remarkable piece on how old injuries can ‘return’ to affect phantom limbs as well as an exploration of the link between brain activity and sporting skill.

Probably my favourite is an article on how forensic science and criminology are increasingly using neuroscience, and there’s also an account of a writer’s experience of being brain scanned and a description of the Total Recall project which aims to digitally record everything about day-to-day life.

There’s also a piece by me, where I go to head-to-head with Baroness Susan Greenfield in the Fight Club section where we debate ‘Is screen culture damaging our children‚Äôs brains?’.

Greenfield goes for the usual “maybe.. perhaps… could it be?… tada! compulsive gambling and schizophrenia!” argument, so I hope I’m a little more evidence-based. Anyway, you can read for yourself.

I also debated exactly the same thing with psychologist Tracey Alloway live earlier today, and you can read the transcript here. It’s more in-depth but is less coherent and has typos and bad jokes.

Also don’t miss out on the fantastic downloadable brain poster, which is available online as a (big) jpg file.

I’m still reading through all the articles but the ones I’ve read so far have been excellent. A motherlode of neuroscience reading.

A study just published in the New England Journal of Medicine reports on how a subset of patients diagnosed as being in a coma-like state can be trained to show specific brain activity to answer yes / no questions despite seeming to be unconscious and unresponsive.

Many news reports seem to suggest that researchers have found a way of ‘reaching inside coma’ with a brain scanner to communicate with patients but the findings are much more modest, only 5 out of 54 patients could reliably produce specific brain activity on command and only one was tested who could answer simple yes / no questions in this way.

Despite this, the study is still incredibly impressive and it indicates that some patients who seem unconscious may have a much richer inner life than we assume and it may be possible to communicate with some of them by measuring their brain activity.

The researchers put people in brain scanners and, in one condition, asked them to imagine standing still on a tennis court while swinging an arm to “hit the ball” back and forth to an imagined instructor, and in the other, to imagine navigating the streets of a familiar city or to imagine walking from room to room in their home. These were chosen because they show distinct patterns of brain activity on a scan.

This was tested both on healthy people, for a comparison of how activity should normally look, and in brain injured patients in a coma-like state.

Only 5 of the 54 patients responded with distinct brain activity, similar to the type found in all the healthy comparison participants, but in this subset, it indicated that they were likely following simple verbal commands.

This has been established before, but one criticism of these past studies was this this could just be an automatic response to the words in the command. We know that the brains of unconscious people respond briefly but automatically to words, even the person is not aware of hearing them.

The brain activity for the ‘tennis’ and ‘walking’ commands was much longer and more sustained than we might expect from the normal automatic response to words, so this was unlikely, but you might still argue that these are automatic, non-conscious responses.

To rule this out in one patient, the researchers asked six yes/ no questions about simple personal details and instructed the patient to imagine tennis for yes and walking for no.

Crucially, during the questions, the researchers prompted the patient with just the word “answer?”, meaning any different reactions that showed up couldn’t be just an automatic response to the word itself which was always the same.

Out of these six simple questions, the patient ‘responded’ correctly to 5, suggesting that they were genuinely understanding, considering and making a conscious response. This was in a patient who had no external signs of consciousness.

The scans for a couple of the questions are in the image above (click for a bigger version). You can see how different the responses are, but also how serious the brain damage is.

Importantly, these correct answers do not necessarily mean that the patient was completely mentally fine but ‘trapped’ their body. One common test used on definitely conscious patients after brain damage asks lots of these yes / no type questions (like “Do cinemas show films?” / “Are bottles edible?”) to test understanding.

Some patients can be fully conscious but their language so damaged that they can’t answer these questions, others can manage the less complex ones (the easiest are usually simple personal details) but not others, for the same reason.

All of the patients in coma-like states were clearly very brain damaged, so it could be that even the one who could make conscious responses might not have full understanding. On the flip side, it could also mean that some of the other patients may have been conscious but could not understand the task, and so did not show up on this test. You can see it’s a tricky area.

However, the discovery that it is possible to communicate, even in a simple terms, with a patient previously though to be in a coma is huge news and this research is likely to lead to further work trying to detect which patients are conscious and to develop methods to communicate with them.

Link to study summary in NEJM
Link to good write-up from New Scientist.

Film-maker Noah Hutton has just released an excellent 15-minute documentary on the Blue Brain project that captures the team as they work and explains the goals of the ambitious attempt to simulate animal, and eventually, human scale neural networks on computer.

It’s an interesting look both inside the scientific mission and inside the mind of project leader Henry Markram, whom it must be said, is largely talking about the potential of the project rather than what it can do now.

It’s probably worth saying that Markram is not known for underselling his efforts, and some of his projections seem a little unrealistic.

At one point he mentions that the project could be used in hospital so doctors can simulate the effects of drugs on a digital brain to see if they’ll work before giving patients the real thing. Best of luck with that chaps.

It’s a great short piece, however, and apparently there are more to come in the future.

Link to Blue Brain: Year One.

BBC Radio 4 has just concluded a wonderful series on medical imaging that overs everything from the microscope, to ultrasound, to the brain scanner.

The series is five 15 minute programmes that tackles the technology and its controversies. The brain scanning programme is particularly good and shows both ends of the spectrum of enthusiasm for the use of functional brain scans to understand human nature.

Because of the BBC’s black hole of death archive, the programmes will start being sucked into the void in three days time, so do catch them before then.

The programmes also cover DNA imaging and X-rays and the website apparently has a gallery of images on but I have given up trying to find them on the dreadful Radio 4 website.

Link to ‘Images That Changed The World’ audio links.

In massive news for neurology, The New England Journal of Medicine has published three important studies reporting that two new drugs for multiple sclerosis are more effective than existing treatments and can be taken in pill form.

Multiple sclerosis is a bitch. It’s a neurological disorder where the immune system starts attacking myelin – the protective covering of nerves in the brain and spinal cord – leading to unpredictable attacks that typically leave the person a little more disabled each time.

Problems can include movement difficulties, chronic pain, fatigue, cognitive problems, mood instability and impairments to the body’s automatic processes like digestion, bladder and bowel control.

One problem with the the current treatments that try and slow down the disease itself, rather than just manage the effects, is that they all require regular injections or infusions via a drip.

These new studies report on two drugs: one is cladribine which is already widely used in leukaemia, and the other is fingolimod, which is not yet available commercially. Crucially, both can be taken as pills without the need for injections.

The studies that investigated these drugs were very impressive. They had large numbers of patients in many countries; they were conducted with the co-operation of drug companies but were led by independent researchers; they continued for about two years; they were compared against placebo and, in the case of fingolimod, against the current best available treatment – beta interferon; and they looked at both chances of relapse and at changes in brain structure.

The studies did not include the most disabled people with MS are all were able to walk, although patients with mild and moderate disability were included.

The results suggest that the drugs are not only easier to take but are better than the current best available treatments and reduced the chances of the patient having a relapse of MS as well as the damage to the white matter in the brain.

The drugs work quite differently from current treatments – which largely reduce inflammation directly – by changing the balance of how the immune system releases T cells so more antiinflammatory ‘helper’ T cells are available.

Unfortunately, the drugs are not without side effects, and although these effects were rare, altering the immune system led to more herpes infections and an increase in the development of cancer.

Herpes infections can take the form of the annoying but relatively benign, like in local infections such as cold sores, shingles and genital herpes, but when it gets into the whole body or brain it can cause serious damage or even lead to death, which happen to two patients in the trial, although in this case it was out of more than 1,100 people in total. The people with cancer generally recovered well – there was one death but it isn’t entirely clear it was linked to the treatment.

Although these drugs are not cures, they only slow the disease down, this is still massive news and a major development in neurology.

One of the practical big issues will be how the drugs are priced by the pharmaceutical companies and you can be sure they’re not going to be cheap.

However, one small hope is that the two compounds are owned by rival companies and as they seem to have broadly equivalent effects it will be hoped that competition will drive the price down.

Link to good write-up from The Times.
Link to good technical summary in the NEJM, sadly paywalled.

I’ve just clocked a stunning experiment, shortly to be published in the Journal of Cognitive Neuroscience, that recorded brain activity from patients who had part of their skull surgically removed for several months and had only flaps of skin between their brain and the outside world.

The operation is called a hemicraniectomy and is often used when the brain swells or the pressure builds up inside the skull to the point where it is damaging the brain.

Neurosurgeons will sometimes remove a portion of the skull (see the scans on the left) and just leave the scalp protecting the brain until the swelling subsides, before replacing the skull flap some months later.

As an aside, sometimes the surgeons will surgically insert the piece of skull into the abdomen so the bone marrow doesn’t die and it can be replaced ‘alive’ when the time comes. There’s a great description of this here.

The patients normally wear helmets, for obvious reasons, but they are unique in having such a thin covering of the brain.

A team of researchers, led neuroscientist Bradley Voytek, realised this provided a unique opportunity to examine the exactly how the skull affects EEG, one of the most common techniques for measuring the electrical activity of the brain.

EEG records brain activity from electrodes on the skull, but the signal gets ‘smeared’ as the electrical charge passes through the bone and so the source of the activity can’t be located very precisely to specific brain areas.

By working with the hemicraniectomy patients, the researchers could compare electrical activity on one side of the brain – recorded through just the skin, and the other, where recordings were made normally – through electrodes on the skull.

The researchers found that the non-skull signals were richer, were less subject to interference, were more closely tied to specific tasks and could be better linked to specific brain areas.

On the right is a comparison of the signal coming from a listening task, where participants are suddenly presented with an ‘oddball’ noise in the midst of a bunch of otherwise identical sounds. The brain reacts strongly to the change and this is reliably reflected in a positive spike in the electrical activity at about 50 milliseconds (consequently, the wave is called the ‘P50’ signal).

You can see that the activity on the craniectomy side is much stronger, tighter and cleaner whereas on the skull side it is quite indistinct. The team found similar results in several other tasks.

This not only helps us better understand EEG results on people with intact skulls, but it also meshes with brain activity recordings that are taken from electrodes implanted directly in the brains of patients undergoing neurosurgery.

Link to PubMed entry for study.
pdf of scientific article.
Link to Bradley Voytek’s blog post about his work.

The New York Daily News reports on a 14-month old Chinese boy who survived brain surgery to remove a chopstick that accidentally ended up in his brain after entering through the nose.

If your jaw has dropped, amazed at such a freaky and unusual accident, you may comfortably close your mouth – there is a surprisingly large medical literature on stray chopsticks that have become lodged in the brain.

In fact, there are no less than 13 published articles on this serious neurological condition. Here are some of the more notable ones:

A case of unusual difficult airway because of an intracranial foreign body of bamboo chopstick. [link]

Transoral penetration of a half-split chopstick between the basion and the dens. [link]

Transorbital penetrating injury by a chopstick–case report [link]

Intracerebellar penetrating injury and abscess due to a wooden foreign body–case report. [link]

Chopsticks and suicide [link]

Unusual craniocerebral penetrating injury by a chopstick. [link]

Link to New York Daily News on boy with chopstick in brain.

The pictures are the interesting results of an MRI scan on a 15-year-old boy who had his hair in ‘twists’ that were held in place with beeswax coloured black with iron oxide.

The iron oxide is magnetic and it interfered with the scanners’ magnetic field causing the rather lovely aura effect on the images.

This is not the only case of a hair style interfering with a brain scan in the medical literature. An earlier report is remarkably similar, as the iron oxide coloured braids of a 51-year-old lady caused similar flame-like patterns on the scans.

Link to MRI ‘aura’ in 15-year-old boy.
Link to MRI ‘aura’ in 51-year-old lady.

A veterinary deworming drug called levamisole has mysteriously appeared in almost two-thirds of cocaine seized in the United States and is now common throughout the world.

No-one is quite sure why, although some researchers have suggested that it may be added to boost the effect of cocaine in the brain.

Now a brief article in the Journal of Analytical Toxicology suggests this may indeed be the case based on the neurological effects of the two substances.

Street drugs are typically ‘cut’ with additional substances, often to bulk them out, but occasionally to alter the effect of the main substance. As we discussed in a post on adulterants in heroin, this can be a way of changing the drug to give it a different effect to benefit the dealer.

As an excellent article on Erowid notes, the fact that cocaine is cut with only small amounts of levamisole (only 6% of the deal in one study) suggests that it is not being used just as a handy powder to thin out the coke – more likely, it is being added for a specific effect.

Levamisole is, in some respects, similar to nicotine and the drug binds to specific nicotine-triggered receptors for the neurotransmitter acetylcholine and causes the nerve cell to respond. It turns out that this is most likely to increase activity in the body’s ‘fight-or-flight’ system – the sympathetic nervous system.

In fact, this is exactly how the drug has its deworming effect. In worms, it targets nerve cells involved in muscle activity, causing the muscles to contract. The worm is paralysed and so can be easily expelled from the body.

As cocaine also stimulates the body, the two drugs could combine to cause additional arousal.

This effect would largely be on the peripheral nervous system, outside the brain, but levamisole might also boost the effect of cocaine directly within the brain – enhancing pleasurable feelings.

In the brain, levamisole likely also enhances the release of glutamate, a neurotransmitter that is known to encourage or excite the function of neurons.

We known cocaine boosts dopamine function in the reward system, but the reward system is not single brain area. It’s actually a network of related structures deep within the brain that have connections that communicate and feedback their activity levels to carefully tune their running. An essential part of the feedback mechanism uses glutamate.

To use a sound system analogy, if cocaine cranks up the volume by boosting dopamine, levamisole might work by increasing power to the speakers by upping glutamate levels. The effects add up and the high is amplified.

What this means is that dealers can sell less actual cocaine but users get a similar effect from the smaller amount.

However, this comes at a price. The additional ramping up of the ‘fight-or-flight’ system is likely to put an additional strain on the heart and heart failure is one of the most common cocaine-associated fatalities.

Levamisole also causes the immune system to stop working so well by killing off white blood cells (in fact, this is why it is rarely used in humans in modern medicine) and several cases of life-threatening illness caused by levamisole-cut cocaine have already been reported.

The fact that this additive has been appearing at all, is, in itself, quite surprising. The fact that this relatively obscure compound has become so common in the global cocaine industry might suggest that it was selected on the basis of its pharmacological properties.

In other words, on the basis of the study of neuroscience. One study reported that professional heroin cutters can charge up to $20,000 a kilo and I wouldn’t be surprised whether the big players in the cocaine industry can afford to pay for neuroscientists or pharmacologists to tweak their products.

Link to PubMed entry for brief article on possible effects of levamisole.
Link to excellent Erowid reviewing findings on levamisole-cut cocaine.
Link to Wall Street Journal on prevalence of levamisole in US cocaine.

Discover Magazine has an excellent Carl Zimmer piece discussing efforts to understand the speed of the human nerves – a quest that has lasted for well over one hundred years.

Although our experience of the world seems instantaneous, different nerves in the body work at different speeds and, of course, cover different distances – to the point where taller people experience a slight sensory lag compared to shorter people owing to the greater length of some of the nerve pathways.

Speed is not necessarily of the essence, however, and as with dancing, it is timing and co-ordination that seems key:

Sometimes our brains actually need to slow down, however. In the retina, the neurons near the center are much shorter than the ones at the edges, and yet somehow all of the signals manage to reach the next layer of neurons in the retina at the same time. One way the body may do this is by holding back certain nerve signals—for instance, by putting less myelin on the relevant axons. Another possible way to make nerve impulses travel more slowly involves growing longer axons, so that signals have a greater distance to travel.

In fact, reducing the speed of thought in just the right places is crucial to the fundamentals of consciousness. Our moment-to-moment awareness of our inner selves and the outer world depends on the thalamus, a region near the core of the brain, which sends out pacemaker-like signals to the brain’s outer layers. Even though some of the axons reaching out from the thalamus are short and some are long, their signals arrive throughout all parts of the brain at the same time—a good thing, since otherwise we would not be able to think straight.

Link to Discover article ‘What Is the Speed of Thought?’

I’ve just found a short case study in the British Journal of Neurosurgery of a 12-year-old boy who suffered a bleed in the brain after taking part in a ‘head shaking competition’. Somewhat curiously, the case study notes that he won, and reports his winning time.

The patient was a 12-year-old, developmentally normal, healthy boy who presented to his primary care doctor with 2 weeks of headache accompanied by intermittent nausea and vomiting. The headaches began after the patient entered a ‘head shaking contest’ with his peers. The object of the contest was to vigorously rotate the head back and forth for as long as one could tolerate. The patient won, with a time of approximately 2 min. Afterwards he noted a mild headache that gradually worsened over the course of 2 weeks. When it was at its most severe, the headache was occasionally accompanied by nausea and vomiting. There were no visual disturbances or other focal neurological signs.

On a follow-up, he was found to have a large subdural haematoma, a type of bleed that happens under the brain’s covering which is known as the dura mater, possibly related to an otherwise benign cyst that existed before hand but may have caused damage during the rather vigorous competition.

Link to PubMed entry for case study.