Category: Inside the Brain

The great British neurologist John Hughlings-Jackson famously described the ‘dreamy state’ reported by some epileptic patients during seizures where they experienced complex hallucinations – sometimes of scenes and faces, feelings of false familiarity and a feeling of ‘weirdness’ or ‘strangeness’.

A study published last year in neurology journal Brain re-examined these experiences by deliberately triggering them by electrically stimulating the brain.

The participants were all patients with epilepsy who were having neurosurgery to treat their otherwise untreatable seizures and the researchers, led by neurologist Jean-Pierre Vignal, specifically stimulated areas in the mesial [inner] temporal lobes.

The feelings of false familiarity are what we normally called d√©j√† vu, but actually we tend to misapply this term as it means ‘already seen’ and refers specifically to a false familiarity for visual perception.

However, it can also occur for anything we experience, such as hearing other people say things, and is more correctly called d√©j√† v√©cu (‘already experienced’) in the literature.

Here are a few of the triggered experiences:

D√©j√† v√©cu (3 volts, right amygdala) – “It’s like yesterday evening … I have the impression that everything around me has been here before, that it has already happened, I feel as if I am going backwards in time”

Scene: reliving a parachute jump (3.5 volts, right hippocampus)

Familiar television advertisement (4 volts, right amygdala)

Impression of being elsewhere (3 volts, right hippocampus)

Scene from childhood (2 milliamps, right amygdala) – “Vision of a bald man dressed in black, coming towards her from behind; associated with a feeling of imminent death; she is pale, with piloerection. She is re-experiencing an experience of anaesthesia by facemask during a tonsillectomy at the age of 14 years”

Impression of being someone else (2 milliamps, left amygdala)

Impression of leaving his body (2.5 milliamps, left amygdala)

Night-time scene (1.2 milliamps, left hippocampus) – “I’m starting to see lots of things, loads of people … it’s still vague and strange. I’ve got an initial picture, a memory … I feel locked in again, something to do with the evening, the night … it’s strange … . like after a party, sad things … there is a mixture of last night and this morning … ‚Äô These remarks were peri-ictal [during the seizure]. After the end of the discharge, there was complete amnesia.”

Scene (4 milliamps, right hippocampus) – “It’s starting, it’s rising up to my eyes … I’m always frightened of something … I feel something, like in dreams, I always see people, loads of people, people that I see in the hospital…”

Familiar character from a film (1.5 millamps, left amygdala)

Ill-defined, unpleasant vision (1.5 milliamps, left hippocampus)

Familiar vision that he is unable to describe (1.5 milliamps, left parahippocampal gyrus)

Vision of a familiar person (1.5 milliamps, left parahippocampal gyrus)

Recent scene (1.5 milliamps, right hippocampus) – “I see myself playing the drums, with people from my family listening to me”

The technique of electrically stimulating the brain to trigger certain experiences was pioneered by Canadian neurosurgeon Wilder Penfield and there’s an excellent account of his life and work on Neurophilosophy if you’d like some background.

This new study is open-access and completely fascinating, so is definitely worth a read.

Link to ‘The dreamy state: hallucinations of autobiographic memory evoked by temporal lobe stimulations and seizures’.

The British Medical Journal has just published one of the greatest and funniest research articles ever to grace the pages of the medical literature with a paper on the potential neurological consequences of headbanging to heavy metal.

As someone who once caused himself concussion and several hours of puking from head banging to Metallica at the age of 14, I feel this is important and invaluable research.

The researchers, Australian rockers Declan Patton and Andrew McIntosh, attended a number of heavy metal concerts to observe the most common forms of headbanging (the ‘up-down style’ apparently), and then did a biomechanical analysis to estimate the forces operating on the head and brain.

They also convened a focus group of local rockers to list their favourite headbanging classics, and modelled the physical stresses based on the tempo of the tracks.

They discovered that headbanging to songs with a tempo above 146 beats per minute when the head motion was more than 75 degrees was the point at which brain injury was likely to occur.

It’s traditional that the Christmas edition of the BMJ has a more light-hearted article. This study is a little different in that the science is completely bona fide, but the scientific paper is a very funny read.

Their public health recommendations are a particular gem:

Though exposure to head banging is enormous, opportunities are present to control this risk‚Äîfor example, encouraging bands such as AC/DC to play songs like “Moon River” as a substitute for “Highway to Hell”; public awareness campaigns with influential and youth focused musicians, such as Sir Cliff Richard; labelling of music packaging with anti-head banging warnings, like the strategies used with cigarettes; training; and personal protective equipment.

Great article, fantastic title, and completely open access.

Rock on!

Link to ‘Head and neck injury risks in heavy metal’.

I’ve just found this fascinating article on how legendary neurologist Gordon Holmes discovered how the visual cortex represents visual space after studying World War One soldiers who had experienced bullet or shrapnel wounds to the brain.

World War One taught us a great deal about neuropsychology largely due to developments in weapons technology. The German Mauser was an accurate rifle that used small bore ammunition where previous conflicts had largely used single shot rifles mostly designed so a group of soldiers could create a ‘wall of lead’, rather than a carefully aimed shot.

Developments in shell technology also meant that high explosives could be launched with reasonable accuracy into groups of soldiers causing significant shrapnel injuries.

However, both the rifles and shells were at a stage where the velocity of either a bullet or a piece of shrapnel was relatively slow by today’s standards, meaning that the brain was not additionally damaged by shock waves, like with modern munitions.

In other words, they could create small discrete areas of brain damage that left the rest of the brain largely unaffected.

The British Brodie helmet, which sat like a tin bowl on the top of the head, left the lower parts of the head, and hence the brain, exposed. This meant a significant number of injuries were to the visual cortex, at the rear of the brain.

Neurologist Gordon Holmes studied the link between small lesions to this area and which areas of vision had been lost in soldiers coming back from the front.

The diagram on the right is one of his drawings where he demonstrated the link between a very specific shrapnel wound and a crescent-like area of blindness in the visual field. The full diagram is in the article where he also shows how it affected the right eye.

These studies taught us that the visual cortex is ‘retinoptically mapped’, meaning that each part of the cortex corresponds to a specific area of vision. It also taught us that some brain areas can be very specifically localised to certain functions, whereas previously we’d only known of very general connections between function and brain area.

The article, published in opthamology journal Documenta Ophthalmologica, describes Holmes’ wartime experiences, his discoveries and something of his character.

It also contains this curious episode, related by one of his junior doctors, largely notable for the fact that they hid a blonde beauty queen in a bathroom on the hospital ward to boost morale of the medical house officers.

Holmes had no time for neurotics and hysterics, and less … for psychoanalysis … [Once] In the ward there was a blonde bombshell of twenty-one with mild tension headaches. She was as pretty as a picture, plump as a partridge, who the previous year had been the Daily Mirror Bathing Beauty Queen. The first time I took Holmes around, he stopped at the foot of the bed and said ‘Who is this woman?’ I explained, whereupon he jerked his thumb towards the door and said ‘Get rid of her’.

Of course, I did nothing of the sort, for she was useful in keeping up the morale of us house officers. A week later he came around and said ‘I thought I told you to get that woman out of here?’ Yet another week passed. On this occasion I got the Sister of the ward to hide the patient in the bathroom during the ward round. Standing at the foot of the empty bed, Holmes paused, then said to me ‘Look here, my boy, either she leaves the hospital or you do – and I don’t care which.

Link to ‘Gordon Holmes, the cortical retina, and the wounds of war’.
Link to DOI for same.

Discover magazine has a thought-provoking article on the question of whether ‘shaken baby syndrome’, claimed to be a specific type of brain damage that occurs to young children if shaken, actually exists as a useful syndrome. If it doesn’t, it might not only be a medical miscategorisation but also a legal disaster that may have falsely convicted innocent families of child abuse.

Critics argue it’s a bit like calling a broken nose ‘punched in the face syndrome’. The label is for a non-specific injury but which automatically leads us to assume that an aggressor must exist.

Once a doctor says that an infant must have been shaken, it triggers a hunt for the shaker. In one diagnostic step, the legal system is brought to bear on the baby’s family and anyone else near the infant at the time of the supposed shaking.

The symptomatic triad of bleeding between the brain and skull (known as subdural or subarachnoid hematomas), bleeding behind the retinas, and brain swelling is both the core of an SBS diagnosis and the point of departure for the syndrome’s skeptics. The medical proof that shaking alone can cause these internal head injuries is questionable, the skeptics say, when many other things, from infections to malnutrition to falls onto a hard surface, are known to be causes of similar symptoms in infants.

In contrast, supporters of the condition, which came to world-wide attention in the case of British nanny Louise Woodward, argue that shaking causes babies specific injuries that are unlikely to be triggered by anything else. The article quotes Eli Newberger, an assistant professor of pediatrics at Harvard Medical School:

‚ÄúBy the time I was asked to testify in the Louise Woodward case…there was a great deal of clinical understanding about [SBS-related] trauma,‚Äù Newberger says. ‚ÄúThe infant‚Äôs head is disproportionately larger in relation to the rest of its body than our heads are. A child can‚Äôt stop the to-and-fro excursions of the head with its neck. The brain bobbles about. The infant‚Äôs brain is softer than the adult‚Äôs.‚Äù…

Money, Newberger suspects, has brought otherwise good people over to what he and his colleagues call the “dark side,” doubting SBS. “I have never ceased to be amazed about what highly regarded, well published, scientifically informed doctors will do when they’re offered large amounts of money,” he says.

And indeed, experts on both sides seem to charge a great deal for their time.

The article walks us through some of the studies that have attempted to look at how many children with these symptoms show other signs of abuse, or have tried to simulate the damage with computer or physical models.

It’s a fascinating look at a syndrome I just took for granted as being widely validated and looks at the implications of the scientific work for the legal system, where incorrect diagnosis can lead to abusers going free or loving parents being jailed.

Link to ‘Does Shaken Baby Syndrome Really Exist?’.

I’ve just found this gripping article from The Guardian by photojournalist Tom Bible who was diagnosed with a rare and life threatening brain tumour and had an equally rare and life threatening operation to remove it.

The tumour was located in the superior sagittal sinus, one of the major veins that drains blood from the brain.

Operating on it is very dangerous because it is incredibly difficult to stem the bleeding once it’s damaged. As the author mentions in this passage, it’s so dangerous that the operation needs to be carried out while the patient’s heart is stopped:

I now had a challenge: to find a neurosurgeon who was both willing and able to remove my tumour. Dr Thomas recommended two vascular neurosurgeons in the UK. I arranged an appointment with the first one, who subsequently cancelled, saying that it was not the type of operation he would perform. I visited the second neurosurgeon at the National Hospital in London – the leading UK neurosurgery hospital (and one of the most highly rated in the world). He said he had only heard of one of these before. They had had to remove it by resorting to a practice called the ‘cardiac standstill’. In this, they stop the patient’s heart, drain the blood from the body and reconstruct the tumour-infested sinus area, pump the blood back into the body and kick-start the heart again.

Blimey.

The author eventually had the operation in the US, and gives a compelling description of the process from first symptoms to the extended procedure that eventually also needs the radiation-based gamma knife treatment.

Link to Guardian article ‘Brain storm’.

The annual Society for Neuroscience conference is currently underway in Washington DC and Technology Review has a couple of article that reports on some of the highlights.

One piece is particularly interesting as it focuses on the use diffusion tensor imaging (DTI), a type of MRI scan that identifies the white matter nerve pathways in the brain, to detect otherwise undetectable brain damage.

These white matter pathways are like cabling that runs through the brain and in some forms of head injury they can get twisted, pulled or suffer sheering injuries which may not be easily visible on standard MRI scans.

A minority of people who suffer head injury with no detectable injury on standard MRIs will suffer emotion and behaviour disturbance, memory difficulties, diffuse headaches and problems with concentration.

This is sometimes diagnosed as post concussion syndrome and the researchers hope that DTI scans will find that people with these sorts of complaints will be found to have clear white matter disturbance.

Actually, this is one of the oldest debates in head injury and stretches back to the time when soldiers were first returning from the First World War with ‘shell shock’.

One of the theories, largely championed by Maudsley psychiatrist Frederick Mott, was that the shock waves from the shells disturbed the brains of the individuals causing microscopic brain damage.

However, it soon became clear that some soldiers who had ‘shell shock’ had never been near a shell explosion, while others had genuine brain injury but had similar sorts of problems which weren’t easily explained by the physical damage they’d endured.

One of the key lessons from this time was that our expectations, beliefs, emotions and interpretation of experiences and injuries contributed as much to the actual symptoms and disability as the physical damage.

Interestingly, similar sorts of problems have been reported in soldiers returned from Iraq and, as echoed in the TechReview article, there is a big push to clearly separate cases of ‘genuine brain injury’ from ’emotional trauma’.

History tells us that attempting a clear separation is likely to be futile, because the same symptoms can be produced by either one, or a combination, and knowing that one definitely plays a part doesn’t rule out the other.

So it’s interesting to hear the people quoted in the article suggest that DTI imaging could help assess who is cognitively able or not, who has a ‘real injury or is faking’, or whether someone should be sent back to the battlefield, because it relies on a cut-and-dry distinction between ‘brain injury’ and ‘psychological problem’ which doesn’t exist in the real world.

As an aside, white matter isn’t invisible on MRI or CT scans, as suggested in the article, although some white matter injuries might be.

And if you’re still hungry for more SfN news, TechReview has another bulletin with several highlights.

Link to article ‘Detecting Subtle Brain Injuries’.
Link to latest SfN brain research write-up.

BBC Radio 4’s excellent discussion programme In Our Time just had an interesting edition on neuroscience – what it does, how it does it, and what it’s telling us about the function of the mind and brain.

It’s generally a very interesting discussion, although does get a bit confused towards the end during a discussion of conscious – largely due to a misunderstanding of a famous study.

The discussion touches on neuroscientist Adrian Owen’s study where they wanted to find out whether a patient in a persistent vegetative state (PVS) was conscious by asking them to imagine things and then using fMRI to see if the relevant parts of the brain were active – in other words, if the person was able to consciously hear, understand and carry out the request.

Famously, the patient could – demonstrating that it is possible to be diagnosed with PVS and still be conscious.

However, the guests on the programme discuss the study as if the patient was unconscious and was in a coma, and suggest that this shows the brain can do remarkable things when someone is unconscious which is exactly what it didn’t show.

Otherwise, a fascinating discussion as we’d expect from In Our Time.

Link to programme webpage and audio.

Neurophilosophy has recently published two excellent articles that discuss the recent discovery of very selective psychological problems: one person can’t recognise people by their voice, the other can’t navigate through streets.

In themselves, these sorts of disorders are not that surprising, but they help us understand how the brain develops.

Actually, scratch that last sentence. If you’re familiar with the brain injury literature, these sorts of disorders are not that surprising, but if you’re not, they’re completely mind blowing.

Take prosopagnosia for example. Sometimes rather inaccurately called ‘face blindness’ (people see faces, they just don’t seem distinctive) it was first identified in a patient with a bullet wound to the head who lost the ability to recognise faces but could still recognise other objects.

If you think about it, this is incredible. When we look out onto the world, faces don’t seem different from the rest of the things we look at, but damage to a specific area of the brain (most commonly the right fusiform gyrus) can selectively damage our ability to see faces, suggesting that there are brain functions specialised for this task. How specialised, whether only for faces, is a matter of ongoing debate, but the fact that they are specialised at all is incredible enough.

The explanation for these selective impairments goes something like this: our brain functions are shaped by a combination of the broad outline of genetics and the fine tuning of experience during growth. When we reach adulthood they are fairly fixed. Damaged can knock out these fairly fixed pathways leading to selective impairments.

What has become clear over the last decade is that some people can have selective impairments without suffering brain injury. They seem to have them from birth.

This is the case with the two people discussed by Neurophilosophy. An inability to recognise people by just their voice or an inability to navigate streets after brain damage is interesting but not earth shattering. These sorts of cases have been reported before.

But the fact that these are developmental disorders is an interesting and important twist, not least for what they suggest about how much certain functions might be ‘set’ in the brain early on, but also for what they suggest about the ‘life history’ or our cognitive skills.

The two case studies discussed by Neurophilosophy are both fascinating as life stories of people with atypical difficulties but also scientifically compelling because they help us understand complex dance of brain growth and development.

Link to piece on developmental topographagnosia.
Link to piece on developmental phonagnosia.

Scientific American Mind’s Mind Matters blog has a great interview with neuroanthropologist Daniel Lende who discusses why we need an understanding of both culture and neuroscience to get a fully integrated account of human thought and behaviour.

Lende discusses his work on integrating cultural factors and the neuroscience of the dopamine reward system in a study of addiction in Colombian teenagers.

A common approach in neuroscience is to take experiences labelled by everyday words and try and find what changes in the brain when someone says they are having the experience.

The problem is that the definitions of the labelling words may be indistinct (‘love’), incoherent (‘belief’) or understood differently in different cultures (‘anxiety’).

The approach Lende advocates is to take an anthropological approach to the problem. In other words, attempting to understand what a concept or label means in a particular culture so the neuroscience can be integrated in full knowledge of the diversity of the experience.

This predicament is where neuroanthropology can be so helpful. In order to draw connections between neuroscience and real world situations, I went out and talked to people to understand craving and addiction from their point of view. This type of real-world data can both challenge and inform ideas based on animal models and neuroimaging studies.

In translating the dopamine research, my work with adolescents proved crucial. They knew what they experienced far better than I did. Using systematic interviews across a range of involvement with drugs (hard-core users to having never tried drugs), I saw three areas of overlap between research on dopamine and compulsive involvement with addictive substances.

First was the emphasis that researchers placed on “wanting.” I was lucky in Colombia; addicted adolescents often described their experiences as “querer más y más,” to want more and more. Second, dopamine affects shifts in attention, which meant that some adolescents couldn’t focus on anything else when they knew an opportunity to consume was about to come along. Third, adolescents described a sense of being pushed toward something—an urge that rose up without conscious desire.

You may recognise Lende from the excellent Neuroanthropology blog and he also discusses some of the work of his co-bloggers in the interview, including some fascinating work looking on how people learn balance.

However, if you’re interested in more details about the study on Colombian teenagers, he’s recently posted some more information including links to the full text of the papers.

Link to SciAmMind Mind Matters interview.
Link to Neuroanthropology post on Colombia study.
Link to follow-up and more information.

I’ve just found another curious case report of complex movements in a brain dead patient, following on from our recent piece on the Lazurus Sign.

These reports are fascinating and bizarre in equal measure, not least when you try and imagine what was happening in the room at the time.

Uncommon reflex automatisms after brain death

Rev Neurol (Paris). 1995 Oct;151(10):586-8.

Awada A.

Two cases of unusual complex movements observed in brain dead patients are described. Rapid and sustained flexion of the neck induced slow abduction of the arms with flexion of the elbows, wrists and fingers over 5 to 10 seconds. These movements have been rarely described and although they have similar clinical patterns, they are pathophysiologically different from the Lazarus sign which is observed few minutes after respiratory support cessation. While Lazarus sign is supposed to be due to an agonal discharge of anoxic spinal neurons, the movements described in this article result probably from complex reflexes generated in a disinhibited spinal cord. It is however surprising that they have never been described in patients with high cervical spinal injuries.

For those of you not familiar with the medical terms for movement, I shall briefly translate. When the doctors rocked the dead person’s head side to side forward in a ‘rapid and sustained’ fashion, the body extended its arms to the side and waved them about.

I have two thoughts.

Firstly, isn’t it fascinating that such complex movements can be triggered solely by the spinal cord?

Secondly, what the bloody hell were they doing with that dead body?

Normally, these reports are of spontaneous movements in isolated brain dead patients, but on this occasion the medical team seem to have been rather more involved.

Unfortunately, the full text of the article is in French, so the exact turn of events (e.g. “hey looks what happens when I do this!”) shall have to remain a mystery.

UPDATE: Neuroshrink has added a fantastic correction and comment to this post that suggests what might have been happening and recounts his own experience of observing the Lazurus sign.

Link to PubMed entry for article.
Link to Mind Hacks on the Lazurus Sign.
Link to another Mind Hacks article on the moving dead.

Tim Harford, who blogs as the Undercover Economist, presents a rollercoaster ride through the field of neuroeconomics, <a href="http://www.bbc.co.uk/radio4/science/pip/plke4/"'Money on the Brain' for Radio 4. The documentary is available via Radio 4’s Listen Again site for the next week, and reportedly via a podcast (which I unfortunately can’t find). This whistle-stop tour covers neuromarketing, behavioural economics and the possible effects of hormone levels on risk tasking among stockmarket brokers. The programme features great interviews with some top researchers, such as Paul Glimcher and, Glimcher aside, many of these researchers have an almost relgious optimism about the potential for fMRI-scanning, believing it will eventually tell us how economic decisions are made, why we follow crowds, what we’re thinking at any point in time, what age we should be able to vote and how much we value things like clean air. Admist this heady atmosphere the psychologist Gerd Gigerenzer brings us back to earth again: “You can’t read the mind. We understand quite little about the brain.” he begins. And then,

A former chairman of the Harvard Psychology deptartment once asked me “Gerd, do you know why they love those pictures [the fMRI activity maps]? It is because they are like women: they are beautiful, they are expensive and you don’t understand them”

If you read a classical article on neuroeconomics what you will find is mostly results which have been already known and recycled, and very little new insight.

Boom!

Link to Radio 4 documentary ‘Money on the Brain’
Also on Mindhacks.com The fMRI smackdown cometh
Also on Mindhacks.com Don’t believe the neurohype
Also on Mindhacks.com Is Banking on Neuroscience a false economy?

ABC Radio National’s All in the Mind recently had an excellent programme on amphetamine, discussing its varying uses from its original selling point as a widely abused nasal decongestant to its modern popularity as a kiddie behavioural control agent in the age of methylphenidate (Ritalin).

One of the most fascinating parts is where the guest, history of science professor Nicolas Rasmussen, discusses how after amphetamine was discovered in the 1930s the drug companies desperately tried to find an illness which it could be prescribed for.

Smith, Kline & French wanted to find a big market and so they looked at common diseases that you know might plausibly be treated by an adrenaline derivative and they tried it out on a huge range of conditions. Menstrual cramps, bed wetting, you name it — it turns out actually to work for bed wetting if you give it to little kids who have that problem, probably by making them sleep shallower — but also in psychiatry for depression, and that’s what really caught on.

They tried it for an enormous range of conditions through medical experts and the clinical trials where the drug didn’t work out well weren’t published, because that was already the arrangement then, when a drug company funded a trial unless it fit their marketing needs the results wouldn’t be published.

Great to see the spirit of the 1930s is still with us today.

The programme also discusses how the subculture use of the drug interacted with its ‘official’ uses in the mind of the public and policy makers to give speed the image it has today.

It seems the programme is based on a new book by Rasmussen called On Speed and I love the link at the bottom of the book’s website which says ‘Purchase On Speed’. I’ve drunk a lot of coffee. Will that do?

If you’re interested in a book on the science of amphetamines, Leslie Iverson’s book Speed, Ecstasy, Ritalin is simply wonderful and just so much fun to read, as I noted in an enthusiastic review last year.

The AITM programme is a fantastic introduction to the fascinating story of amphetamine, so a great place to begin.

Link to ‘Wakey Wakey! The many lives of amphetamine’.

Occasionally, brain-dead patients make movements, owing to the fact that the spinal reflexes are still intact. The most complex, and presumably the most terrifying, is called the Lazarus Sign. It is where the brain-dead patient extends their arms and crosses them over their chest – Egyptian mummy style.

About 20% to 40% of brain dead patients can show spontaneous movements particularly when the body is pricked with sharp objects.

While these movements are usually brief twitches, occasionally the movements can be in an extended sequence, as reported in this 1992 Journal of Neurosurgery case study about a 67-year-old lady who died from a brain haemorrhage.

At 11:15 am on February 20, brain death was declared and consent for final respirator removal was obtained from the patient’s family. The possibility of the appearance of Lazarus’ sign was explained to the family, and a video recording was made.

Five minutes after respirator removal, respiratory-like movements occurred three times; both shoulders adducted and slow cough like movements were identified. Lazarus’ sign immediately followed these respiratory-like movements. The forearms were pronated and the wrist joints extended bilaterally. Fingers on the left hand were extended, but those on the right were flexed as if grasping. Subsequently, flexion and extension in the knee and foot joints were repeatedly observed. Slow supination of both feet occurred. Finally, the left forearm was adducted to the side of the body, and the right hand pronated.

The movements continued for about 3.5 minutes, during which time blood pressure was 46/35 mm Hg and pulse rate was about 90 beats/min with a regular sinus rhythm. Cardiac arrest occurred at 11:35 am.

Link to PubMed entry for case study.
Link to brief popular article on Lazarus sign.

Seed Magazine has got video of a great talk by Henry Markham, the director of the Blue Brain Project which is developing the world’s largest simulation of networks of individual neurons in an attempt to understand the large scale dynamics of the brain.

Their ambition is to be able to run a simulation on the scale of the whole human brain within a decade.

If you want a good summary of where the ambitious project is at, Seed recently had an excellent Jonah Lehrer piece on the research that we featured earlier this year.

Markham’s talk is interesting not solely for his take on the project and its aims, but also for the fantastic visualisation he uses to illustrate what it’s doing.

Link to video of ‘Designing the Human Mind’ talk.

Surely this must be the greatest headline for a BBC News story ever: Banjo Used in Brain Surgery.

Although the banjo wasn’t in the hands of the surgeons it was still an essential part of the operation. It was played by legendary Blue Grass musician Eddie Adcock who was having surgery to install a deep brain stimulation device to treat an essential tremor that had been affecting his playing.

The BBC News story has a video of the neurosurgery and the banjo playing, and it is pure genius. Probably the best thing you’ll see all year.

Essential tremor is a condition where there is a continuing deterioration in areas of the brain that control movement. This causes a tremor that usually appears when the person tries to act or move, although can lead to a ‘resting tremor’ that’s also present at other times.

Essential tremor is not Parkinson’s disease, which, while also associated with tremor, is a much more serious and disabling condition in many ways. There does seem to be a link though, as people with essential tremor are more likely to develop Parkinson’s, although this still only happens in the minority of cases.

However, deep brain stimulation can be used to treat the movement difficulties of both Parkinson’s and essential tremor. It involves sinking an electrode into the thalamus, a deep brain area that is part of the motor loop – a circuit that helps co-ordinate movement.

In fact, there are two parts to the motor loop – the direct and indirect pathway – an each play a complementary part in directing movement, and each of which needs to be balanced with itself and with each other. When damage to these circuits affects this balance, the result is that it causes too much activity one way, which causes a compensatory response the other, and so on.

Imagine two people, completely unaware of each other, trying to balance an uneven seesaw. The oscillations in the control system cause oscillations in movement, and this is what you can see in tremor.

DBS works by sending electrical impulses at a certain frequency into the thalamus to dampen down the oscillations. However, the oscillatory push-push cycle is not the same for everyone, and the best spot in the motor loop itself will also differ.

To get the best result the surgeons tweak the electrical pulse settings and try different areas.

To make sure it’s having the desired effect, the patient is awake and they ask them to move. When they see that they’ve hit the sweet spot and the pulses are in time, they know their job is done.

One of Eddie Adcock’s impairments is that he has tremor, but the main impact on his life is that it affects his banjo playing. So the most sensible thing to do is to tweak the system while he’s playing the banjo to optimise the effect for the thing that’s most important to him.

And that’s why a banjo was used in brain surgery.

Link to BBC video of ‘Banjo Used in Brain Surgery’.

I just came across these two beautiful images in a paper by neuroscientist Marek Kubicki and colleagues on diffusion tensor imaging studies in schizophrenia.

DTI is a technique that using MRI scans to track how water moves throughout the brain. As water tends to move in one particular direction when its trapped inside nerve fibres, a technique called MRI tractography can be used to map out all the white matter ‘cabling’, separate from the rest of the brain.

I think the technique produces some of the most beautiful images in neuroscience. You get to see the brain’s connections, disconnected, and suspended in space.

Link to full-text of paper (see page 27 for images).
Link to PubMed entry for same.
Link to more DTI tractography images.