Category: Inside the Brain

Terry Wallis, a man who was in a coma-like minimally conscious state for 19 years after a car crash, seems to have shown brain re-growth since he recovered consciousness.

A research team led by Henning Voss scanned Wallis’ brain using a technique called diffusion tensor imaging or DTI that can pick out the white matter pathways in the brain.

An image from Wallis’ DTI scan is shown on the left, and shows the connections in the rear section of the brain.

The image is shown as if we’re looking down and from the side into the brain. Note how the structures do not match on either side – often a good indicator of brain injury.

Crucially, the researchers re-scanned Wallis’ brain after 18 months and found that the density of the white matter seemed to increase over time, suggesting that his axons were regenerating. These are the long insulated fibres that connect the brain’s neurons.

When scanned using a PET scanner, the increase in white matter also seemed to match an increase in the use of glucose, suggesting greater levels of brain activity in these areas.

In the last decade it was discovered that adults can grow limited numbers of new neurons, but the regeneration of the brain’s connections is still largely unknown, and especially not in people who have suffered such severe brain injury.

Wallis was the subject of a 2005 Bodyshock documentary called The Man Who Slept For 19 Years.

Contrary to depictions in many films (where people tend to gently open their eyes and return to normality), Wallis is still markedly disabled by his brain injury and is not able to care for himself.

Wallis’ recovery is no less remarkable, however, and highlights shortcomings in the scientific understanding of both coma-like states and the neuroscience of consciousness.

UPDATE: Pure Pedantry has a great article looking at some of the background issues to do with this case, such as the exact definitions of different coma-like states. Well worth checking out.

Link to ‘Rewired brain’ revives patient after 19 years from New Scientist.
Link to write-up from The Age (thanks Kate!)
Link to full-text of scientific study.
Link to previous Mind Hacks story on minimally conscious state.

The New York Times has an excellent article on people who experience chronic déjà vu, or, more accurately déjà vécu Рthe feeling of already having lived through something.

The article discusses work by Leeds-based neuropsychologist (and blogger) Chris Moulin who was asked to investigate a recurring feeling of familiarity in Susan Shapiro’s 77 year-old mother.

He was countacted because he is one of the only people to have investigated a similar case, that of a person known as ‘A.K.P.’:

His d√©j√† vu episodes seemed to be “practically constant,” as Moulin and colleagues outlined in a 2005 paper [abstract|pdf] in the journal Neuropsychologia:

He refused to read the newspaper or watch television because he said he had seen it before. However, A.K.P. remained insightful about his difficulties: when he said he had seen a program before and his wife asked him what happened next, he replied, “How should I know, I have a memory problem!” The sensation… was extremely prominent when he went for a walk ‚Äî A.K.P. complained that it was the same bird in the same tree singing the same song… When shopping, A.K.P. would say that it was unnecessary to purchase certain items, because he had bought the item the day before.

A little ironically, the New York Times published another excellent article on déjà vu last February.

Link to article ‘Deja Vu, Again and Again’ from the New York Times.

One I missed the other week – a fantastic edition of the Australian All in the Mind on Early Childhood and the Developing Brain.

Child neuropsychology is now becoming an increasingly important area as the once neglected field is seen as increasingly important both to understand children themselves, and how adult abilities and disorders develop.

This edition of All in the Mind looks at how neuroscientists are uncovering the neurobiological changes that take place during parental care, and how the brain can be markedly altered by abuse or neglect during the early years.

The programme takes a particularly in-depth look at research on children who were largely abandoned in Romanian orphanages during the communist era and had virtually no human contact for the first four years of their life.

Both their social and cognitive development was markedly impaired, suggested that love and attention is needed both for healthy emotional and intellectual development.

Link to transcript and audio of ‘Early Childhood and the Developing Brain’.

The New Yorker magazine has an article on hemispherectomies – surgical procedures which remove half of the cortex, usually in an attempt to cure otherwise life-threating epilepsy.

These operations are usually carried out on children, as remarkably, those in their early years can often develop normal adult skills and abilities if surgery is carried out early enough.

For example, a 2001 book by Antonio Battro (sample chapter: pdf) describes a three year old boy named ‘Nico’ who had the whole of his right hemisphere removed to control life-threatening epilepsy.

Nevertheless, he has developed with very little impairment and has turned out to be a bright and engaging child, despite the fact that a similar operation in adults would be profoundly disabling.

The New Yorker article charts the development of this procedure from the first operation on a human in 1923, to the latest in neurosurgical technology and practice.

Two of the pioneers of the procedure, Dr John Freeman and Dr Ben Carson are also featured, who explain how the team at John Hopkins first tackled a left hemispherectomy. Potentially hazardous, because the left side of the cortex has the majority of the language function in most people.

The article also introduces us to some of the patients who have had the procedure. Christina now drives, graduated from high-school and is studying at university, despite on having only one hemisphere of her brain left.

Link to New Yorker article ‘The Deepest Cut’.
pdf of sample chapter from ‘Half a brain is enough’.
Link to ‘Half a brain is enough’ book details.

The American Civil Liberties Union has filed a Freedom of Information Act request to try and find out whether the US goverment is using brain scan lie detection technology on suspected terrorists.

The most likely technology to be used for anti-terrorism purposes is Functional Magnetic Resonance Imaging (fMRI), which can produce live, real-time images of people’s brains as they answer questions, view images, listen to sounds, and respond to other stimuli. Two private companies have announced that they will begin to offer “lie detection” services using fMRI as early as this summer. These companies are marketing their services to federal government agencies, including the Department of Defense, Department of Justice, the National Security Agency and the CIA, and to state and local police departments.

While fMRI is certainly a hot-topic at the moment, EEG-based lie detection technology based on the same principle has been around for almost two decades now, and has the advantage of being more portable and considerably cheaper.

It’s interesting that it’s still not clear (publically at least) whether fMRI has any advantages over the existing EEG method, so it will be interesting to see if anything comes out of these enquiries.

Link to ACLU press release (via /.)
Link to actual Freedom of Information Act request.

As an update to our previous post on new neuroscience-based technology for lie detection, thanks very much to Swivel Chair Psychologist for pointing out that National Public Radio’s Talk of the Nation science programme just had a programme on fMRI lie detection with Penn psychiatrist Daniel Langleben and bioethicist Paul Wolpe.

Link to NPR Talk of the Nation on ‘The Future of Lie Detecting’.

Mixing Memory has a fantastic account of recent research on memory distortions in schizophrenia that might explain the unusual experiences and strange ideas that characterise the condition.

Memory distortions are often tested by the use of ‘source monitoring’ or ‘reality monitoring’ experiments (largely invented by Marcia Johnson), where participants are given a list of words and asked to read some of the words out loud, and imagine themselves reading the others out loud.

Afterwards, participants are given a recognition test where they are shown each word and asked whether they read it out, or imagined reading it out.

There are many variations on this theme, but a consistent finding is that those with symptoms of psychosis are more likely to confuse words they imagined reading out with those they said out loud.

The Mixing Memory article tackles a recent study which ran a similar experiment while brain-scanning participants to see which areas would be active when distortions were present.

It turns out that less activity in an area of the frontal lobe called the the medial anterior pre-frontal cortex was linked to more memory distortion errors.

One difficulty though, is that this form of memory distortion is also present in people who have no signs of mental illness but have some delusion-like ideas or experience sensory distortions, suggesting that this effect cannot explain psychosis completely.

Link to ‘Was it Real or Did I Imagine It? Source Monitoring, Schizophrenia, and Our Grip On Reality’

The Times recently published a curious article on the science of empathy after a case where an eight year-old girl broke her leg and several drivers apparently drove past without caring to stop and help.

Apart from the grating “empathy has a physical location” (the spirit of phrenology lives on…) it’s a brief but interesting look at some of the emerging research into empathy, although doesn’t do a great job of tying it together into a coherent overview.

For those wanting a more in-depth (and more accurate) look at the neuroscience of empathy, a 2003 review article (pdf) by Drs Jean Decety and Philip Jackson is a fantastic four-page romp through the recent research in the area.

Link to article ‘In a sorry state of mind’.
Link to Decety and Jackson article on empathy.

The use and abuse of psychiatric medication has been a hot topic in the news recently with discussion about whether we are too keen to medicate ourselves, and too keen to medicate our children, all in the hope of improving performance and behaviour.

The Washington Times Post recently published a widely circulated article, on the extent of ‘smart pill’ abuse on US college campuses. These ‘smart pills’ are largely pharmaceutical drugs designed to treat conditions where attention or alertness is impaired, such as ADHD and narcolepsy.

They include amphetamine-related drugs such as Adderall, Dexedrine and Ritalin; and non-amphetamine drugs such as Provigil and Strattera. These are often acquired from people who have genuine prescriptions.

The other side of the coin is that these drugs are available illicitly, partly because of the massive increase in prescriptions of these sorts of drugs to children and young people.

NPR’s Talk of the Nation show discussed the extent and effects of prescribing psychiatric drugs for young people in a recent show with guests David Cohen, professor of social work from Florida International University and Jeffrey Lieberman, director of the New York State Psychiatric Institute.

Link to Washington Post article ‘A Dose of Genius’.
Link to NPR Psychiatric Medication Debate (via World of Psychology)

Although headaches are a traditional turn-off for amorous couples, new research published in the journal Headache suggests that people susceptible to migraines actually report greater levels of sexual desire.

The authors suggest that the link may be levels of the neurotransmitter serotonin – which are linked to libido and have also been found to increase during migraine onset.

Luckily, greater levels of sexual desire tend to be a general trait in those susceptible to migraine, rather than being linked to the experience of headache itself.

Link to study abstract.

Science have an interesting snippet on a study that shows that shy children may not only be more sensitive to unpleasant things, and also to pleasurable and rewarding experiences as well.

A brain scanning study led by Dr Amanda Guyer showed that areas of the brain sensitive to both anxiety and reward were more strongly activated in shy children than other children.

The study subjects – who were classified as either shy or outgoing based on psychological testing – were instructed to press a button as quickly as possible after being shown a signal. If they pressed the button in time, they won money, or at least prevented themselves from losing it.

Both groups performed similarly, and there was no difference in the activity of their amygdalas – the brain region that governs fear. Shy children, however, showed two to three times more activity in their striatum, which is associated with reward, than outgoing children, the team reports in the 14 June issue of the Journal of Neuroscience. “Up until now, people thought that [shyness] was mostly related to avoidance of social situations,” says co-author and child psychiatrist Monique Ernst. “Here we showed that shy children have increased activity in the reward system of the brain as well.”

Link to article ‘The Rewards of Being Shy’.
Link to study abstract.

A recent study examining how the brain reacts to different types of image has found that women show a quicker reaction to erotic images than other image types. This is the first time that a difference in brain activity for erotic images has been found in women.

The research was led by neuroscientist Andrey Anokhin and used a technique that measures electrical activity from the brain by recording event-related potentials or ERP.

ERP is not very good at detecting which exact areas activity comes from, but can detect changes over very short periods of time (less than a millisecond). This makes it very good for determining differences in when the brain reacts.

Previous studies have found that men tend to show a stronger physiological response to erotic images than other images, as well as having larger areas of brain active when viewing such images.

Until now, no difference between erotic and non-erotic images had been found in women.

The study found that erotic images differently activated the mid part of the female prefrontal cortex (the red area in the image on the left) when compared to other images, within 185ms. Interestingly, this was regardless of how arousing or emotionally strong the images were.

185ms is an incredibly short time for the brain to differentiate between image types, and is almost certainly an automatic response. The prefrontal cortex is known to be involved in attention, and the authors suggest this activity reflects a vigiliance for socially relevant visual scenes.

When taken with the other research in the area, these findings suggests that men and women show differences in both where and when brain activity occurs when viewing erotic images.

However, it is still not clear what these differences might mean, and more extensive studies will need to be conducted to better understand this response.

It is also interesting that Anokhin and colleagues didn’t ask the female participants about sexual activity, orientation or a number of other things (such as stage in the menstrual cycle) that might affect reaction to erotic images.

It may be that these might have their own unique effect upon the new form of response reported in this study.

Link to study abstract.
Link to write-up from Live Science.

Transcranial magnetic stimulation (TMS) is a technique whereby magnetic fields are used to temporarily alter the function of the brain by inducing an electrical current in the brain tissue.

In neuroscience research, TMS usually refers to the use of powerful magnetic fields (about 1.5 tesla or 40,000 times the earth’s magnetic field) focused on approximately 1x1cm areas of the cortex.

Repetitive TMS (rTMS) can be used either to make the area more active or less active over a specific time period (often 30 minutes or so), while single pulse TMS is used to harmlessly ‘knock out’ an area for approximately 100ms.

Much weaker magnetic fields (about the strength of a loudspeaker) but much more complex in form, have also been used to induce unusual experiences by stimulating the temporal lobes, most notably by neuroscientist Dr Michael Persinger.

A new project called Open-rTMS aims to develop this latter type of system (actually, generally not referred to as TMS in the neuroscience literature) and publish the plans and software online.

They’re currently looking for people to sign up to the mailing list and kick the project off, so if you’re looking for a way to alter your state of consciousness with magnets, this might be your chance.

The project is similar in approach to the OpenEEG project, which aims to provide software and plans for a home EEG system, so you can read the brain’s electrical activity.

Link to Science News article on high-strength TMS.
Link to low-strength Open-rTMS project page.

New Scientist reports on a recent study that looks at the differences between epilepsy and psychogenic non-epileptic seizures – a mysterious condition that looks like a standard epileptic seizure (e.g. falling to the floor, limb shaking and unconsciousness) but does not seem to involve any disturbance in brain activity and instead is linked to underlying emotional issues and psychological distress.

It has been suggested that patients with psychogenic non-epileptic seizures consciously fake their attacks, but it now seems that although not related to a disturbance in brain function, the attacks are not under conscious control and seem to be related to conversion hysteria, where psychological stress leads to otherwise unexplained medical symptoms.

There’s more on these type of seizures in a previous post on Mind Hacks, for those that are interested.

A recent study by Dr Steve Chung and his colleagues attempted to distinguish between epileptic and non-epileptic seizures by carefully watching videos of people when they have a seizure.

They noticed that in genuine generalised epileptic seizures, the patients had their eyes open during the attack, whereas those with non-epileptic seizures had their eyes closed.

This can be seen in their video of a genuine epileptic seizure (WMV file) when compared to a non-epileptic seizure (WMA file).

The head and eye turning that occurs at the start of the genuine seizure is typical in some forms of epilepsy, and usually indicates that the seizure starts in the side of the brain opposite to the side of turning.

The ability to easily distinguish between seizure types is important, as genuine seizures are best treated with anti-epileptic drugs, whereas non-epileptic seizures can be treated with psychological therapy.

Link to New Scientist story.
Link to abstract of study from Neurology.
Link to previous Mind Hacks post on non-epileptic seizures.

The Economist has a short but interesting piece on the use of vagus nerve stimulation to treat depression.

The technique involves implanting a pacemaker-like device into the body that stimulates the vagus nerve (in the neck) at regular intervals.

The technology was originally developed as a treatment for epilepsy, but it was discovered that some patients felt better after the device had been implanted, even if it didn’t help control their seizures.

I’m not quite sure of The Economist’s claim that the treatment “builds on” deep-brain stimulation, which is newer and more advanced in many respects and directly stimulates areas of the brain with an implanted electrode.

Nevertheless, the article is an engaging look at the increasing interest in this technology, and notes that no-one is really sure how it works – either in treating epilepsy or depression.

Link to Economist article.

Wow. I’ve just found a corporate video for a brain computer interface device. With spiffy animation and video of the real thing in action.

It seems to be a video of this device currently in development.

I didn’t realise the technology was at the stage where slick videos would be necessary.

UPDATE: Thanks to the researchers from the lab who are developing this technology for passing on more info (pdf) in the comments page. I also notice there’s more info here and here on the science behind ‘BrainGate’.

Link to video (on YouTube).
Link to more info.