Trauma from events that never occurred

A study just published in the medical journal Psychosomatics reports four case studies of people who developed PTSD after experiencing a traumatic event that never occurred – while their emotional reaction was real, the events were hallucinated.

Post-traumatic stress disorder can occur when someone has experienced a traumatic event over which they had no control. PTSD is diagnosed when memories of the event intrude into everyday life, the person feels the need to avoid anything which could remind them of the situation, and they feel excessively anxious and on edge.

The patients described in the article had all been admitted to intensive care for serious medical conditions, but this was not the direct cause of their trauma.

While in intensive care the patients became delirious, a state where consciousness is clouded, thinking is impaired, and delusions and hallucinations are common.

In these cases, the delusions and hallucinations led the patients to believe they were about to die horrible deaths, were being threatened or were experiencing horrific events.

Later, when they recovered from their primary condition, they had all the symptoms of PTSD – but specifically for the incident that had only occurred in their disturbed thinking.

Here’s one of the case studies:

“Mr. A” was a 56-year-old white man who developed end-stage liver disease from a combination of alcohol and viral hepatitis. Aside from remitted alcohol dependence, he had no other psychiatric history. After liver transplantation, he experienced a difficult medical course, with sepsis, renal failure, biliary reconstruction, respiratory failure, and immunosuppressive medication neurotoxicity from tacrolimus. Several electroencephalograms showed diffuse generalized slowing of the background rhythms and documented seizures. He had persistent delirium for several months postoperatively.

While having delirium, he was extremely agitated, requiring restraints to prevent him from hurting himself and/or dislodging lines and catheters. He appeared awake, but was frequently incoherent and disorganized. However, he was able to articulate paranoid delusions that the staff were trying to kill him and his son. He was also observed to be responding to auditory and visual hallucinations.

Four months after the transplant, when he was discharged from the hospital, his delirium had resolved. He was no longer confused or disoriented, was not actively hallucinating or delusional, and his mood was good, with only occasional, transient symptoms of anxiety.

Several months later, in the transplant clinic, he reported reexperiencing events he had hallucinated while having delirium in the intensive care unit (ICU), and, thus, he met DSM‚ÄìIV criteria for PTSD. He recalled detailed paranoid delusions that the hospital staff had chained his son to his bed and were beating him to death. He recalled struggling against the restraints, hoping to free himself to save his son. He described hearing his son’s screams for help and sounds as if his son was being pummelled.

He reported recurrent nightmares of these events and even daytime flashbacks of these experiences, typically when spending time alone. He attempted to avoid thinking about these events and the hospitalization, but described difficulty doing so because the thoughts were intrusive and difficult to dismiss. Not only did he avoid discussing the events, but he also had difficulty returning to the hospital because it caused him to recall these images. He was observed to be restless and hypervigilant in the transplant clinic.

Both the medical illness and the psychoactive painkillers can contribute to the disturbed thinking that lead to delirium. This in turn can significantly affect how people remember their recovery.

In fact, one study found that some patients had no factual recall of intensive care at all, their only memory of the time was of their delusions. This group were particularly likely to be traumatised.

People are sometimes embarrassed to talk about these experiences, but they are surprisingly common. Studies have estimated that between between 12.5% and 38% of ICU patients experience delusions and hallucinations.

Link to study abstract.

ATDT

I’m not really one for blog memes, but I was pleased to see Psych Central has given us a nod. Actually, we’ve had a few of these now and they always give us a boost, but getting one from John Grohol is especially welcome because he’s the granddaddy of online psychology info.

It’s a bit like having Freud announce that you’ve got good taste in cigars.

For those of you who don’t know, Grohol is a psychologist who’s been putting mental health information on the net since the early nineties, and was putting information on BBS’s before that. He’s officially old school (if you thought ZMODEM was the best thing since sliced bread, you’re old school too).

At this point it’s probably worth mentioning that Mind Hacks is a substantial team effort of which my hypergraphia is just one part. Just Tom and Matt’s behind the scenes emails would fill a blog of their own. Plus we get a load of material sent by friends and readers (you know who you are! at least, Christian certainly does). Thanks!

Distant echoes of Shatner’s Bassoon

Language Log is doing a sterling job of keeping up with the increasing pace of Dr Alfred Crockus’ research, and seem to have found an important neuroanatomical link between the Crockus and another surprisingly neglected brain area, Shatner’s Bassoon.

The Crockus is the shameless and unintentionally hilarious invention of educational consultant Dan Hodgins, which he claims is four times larger in girls and so supports his own ideas about teaching (incidentally, he’s currently ‘on tour‘ if you want to hear his crockus first hand).

Shatner’s Bassoon was the invention of satirist Chris Morris, who persuaded various media figures that it was an area of the brain targeted by the fictional street drug ‘cake‘.

Several TV personalities and David Amess, a Tory MP, took part in Morris’ spoof TV programme with absolutely no insight into the completely ridiculous premise of the whole affair.

The best bit is when they do an earnest public education announcement, warning of the drug’s dangers and informing the viewers that it may be sold under the names of looney toad twat, russell dust, chronic basildon donut, Joss Ackland’s spunky backpack, bromicide, ponce on the heath, cool thwacks, and Hattie Jacques’ portentious cheese wog.

The video is available online, and it is a testament both to the fact that people are easily blinded by scientific sounding nonsense, and to the fact that celebrity endorsement of good causes can be as much about their public profile as it is about the cause itself.

David Amess went as far as asking a question about “cake” in parliament which you can read in Hansard, the official parliamentary record.

Interestingly, the Home Office assumed his question about ‘cake’ referred to 3,4-methylenedioxy-N-benzylamphetamine (MDBZ), one of the drugs synthesised by legendary psychedelics researcher Alexander Shulgin. The description of the drug appears in his book PiHKAL – a sort of Principia Psychedelica of mind-bending phenethylamines, of which ecstasy (MDMA) is probably the best known.

Morris’ spoof news series, The Day Today and Brass Eye, function equally well as hilarious entertainment and a careful analysis of the language of news media we’ve come to uncritically accept.

As a result, Chris Morris taught me more about deconstructing the media than Derrida ever did.

Language Log has been just as funny lately, and is doing an equally important job in pointing out how the language of neuroscience is now so all-pervasive, that people are willing to make up areas of the brain to support their point of view.

As an aside, if anyone knows of any other fictional brain areas, do get in touch. I feel these need collecting in one place.

Link to Language Log on ‘The Crockus and the Bassoon’.
Link to Brass Eye on ‘cake’.

Seeking free will: a debate

The Dana magazine Cerebrum has just published a debate between a psychiatrist and neurologist on how we can make sense of free will in the age of neuroscience.

The choice of professionals is an interesting one because each typically deals with what are assumed to be quite different disruptions in free will.

Neurologists often treat patients who have problems controlling their movements, cognition or consciousness – owing to clear, identifiable brain damage to the systems involved in these processes.

Someone with Parkinson’s disease, for example, seems to have little conscious control over their tremor or rigid movements.

Psychiatrists on the other hand, typically deal with people who don’t have clear brain damage, but whose brain’s are nonetheless functioning in such as way that they experience unstable moods, odd perceptions, or come to hold seemingly impossible beliefs.

Here the idea of free will is a bit more conceptually tricky. We can clearly say that someone who has Parkinsonian tremor is not ‘willing’ their movements, but what about someone whose brain disturbance means they hear voices?

Some people who hear voices can have conversations with them. In this situation, the person would seem to be exercising some influence over their hallucinations, because the voices respond to what’s being said, but many people can’t ‘will’ the voices away.

One particularly interesting phenomenon in this regard is ‘command hallucinations’ – usually hallucinated voices that command the person to do something.

Often, the commands are pointless – touch the table, cross the street, take off your hat – but sometimes they can be terrifying instructions – for example, that the person must harm themselves.

In some cases, these commands seem irresistible, the person feels completely compelled to follow their hallucinated instructions.

We don’t really have a good understanding (or, to be fair, even a bad understanding) of why some command hallucinations are distressing but impotent, while others seem to compel the person to comply.

There are many more examples of how free will is affected in both psychiatry and neurology. In both specialities, there are conditions where the boundaries of free will cover a big grey area, and all of them raise really quite profound questions about our freedom to act as we want.

The Cerebrum debate tackles exactly these sorts of issues by two people who undoubtedly have to deal with them on a daily basis.

Link to Cerebrum article ‘Seeking Free Will in Our Brains: A Debate’.

Advancing the history of psychology

I’ve been enjoying the Advances in the History of Psychology blog lately, which is full of interesting snippets about the past and often digs into the historical background of contemporary hot topics.

For example, here’s an interesting bibliography about psychoactive drug use in psychology, and here’s another about Benjamin Franklin’s interest in ‘electrotherapy’.

It’s run by the same people who produce the completely invaluable Classics in the History of Psychology archive, that has a huge website with some of the most important texts from psychology’s colourful past.

Both are excellent, and I look forward to reading more.

Link to Advances in the History of Psychology blog.
Link to Classics in the History of Psychology archive.

Want fries with that?

Neurophilosophy discusses a recent study that suggests that the inclusion of large amounts of starchy foods into our diet helped fuel the evolution of the brain.

It’s interesting because it’s not the first study to suggest that specific changes in diet improved nutrition and brain development:

According to one theory, increased consumption of meat by our ancestors provided the additional energy needed for brain expansion. (Cooking would have further increased the amount of calories obtained from meat.) Another holds that a switch to a seafood-rich diet would have provided polyunsaturated fatty acids which, when incorporated into nerve cell membranes, would have made the brain function more efficiently.

And now, a study published in Nature Genetics adds starchy tubers to the smorgasbord of foodstuffs that may have contributed to the expansion of the human brain.

These theories tend to be quite controversial and tend to cause numerous back and forth arguments in the literature, partly because they’re quite hard to test, largely owing to the fact that the brain has the consistency of toothpaste and so doesn’t leave much of a fossil record.

The study picked up by Neurophilosophy is interesting because it tracks a gene that codes for a starch enzyme, needed to break down starch into glucose.

It’s a relatively new approach to an old problem, although as the article mentions, the link to brain evolution is still circumstantial.

However, it’s an interesting areas and the Neurophilosophy article is a great brief guide to some of the thinking behind these theories.

Link to Neurophilosophy on ‘Diet and brain evolution’.

2007-09-21 Spike activity

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

SharpBrains has an interview with cognitive behaviour therapy guru Judith Beck about using CBT for effective dieting.

Wired wonders whether EEG-based brain-to-game interfaces may mess with our heads.

Hard-up students: Aren’t there a lot of psychology textbooks on torrent servers these days? Just sayin’

Genes which raise risk for schizophrenia have likely been positively selected for during evolution, reports SciAm.

The BPS Research Digest reports that having a pen in your mouth impairs your ability to recognise emotions in others, as you’re not as good at mirroring their facial expression.

Sally Satel discusses the early rumblings over the new DSM (due out 2012) in The New York Times.

NPR has an interesting programme on the the application of mathematics to tracking social networks of terrorists.

A lovely snippet from Cognitive Daily: more evidence that everyone has a little synesthesia.

Pinker’s working the crowd: An NPR radio interview on the new book, and Discover Magazine interview on the same.

Can information be directed to different networks in the brain depending on the “transmission frequency“, like the channels on a TV? Developing Intelligence investigates.

Forget troubled teens. The New York Times reports on baby boomers behaving badly.

To the bunkers! Further evidence that Skynet is about to become sentient:
* AIs set loose in virtual worlds to ‘hone their skills’.
* Reason Magazine will be saying ‘I told you so’ when AIs keep us as pets!

OmniBrain notes that the 2008 Visual Illusion Contest is open and accepting entries.

Track the performance of the neurotech industry!

Dr Petra discusses a recent study that asked teens about their definition of virginity – which is remarkably variable.

US Government outsources their wacky mind-control fantasies to Russia.

Analyse the negative, bask in the positive. PsyBlog has some evidence-based advice for increasing life satisfaction.

PsychCentral notes that the APA have earmarked $7.6 million ($7.6 million!) to upgrade their website over the next two years. PsychologicalReviewTube to be launched in 2009.

Pure Pedantry has found some beautiful pictures of the pre-synapse.

Gone, and yet forgotten

An interesting section from neuropsychiatrist Michael Kopelman’s 2002 review article on the neuropsychology of memory disorders where he tackles transient global amnesia – a form of brief, severe, but mysterious amnesia that resolves in a few hours. No-one really knows what causes the majority of cases.

Transient global amnesia (TGA) most commonly occurs in the middle-aged or elderly, more frequently in men, and results in a period of amnesia lasting several hours. As is well known, it is characterized by repetitive questioning, and there may be some confusion, but patients do not report any loss of personal identity.

It is sometimes preceded by headache or nausea, a stressful life event, a medical procedure, intense emotion or vigorous exercise. Hodges and Ward (1989) found that the mean duration of amnesia was 4h and the maximum 12h. In 25% of their sample, there was a past history of migraine, which was considered to have a possible aetiological role.

In a further 7%, the patients subsequently developed unequivocal features of epilepsy in the absence of any previous history of seizures. There was no association with either a past history of or risk factors for vascular disease, nor with clinical signs indicating a vascular pathology. In particular, there was no association with transient ischaemic attacks.

In 60-70% of the sample, the underlying aetiology was unclear.

Link to full-text of paper ‘Disorders of memory’.

Won’t you help me doctor beat

Musicogenic epilepsy is a neurological disorder where epileptic seizures are uncontrollably triggered by music. Gloria Estefan’s Dr Beat is a catchy 80s pop song where she calls for medical assistance because music is irresistibly moving her body, moving her soul and affecting her brain.

Coincidence? I think not.

Doctor, I’ve got this feelin’ deep inside of me, deep inside of me
I just cant control my feet, when I hear the beat
when I hear the beat
Hey doctor, could you give me somethin’ to ease the pain
cause if you dont help me soon gonna lose my brain
gonna go insane

Despite Ms Estefan’s requests, painkillers are unlikely to help with the acute effects of seizure.

First-line treatment is usually a rapid acting benzodiazepine and long-term stabilisation with a common anticonvulsant such as sodium valproate.

While her concerns about her mental health are understandable (people with epilepsy are at a slightly higher risk of developing mental illness), the majority of people with the condition lead full and active lives, so her fear of insanity is largely unfounded.

There are many cases of musicogenic epilepsy in the medical literature but, unfortunately, only a few few are freely available online. One is particularly interesting though and is available as a pdf file.

It’s a 1957 article published in Psychosomatic Medicine that reports three fascinating cases, including a girl who had her seizures triggered by swing music that induced, among other things, hallucinations of a smartly dressed couple.

For those of you wanting something a bit more up-to-date though, YouTube has the a Dr Beat Mylo remix Dr Who video mashup. Same symptoms, new medical staff.

pdf of ‘Musicogenic Epilepsy: Report of Three Cases’.
Link to Dr Beat lyrics.
Link to original Dr. Beat video.
Link to Dr Beat remix Dr Who tribute mashup.

Building on brain clich√©s

The Financial Times has a slightly bizarre article on the application of neuroscience to architecture that suggests that we’re genetically predisposed to feel relaxed around flowers, the hearth and food, and that homes need to be designed to release certain neurotransmitters.

The piece is about the Academy of Neuroscience for Architecture (ANFA) which aims to use neuroscience in building design and encourage brain research into the effects of buildings.

I’m all for the wider application of neuroscience, and I’m sure there are some relevant findings that could be applied, but the article is full of so many erroneous brain clich√©s that I just despair.

Zeisel is also a director of the Academy of Neuroscience for Architecture (ANFA), an organisation launched in 2003 to encourage scientists to get out of the lab and partner with architects and designers. “It’s the future of the field,” he says. “People might ask what neuroscience has to do with designing an ’emotional’ house but our emotions are managed by our brain,” Zeisel says. “When our brains are happy a certain endorphin gets released, so we need to design homes in order to release that neuro-transmitter.”

Endorphins are the brain’s natural opioids and are released in a wide variety of situations. They are indeed released when we feel pleasure, but are also released when we feel stress or pain.

So designing homes to maximise the release of endorphins will just as likely lead to uncomfortable, stressful hell-holes.

Take our desire for eye contact with others as an example. “A couple of million kitchens are planned each year and probably only about 5 per cent obey the most basic principles for human communication,” [kitchen designer!] Grey says. In most, the person preparing the food at the sink, stove or counter has to face away from his or her family or guests, decreasing sociability in what should be a social zone. “As a result the brain continues to produce adrenalin and cortisol, the hormones associated with fear and anxiety,” he says. “Whereas if they are facing [into the room] then oxytocin, the bonding hormone, and serotonin, associated with relaxation and enjoyment, are released.”

So, it not only makes the common but false link between specific mental states and general neurotransmitters, makes unproven claims between specific activies and the release of these neurotransmitters, but also makes the unsupported claim that facing away from people in the kitchen causes fear and anxiety, while facing towards them causes relaxation and enjoyment.

Zeisel suggests that responses to some features of the home might even be innate. “We are born with genetically developed instincts that make us feel relaxed around flowers, the hearth, food and water,” he says. “It’s simply an emotional need and using those things in the environment will make us feel more comfortable.” On the flip side, places that seem too sterile or too confusing are perceived as dangerous, which can trigger the hypothalamus to release stress hormones.

There’s no evidence that we are genetically predisposed to feel relaxed around “flowers, the hearth, food and water”. Perceiving things are dangerous does indeed lead to the release of stress-related hormones, but there’s no evidence that ‘confusing’ or ‘sterile’ buildings do this.

Of course, buildings that are ‘too sterile’ or ‘too confusing’ might do, but therein lies a circular argument, because you’ve already defined them as having a negative influence.

Professor Joan Meyers-Levy of the University of Minnesota’s Carlson School of Management is another academic interested in how our surroundings affect our physical and mental states. Her research shows that when people are in a room with high ceilings, it activates sections of the right brain associated with freedom and abstract thinking. In low-ceilinged rooms, more constrained thinking is brought to the fore. “There’s a preference in terms of real estate for high ceilings and it‚Äôs [not only] the sense of power and wealth that conveys but also [the fact that] vertical space could have a beneficial mental influence,” she says.

To be completely fair to Meyers-Levey, her study [pdf] was a perfectly reasonable investigation into the effect of ceiling height on priming – an effect where an initial stimulus quickens your ability to react to related things.

However, the brain is not even mentioned in the paper, let alone measured in any way. The bit about high-ceilings activating the ‘right brain’ has just been added, seemingly from nowhere, by the journalist.

Two papers were recently published in Cell about the application of neuroscience to architecture, but importantly, they speculate, but don’t actually reference any studies that have looked at the influence of building design on the brain. The article then goes on to repeat several of the speculations as fact.

I think the article may be a candidate for the Dr Alfred Crockus Award for the Misuse of Neuroscience.

As an aside, Crockus fans may be interested to hear that he’s been tracked down to the hitherto unknown but undoubtedly endorphin stimulating ‘Boston Medical University Hospital’.

UPDATE: Christian just reminded me that he wrote an article for The Psychologist late last year that looked at how psychology is being increasingly used in architecture. It also discusses specific scientific research on psychology and building design. It’s an excellent antidote to the Crockus from the FT.

Link to ropey FT article.
Link to Psychologist article ‘Is there a psychologist in the building?’.

Sexuality special in this week’s Psychiatric Times

The latest edition of the Psychiatric Times has a special section on sexuality that discusses everything from dealing with sex-related problems as a clinician, to the science of sexual orientation.

It’s actually quite a refreshing change from much of the recent hype we’ve seen about sexual dysfunction, which usually suggests that a patch, pill or prostheses is an essential treatment for unsatisfactory sex.

Psychiatrists who develop an interest in clinical sexuality tend to employ 2 different paradigms, depending on the clinical situation. One is quite familiar to modern psychiatric continuing education. The patient has a disorder, we possess a range of medication treatments, and the etiological theories support our treatment. Lifelong premature ejaculation is an ideal example.

Another paradigm is necessary for most sexual disorders, however. We approach these disorders from the viewpoint of general etiology rather than disorder-specific causation. Sexuality unfolds in adolescence and continues to evolve over decades of adult maturation. The sexual problem serves as a window into personal development and individual and relationship psychology. Sex is understood to be about the unfolding of the individual self, the capacity to give and receive pleasure, the capacity to love and to be loved, the ability to be psychologically intimate, and the ability to manage expected and unexpected changes throughout adulthood.

Since few sexual dysfunctions have a specific treatment, diagnosis per se usually is not the determinant of treatment. Rather, it is the invitation to study the context in which the problem arose. Treatment rests on the clinician’s understanding of how biological, psychological, interpersonal, and cultural factors combined in this case to create the symptom. This second paradigm reminds psychiatrists that the management of sexual disorders often requires interest and skills in psychotherapy.

The fact that most sexual problems are a manifestation of wider difficulties with relationships, mood, or adjustment is taken as read by most clinicians working in the area.

Unfortunately, most of the messages we encounter from TV, magazines and V!aGr4 spam suggest sexual difficulties are nothing more than a physical problem that needs a fix – as if you could help someone drive better by selling them tyres.

Link to August Psychiatric Times.

Here’s one we prepared earlier

This week’s edition of New Scientist has a cover article outlining a number of try-it-yourself experiments that give you an insight into the cognitive science of the mind and brain.

Hang on a minute, that sounds familiar.

They say imitation is the sincerest form of flattery, and if so, the British science weekly have just paid a huge complement to Tom and Matt.

The NewSci article has six sections, each covering different areas of neuroscience, and each of which uses at least one example that appeared in the Mind Hacks book, and in some cases several. Here’s the overlap:

NS: Seeing isn’t believing
MH: Hack #17 Glimpse the Gaps in Your Vision
MH: Hack #18 When Time Stands Still
MH: Hack #49 Speech is Broadband Input into Your Head
MH: Hack #59 Hear With Your Eyes: The McGurk Effect
MH: Hack #53 Put Timing Information Into Sound and Location Information into Light

NS: This is not my nose
MH: Hack #63 Keep Hold of Yourself
MH: Hack #64 Mold Your Body Schema

NS: A Brain of two halves
MH: Hack #69 Use Your Right Brain – And Your Left, Too

NS: Probe your subconscious
MH: Hack #80 Act Without Knowing It

NS: Pay attention!
MH: Hack #36 Feel the Presence and Loss of Attention
MH: Hack #40 Blind to change
MH: Hack #41 Make Things Invisible Simply by Concentrating (On Something Else)

NS: Made-up memories
MH: Hack #85 Create false memories

Actually, several of the NewSci sections have completely new examples and have otherwise added updates with the latest scientific findings. A few discuss areas untouched in the book, but mainly they cover the same ground.

If you’ve got the book already, it’s an interesting update with some new experiments to try. And if you haven’t, it’s like the book, but shorter.

In fact, some of the article text mirrors the flow of the book rather closely. And not even a favourable nod to Tom and Matt. Tsk! Tsk! Tsk!

Sadly, the article isn’t freely available online, so you’ll have to buy a copy to have a look.

UPDATE: Grabbed from a comments, feedback from the author:

Yes, Mind Hacks was a major inspiration for this article. But there’s loads of new stuff in there too. And it does give a nod to Tom Stafford and Matt Webb. That’s why it says at the end “Further Reading: Mind Hacks: Tips and tools for using your brain, by Tom Stafford and Matt Webb (O’Reilly 2006).”

Keep up the good work!

Thanks Graham. Unfortunately, the Further Reading section doesn’t appear on the online version, which is why I missed it.

Link to Scientific American. Petty, I know.
Link to NewSci article. The world is at peace.

An annotated guide to books on the brain

The Dana Foundation have collected a list of widely praised books on the mind and brain that cover everything from academic texts to compelling fiction. Every book on the list is accompanied by a brief write-up.

It’s an extensive list with a number of great books on the list. My only reservation is that David Marr’s Vision (ISBN 0716715678) is missing.

I’ll get round to writing more about Marr in the future, as he is probably one of the most influential figures in 20th century neuroscience.

An amazing feet considering his book was written while he was dying from leukaemia, to which he eventually succumbed at the age of 35.

Vision was published after his death and has had a massive impact on vision science, neuropsychology and computational neuroscience – the latter of which was largely inspired by his work.

It’s also the only academic neuroscience book I’ve ever read which starts with the line: “This book is meant to be enjoyed”.

I read about the Dana guide on the excellent My Mind on Books – a site dedicated to mind, brain and cognitive science books – which also comes highly recommended.

Link to ‘Important Books on the Brain’ from the Dana Foundation.
Link to My Mind on Books.

Patient HM marks 50 years in science with new study

A new study has been published on Patient HM, marking fifty years of participation in neuroscience research since the first study was published in 1957.

HM was suffering from incapacitating epileptic seizures that were not helped by any of the medications of the 1950s.

As a last resort, neurosurgeon William Scoville tried an experimental operation to remove 8cms of tissue on both sides of the inner parts of his temporal lobes, including both hippocampi, hopefully also removing the source of his seizures.

Neurosurgery to treat otherwise untreatable epilepsy is still common and highly effective, although this type of operation isn’t used any more.

This is largely because HM’s seizures reduced considerably, but he was left with a severe amnesia, meaning he couldn’t seem to lay down any new conscious memories, although could remember things that occurred before his surgery.

Because of his seemingly unique memory impairment and an exact knowledge of which brain areas were missing, he has become a regular in neuroscience research that has aimed to understand what his impairment tells us about how normal memory is supported by the brain.

This new study is no exception. The researchers, Profs Veronique Bohbot and Suzanne Corkin, guessed on the basis of the existing evidence that the right parahippocampal cortex would be enough to support spatial learning and navigation.

The right side of the brain is known to be specialised for understanding 3D space and some of the parahippocampal cortex, an area adjacent to the surgically removed hippocampus, remained in HM’s brain.

So the researchers used a task where a sensor is hidden under a section of carpet in a room which beeped when it was stepped on.

The participants were asked to find it just by exploration, and subsequently, they were taken to different parts of the room and asked to re-find it.

Despite having no conscious memories of previous tries, HM began to find the sensor quite accurately, much more accurately than if he was just stumbling across it by chance alone.

This suggests that his remaining part of HM’s parahippocampal cortex was enough to support spatial memory, and importantly, that the brain areas missing in HM, although they would help, are probably not essential for navigation.

HM has participated some key studies through the decades and has outlasted many in the field. He probably doesn’t realise it, but he’s been one of the most important people in neuroscience.

Link to abstract of scientific study.
Link to NPR radio show on HM and memory.
Link to Wikipedia entry on HM.
pdf of 1957 study on HM.

Girls have a bigger crockus

The excellent Language Log have discovered that an ‘expert’ invited to give a talk to a district education group not only invented a completely bogus part of the brain called the ‘crockus’, but claimed that it’s four times larger in girls and used this fact to back up recommendations for the teaching of children.

Language Log writer Mark Liberman notes that a study found a minor sex difference in the pars opercularis, a genuine brain area in the approximate location of the fictional ‘crockus’.

Although the study found the opposite pattern (it tends to be larger in boys), Liberman wondered whether the speaker may have misremembered both the name of the genuine brain area and the gist of the study.

So, he emailed the speaker to ask more.

In response, he got an answer that would be comically brilliant if it wasn’t deadly serious:

Thanks for asking….The Crockus was actually just recently named by Dr. Alfred Crockus. It is the detailed section of the brain, a part of the frontal lope. It is the detailed section of the brain. You are right, it is four times larger in females then males from birth.

This part of the brain supports the Corpus Callosum (the part of the brain that connects the right and left hemisphere. The larger the crockus the more details are percieved by the two sides of the brain.

Dr Alfred Crockus, we salute you sir!

Link to Language Log on ‘High Crockalorum’ (via BadScience).

Music, love survives the densest amnesia

Oliver Sacks has written an engaging piece for the latest edition of the The New Yorker on how musical ability can survive even the most severe amnesia, with particular reference to the famous case of Clive Wearing.

Wearing was a renowned classical musicologist and conductor, involved in recreating some of the most challenging Renaissance works. You can still find him in the sleeve notes of some of his professional recordings, usually described as having retired due to ‘ill health’.

In his case, ill health meant being struck by herpes simplex encephalitis, a viral infection that is known to attack the key memory areas in the brain, leaving him with a dense amnesia.

Even today, he is severely memory-impaired and remains unable to maintain anything in his conscious memory for more than a few seconds.

But in an almost Homeric twist of fate, as if he had bargained with the Gods themselves, he retained the memory that he loved his wife, and his ability to play music.

Clive has been the subject of two documentaries (clips of which are available online) and a recent book by his wife, entitled Forever Today (ISBN 0385606265).

He’s also been the subject of various scientific studies, summarised in a chapter of the book Broken Memories: Case Studies in Memory Impairment (ISBN 0631187235).

This chapter is co-written by Clive’s wife and Prof Barbara Wilson, a respected British neuropsychologist who specialises in memory.

The chapter contains a wealth of information about the neuropsychology of his memory, but also contains this interesting snippet:

For many years, Clive has experienced auditory hallucinations. He hears what he thinks is a tape of himself playing in the distance. He refers to this in his diaries as a ‘master tape’ (a term used in broadcasting for the original audiotape which should be protected from casual use and should certainly not leave the studio).

If asked to sing what he can hear – a sound only ever heard in the distance – he picks the tune up in the middle and is puzzled that no-one else can hear it. Half an hour later when asked to sing what he can hear it is usually the same tune but sometimes sung in a different style as if it were replaying in variations.

The New Yorker article is written with Sacks’ trademark sensitivity and wonder, and is a engrossing exploration of music and memory.

It comes shortly before the release of his new book Musicophilia, of which there is a short audio excerpt on the bottom of the book’s webpage.

Link to New Yorker article ‘Music and amnesia’.