Category: Remembering

Neurophilosophy has alerted me to the fact that National Geographic magazine has a fantastic cover feature on memory, forgetting, amnesia and hyper-recall in this month’s issue. It’s both freely available online and is accompanied by an interactive 3D brain map of the key memory structures.

The article discusses some of the extremes of memory that have been reported in the neuropsychology literature and describes an encounter both with EP, a patient with profound amnesia after suffering an HSE infection, and AJ, a woman who seemingly has an almost ‘perfect’ memory for her past.

As well as tackling some of the neuroscience of memory, the piece does an excellent job of communicating the characters and frustrations of the people with these remarkable memories

It also contains some wonderful asides about the place memory has in our society, and how that has changed significantly since the advent of technologies such as disposable writing tools that have allowed us to artificially ‘extend’ our memories.

Before that time, the act of remembering was, in itself, a hugely significant skill and quite literally in some cases, the stuff of legend.

It’s hard for us to imagine what it must have been like to live in a culture before the advent of printed books or before you could carry around a ballpoint pen and paper to jot notes. “In a world of few books, and those mostly in communal libraries, one’s education had to be remembered, for one could never depend on having continuing access to specific material,” writes Mary Carruthers, author of The Book of Memory, a study of the role of memory techniques in medieval culture. “Ancient and medieval people reserved their awe for memory. Their greatest geniuses they describe as people of superior memories.”

Thirteenth-century theologian Thomas Aquinas, for example, was celebrated for composing his Summa Theologica entirely in his head and dictating it from memory with no more than a few notes. The Roman philosopher Seneca the Elder could repeat 2,000 names in the order they’d been given to him. A Roman named Simplicius could recite Virgil by heart‚Äîbackward. A strong memory was seen as the greatest of virtues since it represented the internalization of a universe of external knowledge. Indeed, a common theme in the lives of the saints was that they had extraordinary memories.

After Simonides’ discovery, the art of memory was codified with an extensive set of rules and instructions by the likes of Cicero and Quintilian and in countless medieval memory treatises. Students were taught not only what to remember but also techniques for how to remember it. In fact, there are long traditions of memory training in many cultures. The Jewish Talmud, embedded with mnemonics‚Äîtechniques for preserving memories‚Äîwas passed down orally for centuries. Koranic memorization is still considered a supreme achievement among devout Muslims. Traditional West African griots and South Slavic bards recount colossal epics entirely from memory.

Link to National Geographic article ‘Remember This’.
Link to interactive 3D brain map of the key memory structures.

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’.

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.

The Science website is reporting on a study that has found that people with a variant of the ADRA2B gene, which regulates the effect of key memory neurotransmitter norepinephrine, are more likely to have enhanced memory for emotional and traumatic events.

A strong emotional response at the time of an event is known to make the event more memorable, and the neurotransmitter norepinephrine, also known as noradrenaline, has been found to be a key player in this process.

The researchers, led by neuroscientist Prof Dominique de Quervain, wondered whether a version of the ADRA2B gene, that codes for the alpha-2b norepinephrine receptor, would influence emotional memory recall.

One of the defining features of post-traumatic stress disorder or PTSD is that distressing memories of the original trauma intrude into everyday life.

People differ in their tendency to remember emotional memories, so understanding the factors behind this difference might help us better understand why some people can survive trauma with little long-lasting disturbance, while others are seriously affected.

The team determined the genotype (gene version) of 435 young Swiss adults and 202 refugees from the Rwandan civil war.

The Swiss volunteers were shown a series of pictures from the International Affective Picture System, a series of photos that range from the pleasant (e.g. sunsets) to the disturbing (e.g. mutilated bodies) that have been rated for their emotional impact.

Participants with a common variant of the ADRA2B gene were more significantly more likely to recall the emotional, but not the neutral pictures.

The refugee participants were asked to recall memories from their time in Rwanda during the civil war.

Participants with the same gene variant that was linked to an increase in emotional picture recall in the Swiss participants, recalled significantly more traumatic incidents than others.

However, the rate of PTSD in the refugee sample did not depend on gene version.

This is possibly because a diagnosis of PTSD requires three things: intrusive traumatic memories, hyperarousal (a feeling of being ‘on edge’ all the time) and avoidance of the reminders of the trauma.

The gene variant was only linked to the likelihood of re-experiencing traumatic memories, and not the other symptoms, suggesting that the effect is specific to memory and not trauma in general.

Link to write-up from Science.
Link to abstract of scientific paper.

I leave Dublin today after working in the Fair City since spring.

Many thanks to the psychologists I’ve worked with and learnt so much from, and the people of Dublin for their kind hospitality.

The picture is taken from Sandycove Harbour, looking out across Dun Laoghaire and Dublin Bay.

Only a few hundred yards from where this photo was taken is a tower where James Joyce stayed for several nights until his medical student housemate, Oliver Gogarty, shot at him with a gun.

The tower sets the scene for beginning of Joyce’s novel Ulysses, known for its ‘stream of consciousness’ narrative – a technique first borrowed from psychology by writer May Sinclair.

A poignant short essay from The New York Times on locations that only live in our memories.

It has the lovely image of cities that exist only in our minds, after buildings we knew so well have since been replaced.

Sort of nostalgic landscapes that we carry with us, long after the actual places have ceased to exist.

I’d might as well be looking at the people on the street and imagining all the buildings that have passed through them — places we knew almost by intuition until they vanished, leaving behind only the strange sense of knowing our way around a world that can no longer be found.

Link to NYT article ‘Remembered spaces’.

BBC News has a story with the headline ‘scientists can erase bad memories’, which is, at best, nonsense. What has been found is still an important discovery: a drug given during the recall of a traumatic memory can reduce its long-term emotional impact.

The drug is propranolol, a ‘beta-blocker’ that dampens down the sympathetic nervous system.

One of the roles of this system is to prepare the body for ‘flight or flight’ during stressful situations, by, among other things, releasing adrenaline, increasing blood pressure, and upping anxiety.

The drug has been used for years to help people with high blood pressure and heart conditions, so when they get stressed, it doesn’t put such a strain on their heart.

It’s been known for a while that starting a course of propranolol shortly after a traumatic event reduces the chance of people developing post-traumatic stress disorder – a condition that involves intrusive traumatic memories and hyper-arousal.

This new study is important, because it recruited people who had been traumatised a long time ago – an average of ten years earlier.

The participants were asked to recall what happened. Half were given propranolol and half were given placebo.

A week later, the participants were asked to recall the same memory while the researchers measured heart rate, sweating and muscle tension in the face – all of which are measures of bodily stress.

The participants who had been given the propranolol showed significantly less arousal than those who were given the placebo, suggesting the emotional impact of the memories had been reduced.

The fact that this can have an effect ten years after the event, if used when the memory is recalled, is an interesting finding.

Memory is a reconstructive process – in other words, our brain recreates the best estimation of an event each time we recall it. This might be slightly different each time and, importantly, each time we recall something the ‘store’ of information is changed.

It would be like if a CD remembered the other sounds in the room each time it was played, and included some of them when you listened to it again.

Propranolol might work by reducing the stress associated with the memory by influencing the ‘rewriting’ process.

The study is only a clue though. What it didn’t show is that this selectively reduced the arousal associated with that memory (maybe it affected other traumatic memories which weren’t recalled) and there was no group who were only given the drug and weren’t asked to recall anything.

It’s unlikely that the drug can reduce traumatic memories if just given at any time, but its something that needs to be explored to be sure we know how the treatment is working.

UPDATE: The Beeb have changed their headline to the slightly more sensible ‘Drug can dampen down bad memories’.

Link to abstract of scientific paper.

San Francisco’s interactive science museum Exploratorium has a fantastic online memory exhibit, that includes articles, games, demonstrations and lectures from leading memory researchers.

The exhibit looks at the science of memory, as well as how it is used in art.

There’s a great article that explains memory distortions via Philip K. Dick and a try-it-yourself demonstration.

And for some unknown reason there’s a slideshow of a sheep brain dissection, when what would be genuinely informative would be to see the memory structures in the human brain.

It’s like going to an air show and watching someone take a bicycle apart.

Apart from that, the site’s fantastic. The lectures are particularly good. Most cover the science of memory, but one is on ideas of forgetting in myth and story.

Link to Exploratorium memory exhibit.

The New York Times has just published an article on dissociative fugue, the poorly understood memory disorder where people seem to forget who they are.

It has many similarities to conversion disorder where people seem to experience a disability (such as paralysis) despite having nothing medically wrong with them.

Both conversion disorder and dissociative fugue are often linked to trauma and they are often thought to arise from emotional difficulties being pushed from consciousness and expressed in other ways – all outside the conscious control of the patient.

Brain imaging research has shown that these sorts of states are likely to be different from people purely ‘faking’ the same thing, but in the clinic, fakers might be still quite hard to detect and extensive neuropsychological testing may be required to do so.

Also, there’s always the worry that there is some medical reason for the problem that just hasn’t been found yet.

Despite these difficulties, some researchers are investigating these conditions, which may provide vital clues to understanding the conscious mind.

The article discusses some famous cases of dissociative fugue and deal with some of the differences with amnesia after brain injury.

It also mentions that a play about the condition, entitled Fugue, is running at New York’s Cherry Lane Theatre until April 22.

Link to NYT article ‘When a Brain Forgets Where Memory Is’.
Link to description of dissociative fugue from the Merck Manual.

Collision Detection has some interesting coverage of recently published research suggesting websites with interactive graphics are more likely to produce false memories about the pictured products than sites with static images.

The article also makes an interesting point about the focus of consumer psychology in this area:

One interesting thing [researcher] Schlosser points out is that market-research folks almost never study the false-memory effects of advertising. Sure, they test to see whether consumers who’ve looked at promotional material can recall true information about a product. But they rarely check to see whether the consumers also remember false information.

There’s more in the Collision Detection article and a link to the full-text of the paper.

Link to Collision Detection article (thanks Katerina!).

Science and Consciousness Review has a new feature article by staff writer Alice Kim discussing the role of the parietal lobe in memory.

The parietal lobe is typically linked to the representation of the body, and space in relation to the body, so it might be surprising that this area is being linked to more general memory abilities.

There is now a growing body of evidence for the importance of parietal areas in remembering and the article takes an in-depth look at what the scientific studies are telling us about how it all fits together.

Presumably, the author is not the same Alice Kim who is married to Nicolas Cage, but you can never be too sure.

Link to SCR article ‘The potential role of the parietal lobe in episodic memory and other cognitive functions’.

A widely cited result asserts that experts superiority over novices in recalling meaningful material from their domain of expertise vanishes when random material is used. A review of recent chess experiments where random positions served as control material (presentation time between 3 and 10 seconds) shows, however, that strong players generally maintain some superiority over weak players even with random positions, although the relative difference between skill levels is much smaller than with game positions

Gobet, F. & Simon, H. A. (1996). Recall of rapidly presented random chess positions is a function of skill. Psychonomic Bulletin & Review, 3, 159-163.

Preprint as Word Doc
Gobet’s bibliography here

A curious footnote on p183 from Mary Roach’s wonderful book on the natural history of the dead body Stiff: The Curious Lives of the Human Cadaver (ISBN 0141007451):

People have trouble believing Thomas Edison to be a loopy individual. I offer as evidence the following passage on human memory, taken from his diaries: “We do not remember. A certain group of our little people do this for us. They live in the part of the brain which has become known as the ‘fold of Broca‘… There may be twelve of fifteen shifts that change about and are on duty at different times like men in a factory…. Therefore it seems likely that remembering a thing is all a matter of getting in touch with the shift that was on duty when the recording was done.”

As well as his idiosyncratic views on memory, Eddison also thought that departed spirits might communicate through electrical equipment. In his writing, he refers to a device he had specifically designed for communicating with the dead.

Later, Dr. Konstantin Raudive, a Latvian psychologist and student of Carl Jung, continued Eddison’s work by looking for the apparent voices of spirits that appeared on audio recordings (known as EVP).

Critics suggest that the apparent voices are nothing but our brains trying to making sense out of essentially random data – something known as apophenia.

Raudive is pictured on the right with one of his special devices.

An unusual chapter in the history of psychology.

Link to Fortean Times article on the history of EVP.

The New York Times discusses a recent challenge laid down by psychologists skeptical of claims of recovered memories: find a single account of repressed memory, fictional or not, before the year 1800.

The researchers claim that the earliest account is from the 1782 novel Dangerous Liaisons and have published their findings in the journal Psychological Medicine.

They suggest that the idea of a recovered memory is a cultural invention and people are likely to arrive at the clinic with trauma and memory problems already shaped by these ideas.

The challenge has revisited a long-standing and heated debate over the reality of recovered memories that first exploded in the 1980s.

At the centre of the storm were people who claimed to have recovered memories of childhood abuse, often after hours of unusual or maverick forms of therapy.

The sheer numbers of people claiming to have uncovered repressed memories of abuse led some psychologists to question the reality of many of these memories and doubt that a healthy person could effectively repress whole episodes of their life, only to have them return later.

Researchers began to investigate the psychology of recovered memories in the lab and found evidence that false childhood memories could easily be induced in healthy participants [pdf] but also that memories could be deliberately ‘forgotten’ to some extent [pdf].

In response to the literary challenge, other researchers have offered earlier examples, but the challengers have dismissed them as not fitting their criteria adequately.

How much culture affects the expression of both normal and disordered thinking is currently a poorly-understood area and will probably become a major force in psychology over the coming decades.

Link to NYT article ‘A Study of Memory Looks at Fact and Fiction’.
Link to PubMed entry for the Psychological Medicine paper.

Luminous Lint has published a collection of evocative images by photographer Jean-Philippe Charbonnier who documented French psychiatric hospitals and psychiatric patients in the 1950s.

Some of the most important developments in psychiatry have happened in France.

Physician Phillipe Pinel was one of the first people to advocate humane treatment for patients with mental illness and epilepsy.

A famous painting shows him overseeing the removal of chains from patients at the Salpêtrière Hospital in 1795 Paris.

The photo collection shows French psychiatry in the 1950s and contain both hopeful and desperate scenes.

This sort of historical record is important both to realise how far psychiatry has developed since these bygone days, and to pick up where change still needs to occur.

Link to Jean-Philippe Charbonnier photo collection (via BB).

There’s a great post from Developing Intelligence looking at research on ‘infantile amnesia’ – the ‘amnesia’ we have for events that happened before about 3 years of age.

It turns out that studies done on young babies, even babies in the womb, have shown that infants have got surprisingly good memory.

As reviewed by Hayne, 3-day-old infants were capable of distinguishing a particular passage (from Dr. Seuss’s “Cat in the Hat”) that had been read to them twice daily for the last 6 weeks of gestation from similar passages (matched for word count, length, and prosody). What’s more, these infants preferred the familiar passage even if spoken by someone other than their mother, strongly suggesting that they had encoded (and retained) a relatively high-level representation of the passage’s auditory content.

The post looks at the mystery of how we have such trouble remembering this period, when psychology studies show that infants’ memory is actually quite good.

Link to ‘The Myth of Infantile Amnesia’.