Power naps for better memory

Neurophilosopher has a great review of a recent study on how short naps help improve memory, and how this is supported by the brain.

Participants were asked to learn an action task and were split into two groups. One group was allowed to have an afternoon nap, while the others remained awake.

Afterwards, those who had slept during the afternoon could perform the task better than those who hadn’t.

EEG recordings of the brain suggested how the learning boost occurred:

This study confirms that the consolidation of motor memories is associated with a particluar stage of sleep (NREM), and that this in turn is correlated with electrical activity in an anatomically discrete region of the brain (the motor cortex).

One interpretation of the findings is that power naps trigger accelerated memory consolidation. An alternative hypothesis is that a good night’s sleep consists of multiple stages which are devoted to the consolidation of memories encoded during waking hours; thus, a full night’s sleep may not be necessary for this consolidation to take place; as long as a sleep episode – be it a a short night’s sleep or an afternoon power nap – includes the corresponding stages (NREM), newly-encoded memories will be consolidated.

For more details and link to the full paper, check out the article over at the Neurophilosophy Blog.

Link to Neurophilosophy article ‘Power naps enhance memory consolidation’.

The dynamics of crowd disasters

Science News has an intriguing article on how physicists have applied models of fluid dynamics to successfully understand dangerous crowd stampedes.

The joint German-Saudi team were prompted to conduct the research by the tragic events of 2006 where hundreds were killed during a mass stampede during the Hajj, the annual pilgrimage to Mecca.

Various physical models have been applied quite successfully in understanding crowd behaviour. We reported on one using a model of magnetism back in 2005.

These models work because, perhaps surprisingly, many different types of complex system seem to share higher-level or emergent properties: from atoms to neurons to people to telephone networks, and so on.

When trying to understand potentially life-threatening situations like crowd panic or stampede, it would be unethical to do large scale experiments, but these sort of models could be used to understand how they occur.

The researchers simulated crowd behaviour using models from fluid dynamics and compared their predictions with video of the stampede during the 2006 pilgrimage and found that it could accurately model crowd panic.

In normal conditions, pedestrians tend to spontaneously fall into ordered patterns, such as lanes going in opposite directions, previous research had shown. As crowds get denser, stop-and-go patterns begin to propagate in waves, as is typical for cars on heavily trafficked highways. But in critical situations—as when cars get into gridlock—people can break out in panics that result in random patterns of motion, similar to the turbulence of water in the wake of a boat. Crowd members can get squeezed and asphyxiated or fall and be trampled.

These sorts of models can be life-saving as they enable crowd control measures to be tested in the most dangerous conditions without putting anyone at risk.

The full paper is available online as a pdf file.

Link to Science News article ‘Formula for Panic’.
pdf of paper ‘The Dynamics of Crowd Disasters: An Empirical Study’.

Mood slime

RAY: Peter, this is an incredible breakthrough. I mean, what a discovery! A psychoreactive substance! Whatever this stuff is, it responds to human emotional states.

PETER: Mood slime. Oh, baby…

WINSTON: You mean this stuff actually feeds on bad vibes.

RAY: Like a cop in a donut factory.

Dialogue from one of the only comedy films to star parapsychologists: Ghostbusters II.

A Shock Wave of Brain Injuries

The Washington Post has just published an article on the worrying amount of brain damage suffered by US troops in Iraq because of shockwave injuries from roadside bombs known as improvised explosive devices or IEDs.

These sorts of injuries tend not to damage the skull, but can cause significant injury as the brain rapidly accelerates and decelerates inside the skull, and impacts on the inside of the bone casing.

These types of injury are known as ‘closed head injuries‘ as nothing penetrates the skull.

It’s a common misconception that a skull fracture always leads to a worse brain injury.

In fact, in some cases, if the skull breaks, it can allow some of the force of the impact to be dispersed (this is why bicycle and motorcycle helmets are designed to break).

If the skull doesn’t break, sometimes this can lead to the energy of the impact being more fully absorbed by the brain, often leading to shearing and tearing of the white matter pathways as the brain ‘bounces around’ inside.

The Washington Post article outlines why IEDs are likely to have this effect:

Here’s why IEDS carry such hidden danger. The detonation of any powerful explosive generates a blast wave of high pressure that spreads out at 1,600 feet per second from the point of explosion and travels hundreds of yards. The lethal blast wave is a two-part assault that rattles the brain against the skull. The initial shock wave of very high pressure is followed closely by the “secondary wind”: a huge volume of displaced air flooding back into the area, again under high pressure. No helmet or armor can defend against such a massive wave front.

It is these sudden and extreme differences in pressures — routinely 1,000 times greater than atmospheric pressure — that lead to significant neurological injury. Blast waves cause severe concussions, resulting in loss of consciousness and obvious neurological deficits such as blindness, deafness and mental retardation. Blast waves causing TBIs can leave a 19-year-old private who could easily run a six-minute mile unable to stand or even to think.

The article notes that the military have not had to deal with these sorts of injuries in such large numbers before, as IEDs have rarely been used on this scale.

Apparently, the military are currently poorly equipped to deal with these injuries, which is causing problems both for treatment in the field and for longer-term rehabilitation programmes.

The article also contains an interesting factual error: “Iraq has brought back one of the worst afflictions of World War I trench warfare: shell shock. The brain of a soldier exposed to a roadside bomb is shocked, truly.”

Shell shock‘ was given this name during World War I because it was originally thought to be due to the blasts of shells affecting the brain.

It was later discovered that the cause of the condition was combat trauma (i.e. emotional stress) rather than brain injury, so it doesn’t actually describe any type of closed head injury.

Link to Washington Post article ‘A Shock Wave of Brain Injuries’.

Encephalon 20 hits the net

The 20th edition of Encephalon has just been published containing the best in the last fortnight’s mind and brain writing.

This edition is hosted by science writer Orli Van Mourik’s blog Neurontic and has everything from a neurologist answering questions on computers and consciousness, to studies suggesting that the brain (particularly in mothers) may be specially attuned to the sound of baby cries.

There’s plenty more similarly interesting science stories at the link below.

Link to Encephalon 20.

Violence linked to price of beer

A research report published in Applied Economics has found that the number of patients with violence-related injuries treated in hospital emergency rooms is related to the price of beer.

The paper is available online as a pdf and is from Cardiff University’s Violence and Society Research Group.

The researchers examined admissions to 58 hospital accident and emergency departments over a five year period and found that as the price of beer increased, violence-related injuries decreased.

In general, studies have found that alcohol consumption increases both the risk of being a victim of violence and the perpetrator of it.

There are three main theories on why alcohol and violence are linked: i) due to the drug effects on the brain; ii) because people use alcohol as an excuse for violent behaviour; iii) because people who use alcohol might be more likely to be violent, perhaps due to personality factors like sensation-seeking, impulsivity or risk-taking.

Of course, these theories are not in competition and all the factors are likely to have some influence, but researchers are keen to find out how they interact to better understand the problem.

Interestingly, the Applied Economics study also looked at a number of other factors linked to violence and found that increases in poverty, unemployment, diversity of ethnic population, the summer months and major sporting events also independently predicted an increase in violence.

This combination of an economic and psychological approach to understand violence is particularly important for designing and implementing government or health service policies.

Cardiff University’s Violence and Society Research Group has an interesting history.

It was started by dentist and surgeon Prof Jonathan Shepherd who noticed the amount of facial glass injuries turning up in hospital.

Many turned out to be due to alcohol-fuelled violence and the Group’s research has shown that everything from glass type to availability of recycling facilities can reduce the number of injuries.

The research extended to include violence in general and now takes a comprehensive look at how both social and individual factors influence violent behaviour.

pdf of paper on price of beer and violence.
Link to Violence and Society Research Group page (with full-text papers).

Yes or No would be very misleading

“We are accustomed to think of any particular response as either learned or innate, which is apt to be a source of confusion in thinking about things… Is the response inherited or acquired? The answer is, Neither: either Yes or No would be very misleading.”

Pioneering neuropsychologist Donald Hebb highlights that fact that all human responses are a result of both inherited attributes and learnt experience.

Hebb is best known for his theory of how learning can be supported by networks of single neurons.

The theory, now called Hebbian learning, is a key aspect of artificial intelligence and neuroscience.

I got this quote from Oliver Sacks’ book Migraine but the source isn’t listed. If anyone knows exactly which of Hebb’s writings this comes from, do let me know.

UPDATE: Grabbed from the comments: It is from “The Organization of Behavior: A Neuropsychological Theory” – it’s on Google Books. Thanks John!

This Week in the History of Psychology

Christopher Green, a professor of psychology at York University in Toronto produces a weekly podcast that examines crucial events in the history of psychology.

Each episode of This Week in the History of Psychology looks at a significant development that happened in the same week during the past.

Prof Green also runs the fantastic Classics in the History of Psychology website that has an archive of some of the most important documents in the field.

Link to This Week in the History of Psychology podcast (via BPSRD).
Link to Classics in the History of Psychology website.

Top 10 influential psychotherapists

Psychotherapy Networker magazine is celebrating its 25th anniversary and has conducted a survey to find out the 10 most influential psychotherapists.

Over two and a half thousand (presumably) American psychotherapists responded to the question “Over the last 25 years, which figures have most influenced your practice?” from which the top ten were compiled.

This list is as follows:

1. Carl Rogers
2. Aaron Beck
3. Salvador Minuchin
4. Irvin Yalom
5. Virginia Satir
6. Albert Ellis
7. Murray Bowen
8. Carl Jung
9. Milton Erickson
10. John Gottman

The article discusses each of these key figures and their contribution to psychotherapy, as well as placing them in the wider context of psychological treatments for mental distress.

As well as outlining the most influential psychotherapists, another article looks at the 10 most influential research findings from the last 25 years that have influenced the development of modern psychotherapy.

Finally, an article on ‘Defining Psychotherapy’ cuts to the core of the debate over what psychotherapy is and what is should be in terms of both theory and everyday practice.

The articles are a fantastic introduction to both the theory behind psychological therapies and to what you might expect if you were to undertake therapy yourself, either as a client or a therapist.

Link to ‘The Top 10 Most Influential Therapists…’
Link to ‘Top 10 Research Findings…’
Link to article ‘Defining Psychotherapy’.

2007-04-06 Spike activity

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

The New York Times has a fantastic article on non-medical ways of dealing with auditory hallucinations and the growing hearing voices movement.

Steven Pinker has been doing talks recently on the psychology of violence and published and article in Edge outlining his main arguments.

The Neurophilosopher has a great post on how the brain makes sense of complex visual scenes and hybrid images.

Frontal Cortex looks just published research suggesting that depression may be overdiagnosed.

The New York Times has an article and video on how families cope with epilepsy and the stigma which is sadly still attached to the disorder.

The Times reviews Zimabardo’s new book The Lucifer Effect.

The Memory Hacker: Popular Science magazine looks at how one man is attempting to develop implantable chips to enhance memory function.

Time magazine is Getting Serious About Happiness in an article on the first PhD programme in positive psychology.

A study in consciousness

This month’s Prospect Magazine has an article by neuropsychologist Paul Broks that takes a recent book on consciousness as a starting point for an exploration of how the brain generates this curious form of self-awareness.

The book in question is Nicholas Humphrey’s Seeing Red: A Study in Consciousness (ISBN 0674021797) that takes an evolutionary approach to understanding the ‘hard problem‘.

Broks wrote a fantastic meandering book on the effects of brain injury on consciousness called Into the Silent Land (ISBN 1843540347) and writes in a wonderfully conversational style.

He highlights Humphrey’s novel approach to understanding consciousnes and how this may have arisen through natural selection:

In his 1992 book A History of the Mind, Humphrey argued that consciousness is grounded in bodily sensation rather than thought, and proposed a speculative evolutionary account of the emergence of sentience. Seeing Red is a refinement and extension of those ideas. Put simply, we don’t so much have sensations as do them. Sensation is “on the production side of the mind rather than the reception side.”

The article is both a review and a summary of Humphrey’s ideas and is well worth checking out.

Link to Prospect article ‘The Mystery of Consciousness’.

Is waking a sleepwalker dangerous?

Scientific American has a short article that tackles the common idea that it is dangerous to wake people who are sleep walking. It turns out, it’s often dangerous not to rouse them from their sleep.

The article discusses what causes sleepwalking, and the curious ways in which it can express itself.

Still, more disconcerting than the occasional nocturnal stroll is the potential peril caused by sleepwalking. “Sleepwalkers can harm themselves and others, and even kill themselves and others, and they can engage in highly complex behaviors such as driving long distances, and hurt others with sleep aggression and violence,” Schenck says. “So there are a number of ways that sleepwalkers can be dangerous to themselves and others during their episodes.” For example, Schenck notes, Sandy, a slender female in her teens, tore her bedroom door off the hinges one night. She was unable to replicate that strength when awake. And a young man frantically drove to his parent’s house 10-miles away. He woke to the sound of his own fists beating on their front door. In dramatic cases like these, doctors will prescribe benzodiazepines to ease the patient’s nighttime activity.

Link to article ‘Fact or Fiction?: Waking A Sleepwalker May Kill Them’.

Polonium-210 and psychiatric case histories

BBC Radio 4’s All in the Mind has just kicked off a new series with features on the psychological effects of Alexander Litvenenko’s Polonium-210 poisoning and whether there is still value in detailed individual case studies in psychiatry.

Litvenenko’s poisoning made headline news and was a significant public health risk owing to the powerful radioactive poison.

Considering this, and the 2005 terrorist bombings in London, the programme looks at the psychological impact of these scares on the public, and what this tells us about how we react to large-scale risk.

Detailed case studies have been critically important in the history of psychiatry, with Freud making particular use of individual cases on which to base psychoanalytic theory.

They have recently fallen out of fashion, however, with some researchers and clinicians thinking they are no better than anecdotal evidence.

Others have argued that they provide a different sort of evidence to group studies that rely on quantification, and they are complementary to the wider quest to understand and treat mental disorder.

Link to BBC All in the Mind webpage with realaudio archive.

Shining lights, brain cells sparking

So I prescribed her, something to revive
And surprise her, she’s liver and much more wiser
Than the light I shine when my brain cells spark,
Come to me so we can glow in the dark

A curious combination of psychiatric metaphor and romantic storytelling from Eric B & Rakim’s 1990 track Mahogany. The hip hop duo mention the brain surprisingly often in their lyrics.

New Yorker on child bipolar controversy

April 9th’s New Yorker has a cracking article on the current controversy on whether it’s possible (or even valid) to diagnose bipolar disorder in children.

The article comes at a time when the diagnosis of bipolar disorder is being increasingly used for young children with behavioural difficulties.

It has been of particular interest after the tragic case of four-year-old Rebecca Riley, who died, according to the prosecutors, due to an overdose of psychiatric drugs prescribed after being diagnosed with the disorder.

Her parents, who have been accused of causing her death, have denied the charges.

The case is continuing but it has raised a number of questions about whether it is possible to diagnose the condition in children, or whether it even appears so early in life.

The New Yorker piece traces the popularity of the diagnosis to a book called The Bipolar Child, where psychiatrist Demitri Papolos and his wife included a screening questionnaire so parents can ‘diagnose’ their children.

Notably, there are currently no widely accepted diagnostic criteria, and a number of clinicians quoted in the article criticise the book for including vague or otherwise normal experiences (such as ‘irritability’ or ‘boredom’) as part of the diagnosis.

Unfortunately, the article isn’t available in the New Yorker website, but it was written by Dr Jerome Groopman who usually posts all his articles for the magazine online, so hopefully it should appear there shortly.

Otherwise, catch it in the shops or down your local library.

Link to April 9th New Yorker table of contents (via TWS).
Link to Jerome Groopman’s New Yorker articles.

Review: Freedom & Neurobiology by John Searle

John Searle will be known to most cognitive scientists as the man behind the famous Chinese Room thought experiment. This is based around the idea that a man in a room translating Chinese symbols with the aid of a rulebook does not understand Chinese, any more than a computer producing intelligent-like (understanding-like, consciousness-like) behaviour due to programming rules has intelligence (or understanding, or consciousness). Since I found this line of argument confused, and ultimately frustrating, I didn’t expect to enjoy his new book ‘Freedom & Neurobiology: Reflections of Free Will, Language and Political Power’. I didn’t expect to, but I did.

Searle_Freedom.gifThis short book is made up of two separate lectures of Searle’s, originally published in France, along with an extensive introduction. The introduction is Searle’s tour through the history of philosophy, establishing the ‘basic facts’ as it were, to the point where we are now. A point at which we have dealt with many small problems and can now ‘advance very general accounts of mind, language, rationality, society, etc.’. This ‘large-scale philosophy’ is possible, Searle argues, because of the unity of mind with biology, and, secondly and a consequence of this, the new openness within philosophy to accounting for empirical evidence (for a particularly choice quote from the introduction, see here).

True to this manifesto, Searle’s two essays cover lots of ground. The first is ‘Free Will as a problem in neurobiology’, the second ‘social ontology and political power’. Both are very readable, full of strong arguments and interesting observations. IANAP, but there is nothing of a the obtuse Searle of the Chinese Room that I was expecting, in fact ‘Freedom & Neurobiology’ makes me think that I should go back to the original Chinese Room argument and read it again. If this new book is anything to go by there is sure to be more clarity and subtly there than I remember.