Fake smiles can be done with feeling

The ‘Duchenne smile’ is thought to be a largely unfakeable expression of pleasure that involves a signature ‘crinkling around the eyes’ caused by automatic muscles. A new study covered by PsyBlog pours cold water on this popular idea by reporting that most people can produce undetectable fake smiles that involve these supposedly involuntary movements.

It has been suggested that 80% of us are unable to conjure up a fake smile that will trick others because we don’t have voluntary control over the muscles around our eyes which signal the Duchenne smile…

Writing in a recent issue of the journal Emotion, however, Krumhuber and Manstead (2009) question whether this 80% estimate is anywhere near the mark. In the first of a series of experiments they found that 83% of the people in their study could produce fake smiles that others mistook for the real thing in photographs.

The researchers also explored how people perceived genuine and fake smiles when they saw videos rather than just static pictures. Then it emerged that fake smiles were easier to spot, but the supposedly crucial crinkling around the eyes didn’t help much.

Instead, telling a real from fake smile relied more on dynamic processes such as how long people hold it, the symmetry of the expression and whether conflicting emotions are communicated by other facial areas.

Link to PsyBlog on ‘Duchenne: Key to a Genuine Smile?’

Junk brothers

The fascinating story of the Collyer Brothers, the ‘Hermits of Harlem, is recounted in an article the Journal of the American Academy of Psychiatry and the Law.

The two brothers became famous owing to them living in a chaotic home in New York City, although both met a tragic end as a result of their accumulation of junk:

Most famously, over decades they had filled the huge brownstone with possessions, newspapers, and just plain junk. After their deaths in 1947, over 130 tons of material was removed. There was so little of value that the few auctioned items fetched only $1,800.

So packed was the home of Homer (aged 64 years at death) and Langley (aged 61) Collyer that the interior was a maze of tunnels, many booby trapped to satisfy Langley’s fear of intrusion. Langley, a failed concert pianist and Columbia engineering graduate, would go out at night dragging a carton by a rope, collecting things. Homer, a lawyer, blind and crippled by arthritis, was entirely dependent on his brother. In the end, Langley was crushed to death by debris triggered by one of his booby traps, leaving Homer to starve to death. Running the story as page-one news for weeks, the media fueled a frenzy of interest after Homer’s body was found and a search for Langley revealed that he was buried [under junk] 10 feet from where Homer had died.

At the time the brothers were considered eccentric but not unusual enough to warrant the attention of a psychiatrist.

The article goes on to discuss who their behaviour might be understood by modern psychiatry, which would likely diagnose it as ‘compulsive hoarding‘, usually thought to be a subtype of obsessive-compulsive disorder or OCD.

However, it the piece also a wide-ranging discussion on what different forms hoarding can take and how it is portrayed by the media.

Don’t forget to check out the Wikipedia entry on the brothers that has many more details and also a list of other famous hoarders at the bottom of page.

Link to article on psychiatry and the Collyer brothers.
Link to Wikipedia page on the pair.

Mickey’s amphetamine adventure

Drug information site Erowid recently posted a 1951 Disney comic where Mickey Mouse and Goofy take speed.

In the strip, ‘Mickey Mouse and the Medicine Man’, Mickey and Goofy discover a new medicine called ‘Peppo’ which is clearly meant to represent amphetamine. Their enthusiasm for the chemical pick-me-up leads them to become salesman for the product in Africa.

Although the idea of Disney characters taking speed seems rather incongruous these days, in 1951 amphetamine was legal and widely available over-the-counter in America, mostly in the form of Benzedrine inhalers.

It wasn’t until the mid-60s when these were made prescription only and non-medical amphetamine wasn’t outlawed until 1971.

As well as casual racism, the strip also features various characters eating ‘hash’ which knocks them out.

For those not familiar with American English, this isn’t a direct reference to hashish or cannabis resin but a reference to a peculiarly unappetising type of food of the same name which, in the story, seems to have been spiked with some sort of unidentified sedative.

However, given the rather unenlightened portrayal of Africans in the piece and the 1950s stereotype of marijuana being a drug of black Americans, I wonder the lethargy inducing properties of the ‘hash’ are meant to be an indirect reference to the drug.

Link to ‘Mickey Mouse and the Medicine Man’.

Brain sand

Taken from the Wikipedia entry on ‘brain sand’:

Corpora arenacea (or brain sand) are calcified structures in the pineal gland and other areas of the brain such as the choroid plexus. Older organisms have numerous corpora arenacea, whose function, if any, is unknown. Concentrations of “brain sand” increase with age, so the pineal gland becomes increasingly visible on X-rays over time, usually by the third or fourth decade. They are sometimes used as anatomical landmarks in radiological examinations.

Chemical analysis shows that they are composed of calcium phosphate, calcium carbonate, magnesium phosphate, and ammonium phosphate. Recently, calcite deposits have been described as well.

French philosopher René Descartes famously concluded that the mind and the brain existed as entirely separate entities (a position now known as Cartesian dualism) and believed that pineal gland was the point at which the two interacted.

This was due to the fact that that, unlike most other structures in the brain, there is only one pineal gland and it is located exactly along the midline.

As Descartes largely thought of the mind and soul as the same thing, I’d like to think he would have called these calcified particles ‘soul sand’ had he known about them.

If you want some more details on ‘brain sand’, of which we know very little, this large abstract of a scientific study has a wealth of information.

Link to Wikipedia page on ‘brain sand’.
Link to abstract of scientific study.

Treating people like animals

The New York Times has an important article about how animal cruelty is being increasingly recognised as part of a wider pattern of behaviour including anti-social violence and criminality.

Cruelty to animals has been implicitly recognised as being a sign of behavioural problems in children for some time as it forms part of the diagnosis of conduct disorder, characterised somewhat glibly as ‘kiddie psychopathy’.

However, research has been slowly accumulating over the last few years that animal cruelty is related to lower levels of general empathy and is a signal that the person concerned may have abusive tendencies that extend towards other people.

The link between animal abuse and interpersonal violence is becoming so well established that many U.S. communities now cross-train social-service and animal-control agencies in how to recognize signs of animal abuse as possible indicators of other abusive behaviors. In Illinois and several other states, new laws mandate that veterinarians notify the police if their suspicions are aroused by the condition of the animals they treat. The state of California recently added Humane Society and animal-control officers to the list of professionals bound by law to report suspected child abuse and is now considering a bill in the State Legislature that would list animal abusers on the same type of online registry as sex offenders and arsonists.

The article is an extensive investigation into the cross-over between criminal psychology and forensic veterinary science and, although disturbing in places, is an important and in-depth look at how the two types of abusive behaviour share common roots.

Link to NYT on ‘The Animal-Cruelty Syndrome’.

Forced smile

Neurology journal Brain had a wide-ranging review of the book ‘Insomnia: A Cultural History’ last year which has this wonderful part about Darwin, Duchenne and how he electrocuted the face to study emotional expression.

In the same era and acting on the same beliefs, many experiments were done to study the effect of electricity on sleep and on the nervous system. Beard and Rockwell (1871) claimed that the tendency to insomnia could be removed by electricity, thus galvanizing and causing contraction of the cerebral circulation, and Charles Darwin illustrated his book on the expression of the emotions with many illustrations taken from Duchenne’s work (Darwin, 1904) [see image]. However, some of Darwin’s conclusions, such as that terror and grief were accompanied by automatic contraction of the forehead muscles, may not have been entirely justified by the apparent results since Duchenne’s subjects were admitted to be actors (Duchenne, 1871).

Duchenne was a doctor who studied the link between nerves, electrical activity and muscles. He’s probably best known in medicine for his work on what is now called ‘Duchenne muscular dystrophy‘, a muscle wasting disease caused by inherited problems with muscle protein.

However, his work on the link between facial muscles and emotions, partly researched by electrically stimulating muscles to see what expressions could be created, was groundbreaking and Darwin included Duchenne’s pictures in his book The Expression of the Emotions in Man and Animals.

Even now, psychologists talk of the ‘Duchenne smile‘ which involves raising the corners of the mouth and, crucially, raising the cheeks and wrinkling the eyes through the use of the orbicularis oculi muscle.

A ‘Duchenne smile’ is often regarded as the most genuine display of spontaneous joy or happiness, due to the fact that parts of the orbicularis oculi muscle cannot be controlled voluntarily and so this specific type of smile can’t be easily faked.

Sadly the whole review of the book ‘Insomnia: A Cultural History’ is locked, which is a pity as it works equally well as an article on its own and covers some fantastic ground.

The book itself look fascinating, and I note that the Wall Street Journal made the whole of Chapter 6 available online which is well worth a read in itself.

Link to locked review for ‘Insomnia: A Cultural History’.
Link to more info about the book.
Link to Chapter 6 at the WSJ.

2010-06-11 Spike activity

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

A new study finds that superstitions improve performance by increasing confidence. Some excellent coverage from Not Exactly Rocket Science and from Bad Science.

Time magazine reports the counter-stereotype finding that men are more susceptible to emotional ups and downs after relationship break-ups than women.

Just too much ‘technology is rewiring our brains’ silliness to link to but in the mean time 14 kids at an ‘internet addiction’ camp in China tied up their guard and made a daring escape. Personally, I blame Donkey Kong.

The BPS Research Digest covers a completely fascinating study on how some words (like ‘sympathy’, ‘murderer’, ‘risk’) lack an opposite and these are consistent across languages.

Children raised by lesbians ‘have fewer behavioural problems’ according to research covered by CNN. Raising better adjusted kids while simultaneously undermining traditional marriage. Devious these lesbians, I tell you. See also good coverage from In the News.

Language Log picks up on an interesting linguistic asymmetry. In light of accusations that a female politician has been unfaithful, the blog asks whether she could be a manizer?

An excellent article in the Chronicle of Higher Education questions whether recent interest in the power of intuition is based on solid science.

Frontier Psychiatrist has an excellent piece on the problems with recruiting psychiatrists and why the speciality needs the brightest and best.

The latest NeuroPod has just gone online. Check the page or download the mp3 directly.

Life Matters from ABC Radio National discusses a new US Military treatment programme to help veterans who have both PTSD and addiction problems.

More than 50% of Americans now believe gay relationships to be acceptable reports The New York Times.

The Neurocritic notes that brain area the insula has become high fashion in neuroscience.

The first yardstick for measuring smells is discussed in an article for Discover Magazine.

PsyBlog covers an interesting study finding that the simply technique for saying a word out loud helps you remember it.

Psychologist Irvin Kirsch says antidepressants are just fancy placebos in an interview for Discover Magazine.

Barking Up the Wrong Tree asks whether a female hitchhiker’s bust size affect her ability to get picked up.

Antipsychotic haloperidol reduces gray matter volume within hours of taking it, according to a new study reported by Nature News.

The New York Times has a piece by Steven Pinker which is probably the best response so far to the ‘tech brain damage’ panic. Next to, oh for Christ’s sake not again, of course.

“Kantian ethicists seem to have a reputation among philosophers for behaving worse than other sorts of ethicists. But who has any systematic empirical data on this?” Eric Schwitzgebel does, at the fantastic Splintered Mind.

80 Beats has a fantastic analysis of the recent big autism genetics study that found a great number of copy number variants in genes that non-gene DNA.

The Dana Foundation Brain Blog has had some great coverage of mind and brain events at the World Science festival.

Radio National Breakfast reports on new research finding out a crucial piece in the puzzle of how lithium can treat Alzheimer’s and bipolar disorder.

A lucid insight into consciousness

Photo by Flickr user planetchopstick. Click for sourceNew Scientist has an intriguing article on how the study of people who have been trained to have lucid dreams may help us understand the neuroscience of consciousness.

Lucid dreams are where the sleeper becomes aware that they are dreaming inside the dream. My first thought was that the combination of these and consciousness sounded a bit gimmicky but the justification seem like an interesting bit of lateral thinking with potentially valuable results:

Surprisingly, given the irrationality of the dream experience, many of the frontal areas of the brain involved in advanced cognition such as reasoning and forward planning were also active in the dreamers. But there was one notable exception: the dorsolateral prefrontal cortex (DLPFC) was remarkably subdued in REM sleep, compared with during wakefulness. To Hobson, that strongly suggests that this particular area, above other frontal regions, is crucial for the critical reflective awareness present in waking, and therefore secondary, consciousness (Trends in Cognitive Sciences, vol 6, p 475).

Could this one brain region alone explain our secondary consciousness? It’s here that lucid dreams enter the picture. With their increased self-awareness, lucid dreams share certain aspects of secondary consciousness, so researchers are now vying to observe what happens in the brain when someone “wakes up” within their dream, and whether they exhibit any further signatures of consciousness. “It’s a very interesting leap because it can show you exactly what occurs if you jump from limited consciousness to very high consciousness,” says Victor Spoormaker of the Max Planck Institute of Psychiatry, Munich, Germany. “This should be one of the main themes of lucid dream research.”

The article also has some tips on making lucid dreams more likely while you sleep.

Almost every guide to lucid dreaming has the core advice that you need to get into the habit of constantly checking and asking yourself while awake ‘am I dreaming?’ presumably based on the principle that dreams often contain things we’ve experienced during the day.

One of my favourite ‘reality checks’ comes from the FAQ of the Lucidity Institute, a commercial training course set up by neuroscientist Stephen LaBerge.

It says to wear a digital watch and get used to checking it regularly at two close intervals to see if the numbers have changed as expected. If they haven’t or the numbers don’t make sense, you’re probably dreaming. Apparently checking light switches work is another technique.

No idea how rigorously these specific ideas have been tested but there is good evidence that lucid dreaming can be successfully practised and the typical lab technique to confirm it is happening is to ask participants to make specific horizontal eye movements when they become lucid.

As your eye muscles aren’t paralysed during sleep, it allows the dreamer one of the few ways they can signal to the researchers.

Link to NewSci on dreaming and consciousness (via @researchdigest).

Shamanic transit and the prehistoric hard-on

If you were ever wondering about the representation of the penis in prehistoric art and what this reveals about “the meaning of erection in Paleolithic minds”, wonder no more. The study has already been done.

Male genital representation in paleolithic art: erection and circumcision before history.

Urology. 2009 Jul;74(1):10-4.

Angulo JC, García-Díez M.

OBJECTIVES: To report on the likely existing evidence about the practice of circumcision in prehistory, or at least a culture of foreskin retraction, and also the meaning of erection in Paleolithic minds. The origin of the ritual of circumcision has been lost in time. Similarly, the primitive anthropologic meaning of erection is undefined.

METHODS: We studied the archeologic and artistic evidence regarding human representations performed during the Upper Paleolithic period, 38,000 to 11,000 years BCE, in Europe, with a focus on genital male representations in portable and rock art.

RESULTS: Drawings, engravings, and sculptures displaying humans are relatively scarce, and <100 examples of male genitals are specifically represented. Some depict a circumcised penis and other represent urologic disorders such as phimosis, paraphimosis, discharge, priapism, or a scrotal mass. In addition, a small number of phalluses carved in horn, bone, or stone, with varying morphology, has survived to the present and also reveals a sustained cult for male erection and foreskin retraction not limited to a particular topographical territory. The very few noncoital human or humanoid figures with marked erection appear in a context of serious danger or death. Therefore, erection could be understood as a phenomenon related to the shamanic transit between life and death.

CONCLUSIONS: The erection in Paleolithic art is explicitly represented in almost all the figures defined as unequivocally male that have survived to the present and in many objects of portable art. Circumcision and/or foreskin retraction of the penis are present in most of the works.

I suspect that “erection could be understood as a phenomenon related to the shamanic transit between life and death” is a woefully underused chat-up line. Thank you Science!

Link to PubMed entry for prehistoric pecker study.

Winners wanted: lucky bastards need not apply

A delightful experiment in the Journal of Gambling Studies demonstrates how susceptible we are to social persuasion to the point where even our established cognitive biases yield to the influence of others.

The illusion of control is the tendency to believe that we have influence over uncontrollable events. It has been well demonstrated in gamblers who may often put down wins and losses to their skills and abilities, even on games like roulette where the outcomes are entirely random.

This new study found that roulette players who learnt that someone else had recently ‘won big’ had an increased illusion of control, expected to win more and made more risky gambles while playing.

However, this effect virtually disappeared simply by adding that the ‘big winner’ had put down his bonanza to sheer luck.

Link to PubMed abstract for gambling study.

Threatened psychopath articles suddenly appear

Photo by Flickr user jellevc. Click for sourceWe recently reported on an academic article that criticised one of the most popular methods for diagnosing psychopaths and which had remained unpublished for four years due to legal threats by the designers of the interview.

The article was by researchers Jennifer Skeem and David Cooke who had criticised the PCL-R, a diagnostic scale by renowned forensic psychologist Robert Hare, for its supposed over-focus on criminality.

Their piece was peer reviewed and accepted for publication in 2006 by the journal Psychological Assessment but Hare got wind of the piece which he felt unjustly criticised him and his work and threatened both the journal and the authors with a law suit for defamation.

The article remained unpublished for four years, so it was rather surprising when the journal published the article with subsequent responses from both parties this morning.

I’m wonder if this has anything to do with the fact that the case is being covered in tomorrow’s edition of Science, although the pay-walled article is already available online. The journalist who covered the story has also covered the case in a blog post.

Interestingly, those reports note that the issue was apparently resolved in 2008 but the journal has sat on the articles ever since and the spat only came to public attention a few weeks ago due to it featuring in a journal article about academic freedom.

Seemingly the first to pick up on this was the excellent forensic psychology blog In the News which has also just posted coverage of the days happenings as well as discussing the original article and its responses.

Link to coverage from In The News.
Link to pay-walled Science coverage.
Link to blog coverage by same journalist.

An attack of Open Mole

Stress, anxiety and depression are common terms used in the West to describe ways in which we become mentally distressed. We tend to think these are universal ways of experiencing mental strain but they are not. In fact, the words cannot be directly translated into many of the world’s languages because the concepts do not exist.

The latest issue of the journal Culture, Medicine and Psychiatry is a special collection of articles on ‘cultural idioms of distress’ and tackles ways in which people experience distress after difficult situations from cultures around the world.

One particularly fascinating article discusses a condition from Liberia called ‘Open Mole’ which is widely believed to occur after sudden shocks or after living through tough times.

Across Liberia, a single unified characteristic defines Open Mole. Open Mole is understood to be a soft spot in the center of the skull similar to the soft areas in an infant’s unformed skull, or the sunken fontanel associated with infant dehydration. However, in contrast to the infant skeletal development processes and the dehydration-induced softening with which the Western medical literature is familiar, Open Mole is understood to be an acquired disease state that can occur to adults who experience a sudden fright or shock or who endure chronic adversity and stress. While its defining symptom is the soft spot on top of the skull, Open Mole is commonly associated with many symptoms, including: severe headache, neck pain, back pain, fatigue, weakness, nightmares, troubled sleep, loss of appetite and social withdrawal. Many additional symptoms are believed to accompany Open Mole, but there is little consensus among Liberians about Open Mole’s ethnophysiology [local beliefs about its biological basis].

The etiology of Open Mole is heterogeneous. Although a belief in the existence of Open Mole exists across geographical boundaries and ethnic groupings, it is contested among Liberians on a number of indicators. Some understand Open Mole to be contagious, while others believe that it is not. Some believe that Open Mole is caused by tampering with dangerous spiritual forces, practicing witchcraft or having a dangerous nightmare, while others believe that it can be caused by sharing a hairbrush or a headscarf, getting caught in the rain or sitting in the sun too long. Some believed that Open Mole is caused by committing an act of wrongdoing (like violence, theft or sorcery), while others believed that Open Mole is a victim’s affliction, carried by those who have had wrong done to them.

The issue also has an open-access article on how spirit possession in Nigeria is more likely in people who have lived through traumatic experiences.

It’s a fascinating study, because alongside traditional diagnostic interviews from Western psychiatry the research team create and validate a diagnostic scale for spirit possession symptoms, allowing an empirical look into some of the psychology behind it without ignoring the experience or dismissing it.

Link to special issue (via the excellent Somatosphere)
Link to PubMed entry for Open Mole article.
Link to full text of spirit possession article.

Set adrift on mental bliss

Photo by Flickr user pedrosimoes7. Click for sourceSleeping people are difficult to engage but easy to monitor, meaning that we know a great deal about what happens in the body and brain during our restful hours but little about the actual psychology of slumber.

One of the most interesting stages is the transition into sleep, where we can sometimes detect that our mind is changing as we slip into unconsciousness. These changes are known as the hypnagogic state and are when hallucinations are particularly common because the mind starts to ‘free up’ in poorly understood ways.

A new study has taken an interesting approach to try and understand the nature of this twilight period by using the biological measures to monitor how ‘far gone’ people are as they drift off, and then gently waking them to ask how their mind has changed.

The research team, led by Chien-Ming Yang from the National Chengchi University in Taipei, asked 20 participants to have an afternoon nap in the sleep lab while they were wired up to an EEG machine to measure electrical activity in the brain, with additional electrodes to measure eye movements, heart rate and muscle jerks.

As the participants drifted off they were awakened at different times: either just after eye-closing, the onset of ‘stage 1’ sleep where you’re still aware of the external world, the onset of ‘stage 2’ sleep where awareness starts to diminish, and after five minutes at ‘stage 2’ where awareness should have largely disappeared.

After wakening, participants were asked questions about their perception of being asleep and the experience of their own minds: “Did you fall asleep?”, “Did you see any visual images?”, “Were you able to control your perceptual experiences?”, “How real did any of the experiences seem to you?”, “How well were you able to control your thoughts?”, “Were your thoughts logical?” and several questions to try and capture the conscious experience of sleep onset.

The experience of having control over your own thoughts and how coherent and logical they seemed to begin to change almost as soon as the participants closed their eyes and they continued to seem slightly more unusual and autonomous as time went on.

However, as soon as ‘stage 2’ sleep began there was a step change into a state of mind where thoughts became markedly freewheeling, illogical and seemed to have a life of their own.

In contrast, awareness of the outside world remained largely present until ‘stage 2’ kicked in, at which point it quickly dropped off.

Most interestingly, the perception that ‘I was asleep’ when woken was most associated not with a reduced awareness of the surrounds, but instead largely relied on the experience that the sleeper no longer had control over their increasingly illogical thoughts.

In other words, we seem to know when we’ve been sleeping because we’re quickly drawn back into the world of controlled, logical thought after gently drifting in fantasy.

Link to DOI entry and summary for study.
Link to PubMed entry for same.

The Rat or the Couch

The picture is a wonderful kid’s drawing scribbled on the pages of the sole book on scientific psychology in Medell√≠n’s centre for Lacanian psychoanalysis.

Jacques Lacan was a French psychiatrist who created his own branch of psychoanalysis through an extended post-modernist riff on Freud.

I recently discovered I live in a barrio once famous for being the centre of psychoanlaysis in the city, and after some searching, found one of the parts still going strong is the presence of the centre for Lacanian analysis.

While browsing through the library I discovered a battered photocopy of a book by Hans Eysenck, the late psychologist from the Institute of Psychiatry in London known for his vehement opposition to all things Freudian.

The photocopy is a translation of the 1971 book he wrote called ‘Psychology is About People’ although the title in Spanish is rather more polemic: ‘La Rata o el Div√°n’ – The Rat or the Couch!

On the back of virtually every page, it seems a child has decided to add their own artistic contributions, presumably while the analyst who borrowed the book was distracted.

Which, psychoanalytically speaking, is very telling.

Neuroplasticity is a dirty word

Photo by Flickr user jamelah. Click for sourceThe latest refrain in popular science is that ‘your brain is plastic’, that experience has the potential to ‘rewire’ your brain, and that many previous mysteries in cognitive science can be explained by ‘neuroplasticity’. What they don’t tell you is that these phrases are virtually meaningless.

Neuroplasticity sounds very technical, but there is no accepted scientific definition for the term and, in its broad sense, it means nothing more than ‘something in the brain has changed’. As your brain is always changing the term is empty on its own.

This is from the introduction to the influential scientific book Toward a Theory of Neuroplasticity:

Given the central important of neuroplasticity, an outsider would be forgiven for assuming that it was a well defined and that a basic and universal framework served to direct current and future hypotheses and experimentation. Sadly, however, this is not the case. While many neuroscientists use the word neuroplasticity as an umbrella term it means different things to different researchers in different subfields… In brief, a mutually agreed upon framework does not appear to exist.

It’s currently popular to solemnly declare that a particular experience must be taken seriously because it ‘rewires the brain’ despite the fact that everything we experience ‘rewires the brain’.

It’s like a reporter from a crime scene saying there was ‘movement’ during the incident. We have learnt nothing we didn’t already know.

Neuroplasticity is common in popular culture at this point in time because mentioning the brain makes a claim about human nature seem more scientific, even if it is irrelevant (a tendency called ‘neuroessentialism‘).

Clearly this is rubbish and every time you hear anyone, scientist or journalist, refer to neuroplasticity, ask yourself what specifically they are talking about. If they don’t specify or can’t tell you, they are blowing hot air. In fact, if we banned the word, we would be no worse off.

As every change in the brain can be referred to as ‘neuroplasticity’ you need to look out for what is actually meant. As we are constantly learning more about the brain, the possible list is endless, but here are some of the most common processes associated with the term:

Structural changes in the brain

Synaptic plasticity refers to changes in the strength of connections between synapses, the chemical or electrical connection points between brain cells. Synaptic plasticity is an umbrella term in itself, and means nothing except something has changed at the synapse, but may include many specific processes such as long-term potentiation (LTP) or depression (LTD), changes in the number of receptors for specific neurotransmitters, and changes in which proteins are expressed inside the cell, among many others known and unknown. As a rule of thumb, nothing changes in the brain without changes in the synapses.

Synaptogenesis and synaptic pruning refers to the creation and removal of whole synapses or groups of synapses which build or destroy connection between neurons.

Neuronal migration is the process where neurons extend from their ‘place of birth’ to connect to far reaching areas across the brain.

Neurogenesis is the creation of new neurons. It largely occurs in the developing brain although over the last decade or so we’ve realised that limited neurogenesis occurs in the adult brain.

Neural cell death is literally where neurons die. This can happen through damage, over-excitation or disease, but also as a natural ‘programmed’ process including apoptosis. When this programmed cell death fails, it can sometimes lead to cancer.

Other forms of ‘neuroplasticity’ may be inferred from structural changes in the brain that do not involve direct measurement of individual neurons.

These usually come from brain scans and can involve changes in the density of white matter or grey matter on structural MRI scans, or to how densely radioactively labelled markers bind to specific receptors in parts of the brain.

Functional reorganisation – changes in how tasks are organised in the brain

As we develop, brain areas becomes specialised for specific tasks and ways of making sense of the world. For example, the very back of your brain is labelled the visual cortex, because it deals with sight.

If experience changes dramatically or parts of the brain are damaged, areas previously specialised for a certain function can ‘take on’ some of the work of other areas, without necessarily detectably changing in structure. For example, the ‘visual cortex’ in blind people can be used to perceive touch.

Functional reorganisation is often inferred without directly measuring the brain. For example, immediately after brain injury, someone might not be able to speak because the areas previously used for language are damaged. However, speech may be regained or it might improve, depending on the extent of damage, as the brain has a limited ability to reorganise the share of work to undamaged areas.

Learning or habit

This is the loosest and most problematic use of ‘neuroplasticity’. By definition if we learn something, acquire a habit or tendency, good or bad, something has changed in the brain. Without specifying what the brain is doing, we know nothing more.


UPDATE: You might also be interested in a subsequent post that tackles the myths that neuroplasticity is a new idea and, until quite recently, we thought the brain was ‘fixed’.