Richard G. Petty, MD

Sex, Handedness and the Brain

I have commented before on my longstanding interest in handedness and laterality, as well as gender differences in the brain. A recurrent question when we look at both of them is whether culture has any role in the development of either. Are some of the differences in male and female brains driven by educational opportunities and cultural expectations, or is there something innate about them?

A recently published paper in PLoS ONE reports finding both sex and handedness influences on the relative size of the corpus callosum in Capuchin monkeys.

Capuchin monkeys are playful, inquisitive primates best known as the “Organ Grinder” monkeys. They have great manual dexterity, complex social behavior, and cognitive abilities. The new research now shows that just like humans, they display a fundamental sex difference in the organization of the brain, specifically in the corpus callosum, the band of white matter that connects the two hemispheres of the brain.

In the study, thirteen adult capuchins underwent magnetic resonance imaging of the brain to determine the size of their corpus callosum. The monkeys were later given a task to determine hand preference. The authors' results led them to conclude that, as in humans, male capuchins have a smaller relative size of the corpus callosum than females, and right-handed individuals have a smaller relative size of the corpus callosum than left-handed individuals.

As the two hemispheres show greater independence of function, the relative size of the corpus callosum is expected to be smaller. This has been documented in humans, and same pattern was found in capuchins.

This finding may be related to hemispheric specialization for complex foraging tasks that require the integration of motor actions and visuospatial information. In the wild, capuchin monkeys live in trees as well as on the ground, and they are known to be very good at capturing small swift prey such as birds, lizards, and squirrels.

Musical Hallucinations

A paper on auditory hallucinations of music was presented this afternoon at the 2007 Annual Meeting of the American Psychiatric Association in San Diego, California.

The researcher looked at 22 people diagnosed with schizophrenia and 23 with schizoaffective disorder at Maimonides Medical Center in Brooklyn, New York. The question was whether it would be possible to use the presence of musical hallucinations to distinguish between schizophrenia and schizoaffective disorder. The conclusions from the study were that these auditory hallucinations of music were more common in people with schizoaffective disorder and that voices with a religious or superstitious content were more common in people with schizophrenia.

Though it is good to see someone examine the content of hallucinations, this was a very puzzling study.

First, there is always a lot of debate around the “schizoaffective” diagnosis. Although there are clear criteria for it in the DSM-IV, many experts believe that most people who have been labeled “schizoaffective” actually have a form of bipolar disorder. But in any case, bipolar disorder and schizophrenia probably lie on a spectrum. People’s diagnoses often change over time. Not because of disagreement or inaccuracy, but because people change over time. The term “phenomenological drift” has been used to describe this observation. What that means is that we always need to be sure of the diagnosis at the time of the study, rather than what was written in the chart in the dim and distant past.

The other point is that genuine musical hallucinations are very rare. The world literature contains under a hundred papers in European languages, and the classic paper, published by German Berrios in 1991 was an analysis of just 46 cases. Berrios is regarded by many as one of the finest phenomenologists in Europe, so it is surprising that the investigator in New York found so many cases.

It will be good to see if the author or someone else can replicate the work. The classic teaching about musical hallucinations has been that they:

• Are more common in women
• Are more common in people who have hearing problems or are deaf
• Are more likely to occur in people with neurological diseases, including Alzheimer’s disease
• If they occur in people with neurological disease, it is more likely that the damage will be in the right or non-dominant hemisphere of the brain. (In men, language tends to be in the dominant hemispheres and music in the non-dominant. The pattern is a bit more complicated in women, but they also usually sing and recognize music with the right or non-dominant hemisphere)

A recent report from Japan reported that an elderly man with musical hallucinations was helped with the cholinesterase inhibitor donepezil (Aricept), suggesting that cholinergic neurons are somehow involved in generating musical hallucinations.

Many of us have music or tunes giong round in our heads, but that is quite different from hallucinating music.

And let me repeat: hearing things is common, and does not mean that someone is mentally ill.

 

Altruism and the Brain

There is a fascinating new study which will be out next month in the journal Nature.

Colleagues from Duke University Medical Center in Durham, North Carolina, believe that they have found a region of the brain that is associated with altruism: selfless concern for the well-being of others.

Some scientists have claimed that it is of no value because it has no survival advantage. I've never been able to agree with that extreme position. Another view is that the survival advantage comes from an ability to perceive the intention of others and therefore to anticipate their actions. I'm also not certain that this is genuine altruism, in the sense that altruism should be selfless.

45 volunteers were asked to play a computer game and also to watch the computer play the game. In some instances successful completion of the game resulted in the volunteers winning money for themselves, and in other instances it resulted in money being donated to a charity that each person had chosen at the beginning of the experiment. During these games the researchers took functional magnetic resonance imaging (fMRI) scans of the participants' brains.

According to the old fashioned - and false - theory that pleasure and pain are THE main drivers of behavior, it was assumed that altruistic acts would activate the reward systems in the brain.

They do not.

A region of the brain called the posterior superior temporal cortex (pSTC) is activated by altruism and is very sensitive to the difference between doing something for personal gain and doing it for someone else's gain. The pSTC appears to help us tune into perceiving and giving meaning to the actions of others. It is not focused on reward.

In the next stage of the research the participants were asked questions about the type and frequency of their altruistic or helping behaviors. The researchers then analyzed the responses to generate an estimate of a person's tendency to act altruistically and compared each person's level against their fMRI brain scan. The results showed that pSTC activity rose in proportion to a person's estimated level of altruism. Note that it was their estimated level rather than their actual altruistic acts.

The suggestion by the researchers is that the ability to perceive other people's actions as meaningful is critical for altruism.

I am going to be a Devil's advocate and interpret the data differently. I think it more likely that people who have a good understanding of social relationships are more likely to do things for other people. Helping other just makes sense to you. Both the tests and the imaging could be interpreted in terms of social understanding and empathy. In other words we are looking at an aspect of social cognition.

There may also be another correlation here. Some years ago we showed that in people with chronic schizophrenia there is a shift in the handedness of a particular region of the brain called the planum temporale, which lies on the top of the temporal lobe. This lead to the hypothesis that when people are hearing voices, they really are hearing something being generated in the right hemisphere of the brain. People with schizophrenia sometimes have trouble with reading other people's intentions and may attach meaning to random events. This new research mat help us understand why that can happen.

It also makes clinical sense: the best ways of helping people with mental illness who have these problems is to ensure that they are not on medicines that impair their social cognition, and to use social skills training.

“What we have done for ourselves alone dies with us; what we have done for others and the world remains and is immortal.”
--Albert Pike (American Lawyer, Masonic Author and Historian, 1809-1891)

“Spiritual energy flows in thankfulness and produces effects on the phenomenal world.”
--William James (American Psychologist and Philosopher, 1842-1910)

Left-Handedness and Sports

There seem to be a number of potential downsides to being left-handed. Not only is the world designed for right-handers, but they may also fall victim to some illnesses.

However, there has been a lot of interest in the apparently greater success of many left-handed sportspeople. Amongst the elite in many sports, left-handers appear to be over-represented. The folk psychology explanation has been that if the effect is real, then it is likely all due to some attempt of the left-hander to over-compensate.

I’ve always been very skeptical about explanations like that, and there is new research from Australia to show that my skepticism was justified.

A study in the journal Neuropsychology shows that left-handed people can think more quickly when carrying out tasks such as playing computer games or some sports.

The research shows that in left-handed people there is a faster transfer of information between the hemispheres of the brain. This makes them more efficient when dealing with multiple stimuli, because they are able to use both sides of the brain more easily than people who are purely right-handed.

The researchers used a simple technique in which they measured reaction times of the two sides of the brain when white dots were flashed to either side of a fixed cross.

They then compared this with how good participants were at carrying out another task in which they had to spot matching letters in the left and right visual fields. This task would require them to use both sides of the brain at the same time.

Tests in 80 right-handed volunteers showed there was a strong correlation between how quickly information was transferred across the left and right hemispheres and how quickly people spotted matching letters.

But when the tests were repeated in 20 left-handed volunteers, the researchers found that the more left handed people were the better they were at processing information across the two sides of the brain. The more left-handed people were, the greater the efficiency of their hemispheric interactions.

When you have to do increasingly complex tasks, the brain recruits more circuits to help. People tend to use both hemispheres for tasks that are very fast or very complex and that require the interpretation of a lot of information. Good examples would be computer games, driving in heavy traffic or playing most sports.

Although there is a genetic component in handedness, it is an odd kind of genetic pattern and we also have some evidence that you can train yourself to make greater use of both of the hemispheres of the brain, and this can likely lead to a re-wiring of entire regions of the brain.

If you are right or left-handed try to spend five minutes each day using your non-dominant hand for some task. If you are right-handed, you might want to try shaving with your left hand. (Obviously electric or safety razors only please!). Or you might try something more complex: writing with your other hand. See if you notice any difference in yourself and feel free to report back.

Treating Posttraumatic Stress Disorder

There is an important article in this month's issue of the journal Psychological Medicine.

Researchers from the University of Heidelberg in Germany carried out a systematic literature review concerning two treatments that are widely used in the treatment of posttraumatic stress disorder (PTSD): Eye movement desensitization and reprocessing (EMDR) and trauma-focused cognitive-behavioral therapy (CBT).

They identified eight publications between 1989 and 2005 describing treatment outcomes of EMDR and CBT in active–active comparisons. Seven of these studies were investigated in a meta-analysis.

What they found was this. Both trauma-focused CBT and EMDR seemed to be equally efficacious and any differences between the two forms of treatment are probably not of clinical significance. Our main focus now should be to attempt to establish which trauma patients are more likely to benefit from one method or the other. The authors comment that it remains unclear is the contribution of the eye movement component in EMDR to treatment outcome.

This paper is interesting in light of our recent discussions concerning brain laterality and PTSD. It seems likely that part of the mechanism of both forms of therapy is to re-wire the brain. I tend to think that the eye movements probably are of importance, since they are also used in thought field therapy which appears also to be helpful to many people with PTSD.

Cluster Headache

There are dozens of types of headache, but one of the most serious and debilitating is called "cluster headache."

It is a very severe headaches of a piercing quality that most often occurs near one eye or temple. The pain typically lasts for fifteen minutes to three hours. The headaches are usually unilateral and occasionally change sides.

It is difficult to overstate the severity of the pain. I once mentioned that I could always tell if there was someone in the clinic experiencing a cluster headache because everyone could hear him banging his head against the wall to try and get some relief. They may also be described as "suicide headaches:" a reference to the excruciating pain and resulting desperation that has culminated in actual suicide.

There are some odd symptoms that may accompany the headache, such as:

• Stuffy or runny nose in the nostril on the affected side of the face
• Red, flushed face again on the side of the headache
• Swelling around the eye on the affected side of the face
• Reduced pupil size
• Drooping eyelid

As the name implies, cluster headache usually comes in clusters that last for a week or two or as long as two months. In about 10-15% of people they are chronic. The periodicity of the clusters is remarkable and has lead many of us to speculate an involvement of the brain's "biological clock" or circadian rhythm. In an observational study we found that clusters were more likely to begin in the month of birth of the sufferer, though we never knew how much to read into this.

Cluster headache is far more common in tall men: most are over six feet tall. When we first described cluster headache in women in the early 1980s it was a rarity, though more women have been getting cluster headache in recent years: we have no idea why. Some years ago we also described that they were more common in men who smoked heavily and drove more than 15,000 miles each year. It was impossible to say whether the smoking was cause or effect. Cluster headache is, along with diabetes and multiple sclerosis, an illness that becomes more common in peple who live far from the equator.

We and others also found that nitrates could trigger episodes in some people: that first came to light when we saw three men who used them during sex.

Cluster headaches are most likely to be due to an abnormality in the hypothalamus, which could explain why cluster headaches frequently strike around the same time each day, and during a particular season, since one of the functions the hypothalamus performs is regulation of the biological clock and the metabolic abnormalities that have been reported in some patients.

During the onset of a cluster headache, the most rapid abortive treatment is the inhalation of pure oxygen (12-15 litres per minute in a non-rebreathing apparatus). When used at the onset of headache this can abort the attack in as little as 5 minutes. Once an attack is at its peak, using oxygen therapy appears to have little effect. Alternative first-line treatment is subcutaneous administration of triptansumatriptan and zolmitriptan. Because of the rapid onset of an attack, the triptan drugs are usually taken by subcutaneous injection rather than by mouth. While available as a nasal spray, it had been thought that the spray would not be effective to sufferers of cluster headache due to the swelling of the nasal passages during an attack. However new research from London has shown that 5-mg and 10-mg doses of zolmitriptan intranasal spray are effective within 30 minutes and well tolerated in the treatment of acute cluster headache.

Lidocaine (or any topical anesthetic) sprayed into the nasal cavity may relieve or stop the pain, normally in just a few minutes, but long term use is not suggested due to the side effects and possible damage to the nose and sinuses.

Previously vaso-constrictors such as ergot compounds were also used though less so now becuase of their side effects and new options being available. Oddly enough some sufferers report a similar relief by taking strong cups of coffee immediately at the onset of an attack.

Many different types of prophylaxis have been tried, with lithium, the calcium channel blocker verapamil at a dose of at least 240mg daily, and the anticonvulsant topiramate.

Now a new report in the journal Neurology suggests that 22 out of 26 people with cluster headache who used psilocybin reported that the drg aborted their attacks. 25 of 48 psilocybin users and 7 of 8 LSD users reported cluster period termination; 18 of 19 psilocybin users and 4 of 5 LSD users reported remission period extension. The authors conclude that research on the effects of psilocybin and LSD on cluster headache may be warranted.

From what we do understand about the pathogenesis of cluster headache it is not difficult to see how psilocybin and LSD may help. But it did worry me that this report might lead to people self-medicating with hallucinogens without any kind of support or guidance.

That being said, this recent report shows once again the importance of listening to what people have to say: they often have the answers inside of them. And those answers may lead to a new range of treatments.

 

Posttraumatic Stress Disorder and Brain Laterality

I’ve just received an intriguing article from an individual who’s really been through the mill with an array of psychiatric problems going back to childhood.

The last diagnosis that he attracted was posttraumatic stress disorder (PTSD), and he seems to have cured himself by a combination of omega-3 fatty acids and learning to play the banjo left-handed.

This may sound like a bit of an odd claim, but although the writer did not realize it, there is actually some solid science behind his observation.

For years now we have known that if someone is paralyzed down one side after a stroke, binding the good arm or leg leads to rapid reorganization in the cerebral cortex, as a result of which the paralyzed arm or leg may begin to regain function.

One of the most potent ways to improve the functioning of regions of the brain is to try doing things with the opposite hand: if your are right-handed, brushing your teeth or writing with your left hand or using your knife and fork the other way round can all be very illuminating, and can help train your brain. A common tactic in couple’s therapy is to get people to change some habits, like switching the sides of the bed on which a couple sleeps.

The hippocampus of the brain is involved in many functions, but key amongst them is the laying down of short-term memories. People with several stress-related psychiatric disorders, including PTSD, borderline personality disorder with early abuse, depression with early abuse, alcoholism and dissociative identity disorder all have smaller hippocampi, presumably because this part of the brain is exquisitely sensitive to cortisol: high levels can damage and destroy hippocampal cells. Antidepressant medications and some types of cognitive training are thought to lead to the growth of new cells in the hippocampus. It is also possible that having a small hippocampus may predispose someone to the development of PTSD. There is also some evidence that mixed lateral preferences and parental left-handedness may all predispose someone to the development of PTSD.

In PTSD, the left hippocampus and two other brain regions: the left anterior cingulate cortex and both sides of the insula are all smaller than normal. Regions of this small left hippocampus associated with episodic and autobiographical memory is activated by stimuli that wouldn’t have much effect in people without the problem. Some researchers have also found that if the right hippocampus is smaller and more active, it correlates with the severity of PTSD symptoms.

Adults with PTSD have a higher incidence of mixed laterality with respect to handedness than the rest of the population. This has recently also been found in children: there is a positive correlation between PTSD symptom severity and mixed laterality. This strongly suggests that neurological abnormalities may be related to the severity of symptoms in PTSD.

In PTSD, the right amygdala, a region involved in fear and rapid emotional learning and processing, is smaller than the left. In healthy volunteers it’s the same on both sides.

When people with PTSD recall the traumatic event, especially if it involved assault, they over-activate the right hemisphere of the brain. It is not just cerebral blood flow: recent experimental work has shown that PTSD may be associated with a functional asymmetry of the brain, which favors the right hemisphere.

There are actually a number of therapeutic techniques that involve trying to switch the way in which the hemispheres interact. EMDR (which the writer had tried) is one. It is also amongst the techniques developed by Paul Dennison to aid learning.

I also wonder whether the writer has accidentally happened upon a method for treating psychological reversal.

I do wish the writer well, and I also hope that some of my colleagues in research might be interested in exploring some of these training techniques in PTSD.

More on Brain Laterality and Attention Deficit Disorder

I recently wrote about the connections between attention deficit disorder and disturbances of the normal lateralization of the brain.

I had a very interesting question from a correspondent:
"Is there any CHANGE in handedness related to the use of stimulant medication?

I have been taking dexadrine (RP: That’s methamphetamine) at 60 mg/day for several months now to address ADD after diagnosis as an adult. I have found that I now use my left hand for some tasks that I would have solely used my right hand previously. For example, I am painting trim with a brush at home currently and have found myself, without forethought, switching hands and cutting in against the walls and other paint colours with my left hand at a skill level that matches my right hand. Is it possible that this is the result of increased "cross-talk" between the hemispheres? My father was not classically ambidextrous but he did play hockey and golf as a "lefty" while writing using his right hand.”

This is a fascinating question. There is evidence of shifts of functional lateralization in a number of situations, including severe changes in mood.

There is also some experimental data to support what the writer’s observations, though most of it comes from research in children.

1. A study from the Netherlands showed that in children treated with methylphenidate, their manual dexterity and handwriting improved and became more accurate.
2. Research from Germany using high density magnetoencephalography (MEG), showed that treatment improved activity in the frontal lobes of the brain.
3. Investigators in New Mexico found that unmedicated children with ADHD had slower reaction time in their legs, which got better, particularly in the right leg, when they were given treatment.
4. Another study, this time from Israel, also showed that children with ADHD had a lateralized attentional deficit that got better when they were treated.
5. Children off treatment seem to have lower activity in the right hemisphere of the brain, which normalizes with treatment.
6. Stimulant medications do not themselves seem to have an impact on inter-hemispheric transfer. But what it may do is to improve the imbalance between the hemispheres.

So I would suspect that the writer’s brain is becoming generally more efficient.

And his letter has also suggested a small research project.

I sense a grant proposal in our near future.

The Evolution of Handedness and Laterality

The evolution of bilaterality marked a great change in the organization of animals and to this day some illnesses are associated with disturbances of the normal balance between the two sides of the human body, most especially of the hemispheres of the brain. Presumably they would not occur if we were still arranged like jellyfish or sponges. But then we would probably not have become the species that we are without that great evolutionary leap forward.

A new report has shown that at the molecular level, the first signs of genes that are expressed asymmetrically are in the lowly sea anemone. What is even more extraordinary is that the same asymmetric genes found n the sea anemone can induce lateralization in the embryo of a frog.

This is of more than just academic interest: it tells us that the move toward lateralization was already present hundreds of millions of years ago, and primitive versions of some of the same genes in your body are also present in the simplest of organisms. This is incredible evidence for the oneness of life. There is also something else. Nature is economical: genes that are not needed are discarded. The fact that these lateralization genes have been around for such a long time indicates that they were critically important in our development. And disturbances of them may be important to this day.

The scientists doing the study have speculated that creatures with radial symmetry, like starfish, might have evolved from asymmetrical animals. I couldn’t help but remember the apparently strange speculations of Rudolf Steiner, who said that the essential form of humans was present hundreds of millions of years ago, and that other animals devolved from them. The idea was that sentience and spirituality did not just crop up with homo sapiens. but have been present since the beginning of time. Be that as it may, understanding more about the fundamental processes of lateralization will likely have important implications for understanding human evolution and disease.

“The wise man remembers that while he is a descendant of the past, he is a parent of the future.”
--Herbert Spencer (English Evolutionary Philosopher, 1820-1903)

“We are descended not only from monkeys, but also from monks.”
--Elbert Hubbard (American Editor, Publisher and Author, 1856-1915)

“As Aurobindo and Teilhard de Chardin knew, the future of humankind is God-consciousness...”
--Ken Wilber (American Philosopher, 1949-)

Handedness and Immunity

In 1982, one of my mentors, the late Norman Geschwind, and two colleagues – Al Galaburda and Peter Behan - proposed an extraordinary hypothesis. It was that the levels of testosterone to which a baby is exposed before birth influence the development of both the cerebral and immune systems. According to this theory, high levels of testosterone result in greater incidences of left-handedness, deviations from the standard distribution of cerebral functions and increased autoimmune dysfunction. If the theory is right, then male brains should mature later than female brains, and the left hemisphere should mature later than the right.

It is certainly true that if a boy gets a head injury or infection involving the brain, he is less likely to recover than would a girl, and boys are far more likely to have some types of neurodevelopmental problems like dyslexia.

For a while it seemed as if there was also a strong association between left-handedness and certain types of allergy, and also with inflammatory bowel disease. This association with immunity also seemed to be present in mice: those who had left paw preference had more reactive immune systems, and they were thought to be more likely to produce auto-antibodies, suggesting that the central nervous system was involved in the genesis of some autoimmune diseases. Over the years the data has become less clear-cut, but the idea of an association between anomalous cerebral asymmetry and autoimmune disease never completely went away.

Recent data has again found an association between inflammatory bowel disease and laterality. And left-handers really do have more autoimmune disease.

The Geschwind-Galaburda hypothesis proposes that there should be a four-way association among neurodevelopmental disorders, special talents, non-right handedness, and immune disorders. In a huge study of 11,578 children, less than 1% had all four.

So where does this leave us?

The original theory was half right:

1. There is indeed a link between testosterone and early brain development
2. People who are left-handed or have a strong tendency toward left-handedness do seem to be at slightly increased risk of several autoimmune conditions
3. People who are left-handed or have a strong tendency toward left-handedness may have a slightly increased risk of high blood pressure, asthma and migraine
4. People who are left-handed or have mixed handedness are more likely to excel in certain disciplines: creative arts, music, computer programming and mathematics. What we don’t know is whether people with these special skills are more likely to have autoimmune diseases
5. Amongst very successful tennis players,  there are far more left-handers than would be predicted by chance. This supports the idea that support the notion that left-handed people have neurological advantages in performing certain tasks, such as visuospatial visuomotor cognitive tasks.

I was reminded of the way in which Nature seems to like to balance things out a bit: with some notable and famous exceptions, many successful athletes have not done so well academically and many academics would be unlikely to survive on the plains of Africa. Only some of these differences can be explained in terms of early direction and encouragement in school or while growing up: it seems that most of us cannot hope to become the kind of superman that Nietzsche used to dream about.

Perhaps it’s a way of stopping us from getting too full of ourselves.

Attention Deficit Disorder and Brain Laterality

Here two topics that are very close to my heart: the puzzle of laterality and asymmetry and attention deficit disorder.

We live in an asymmetric Universe. Fundamental particles tend to rotate and wobble to the left rather than the right; most molecules show a lateral shift; and all the biologically active amino acids - the building blocks of proteins - are in the L-form. Meaning that in solution they bend light to the left. The R-forms, that bend light to the right, for the most part don’t work in biological systems. Some of the most extraordinary asymmetry is seen in the human brain. There’s a myth that about the hemispheres of the brain that I’ve talked about before, but bears repeating.

The idea that the left hemisphere of the brain is specialized for logic, analysis and language, while the right hemisphere is holistic, artistic and mystical has been circulating for over thirty years. It has even been suggested that the right hemisphere of the brain is the seat of intuition, which cannot be correct. It may be involved in instinct, but it is impossible to reduce a non-local psycho-spiritual experience to groups of brain cells. There may be correspondence – the right hemisphere becoming activated during intuition, but not causality: right hemisphere activation as the cause of intuition.

This notion of discrete functioning of the hemisphere has become so pervasive that it is commonplace to hear people describing themselves as being "right brained,” or accusing someone else of being "left brained."

A simple concept that is also profoundly wrong. This is fine as a metaphor, but not as a fact. It is true that language is more highly represented in the left hemisphere of the brain in right-handed men. But language is bilaterally represented in women. Most men tend to use a small strip of the left hemisphere for language, women tend to use both hemispheres at once. There’s still a left-sided predominance, but it’s quite a different pattern from most men’s brain.

Boy’s brains mature more slowly than girls’ brains, and by adolescence are more lateralized than are the brains of girls and women. The truth is that we cannot neatly divide up the functions of our brains, and we need both sides of our brain if we are to function at our best.

Until very recently most experts said that handedness was a purely human attribute. Yet anyone who has every lived with a cat, dog or horse knows that that is wrong, and now there’s literature to prove it.

I tried to put that mistake to bed in a review article that included a detailed discussion about brain asymmetries in animals. I also reviewed the excellent evidence that certain regions of the brain have been becoming more lateralized over the last 100,000 years.

I’d like to show you why this talk of brain lateralization is not a sterile academic debate.

We do not know if left-handedness or mixed handedness is more common in ADD/ADHD. But the evidence is getting stronger and stronger that there is something different in people with ADD/ADHD in how they use the two sides of their brains.

Three conditions: autism, dyslexia and ADD/ADHD share one characteristic: they are all marked by what we call atypical cerebral asymmetry in that they don’t have the normal left hemisphere dominance for language. This is more of a problem for boy, since they normally make more use of their left hemispheres. But it’s not all bad: atypical cerebral asymmetry may also be associated with certain aspects of creativity.

Researchers in New Zealand have just reported something strange, but which is consistent with previous research. When healthy right-handed children are asked to bisect a line drawn on a page, when they use their right hand they tend to bisect the line toward the right, and with the left hand toward the left. But children with ADD/ADHD don’t do this. The researchers have now gone further and suggested that there are at least two types of ADD/ADHD, in one of which – ADHD-I – the primary problem is in the right hemisphere of the brain.

Using an entirely different methodology, researchers in Baltimore, Maryland, have found that children with ADHD use their brains differently when engaged in patterned motor activity.

In an earlier post I talked about the dorsolateral prefrontal cortex, and there is an important connection to it is called the cingulate cortex. A new study has shown that adults with ADD had significantly smaller overall amounts of cortical gray matter, and reduced volumes of their prefrontal and anterior cingulate regions. Both are highly lateralized in the human brain.

Compared with controls, unmedicated children with ADHD have a small right cingulate cortex, but it is normal in children who have been treated, indicating that the treatment is doing more than treating symptoms: it may actually be re-wiring the brain.

Research from the UCLA Neuropsychiatric Institute and David Geffen School of Medicine showed that in adults with ADHD, showed reduced left hemisphere specialization, were better at processing emotions, and worse at processing words compared to controls. They tend to use their right hemispheres more and their left hemispheres less.

Unaffected individuals constantly shift their attention toward the important or salient things in their environment. Children with ADHD have a problem with directed attention: the ability to allocate and direct attention toward a salient stimulus. New research has discovered that this is due to problems in a region of the brain called the parietal lobe that is known to play a significant role in shifting attention and detecting specific or salient targets in the environment. As a result the child’s brain does not know what is important.

These findings do not tell us whether the primary problem is a way in which specific parts of the brain talk to each other, or whether the scientists are actually measuring the way in which the brain reacts to deficits in one region. Perhaps other regions take over the functions of parts that are not working as they should.

The most important take home message is that we already have methods for stimulating and integrating the hemispheres of the brain. Few have so far been much used in ADD, but this information gives us a whole new way forward.

Child Prodigies

I’ve recently had cause to look at the published literature on child prodigies and there’s not much there. It is very surprising that such an interesting subject has been so little researched.

First a definition from a paper by David Feldman: A “prodigy was a child (typically younger than 10 years old) who is performing at the level of a highly trained adult in a very demanding field of endeavor.” There are three fields in which high-level creative results have been produced before the age of 10: Chess, Mathematics and Music. There are other fields such as art and writing in which young people may be precocious imitators. Pablo Picasso exactly mimicked his father’s drawings. There is an impressive list of child prodigies in other fields as well, but it seems that only in chess, mathematics and music have profound, original insights been contributed by preadolescent children.

There is an interesting association between mathematics and chess: many top chess players are also extremely good at mathematics. In a previous post I mentioned the English Grandmaster John Nunn, and there are many other examples. Men dominate both fields, but that does not necessarily mean that there is a natural gender difference. There’s a very interesting book entitled Breaking Through, by the chess Grandmaster Susan Polgar who was herself a prodigy, as were both of her sisters. Girls have been excluded from many of these events, or they’ve been forced to play only against girls or women. I know a young person who as a pre-teenager wanted to join the school chess club, but only went once, after discovering that all the other members were boys. A shame: she was already quite a strong player.

Both chess and mathematics involve highly developed non-verbal and visuospatial skills. The writer and critic George Steiner had this to say: “The solution of a mathematical problem, the resolution of a musical discord or conclusion of a contrapuntal development, the generation of a winning chess position can be envisaged as spatial regroupings, that have their own internal logic.” He went on to speculate, “All three fields involve enormously powerful but narrowly specialized areas of the cortex. These areas can somehow be triggered into life in a very young child and can develop in isolation form the rest of his psyche. Sexually and socially unformed, very possibly backward in every general respect, the child virtuoso or pre-teenage chess master draws on formidable but wholly localized synapses in the brain.”

In the book The Exceptional Brain, Lee Cranberg and Marty Albert suggested that these “localized synapses” lie in the right hemisphere of the brain, which is primarily involved in non-verbal visuospatial skills and pattern recognition. They also suggested that gender differences in proficiency in chess support the right hemisphere idea. But after reading Susan Polgar’s book, and spending a great deal of time analyzing the world literature on gender differences in cognition, that last point doesn’t convince me.

It is striking that three of the code breakers at Bletchley Park during the second World War, were outstanding international chess players Stuart Milner-Barry, Harry Golombek and Hugh Alexander. These code breakers who helped win the War also utilized similar skills to those needed to master a chess position or to calculate a mathematical problem.

The child prodigies seem to have some things in common:

1. An unusually strong talent in a single area
2. Reasonably high but not necessarily exceptionally high IQ: some people with astronomically high levels of intelligence have had problems with interpersonal adjustment, unless very carefully nurtured as children.
3. Focused energy.
4. Sustained effort to achieve the highest levels in their field: even chess prodigies need thousands of hours of practice, and mathematical prodigies need to work at their field.
5. Unusual self-confidence.

Adults who want to improve in chess are constantly told to practice as much as possible, and to work on pattern recognition and problem solving. It is just the same in music and mathematics.

Although child prodigies may simply have better neurological equipment, usually coupled with extraordinary encouragement by their parents, I am left with a question that I posed in an earlier post. Mozart often said that when he was composing he felt as if he was taking dictation from God. That he was not the one composing, but that he was in effect picking something up from the Universe. I’ve seen countless highly gifted people tell me that their greatest insights in science, music philosophy or chess just “came to them.” The former chess World Champion Tigran Petrosian once said that he could tell when he was out of form when his calculations did not confirm the validity of his first impressions. All this implies unconscious processing to be sure, but I am not sure that it is all in the brain.

Because there is another phenomenon that has also not been much researched, and that is the phenomenon of simultaneous breakthroughs: two or more people in different parts of the world coming up with new creative solutions at the same time and without any personal contact. I shall have more to say about this in another post, but it speaks to the fundamental interconnectedness of all of us.

Maybe the child prodigies not only have special brains and special parents, but they also have access to a store of information not available to everyone.

At least not yet: We already have training methods that help people access accurate information that they did not know consciously. A story for another day.

“Genius is characterized just by the fact that it escapes classification.” --Leopold Infeld (Polish Physicist, 1898-1968)

Memory and Anticipation

“Nothing is so wretched or foolish as to anticipate misfortunes. What madness is it to be expecting evil before it comes.”
--Lucius Annaeus Seneca (a.k.a. Seneca the Younger, Spanish-born Roman Philosopher and Statesman, c.4 B.C.E.-A.D. 65)

We are all aware that memories of powerful and in particular disturbing emotional events - such as an act of violence or the unexpected death of a loved one - are more vivid and deeply imprinted in the brain than mundane recollections of everyday matters. When I was sixteen years old I was in a head-on car crash: I can still recall the number of the license plates of the car that was driving down the wrong side of the road as it barreled into us. But particularly positive emotions are also remembered in far more vivid detail, and those memories are less likely to be lost. This all makes good sense from an evolutionary perspective: we need to be able to remember things that carry a strong emotional charge.

Colleagues at the University of Wisconsin in Madison have found that the mere anticipation of a fearful situation can activate two memory-forming regions of the brain: even before the event has occurred.

The investigators used functional MRI scans with 40 healthy participants who viewed aversive or neutral pictures preceded by predictive warning cues. Previous research reported sex differences in the way in which memory and emotion interact: in women, memory associations were found with a region called the left amygdala. But the association was with the right amygdala in men. This new study refines these findings: they were confined to the ventral amygdala during picture viewing and delayed memory.

Both men and women who had previously been given an indication that gruesome pictures were going to be shown were more likely to remember them.

What this means is that the act of anticipation may play an important role in whether the memory of a tough experience remains fresh and vivid. This makes sense based on our own experiences of events: do you remember the fear associated with a visit to the dentist that built and built before you got there? That anticipation can itself modify the memories of an event.

The findings are published in this week’s issue of the Proceedings of the National Academy of Sciences. They have important implications for the treatment of some psychological conditions such as post-traumatic stress disorder (PTSD) and social anxiety that are often characterized by flashbacks and intrusive memories of upsetting events

We have long known that our memories are not like some video recording forever preserved within our neurons. Some memories are false, many change over time and others lose their emotional charge. It is possible to implant false memories in people, and by re-writing our own life stories we can change the narrative of our lives and how we react to life events.

Samuel Johnson once said that, “The true art of memory is the art of attention.”

I’m quite sure that he is correct, and this research proves it. I’ve always been blessed – or cursed – with a prodigious memory, to the extent of being able to remember the lab values on every patient that I ever saw during my clinical years, and when I was younger being able to read pages of a textbook from memory. I’m quite convinced that my memory is no better than anyone else’s: I’m just a little better at using it.

The trick to using my memory was discovering at an early age that I could remember virtually anything if I really focused my attention on it. So I would focus on the book to the exclusion of everything else for a minute or two. Rest for a minute and then do it again. To this day, that is the best technique that I know for laying down long-term memory. My father also had this faculty, and when I was a youngster he would tell me not to write down things like shopping lists or to construct “To do” lists. He told me that, “if you really have to remember things you will. And if you’re not interested in something you don’t need a “to do” list.”

I only use lists if I have to do something tedious. This is a good test for you. If something that you are doing really engages your attention it is likely one of your core desires, and there is no need to be writing down a list of things to do. If it does not, and you have to write everything down, it’s probably not a core desire. You may still need to write down an action plan, but that’s to get your creative juices flowing, not to stimulate your memory.

I have developed quite a number of techniques for improving memory and concentration. Some are home grown, others modified from methods and techniques that others have taught me. I’ve been collecting and testing them for years. I’m doing a lot of flying this week, so I shall have the time to be put some of them together into a free report. I shall let you know when it’s ready and if you ask, I shall send you a copy.

There is one important reason for writing down thoughts once you have done something, and that is to help them be part of your legacy. That’s a topic to which we are going to return many times in the next few weeks.


“What we anticipate seldom occurs, what we least expected generally happens.”
--Benjamin Disraeli, 1st Earl of Beaconsfield (English Statesman, Novelist and, in 1868 and from 1874-1880, British Prime Minister, 1804-1881)

The Canine Gandhi: Cats, Dogs and Interspecies Communication

“Thousands of years ago, cats were worshipped as gods. 
Cats have never forgotten this.”
--Unknown Author

I need to tell you about something remarkable, that, if you think about it, has amazing implications.

We have a new little kitten. An eight-week-old little girl, and already a brave explorer who wants to play with everyone. Interestingly, she is already strongly right-handed. (Yes there is clear evidence of handedness in most mammals, and even some fish. But in cats, dogs and horses it’s not always clear until they are a little older than this.)

The other cats are not best pleased by this turn of events. After all this is their house, even if they do have to put up with the occasional human and a large mobile rug called Shannon. Shannon is an enormous dog of questionable pedigree but extremely calm disposition, who just hates any kind of noise or commotion: she is the original gentle giant.

The humans in the house are tolerated only because they are the suppliers of food, treats and comfy laps.

After all, as an unknown author once pointed out,
“Dogs have owners. Cats have staff.”

Little kitten thought that with Shannon fast asleep on the floor, it would be fun to play with another cat called Hannah. Now Hannah’s an older and very dominant cat who survived in the wild for a year. She didn’t take kindly to the small ball of fluff skipping toward her. Little kitten did not have the wit to understand that Hannah’s taut, crouched posture and narrowed eyes were not an invitation to a game, but preparation for the pounce that would quickly generate a kitten-shaped snack. We were about to intervene when something remarkable happened.

Shannon, who had been busily stacking ZZZZZs, got up shambled forward and put her enormous head between cat and kitten. No sound was made. She didn’t look at either of the protagonists. She was just like a great big bouncer getting between a couple of drunks in a bar.

She just stood there, unmoving and implacable. Like the Black Knight in Monty Python and the Holy Grail, "You shall not pass!"

After a few moments the kitten realized that there’d be no way through, and went off in search of one of her toys. And Hannah cat saw that kitten tartar was off the menu. She slunk off to go and groom herself.

With which Shannon went back to her spot, lay down and promptly fell asleep again. She was soon back to a dream that involved a lot of running.

There can be absolutely no doubt about Shannon’s intent. She wanted to keep the peace, and she woke from sleep to do so. It’s not the first time that she’s protected the cats from harm.

Late at night a couple of weeks ago, we couldn’t get her to come in the house. She kept running back outside and growling. Very odd for a sweet natured creature who normally always comes running when called. It was only when I went outside for a third time that I realized that I’d been a bit slow. A few feet away was a large feral cat that we’d not seen before. He had Hannah cornered against a pillar and Shannon was trying to protect Hannah and chase the away the interloper.

As soon as the dumb humans got out of the way, Shannon saw the gatecrasher off the premises and escorted Hannah back into the house.

These can’t be unique examples of inter-species communication. Do you have either anecdotes or research to share?

“Always remember, a cat looks down on man, a dog looks up to man, but a pig will look man right in the eye and see his equal.”
--Sir Winston Churchill (English Statesman, British Prime Minister, 1940-1945 and 1951-1955, and, in 1953, Winner of the Nobel Prize in Literature, 1874-1965)

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