Neurogenesis 101
The great Spanish histologist and Nobel Prize winner in Physiology or Medicine, Santiago Ramón y Cajal, was probably the first modern scientist to say that neurons in the adult brain did not divide. In other words, humans are born with a finite number of brain cells and an individual cannot develop/grow/replicate new cells over the course of their adult lives. This is an axiom that underlies some parts of the stem-cell debate.
There is emerging research that seems to refute this notion. I have written a long article for my friends over at Psychiatric Resource Forum discussing the research indicating that humans may have the ability to produce new neurons in key regions of the brain throughout life, a process called neurogenesis. I also discuss what this means for field of psychiatry.
The concept of neurogenesis also engenders hope for the fields of personal and spiritual development. I will discuss these at a later date. I just wanted to link to this article because it provides (along with the links) a good primer on neurogenesis that will be helpful as I write new posts.
Technorati tags: neurogenesis, personal growth, Self Improvement
Integrated Health and Aging
An important principle of the emerging laws of health and healing is that anything helpful should help more than one system of the body at a time. So a diet that might help mitigate the effects of aging in the skin should also have beneficial effects on the major organs of the body.
So I was encouraged to see a new report indicating that cardiovascular health and a healthy lifestyle are associated with maintaining the health of our brains as we age. This is, of course, intuitively obvious, but it is always nice to see such things confirmed by empirical research.
The new report is from a multi-Institute collaboration of the National Institutes of Health (NIH) published online in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association. The chair of the committee was Hugh Hendrie, the Scottish-born professor of psychiatry from the University of Indiana, and the committee members were many of the most eminent people in the fields of aging and Alzheimer’s disease.
What is encouraging about this new report is that many of the factors associated with cognitive decline as we get older are eminently remediable: we have within our reach a set of potential interventions that could significantly reduce our personal risk of developing cognitive problems later in life. These are the things that we need to work on if we want to reduce our risk of developing cognitive decline later in life:
- Hypertension: There is excellent evidence that inadequately treated hypertension correlates strongly with cognitive decline.
- Physical activity: There is good evidence that elders who exercise regularly are less likely to experience cognitive decline. This is over and above the general improvement in quality of life that accompanies regular exercise. The earlier in life that we start, the easier it is to continue.
- Increased mental activity throughout life, including learning new things and going through higher education may benefit the health of the brain.
- Moderate alcohol use and the use of vitamin supplements also seem to be brain protectors, though the report does not specify which supplements.
- Social disengagement and depressed mood are both associated with poorer cognitive functioning, so it is important to be alert to signs of depression, and to maintain a social network. I discuss this in more detail in my book Healing Meaning and Purpose.
There are doubtless some genetic and environmental factors about which we can do little. But the idea that we now have a list of things that we can do to protect our brains is very exciting.
This report also signals another important change. In recent years we have seen the growth of Positive Psychology, the study of how to improve ourselves rather than the constant focus on psychopathology. This report calls for the research community to study health maintenance of the brain with the same energy that it has brought to bear on the study of diseases of the brain. To which I would add, that we must not just focus on how to maintain the health of the brain, but how we can enhance it’s function so that we can all reach and exceed our full potential.
Technorati tags: aging, Integrated health, Positive Psychology, healthy lifestyle,
The Ethical Brain
There is a nice blog, Brainethics, that discusses an interesting new book Hardwired Behavior by Laurence Tancredi. This really is an outstanding piece of work. The author is both a psychiatrist and a lawyer who argues that Society’s assumptions about free will and individual responsibility must be drastically revised in the light of scientific discoveries about the brain.
This is part of a large debate that is going on within psychiatry and psychology and within the legal profession. As an example, at what age should a young person be able to drive a car or be legally liable for their decisions? The driving question comes up because the brain and nervous system of a fifteen-year-old is still far from being fully mature, and may lead to poor coordination and decision-making. Can an eighteen-year-old be held liable for his behavior, at a time that his brain is not fully formed? Yet he is able to fight for his country. You will see that your answers to those questions are likely to be a mixture of political positions and personal experience. But there is also no doubt that the explosion of knowledge about the brain will be factored into some future legal decisions.
In Tancredi’s book, he applies knowledge derived from recent research to such traditional moral concerns as violence, sexual infidelity, lying, gluttony and sloth, and even financial fraud and gambling. For anybody working in the field, it is very clear that hormones, nutritional status, drugs, genetic abnormalities, injuries and traumatic experiences all have profound effects on the structure and functioning of the brain. Therefore they may all have an impact on our moral choices. Some experimental work implies that our actions are initiated by pre-conscious and unconscious processes in the brain before we are consciously aware of them. Does that mean that our sense of moral agency is a retrospective illusion? And what about free will?? Is that an illusion too?
I like this book, and also the recent book by Michael Gazzaniga, entitled The Ethical Brain. But I need to sound a note of caution: we are bewilderingly complex creatures, and there is powerful evidence for the existence of systems that can over-ride some of the neurological ones. So even after reading and studying hundreds of books and scientific papers and talking to hundreds of scientists around the world, I remain convinced that free will is not an illusion, and that there really is a genuine morality which is a great deal more than the firing of neurons in the brain.
Hypnosis and Electrical Activity In the Brain
Following my post on Meditation and the Brain a perceptive reader just asked a great question:
“Has any of the research found any difference between hypnosis and meditation as it relates to brainwaves. And do people in a state of hypnosis demonstrate these high gamma waves?”
This is so interesting that I thought it was worth a short note of its own.
On the first occasion that I was hypnotized during my training, I remember thinking that the experience was very like the first stage of meditative practice: I was primarily using Vipassana back then. Subsequent subjective experiences have all tended to confirm that view: there are some similarities between trance and early meditative experiences.
There is a good amount of empirical research that tends to confirm that. John Gruzelier’s group at Imperial College in London has published some very fine work using not just electroencephalographic (EEG) measurements, but also functional MRI (fMRI). Gamma waves are between 30 to 100 Hertz, or cycles per second, and appear to reflect the way in which cells exchange information about the environment and form mental impressions. Gamma oscillations have a role in the subjective experience of pain. Not only has Gruzelier’s group shown some of the same gamma wave coherence, but also, research published in October of last year suggests that individual differences in hypnotic susceptibility are linked with the efficiency of the frontal lobe attention system. Hypnosis appears to involve a dissociation of the prefrontal cortex from other neural functions. Both the meditation and hypnosis studies have indicated that the key regions are primarily in the left frontal lobe.
The difference is that although people can demonstrate similar gamma wave activity when hypnotized, in the experienced meditators the gamma wave activity was there all the time, but would increase dramatically when meditating. How dramatic? Thirty fold higher activity than in a non-meditator. The trained brain is physically different from the untrained one.
Bob McCarley’s group at Harvard has done some interesting work in which healthy volunteers and people with schizophrenia were asked to look at images. The people suffering from schizophrenia showed no gamma wave activity at all.
Interestingly, there is also a very recent paper out in the Journal of Psychoactive Drugs showing the same EEG gamma coherence in two experienced people using the Brazilian drug ayahuasca, which suggest further similarities between meditation and shamanic psychedelic practices.
Technorati tags: brain waves, hypnosis
Prairie Voles Again!
I do hope that we are all properly appreciative of the scientific contribution of these cute little creatures. I mentioned them in one of my Valentine’s Day posts, but you will find a picture and an accompanying story here.
Thomas Insel’s group at the National Institute of Mental Heath in Bethesda have spent years working on pair formation and partner preference in these little fur balls.
It seems that pouring dopamine into a region of their brains known as the nucleus accumbens makes male prairie voles seek out girlfriends. There are at least seven major subgroups of dopamine receptors. But in these little creatures D2 receptors are involved in approach behavior that is associated with the formation of a pair-bond, and D1 receptors maintain the bond. While forming a relationship the little vole’s brain actually changes.
I am always a bit worried about trying to read too much into these experiments, because human behavior really is a great deal more complicated. But I have a couple of thoughts:
1. Dopamine receptors are proteins, so they are products of genes that get switched on by the formation of a relationship. Might some people have a genetic reason for having difficulties in relationship formation, and how would that play with environmental factors? You may well know some people who seem cold and uninterested in relationships, and indeed, there are some personality disorders in which people have chronic difficulties in forming relationships. Yet certain types of psychological therapy can help them.
2. Some antipsychotic medications block D2 receptors. Is that a further explanation for the relationship difficulties of some people receiving these medicines?
3. I think that we should thank the Prairie Vole Kingdom for their help…..
Technorati tags: relationships, dopamine, love, science of love
Meditation and the Brain
1. There are many types of meditation: many are a form of intense concentration, others are a witnessing or watching of thoughts, yet others are a form of profound devotion. So it is no surprise that different forms will produce different effects in the brain.
2. The fact that the brain can be trained to produce certain types of electrical activity is in line with multiple lines of evidence demonstrating that the brain is not the static structure that we used to think it to be: it can learn and develop. We already knew that with motor functions and some cognitive abilities, but now we can extend those findings into the emotions: feelings of love and empathy can be developed, expanded and deepened. The old metaphor that the brain can be exercised like a muscle may not be a metaphor after all, but a biological fact.
3. The fact that there are neurological correlates of meditation or of any emotional or psychological state does not mean that we can reduce the experience to the firing of some neurons or the synchronization of regions of the brain. Some of this research has been misinterpreted to mean that meditative states or mystical insights are no more than the calming of neural activity. It is vital that we also acknowledge the subjective experiences and reports of individuals and recognize that they are as valid descriptors as changes in the brain.
4. Meditation has been shown to have a great many physiological and psychological effects, from lowering blood pressure, to improving the performance of sleep-deprived individuals, reducing age-related cortical thinning and ultimately leading to demonstrable psychological and spiritual development. So the neurological and psychological findings provide a partial explanation for those observations.
Technorati tags: meditation, Dalai Lama, brain, Neuroscience
Love, Sex and Cupid’s Chemicals?
1. Lust: This is supposed to be driven by the sex hormones testosterone and estrogen and happens together with rises in the nerve growth factor (NGF). So the idea is that we learn to enjoy lust. I don’t think that we needed millions of dollars of research to tell us that!
2. Attraction: This is the phase when we are supposed to be thinking of nothing else but the new significant other, and even reduce our need for food and sleep. The NGF is still lurking around here, but now there are supposed to be other chemicals coming into the picture: Serotonin, that makes us feel good; Dopamine, that is involved with emotion and the important facility of salience: deciding what is important in the environment; and norepinephrine, that cranks up our metabolism and also gets involved in the formation of memories and behavioral responses.
3. Attachment: This is supposed to be what happens after the initial stage of attraction, if a relationship is going to last. This is said to be mediated by the hormones vasopressin, which is involved in memory and fluid balance, and oxytocin, that is produced during childbirth and during breast feeding, and is thought to be involved in cementing a bond between mother and child. Oxytocin is also released during sexual orgasm, so it has been thought that oxytocin is the reason why having a lot of sex brings a couple closer.
1. Yes, there is a chemical contribution to many of our experiences, but it is a contributor, and not the explanation for them
2. We have huge amounts of data to prove that our emotional and psychological reactions cannot be reduced to chemicals alone. There is a human mystery that is way beyond such reductionist notions
3. These chemical studies will eventually need to include not just our subjective experiences, but also the role of other individuals: our relationships
4. None of the studies is yet ready to deal with the subtle systems that pervade our world. Let me ask you a question: Have you ever had an intimate partner who drained your energy and another who flooded it with positive energy? That’s pretty good evidence!
5. Have you ever felt that you had a soul connection to your partner? If you have, you know that it cannot be reduced to chemicals. It affects every part of your being.
Addendum: CNN has just published a similar article: please click here to read it.
Technorati tags: love, science of love,
Sit and Smell the Roses
“O, my love’s like a red red rose That’s newly sprung in June.”
–Robert Burns (Scottish Poet, 1759-1796)
Just in time for Valentine’s day, comes some research from McGill University in Montreal, Canada, that may have important implications for many people. Researchers discovered that the sensitivity to the smell of roses was greater in people sitting than in those who were lying down.
This is consistent with other research that has found that many of our senses are less acute when we lie down. It is not simply that when we lie down our noses are less exposed to wind drafts carrying odors, it is likely part of a complex series of partial shut downs of the senses that take place as we prepare for sleep.
There are two messages from this research:
1. Most brain imaging studies are done when people are lying down in a scanner, so when we are doing experiments involving the senses, we may need to rethink that, and see if we can re-arrange things so that subjects can be seated.
2. If you are planning on scattering rose petals, or giving someone special a bouquet of roses, perhaps you should wait until they have got out of bed…..
Learning About Ourselves
Previously, I have recommended a fine weblog, Brainwaves, and Zach Lynch, the author, has another very important and interesting article. This time dealing with the way in which our brains handle different types of information.
We have known for some time that there are different types of memory that are stored in different regions of the brain and are accessed differently. The main types are episodic memory, that stores facts about personal episodes, and semantic memory, that stores general knowledge, such as the meanings of words, the capital of Peru and the way to the supermarket.
This new study builds on this knowledge, showing that self-referential thinking is associated with activation of a region deep in the right prefrontal lobe of the brain that is involved in coordinating many higher functions. In his blog, Zach makes a couple of good points:
- Personal learning is both more memorable and more motivating. I think that a moment’s introspection will confirm that. It does not apply for some people struggling with certain types of psychological problems, but for the rest of us, we would rather learn something about ourselves, than some dry facts about cotton production in India. Most of us learn by association and connecting facts with personal events, interests and histories is likely to be much the most effective way of educating people. In fact most good teachers do this already. When I’m lecturing I constantly weave in stories that will personally engage the people whom I’m teaching. This research provides a rationale for doing so.
- Some students have such a strong preference for personal learning that this may be the only way that they learn, so teachers need to be alert to these people and adjust their teaching methods accordingly.
In future research, it would be very valuable to see if these different styles link up with Howard Gardner’s concept of multiple intelligences. We are getting ever closer to the goal of being able to tailor teaching to the individual, to allow more people to fulfill their true potential.
Technorati Tags: personal learning, learning styles, Howard Gardner, multiple intelligences
Nutrition and Mental Health
Our brains are delicate organs sustained by a fine balance of fatty and amino acids, minerals and vitamins.
Virtually everyone of us has had the experience of a mood change if we become hypoglycemic, or sleepiness after eating chocolate or tryptophan-containing turkey. The scientific literature is full of reports about the impact of different foods and combinations of food on mood, alertness and cognition. Some of the links are not obvious. I was brought up with the old wives tale that children become sleepy after lunch or dinner because blood was being diverted to the intestines. Not so: sugary and fatty foods cause sleepiness by altering the secretion of insulin by the pancreas, which in turn effects the uptake of key amino acids in the brain, which in turn impact the synthesis of some neurotransmitters.
There has also been another yet more serious issue that has been turning up in the literature for decades, and that is the inter-relationships between diet, nutrition and mental illness. Epidemiological studies have found a clear relationship between the consumption of fish and the incidence and prevalence rates around the world: high fish consuming countries tend to have less depression. This relationship has held up in studies around the globe, so it is unlikely that it is simply that people living by the ocean in warm sunny countries are less likely to become depressed. These observations were part of what led Dr Andrew Stoll at Harvard to first study the impact of fish oils, containing omega-3 fatty acids, on mood. The results of the early studies were more impressive than the later ones, but the fact remains that fish oils have been helpful in a proportion of patients. The experimental work continues, in order to try and find the best and most effective mixture of fatty acids.
There is a theoretical reason why this might be: fish oils can change the characteristics of the membranes of many cells, including those in the brain, and thereby influence the firing and response of some neurotransmitters important in the maintenance of mood.
There have been recent reports from well-conducted studies of the impact on nutritional supplementation on reducing violence in prisons and that work is also continuing. The BBC has picked up on an eagerly awaited report from the Mental Health Foundation and Sustain. Called Feeding Minds this report by mental health advocates and food campaigners is ambitious and presents a good summary of the current state of the evidence, though its findings are sure to be controversial.
The report points out that changes in the composition of Western diets with the proliferation of industrialized farming and pesticide use and the depletion of some essential nutrients in the soil has coincided with a continuing increase in the incidence and prevalence rates of mental illness. It is always difficult to prove causality with research like this, since there have been many other social changes which could equally account for a rise in the rates of mental illness, to say nothing of ever-changing diagnostic criteria, that have sometimes labeled people with mental illness who would at one time have been described just as “different” or “eccentric” or “difficult.” But it is also fair to say that few people doubt the link between cigarette smoking and lung cancer, but to prove causality is bound to be difficult. This is very different from the situation with infectious diseases. Here we have had a set of four criteria which we can use to show whether or not an infectious organism is the cause of a disease. Known as Koch’s Postulates, which have guided us for 122 years and have so far been proven time and time again. These postulates have been modified over the years, yet still formed the basis of the work which lead to the 2005 Nobel Prize in Physiology or Medicine.
Sad to say, things are not so clear when looking at nutrition and mental illness. But let’s look at a few key items in the report:
1. Depression: I have mentioned this one already, and the report also emphasizes the link between depression and low consumption of fish that are high in omega-3 fatty acids
2. Schizophrenia: A link between some fatty acids and schizophrenia was first proposed by the late Dr. David Horrobin in the 1970s, and increasing epidemiological evidence has shown that sufferers have lower levels of polyunsaturated fatty acids (PUFA). There have been many studies which have attempted to modulate them to treat the disease, with some measure of success. Just this month there is a report in the British Journal of Psychiatry on the adjunctive use of PUFAs in the closely related condition of bipolar disorder.
3. Alzheimer’s disease: Some studies have suggested that a high consumption of vegetables, particularly those containing folate, can protect against or slow the progression of this brain disorder.
4. Attention deficit and/or hyperactivity disorder: Research shown that some children with these disorders are low in iron and fatty acids, though it is not so clear whether treatment with these agents will help these children.
In my book Healing, Meaning and Purpose, I talk at length about the dietary and other physical changes over the last 100 years, and this report adds more. In the last 50 years, our consumption of omega-3 rich fish has fallen by two thirds, and over the same time course we have dropped our consumption of vegetables by 34%. There is something else more subtle, that I did not see in the report. In the decades after the second world war, British children were routinely given daily cod liver oil tablets rich in omega-3 fatty acids, as well as free school milk.
The report makes a point that I have before in entries here: people cannot be held totally responsible for maintaining healthy diets: some food and farming policies have lead to a situation in which people may no longer have access to healthy and nutritious foods. And that will likely cause further increases in some mental illness. And artificial supplements can rarely replace the real thing.
The evidence base associating nutrient intake and mental health is in its infancy, but it is clearly an area that needs a great deal more attention.
The recommendations in the new report are eminently sensible, and few would quibble with any of them. Before making any nutritional changes, always discuss them with your health care provider.
I would like to make a final point that I am going to amplify elsewhere:
If any health intervention is good for you, it should help more than one system of the body. So a diet that is good for mental health should also be good for the health of blood vessels, heart and skin. A diet like Nicholas Perricone’s, that aims to help skin aging, should also be good for the brain and the cardiovascular system. This is always a good way of checking to see if something is good for you and whether to adopt someone’s advice.
Technorati tags: Mentall health Nutrition Feeding Minds
