Archive for 'Brain Biology'

Does height affect our health?

If you’ve always felt a little vertically challenged, perhaps a bit disadvantaged due to your inability to see the stage in large crowds, or envied your taller counterparts who don’t have to carry a footstool in order to reach your higher cabinets, you have one more reason to feel slighted. People with shorter armspans and leg lengths have a higher risk of dementia and Alzheimer’s disease.

According to the article “Fact or Fiction?: It’s No Tall Tale, Height Matters”, in Scientific American online, people who are taller tend to be more successful and earn higher saleries. Height is associated with intelligence and educational attainment, and now, according to a paper titled “Knee height and arm span: A reflection of early life environment and risk of dementia” published in Neurology, people with shorter limbs are also at greater risk for dementia and Alzheimer’s disease and other chronic diseases as well.

OK. Full disclosure. The author of the study in Neurology was me. I learned from an anthropologist I met at a conference that limb length is primarily determined in the first few years of life. Given that the brain is also developing at that time (especially the regions involved in Alzheimer’s disease), we decided to use limb length as marker for early life nutrition to examine risk of dementia. Limb length had already been associated with hypertension and other chronic diseases, like cardiovascular disease and diabetes, and had been shown to be associated with dementia in a Korean population. Ours was the first to show the effect in a Western population.

So now, dear reader, you are probably thinking, “isn’t height genetic?” and either “but I am/my friend is/my brother is… vertically challenged, and we weren’t starving”. “Yes” I say to both questions. Height is 80% genetic and 20% environmental in Western developed countries, but the proportion of variation due to genetic factors is lower in developing countries where there are more people who can’t afford a well balanced diet. The population we were looking at was born between 1888-1924. Given that so little was known about nutrition back then, its likely that that proportion of variation due to environmental factors (mostly nutritional) was much higher than 20%. Much research has been done on the causes of stunting, and consensus by those in the field is that stunting is not determined by the total number of calories, but the quality of nutrition (the variation of nutrients and amount of protein) in the diet. Furthermore, there is still much to learn about the effects of minerals, nutrients and phytochemicals on our health. So while there are recommendations for new mothers on how to adequately feed their newborns, recommendation are continuing to evolve with more research.

I was advised that this research was not worth pursuing as “there is nothing you can do about height”. But is there something we can do about the height of future generations? “Yes we can!”. Readers can help educate young parents, contact your legislators to help fund programs that help feed young children, or donate to organizations that do. And is there something that we can do to lower our risk of developing dementia and Alzheimer’s? “Yes we can!”. For those who are vertically challenged, or have a genetic susceptibility to any disease, it’s important to keep in mind what you can change. You can make sure that you eat a balanced diet, eat plenty of fruits and vegetables, get enough fatty fish (or alternative sources of omega-3′s). You can keep abreast of current research on nutrition, exercise and health. You can consult a nutritionist to make sure that your diet contains all the essential nutrients you need to stay healthy. We need to exercise, keep their mind active, and maintain social connections.

And if you are not completely soothed by what knowing what you can do to lower your risk, keep this in mind: Being vertically challenged does not prevent you from publishing in Neurology, or from Scientific American from picking up your story!

Brain asymmetry and why it is important

As most people know, different parts of the brain are assigned different tasks. The brain is lateralized – asymmetrical, by design. And, there is a very good reason for that. The split-brain design allows us to process many things at once. We owe our ability to multi-task to the hemispheric design of the brain.

Like the human brain, many modern computers are coming with essentially 2 hemispheres, or Dual Core processors. When one processor is busy checking email, the other can be scanning for viruses. This is analogous to how brain hemispheres work.

To test the theory of the split-brain advantage, Aneglo Bisazza and Marco Dadda  of the University of Padova bred two different strains of the same species of fish. One strain was bred to have asymmetrical brains like most vertebrates, and the other strain was bred with symmetrical ones (both sides processing the same thing).

Both fish groups could handle a single task equally well, such as catching shrimp. But, if a second component was added to the mix -  a predator – the split-brain advantage became quite apparent. The symmetrical-brained fish took twice as long to catch their prey, having to divide their attention between watching for prey and catching a meal. Their asymmetrical cousins, on the other hand, were able to focus on both tasks at once, and the introduction of a predator hardly affected their ability to catch food at all.

Asymmetry is absolutely essential in order to complete the complex tasks we take for granted. In a conversation with someone, the left brain will be processing the verbal language, while the right brain interprets tone and inflection.  If you are asked to imagine a scene, the left brain will create the details, while the right brain handles the overall shapes, sizes and their spatial locations. Without both sides processing all of these details at once, we would never be able to function at the advanced level we do.

But there are also disadvantages to asymmetry. Certain tasks may be easier to execute on either the left or right side of your body. The left side of the human face tends to be more expressive because it is controlled by the right hemisphere. Most people are right-handed because the left brain is usually dominant. According to Bisazza and Dadda, the aforementioned fish will tend to guard one side of their body over the other and as a result their predators will tend to approach them from the unguarded side.

Brain asymmetry means that both hemispheres have to work closely to ensure a smooth ride, and having an overly dominant hemisphere is invariably a bad thing.  Brain damage to the right hemisphere can leave a person indifferent and uncaring, while brain damage to the left can leave them with severe depression, or without speech.

You’ve probably heard quite a lot about “hemispheric synchronization” already (just look at how many brain stimulation companies have “sync” in their names).  The word synchronization can be misleading in the context of the brain, since it implies that the two halves are processing information in the same way, which isn’t usually the case. However, brain activity can be more evenly distributed across both hemispheres. In a healthy, intelligent brain, the two halves are communicating fluently, and working closely together. There is a reduction in dominance of one hemisphere over another.

To see for yourself the manifestation of hemisphere-specific neural processing, check out the below video to see what happens when the corpus callosum, which facilities cross-hemisphere communication, is severed:

[YouTube]ZMLzP1VCANo[/YouTube]

Men think using gray matter, women with white

If you keep up on the news, you may have seen a lot of talk recently about new research that calls into question the common assumption that women talk more than men. It turns out, men talk about the same amount, or 16000 words a day. Here is a link to an article about it. Actually, men did talk less than women by around 500 words a day, but that was statistically insignificant.

In light of this, it is interesting to explore the differences between the way the two sexes think, and to analyze whether it could have any effect on language.

One such study found that men think more with what is called “Gray Matter”, while women use more “White Matter”. Men have 6.5 times more gray matter related to general intelligence than women, and women have almost 10 times more white matter related to intelligence.

Gray matter refers to nerve cell bodies, while white matter refers to the axons that transmit nerve cell messages. You could think of gray matter a bunch of little computers, and white matter as the internet.

The interesting part is that this fact doesn’t significantly affect cognitive performance. Men and women both perform equally well on a large variety of cognitive tests, although the neural methods used to reach the same correct answer may be different. Neural processing in men is more localized, while in women it is distributed, integrating information from many different areas.

“These findings suggest that human evolution has created two different types of brains designed for equally intelligent behavior,” said Richard Haier, professor of psychology in the Department of Pediatrics and longtime human intelligence researcher, who led the study with colleagues at UCI and the University of New Mexico.

However, this could help explain why certain fields are preferred by either sex. The localized processing favored by the male mind is ideally suited to mathematical processing, while the distributed computing of the female mind is ideally suited to – you guessed it – highly developed language skills.

Here is an article on the topic: http://today.uci.edu/news/release_detail.asp?key=1261

Weekly Brain Video: Thoughts on Gamma Brainwaves 70-200+ hz

Extremely high frequency gamma was previously thought not to exist because it is difficult to measure from the scalp. However, if electrodes are implanted in the brain, it becomes clear that ultra high gamma plays an important role, and could even be the dominant frequency band of the brain.

Today’s video is a lecture by Robert Knight, a neuroscientist at Berkeley, talking about his work with high gamma.

This video is (unfortunately) only available in Real Player format. Click the image below to open it.

Robet Knight

EEG research on psychedelics, or what your brain REALLY looks like on drugs

Here is an interesting study on the effects of psychedelics measured from an EEG. For those of you who lived throught he 60′s, this is what was happening to you.

Some of the results may not be what you expected.

Effects of a Psychedelic, Tropical Tea, Ayahuasca, on the EEG Activity of the Human Brain during a Shamanistic Ritual - MAPS Magazine, Spring 2001

By Erik Hoffmann, Jan M. Keppel Hesselink, Yatra-W.M. da Silveira Barbosa

Abstract
EEG data from 12 volunteers participating in a workshop in Brazil were recorded under field conditions before and after a shamanistic ritual in which the psychoactive tea, Ayahuasca, was consumed. Following three doses of the tea, the subjects showed strong and statistically significant increases of both EEG alpha (8-13Hz) and theta (4-8Hz) mean amplitudes compared to baseline while beta (13-20Hz) amplitudes were unchanged. The strongest increases of alpha activity were observed in the occipital lobes while alpha was unchanged in the frontal lobes. Theta amplitudes, on the other hand, were significantly increased in both occipital and frontal areas. Our data do not support previous findings of cortical activation with decreased alpha and increased beta activity caused by psychedelics (e.g. LSD, mescaline, psilocybin). They rather point to a similarity between the altered states produced by ayahuasca and marihuana which also stimulates the brain to produce more alpha waves. We suggest that these findings of increased EEG alpha and theta activity after drinking Ayahuasca reflect an altered state of consciousness. In this state the subjects reported increased awareness of their subconscious processes. This is an altered state comparable to, however more profound than, the meditative state. Ayahuasca seems to open up the individual to his feelings and provide personal, psychological insights, and thus it may be a valuable adjunct to psychotherapy.

Also an excerpt from the study:

EEG research of psychedelics.

The majority of EEG studies done on psychedelics appeared in the scientific journals some 30 years ago before these compounds were banned. Wikler (1954), Itil (1968) and Fink (1978) are all in agreement that psychedelics, regardless of the substance (LSD, mescaline, psilocybin), produce decreases in slow wave (alpha and theta) activity together with increases of fast (beta) activity. This low amplitude, desynchronized EEG pattern induced by psychedelics reflect an activation of the brain and is in opposition to the highly synchronized alpha pattern observed during deep relaxation. Fink (1978) found that regardless of the nature of the drug administered, EEG synchronization (alpha/theta waves) was associated with euphoria, relaxation, and drowsiness; while EEG desynchronization was associated with anxiety, hallucinations, fantasies, and illusions. Don et al. (1998) found an increase of high frequency beta (’40Hz’) with no significant change of alpha and theta activity in the EEG following the ingestion of ayahuasca. All the above studies indicate that most psychedelic compounds tend to suppress low EEG frequency activity (alpha and theta) and enhance beta activity reflecting an activation of the brain. However, other psychedelic-like compounds such as marihuana and MDMA (ecstasy) seem to have the opposite effect and increase alpha activity. In a recent, controlled placebo study, an increase of EEG alpha power, correlating with intense euphoria, was found after smoking marihuana (Lukas, et al., 1995).

Long-term effects of the use of psychedelics, using qEEG monitoring, have rarely been studied. However, in a recent study of 23 recreational MDMA users Dafters et al. (1999) found that the use of MDMA was positively correlated with absolute power in the alpha (8-12Hz) and beta (12-20Hz) frequency bands. These findings were supported recently by another study by Gamma et al. (2000) who found global increases of theta, alpha and beta power in a group of regular MDMA users compared to a control group.

You can download the full PDF version here.

Weekly Brain Video: Mirror Neurons

Mirror Neurons are a relatively new discovery, and are being touted by many as one of the most important discoveries in the last decade of neuroscience. There was a lot of media attention on these buggers last year, primarily because of what they indicate fundamentally about human social interaction.

Essentially, Mirror Neurons are built to respond to actions that we observe in others. The interesting part is that mirror neurons fire in the same way when we actually recreate that action ourselves! For example, if you move your arm up and down groups of motor neurons in the brain will fire. But, if you observe someone moving their arm, many of those same neurons will fire in the same way!

Now, if you have read the documentation of our Neuro-Programmer product, you might not be too surprised by this. One of the fundamental concepts behind the program is that neural responses to observed or imagined actions will be similar to the brain activity of actual events, and this is one of primary reasons why creative visualization is so effective. In a sense, mirror neurons have been known about and studied for a very long time. Ask any professional athletic coach about visualization and you’ll hear all about it. Ask anyone who feels like they can perform huge feats of kung fu after a Bruce Lee movie. Ask me why I can’t bear to watch the particularly embarrassing scenes from The Office.

But, it is great to see analysis going into the exact neurology behind this brain phenomenon. And not only that, but it is giving us valuable insight into brain disorders. Defective Mirror Neurons are now thought to play a role in Autism, since many Autistic individuals often have perfectly functioning brains, but seem to struggle in social situations.

Mirror Neurons are also helping to explain how humans interact, and are showing empathy to be a much more powerful and pronounced neurological process than previously thought. On a related note, in EEG tests mirror neuron responses seem to be stronger in women than in men. ;)

[youtube]WM9MaIU3zVU[/youtube]

 

Also, here is a link to another video on Mirror Neurons and Autism: http://www.youtube.com/watch?v=_8WV1zAh9zU

 

The Neurobiology of Morality

“Given the chance to get food by pulling a chain that would also deliver an electric shock to a companion, rhesus monkeys will starve themselves for several days.

Biologists argue that these and other social behaviors are the precursors of human morality.”

I’ve used this blog-space to talk about the neurology of free choice, politics, creativity and other topics that I find interesting. Yesterday a fascinating article appeared in the New York Times about the biology of Morality that I thought I would share.

Traditionally, morality has been the heavily guarded dominion of theologians and philosophers. It is also thought by most people to be a uniquely human quality. Not so, according to this article. After studying primates it seems we share with them the amazing gift of empathy, and so the place of morality in the realm of religion and philosophy could be shifting to a more biological perspective.

Here is another excerpt:

“Social living requires empathy, which is especially evident in chimpanzees, as well as ways of bringing internal hostilities to an end. Every species of ape and monkey has its own protocol for reconciliation after fights, Dr. de Waal has found. If two males fail to make up, female chimpanzees will often bring the rivals together, as if sensing that discord makes their community worse off and more vulnerable to attack by neighbors. Or they will head off a fight by taking stones out of the males’ hands.

Dr. de Waal believes that these actions are undertaken for the greater good of the community, as distinct from person-to-person relationships, and are a significant precursor of morality in human societies.”

The deeper you dive into it, the more mysterious and ambiguous the subject of Morality becomes. Even looking at it through the lens of biology, there are many unanswered questions. For example, monkeys will kill those who act or look different than them – something they are genetically programmed to do, for the better of the group – yet still something we as humans would find horrifying and certainly not moral.

The NYT article hinted at a part of the brain dedicated to morality, similar to the neural areas of Broca and Wernicke for language. But I wonder what triggers this area. What stimulus triggers the “moral consciousness” in our brains. For years the phenomenon of road rage has been studied. In the enclosed confines of a car, morality seems to deteriorate significantly, allowing people to behave in a way that they would never do were they face to face with someone. More recently, the decline of online etiquette is becoming a huge problem. Behind a screen, without a human face in front of you, seeing their emotions, seeing how they react to what you are saying to them – all of this leads to a sharp decline in moral behavior. Conversely, it has been proven that theft can be reduced by putting up posters of human eyes (you know, the kind of pictures that seem as though they are always looking at you no matter where you are in the room).

Many of you also may have heard of the famous Milgram Experiment, which studied the effects of authority on morality. It seems that if there is an evolutionary system for morality, it can break down or become transferred to a person of higher social authority.

Here is a link to the NYT article:  http://www.nytimes.com/2007/03/20/science/20moral.html?pagewanted=1&ei=5090&en=84f902cc81da9173&ex=1332043200&partner=rssuserland&emc=rss

 

Also, here is an interesting morality game you might enjoy: http://www.philosophersnet.com/games/morality_play.htm

- Adam

New brain cells in adults and the “miraculous” ability of the brain to adapt

The rules that we think govern the brain are as fickle and malleable as the brain itself. As our ability to observe the brain in action increases, new discoveries shed light on how so-called brain miracles are possible.

Most people view the brain as unchanging, like a computer that can never be upgraded or replaced. This is not surprising since we have all been taught from an early age that the brain does not produce new cells – what you are born with is what you will have when you die, provided you don’t waste your cells by drinking alcohol or sneezing too often :)

Recoveries from strokes and severe head injuries are often labeled as miracles. If you have been keeping up on the news lately, you might have heard about journalist Bob Woodruff, who was injured while reporting in Iraq. One of the doctors commented “You have no business speaking right now”, referring to Woodruff’s seemingly miraculous recovery.

The reason these miracles are possible is because the brain DOES produce new cells. In fact, it produces them all the time, as long as you live. There will never be a time in your life when your mind is not ready to change or grow.

The Scientific American blog “Mind Matters” recently explored this topic: http://blog.sciam.com/index.php?title=where_new_neurons_go_to_work_1&more=1&c=1&tb=1&pb=1

Here is an excerpt:

Neurogenesis, as this neuron creation is known, has ignited interest in all kinds of latent stem cells in the adult brain, and it comes as an enormous relief to aging baby boomers mourning neurons lost during overexuberant college days. The latest news even shows that the crop of new neurons increases after physical exercise! What a relief to know that you can repent and repair simply by jogging around the block if you wanted to.

The Plasticity of the brain, or it’s ability to “rewire” itself, has also been studied for some time. When a part of the brain is injured, other parts of the brain can compensate. One amazing example of this is the case of Sarah Scantlin who was in a vegetative state for 20 years before she miraculously began to speak in 2005.

One very intriguing (and controversial) example of brain plasticity is an experiment involving monkeys and joysticks. The brains of the monkeys were wired up and recorded as they used a joystick to control a virtual display. Eventually, the monkeys realized that they didn’t even need to use the joystick. The brain had literally rewired itself to control their virtual arm as well as the real one! This is called a Brain Machine Interface, and you can see this particular experiment in action by viewing the video I posted here.

 

An example of this in humans would be the use of the tongue’s nerves to transfer visual information, giving sight to the visually impaired. The tongue is actually one of the best information pathways to the brain. Here is an article on this neurotechnology breakthrough: http://www.sciencenews.org/articles/20010901/bob14.asp

Lack of sleep prevents brain cell production, and midday napping strengthens the heart

Recent research reported by the BBC suggests that missing sleep causes the brain to stop producing new cells: http://news.bbc.co.uk/1/hi/health/6347043.stm

This research focused on a region of the brain called the hippocampus, which is involved in memories. I’ve spoken with many insomniacs who also suffer from memory loss, along with depression and a host of other problems. A short relaxation session can work absolute wonders for these people, and if a normal sleep pattern can be restored many (if not most) other issues simply evaporate. I often wonder how often sleep deprivation is the root cause for many psychological issues people grapple with. Insomniacs aside, most people I know do not get enough sleep.

There was also some recent buzz about a study at the University of Athens Medical School which indicates that a short midday nap may reduce risk of heart problems by up to 64%!

Some employers have started installing special recliners in the office, specifically designed for cat napping. Now all they need is a brainwave entrainment session for that unlucky majority that can’t nap on command. ;)

Article on Prosopagnosia (face blindness)

I mentioned “Face Blindness” in another recent entry. As a follow up on that, there is an interesting article about it today on CNN.com:

http://www.cnn.com/2007/HEALTH/conditions/02/02/face.blindness/index.html