Friday, 18 December 2009

Friday, 11 December 2009

Lies, damned lies or statistics?

Here's the link to a thoughtful piece on what really matters in the climate debate: data and not mere presentation or personalities. It seems as if there is frequently a fundamental misunderstanding about the scientific method, with either each experiment individually being characterised as delivering some kind of fundamental truth or it being dominated by personal biases and human failings. The truth, as ever, falls somewhere in between (cf. a possible future post on our incessant desire to dichotomise).

Thursday, 12 November 2009

Muscle aches and vibrators

I am sitting at my desk, my legs are gently aching and I can feel - slowly but surely - that the muscles in my upper body are stiffening as well. As long as I stay absolutely still everything is alright, but as soon as I move my body protests heavily. My condition has a name: delayed onset muscle soreness or DOMS.

This highly common phenomenon usually presents itself 24-48 hours after an intense work-out of muscle groups that are not used to exercise. Though it has a slow onset, DOMS comes with a vengeance: it causes a weakness in the muscles that leaves you to wobble around, it drastically reduces the types of movements you are able to make, and the energy levels in you muscles are lower. What I find most shocking though is that it can last from 4 up to 7 days!

According to popular belief the pains are caused by lactic acid in the muscle, but no scientific proof has been given for this idea. The real cause has still not been unveiled. However, it is generally thought that the damage done to the muscle tissue causes inflammation of the muscle and the inflammation is what gives you pain.

Stretching your arms far away from your body to catch that impossible ball or trying a high kick are likely causes of DOMS. These actions require an extension of the muscle and in an untrained muscle may perhaps result in small tears in the muscle tissue. The weakest, most likely to be affected spots in your body are those places where muscles join tendons, but it is by no means limited to these places alone. In due course the soreness can, and often will, spread through the entire muscle.

What yields for every disease or disorder applies here too: not knowing the mechanisms behind DOMS does not make the search for cures and therapies easy. Many types of treatments have been tried and failed. Some non-steroidal pain killers such as ibuprofen may alleviate the soreness by damping down the inflammation. Massage techniques may, if applied at length, help too. Bathing in ice is – thank goodness – not a scientifically proven method to cure DOMS. There is one glimmer of hope though. An Australian research group at the university of Victoria in Melbourne found that when vibrations are applied to heavily exercised muscles, soreness does still occur, but to a lesser extent.

So, apart from using my vibrator to cause a buzz in my muscles, there is not much I can do. And even if there was, I wonder if I would. In a weird kind of way, I find this pain quite satisfying and addictive.

Sunday, 8 November 2009

Brains powered by light

In the 1920s Felix the Cat had a brilliant idea and over his head a light bulb appeared; thus was created the signature of an epiphany. But recent advances in neuroscience leave you to wonder whether in the future a light bulb will be seen as the source of such inspiration rather than just the visual metaphor.

In the 1990s Peter Hegemann, a German biologist, discovered that green algae commonly found in ponds respond to light by wagging their tail, an interesting phenomenon given that they do not have eyes. When light photons hit the protein coils packed in the algae's cell membrane, a chemical reaction created a tiny gap, causing an ionic current to be produced and the algae's tail to wag. The protein that allowed this reaction is channelrhodopsin-2.

Some years later, American researchers started to wonder whether a similar mechanism could be used to control brain cells if certain neurons were made to behave somewhat like algae. By genetic engineering these scientists were able to do just this: not to make brain cells move but, using channelrhodopsin, to turn them on or off simply with light. The field of optogenetics was born.

What is so beautiful about this technique is that, by harnessing the cunning of viruses, it is possible to make the channelrhodopsin-encoding gene only be expressed in particular targeted neurons. And so far the results have been startling. Flies have been made to jump, mice made to walk in a certain direction, and both to remember events that never happened, all through the power of light. Optogenetics could therefore open the door to precise therapeutics in diseases such as Parkinson's disease and schizophrenia where presently only drugs or surgery can help, neural sledgehammers compared to the surgical scalpel enabled by light-controlled tools.

If its promise holds up, a bulb over someone’s head may someday be seen in a completely new light.

Thursday, 29 October 2009

A long time ...

It has been a while since I last posted something on my blog thanks to a lovely long holiday in Turkey and a conference in the US, but I am back now and eager to do some more science writing.

I am going to start off gently by just pointing you to an interesting article I read in New Scientist this week about how in a scary situation it can feel like time slows down and the agony suffered seems to last for much longer [than it actually does]. Can it be that, in a scary situation, our brain works faster as a result of flight or fight? Or do we create memories about such events that are much more precise and therefore seem longer?

David Eagleman, a neuroscientist at Baylor College of Medicine in Houston, Texas, looked into the issue of the slowing of time by letting his colleagues experience a thirty meter free fall - a scary event over which you have no control. Afterwards he asked them to indicate how long they felt the fall had lasted for. All estimated times were about twice as long as the actual duration of the fall. I have uploaded a video to give you a sense of the experiment.

Proving that we perceive time slowing down in such scary situations is one thing, finding out its cause is a wholly different issue, one that is discussed in the New Scientist article 'Timewarp: How the brain creates the fourth dimension'. The mechanism that keeps track of time may well be important for the understanding of diseases where people experience delusion, such as schizophrenia.

David Eagleman's interest in time does not stop in the past and present. In his recent book SUM ('I am' in Latin) he deals with the more existential issues of the afterlive.

video

Tuesday, 18 August 2009

Rewire your brain after a long period of stress

We all know that stress can be very bad for your health, with post-traumatic stress syndrome being one of the severest expressions. Stress causes the release of cortisol in our blood stream. Cortisol is a hormone involved in many important functions in the body such as the regulation of our metabolism, regulation of blood pressure, maintenance of blood sugar levels, and it has an important immune function. 

Cortisol is often dubbed the stress hormone because it serves an important role in 'fight and flight' responses to potentially threatening situations. Small increases in cortisol can have very positive effects in situations where split-second decisions have to be made in order to survive. It can give that extra bit of alertness to dodge a punch or prevent a car crash, it heightens your memory temporarily, it briefly increases immunity and it even makes you less sensitive to pain.

Unfortunately, when the cortisol levels in your blood are constantly high as a result of ongoing exposure to stress, they can lead to many physical problems such as blood sugar imbalance, a decrease in bone density and muscle tissue, high blood pressure, a lowered immune system, and even impairments in your cognitive abilities such as memory and perception.



Scientists from the university of Minho in Portugal showed that the plasticity of the brain of rats under constant pressure diminished significantly. Four weeks of stress made the rats less flexible in solving problems in order to get their rewards. They would persist with one possible option and not try to explore other ways of getting their rewards, unlike their unstressed controls who would try to get to their goal in any way possible.

They did find that there is some hope though. After four leisurely weeks the rats started behaving more like the controls again, and their brains seemed to rewire too. You can read more about this research and on the New York Times website in the Science section.

Wednesday, 12 August 2009

Thursday, 16 July 2009

Was Darwin really right?

There are numerous theories and stories about the very beginning of the earth and human life, some more believable than others. Darwin's evolutionary theory is widely believed to be closest to the true evolution of the earth and its past, present and future inhabitants, but is this theory really true? Or does our strong belief in this theory cloud our vision? Does it stop us from exploring other possible origins of life? Listen to yesterday's 'A life with ...' for an interview with Lynn Margulius, biologist and professor in the department of Geoscience at the university of Massachusetts. Professor Margulius, in stressing the importance of symbiotic relationships between species, opposes to the very foundation of Darwin's evolutionary theory where there is always competition for survival.

Saturday, 11 July 2009

Run run run!

Here's a link to a very interesting article in the New York Times about a woman who had a small piece of her brain removed to relieve her from the many epileptic seizures she suffered from.
Brain Surgery Frees Runner, but Raises Barriers

Tuesday, 7 July 2009

A simple drug for Alzheimer's disease?

Alzheimer's disease is the most common form of dementia, affecting 1 in 10 people over the age of 65 and 1 in 5 over the age of 80. This truly debilitating disease gradually reduces the patient to living in the past without the ability to make new memories, and is not only devastating for the patients and their families, but is also a heavy burden on our health system.

Researchers at the Florida Alzheimer's Disease Research Center may have found that one of the most harmless and commonplace 'drugs', caffeine, may have a positive effect on the cognitive abilities of patients who suffer from the disease. The research group studied 55 mice that were genetically modified to develop Alzheimer's disease. After the mice had developed the disease, half of the group was given 500 milligrams of caffeine – the equivalent of 5 cups of regular coffee - in their drinking water every day. The other half did not get any caffeine. The researchers showed that caffeine improved memory and thinking abilities significantly after only two months of treatment, and were able to perform as well as healthy mice of the same age. The mice that had not received treatment continued to deteriorate.

The main cause of Alzheimer's disease is the formation of tangles and plaques in the brain, causing brain cells to die and communication pathways to be disrupted and destroyed. Broadly speaking, there are two enzymes responsible for the formation of the plaques and tangles, tau and amyloid beta/β. Plaques are formed by large clumps of amyloidβ in the spaces between cells. Tangles are formed by tau. Tau, normally a building block of the transport system of a cell, starts to disintegrate this transport system as a result of a chemical change, causing damage to the cell's nutrition- and communication, eventually leading to the death of the cell.

In patients with Alzheimer’s disease, an abnormally high level of amyloidβ is found in the blood. The study published in the Journal of Alzheimer's Disease this week shows a remarkable decrease – nearly 50% – in the abnormal levels of this protein in the blood and brains of mice treated with caffeine. Thus, the improvement in memory and thinking thus seems to be related to the decrease of tangles and plaques in the brain.

Although mice, needless to say, are quite different from humans – and the development of the disease is different in both species – these results are really promising. The first very preliminary results from tests in elderly people indicate that levels of amyloidβ decrease rapidly after treatment with caffeine.

But don’t think you will be able to boost your memory by drinking coffee; when healthy mice drank 500 milligrams of coffee each day, their memory did not improve. So though we may have a wonder drug to cure one of the most debilitating diseases of our time, alas, we still haven’t found a way to become smarter.

Saturday, 6 June 2009

The reptilian brain: the new left brain, right brain?

Over the past couple of weeks I have heard a number of different people on the radio – a scientist in one case, psychologist in another – talk about our intuitive brain, our reptilian brain, our emotional brain as if it were a separate entity within our brain. Slightly surprised by this idea, I decided to look at it in a bit more detail – surprised because my conception of the brain as someone who has studied it is that of an integrated, unified entity in which different regions throughout are working together in order to perceive the world, make sense of it and act in it appropriately. The idea of the existence of a special system dealing with our emotions and intuitions seems counterintuitive in a system where every single part works together with other parts in order to think, act, memorize, speak.

We like to believe that the decisions we make, the actions we take and, at least sometimes, the thoughts we have are based on rational weighing up of pro’s and con’s. Equally, I think that most of us would admit that at times we do things because our gut feeling tells us to do so. This idea is not a new one; even Aristotle suggested that a logical decision can be overturned by mere appetite for pleasure or anger. But even if there is the existence of gut feeling alongside reason, does this mean we have a separate set of brain regions to deal with our different states of mind?

According to a number of researchers, it does. Several groups of prominent neuroeconomists, such as Douglas Bernheim and Antonio Rangel, have proposed models that describe the brain as operating in a “cold” deliberative mode or a “hot” emotional mode, depending on the situation in which a decision is being made. Based on the anatomical structure of our brains, back in the 1960s Paul MacLean proposed the influential theory that we have a ‘triune’ brain consisting of three parts, each formed at a different time in evolution. In essence, he too argued that our brains contain ancient reptilian fight or flight mechanisms, animal instincts and emotions, and new thoughtful cortex to offset these other urges.

While some of these principles are generally accepted, the existence of entirely separate systems underlying emotional, intuitive impulses on the one hand and rational considered behaviour is more controversial. Nonetheless, the notion of a direct anatomical basis for separate intuitive and rational systems seems to have caught the public imagination. A quick Google search on “reptilian brain and decision” brings up numerous self-help and business-based writings about how to tame your reptilian brain, live with your emotional urges and stop it buying your Starbucks lattes.

It doesn't seem too long ago to me that another dichotomous idea from neuroscience, that the two halves, or hemispheres, of our brain have highly specific functions, was providing this market with these metaphors. Again, the science suggested (not without challenge) that left part of the brain was the dominant linguistic side, cold and calculating and dealing with details (the cognitive side) whereas the right was the imaginative but suppressed side that dealt with the global processing of information and emotions (the intuitive side). And again, this spawned a large industry of self-help and business books on everything from how to unshackle your right hemisphere in order to become more imaginative and even to help us get in touch with the opposite sex.

Looking at the persistence with which ideas of a separation between intuition and reason have popped up in the past and present, is it likely whether these theories will ever fade? Or does our hunger to become a better person – more creative or more logical – make us embrace the idea of separate systems because we feel they give us (false?) opportunity to enhance certain qualities in ourselves to make us into the person we want to be?

I wrote this article for 'Matters Scientific', the science blog of Cherwell, the Oxford University student newspaper.

Wednesday, 13 May 2009

Neuroeconomics

Why are you reading this? Perhaps you found the Oxford Student in the JCR and are trying to take your mind off that all-too-nearby exam. Or maybe you spotted someone else reading it intently. Or, more likely, you picked it up as it was there, and, as we all know, anything free is good. It may surprise you that how we make such decisions is engaging some of the finest minds in three disciplines - economics, psychology and neuroscience – resulting in the invention of a new field of study: neuroeconomics.

Economists have long thought that we calmly weigh our decisions, thinking out all possible short- and long-term consequences, and always choose the option that will give the best results. Homo economicus drinks in moderation, never smokes, does the laundry and ironing, and never wakes up next to someone who only seemed attractive the night before, right?

That's where psychology – or common sense – comes in to point out that this is a terrific model of a saint/robot but might fall down for you or me. But psychologists themselves do not always seem attached to the real world, spending their time researching fractional differences in response times, for instance, when your hear the name of a dog if your arms are crossed – hardly everyday occurrences for us or homo economicus. And with neuroimaging, psychologists now demonstrate that certain parts of the brain (rather than say the liver) light up when hearing dog names if your arms are crossed too.

But, put these ingredients together and something exciting occurs. Economists and psychologists start to consider how real people might make irrational decisions. Neuroscientists look in the brain and find reasons why this may happen.

Here's one example. I shop on eBay, and am often willing to pay more than I ought. Why am I so irrational? Neuroeconomists show this is perfectly natural; in a social context we never want to lose out. No way someone else is going to run off with my shoes! And for this we can blame our brains: a small clump of cells which values the important things in life (food, drink, sex) tells us that winning against competitors is worth more than the shoes themselves.

But does wanting to win make us losers? Perhaps. As someone once said, “Success is getting what you want. Happiness is wanting what you get.” Neuroeconomists are well on the way to making our irrationality seem logical - even if our logic may forever remain irrational.

Wednesday, 29 April 2009

The autistic gene

When my nephew was 9 years old he was obsessed with taps. Whenever he saw a tap, he had to turn it on. He has always been very good at drawing, he likes to draw even the smallest details you and I would miss. And if you want to know what day of the week March 23 is in 2050, just ask him and you will get the answer within seconds. He is a grown man now. He does not have many friends, he prefers being on his own. He has autism.

This week a study in Nature revealed evidence for a link between a specific gene and the development of autism.

Autism is a so-called neurodevelopmental disorder whereby the normal growth patterns of the central nervous system and the brain are altered. This abnormal development often results in learning disabilities, and social and emotional problems.

Over the years, there has been a lot of speculation as to what causes the brain and nervous system of autistic people to develop in a different way compared to the normal development. This has led to outrageous speculations about the lack of oxygen at birth, and to masses of people refusing to vaccinate their children with the MMR vaccine to protect them from getting measles, mumps and rubella, because of a falsely assumed link between autism and the vaccine for which no-one ever found any convincing evidence.

More controlled research has recently led to the discovery that the abnormal development seen in autism is especially affecting frontal regions of the brain. With the help of these regions we make plans and decisions and they do also support our interactions with other people. Another important discovery about the structure of the autistic brain is that there are a smaller number of pathways used for communication within the frontal lobes and between the frontal lobes and other regions in the brains of autistic people.

The article in Nature describes how in a group of 10.000 subjects consisting of autistic patients and their families, common genetic variants on 5p14.1 were identified. This gene has been tentatively linked with autism before, and this study confirms its importance in autism.

Thus, this study does not only show us the gene involved in autism, we can also derive from it that the class of genes to which this specific gene belongs is important for the normal development of structure and communication pathways in the healthy human brain.

Having a gene to hold accountable for autism does pose some ethical questions; with genetic screening it is possible to look at the genetic make-up of the unborn child and you could, based on the results, decide whether to proceed the pregnancy, or that, maybe, it's better for everybody not to have the child ... But given that the development of autism is not solely dependent on the genetic expression and there is a likely chance your child will be completely healthy, do you really want to make these decisions? And do we really want to rid the world of the Lewis Carrolls, Glenn Goulds, Beethovens, Vincent van Goghs and Wittgensteins, all of whom are suspected to have had autistic traits?