Keep your eye on the ball

For all purposes, our nervous system has one hell of a difficult task to accomplish – it needs to take in numerous stimuli all occurring either simultaneously or in some sort of temporal order and determine if there is a pattern worth responding to. While other tissues only need to make a few hormones or make some polymer twitch, neurons need to be constantly opening and closing protein gates to balance various ions. In other words, your brain does a lot of work, and therefore uses the lion’s share of energy your body takes in to do so.

Change blindness is one of those classic demonstrations of the gaps that exist in our perception where our nervous system has evolved to take a bit of a gamble. While the specific neurology of it is still questioned, it is an indication that sensing visual information isn’t the same as observing it, and our short term memory isn’t always as reliable as we might believe. A flicker, or momentary change of attention, is all it takes to reset our comprehension of what sits in front of us in plain sight. Take this aircraft, for example. It might take you a while to notice what is missing*.

Psychologists from Harvard University have demonstrated a rather interesting illusion which goes further in showing how easily overwhelmed our perception can be through simple change and movement. There findings are due to be published in Current Biology.

Watch the clip below by paying close attention to the cross in the middle. The dots will change colour for about five seconds before the surrounding ring begins to rotate back and forth.

Now, watch it again, only this time watch one of the coloured dots. Where before they appeared to cease changing, on closer observation they do nothing of the sort.

Why?

The phenomenon has been termed ‘silencing’, and describes how it’s difficult to recognise change in a moving object. There could be two reasons this happens. One is that the observer sees the original state of an object and simply doesn’t update it with the new information (termed ‘freezing’). The other possibility is that the observer sees whatever the current state is, but doesn’t mark a change between the two therefore isn’t aware of any moment of difference (known as ‘implicit updating’).

Both explanations are shown to occur with other forms of illusion. But the results of the study indicated that the illusion is a case of seeing different colours without seeing them change.

The likely reason for this has to do with how our retina maps onto our brain. As a moving image drifts across the back of our eye, it proceeds to activate a line of photoreceptors, which in turn send those messages to a corresponding line of tissue in our brain’s visual processing system. Normally, a static, changing image will prompt a nervous reaction that says ‘this pattern isn’t like it was before’. But, if it moves quickly enough from one patch of neurons to another, the same resources aren’t capable of performing this act of recognition.  To do so would demand something a little more complicated than we currently have.

If the eye tracks the changing object, however, the object remains on the same section of retina, allowing it to persist long enough in the corresponding section of the visual processing system for a variation to become apparent. The take-home-message from this is that if your eye isn’t tracking it, change simply isn’t important enough for the brain to waste energy on bringing it to your awareness.

Yet another example of how our circuitry isn’t wired for truth, but rather for economy.

*Check out the engine beneath the wing.

For additional illusions used in the study, see this Harvard website.

If you please – just don’t lie

Believe it or not...it still might make you feel better

When it comes to alternative medicine, there is arguably no greater misunderstood phenomenon than the placebo effect. It’s not uncommon to hear it feature as a defence supporting the efficacy of treatments that otherwise have no evidence for performing as claimed. It is the modicum of benefit that is proferred when it has been scientifically determined that a touch, tincture or totem has been shown otherwise impotent.

Much of the present common understanding of the effect stems from a 1955 book titled The Powerful Placebo by Henry Beecher – an American anaesthiologist who stressed the need for double blinding in clinical testing and was the first to attempt to quantify the placebo’s action. While the placebo effect is argued to be a significant confounding factor in determining useful from useless treatments, Beecher presented the placebo effect as clinical, citing data that demonstrated a percentage of patients were ‘satisfactorily relieved’ by sham treatments.

Since then, other studies have suggested the placebo effect is physiological – that in spite of having zero bioactive components, the act of treatment alone can still help improve a patient’s biophysical functioning. For example, in a 1977 study stomach ulcers were found to have decreased in size following a placebo treatment.

On such evidence, it seems that the mind truly holds sway over the body’s matter. By merely perceiving a treatment works, an individual’s biology will make a greater effort to fix itself.

Yet there is an increasing amount of evidence showing that the placebo effect – or at least, this interpretation of it – is a myth. Any influence a sham treatment has over the variables can be reduced to psychological factors, with past studies falling foul of poor methods.

However, in the very least, it still leaves room for inactive treatments to make patients believe they’re feeling better. And, given western medicine primarily concerns itself with the individual patient ‘s sense of wellbeing, it might be argued that placebos could be used to placate a patient where no other treatment is available.

Ethically, such actions are highly questionable. Few physicians would feel comfortable duping a patient into thinking they’re receiving a treatment, when in fact they’re getting a fake pill or potion. Not to say this has stopped some from administering fake treatments without patient consent.

A new study now shows we might have the wrong end of the stick altogether – that any psychological bias towards placebos comes as a result of its superficial resemblance to treatment. Giving rationality too much credence, it was assumed that a patient needed to suspect that their treatment was legitimate. Instead, it seems the same effects might arise regardless of whether the patient knows the treatment has no bioactive components, putting lie to the claim that ‘it’ll work if you believe it will’.

Ed Yong has a great write-up on the study at his blog. While the study’s method left room for plenty of questions, if its results are legitimate it demonstrates that simply engaging in medical ritual might be enough to bias a patient’s disposition towards their wellbeing. The patient needn’t be led to accept there is a biophysical foundation to the ritual – just that there is a semblance of medical intervention.

The precise limits of the placebo effect and its cultural relationship remain fuzzy. Whether it will ever be an ethical approch to medication is hard to ascertain. However, knowing that a personal rationalisation might not be necessary for a patient to benefit from medical ritual is a positive step to better understanding how the way a patient is treated can be as important as the treatment itself.

 

 

Microbial melodramas make for good soap

There might be no ‘I’ in team, but there is definitely one in ‘bacteria’. While microbes aren’t traditionally recognised for their altruism, James Collins and a team of researchers from the Howard Hughes Medical Institute have found individual bacteria can pay a price that ultimately benefits others in the colony.

The text-book microbe competes in a bug-eats-bug world, where a subtle physiological variation in a select few can make the difference between a population’s survival and its annihilation. As the mutants come to represent the majority, resistance to old threats increases. Whether it is antibiotics or plain old disinfectants, chemical warfare loses its punch when a few bacterial mutants come to represent the species.

However, these new findings (Nature, Vol467, pg82) demonstrate the bacterial struggle for mutant dominance might not be so selfish. In an effort to observe how genetically identical bacteria developed the initial variations, Collins and his team subjected a population of cloned Escherichia coli to a steady gradient of the antibiotic norfloxacin. Routine tests of sample bacteria were taken to record the minimum concentration of antibiotic that would halt their growth.

On comparing the samples with their home population it was revealed that the very act of removing bacteria decreased their resistance to norfloxacin. Stranger still, individuals gifted with the ability to deal with the chemical attack were in the extreme minority, making up less than a mere one percent of the colony. Their talent lay in their ability to produce tryptophanase, an enzyme that breaks the amino acid tryptophan down into the chemical indole. Fortunately for its less capable siblings, an increased concentration of indole in the environment helps switch on useful metabolic pathways that combat the antibiotic’s effect, allowing the rest of the population to benefit.

Of course, given there is no such thing as a free lunch, the production of this enzyme requires the devotion of precious energy. ‘Kin selection’ is one explanation for this behaviour. A process first suggested in the 1960s by the evolutionary biologist William Hamilton, it suggests individuals act altruistically to increase the chance of survival and reproduction for those with a close genetic relationship.

What, then, of their nefarious counterpart, the bacterial bum? Led by Steven Diggle at the University of Nottingham’s Centre for Biomolecular Sciences, microbiologists have found that individuals within a population of Staphylococcus aureus can opt to coast along for the ride when it comes to contributing to the costs of an infection.

After deliberately infecting waxworms with the bacteria, the researchers eavesdropped on the developing colony by observing a chemical coordination process called ‘quorum sensing’. They discovered those which lacked the means to engage in this microbial forum could also refrain from making toxins, saving them energy which could be devoted instead to reproduction. In effect, these bacteria were relying on their siblings to provide them with their nutrients. Seeding an infection with these freeloaders could present physicians with a novel form of treatment.

While this could be great news for the medical world, it does present a rather perplexing contrast to their more charitable cousins. Understanding how microbes interact with their host’s environment is vital if we are to find additional ways of controlling infection. Just last year, the World Health Organisation released a warning concerning the potential threat posed by the NDM-1 strain of E. coli – a potential superbug that is on the rise across the globe. It could very well join the likes of more familiar foes such as the vancomycin-resistant enterococcus and the rather formidable methicillin-resistant staphylococcus aureus.

Paying attention to the melodramas unfolding in these microbial ‘Days of our Lives’ is certainly better than any daytime soap. What’s more, it might be the key to turning the tide on the twilight of the antibiotic.

Better than any Da Vinci code

For all of my passionate fascination over use of symbols and optical illusions in art – especially in historical paintings – I’m usually hesitant to give much credibility to claims of hidden meanings or codes embedded in the works of the ‘masters’. I’ve never been convinced that Da Vinci was dropping some subtle hints in his famous depiction of the last supper, for example. Nor do I think there’s anything mysterious about the Mona Lisa, other than the fact that Da Vinci had an amazing talent for the use of sfumato. And don’t get me started on the legendary ‘golden ratio’ that can be found anywhere you care to look hard enough.

But there has always been something rather odd about the depiction of God in Michelangelo’s Sistine Chapel ceiling work. The painter knew his way around the folds and crevices of the human body thanks to his experience cutting into corpses as an adolescent, and his anatomical knowledge was evident in both his paintings and sculptures. Every bulge, lump and node correctly corresponds to the subcutaneous landscape of your typical man or woman.

Now, maybe God simply has a bung neck, according to Michelangelo. Or a goiter. While it’s possible that The Lord hasn’t had enough iodine thanks to a diet rich in ambrosia and low in haddock, a professor of neurosurgery at the Johns Hopkins University School of Medicine seems to think the Renaissance genius turned Our Heavenly Father’s larynx into a cerebellum. In other words, there’s the faint image of a brainstem overlaying God’s trachea, chin and beard in an anatomical version of ‘find the hidden animals’.

God's goiter was a master at solving sudoku puzzles.

My first thought was to account for pareidolia, which remains a distinct possibility. But in this instance, I suspect the good neurologist might be onto something. Unlike the common ‘Christ is risen damp’ and ‘Mary in a biscuit’, or the demonic giraffe that lurked in my childhood wardrobe door, there’s a pretty good match for each of the brain bits and the deity’s upturned head. There’s been past speculation that the billowing cloth surrounding God and his chorus of seraphim in the famous ‘Creation of Adam’ is a brain seen from the side, indicating Michelangelo might have had something of a cerebral fetish. Or he simply thought there was something profound about connecting such a divine scene with a map of our grey matter.

God had spent all morning rubbing his feet along the carpet - this one was going to be a cracker!

As with most artists, we’ll never really know what he was thinking. But there is something about this Renaissance connection between God and the human brain I find rather appealing. Maybe I should write a best-selling pulp-adventure novel based on an academic neurologist who finds the Church is trying to hide the truth about God being a figment of our imaginations? Nah…who would want to read anything so blatantly ridiculous?

Which came first: good science or bad headline?

Chicken Caesar: not of egg was born.

If you’d been in one of my senior biology classes, chances were you would have had the question ‘Which came first; the chicken or the egg?’ as a complex reasoning question on one of your mid-semester exams. I found it to be a great way of assessing the student’s understanding of principles of evolution.

To get full marks, the student had to comprehend that somewhere during the ancestry of the species we call ‘chickens’ today, there came sufficient evolutionary change to warrant a new species. In other words, while this precise point might be debatable as far as what defines a species, a bird-thing that couldn’t be called a chicken produced an egg, from which hatched something with the characteristics of the modern chook. Even if the students didn’t get that far, they’d get a mark or two for realising that the egg defines a characteristic of the embryonic bird.

Now, as a science writer, I completely sympathise with a journalist’s desire to use a lede or a heading that draws the  attention of an audience that is too often intimidated by anything that sounds overly ‘sciency’. The age-old pseudophilosophical ‘which came first’ conundrum is a light-hearted riddle that most of us find to be familiar. If only it made sense in this particular case, with such head-scratching headers as They’ve cracked it at last! The chicken DID come before the egg and Scientists think chicken came first, I might have merely ignored it as another cheesy attempt at making science look appealing.

The science behind the story is actually quite interesting; British chemists at the University of Sheffield and the University of Warwick developed a computer model  showing that egg shell production is reliant on a protein called ovocleidin-17 which serves as a catalyst, creating a nucleus for calcium carbonate particles to crystalise and form the egg’s hard shell. Not exactly the cure to cancer or alien contact, but not the most boring discovery to have ever been uncovered in a laboratory.

But what does this have to do with the chicken coming first? Is it presuming the early embryo is an eggless chicken, and it’s only with the latter formation of a hard shell that we can say the egg then develops? Perhaps…but for a gimmick headline, it is an unnecessary addition that risks confusion for the sake of an ice breaker. Worse still, in situations such as these, the line between a glib, light-hearted angle and a serious scientific question can be blurred. While I’m no longer teaching, I can almost imagine a student earnestly presenting such a headline as serious evidence for ‘chickens coming first’, not understanding that the research and the riddle are as related as a knock-knock joke and the science of acoustics.

Nobody says science always has to be serious. Humour can be extremely effective at grabbing attentions. From the popularity of the angle’s use throughout the media, it’s easy to presume it was lifted straight from the press release, and few journalists (in their rush for a deadline) would be tempted to spend precious moments considering an alternative. But the cost is misrepresentation of otherwise good science and public confusion over the real issues that scientists deal with.