Believe It Or Not, Placebos And Pain Control

Placebos and pain control do not have a clear mechanism. Neuroimaging has shown that the belief in that the magic pill reduces activity in the various parts of the brain called the “pain matrix”. What doesn’t appear quite so straightforward is that a couple of other parts of the brain show increased activity, that is the medial and lateral prefrontal cortex light up.

This intrigued Koban et al who postulated that decision were being made that there were errors in the signals that the brain was processing (1). They decided on a series of experiments with 18 undergrads from Ghent who were fed a story that their brain activity was being measured to determine the effects of a regular painkiller on their ability to work an attention task on the computer.

Some had the placebo and the control group was told that the pill was a sugar pill and they were the control. So far, so good, but they were dealing with a so-called painkiller so pain had to be introduced. This was in the form of a heated pad on their arm. They had to indicate the intensity of the pain so the “effect” of the painkiller could be monitored.

Errors in the attention task showed up as potential changes in the EEG measurements. A negative potential spike occurred as an error was being made and this was followed by a positive potential spike a fifth of a second later as the awareness of the error was being processed.

Although there was no placebo effect on the negative potential, there was an increase in the positive potential spike with those making an error who had the placebo, suggesting that the cognitive circuits were working harder at processing the error in incoming signal compared to the perception of what it should be – they were doing their best at a cover-up.

So it seems that placebos work by both turning down the pain monitoring activity, but in addition increase the error handling to confirm the misrepresentation.

I wonder if our brains respond in the same manner when we are told that the new austerity measures won’t really be as painful as we think.


Ducking The Issue –2

Too many distractions for lame ducks?

3D Printed Bio-bots

3D printed bio-bots are crawling about the Heartland. Not very rapidly it is true, but at ¼mm each second, just fast enough to be creepy. The body of cross-linked hydrogel may seem harmless enough, but the power supplies were muscle cells from a rat’s heart.

The work was done in the U of Illinois and the paper by Chan et al was published in Nature’s Scientific Reports (1, 2). The bodies of the new breed of bio-bots were printed out from an acrylate-modified polyethylene glycol, which was cross-linked by UV light.

These body were printed on top of the “legs” of the bio-bots, which were also of a cross-linked polyethylene glycol, but with a lower cross-linked density so that their elasticity would be a good match for that of the heart-muscle of the lab rats destined for immortality. Finally, a layer of rat heart-muscle cells was added onto the underside of the legs.

With the beating of the heart cells with a rhythm around one beat per second, their single legs twitched back and forth kicking the bio-bots forward. In the future, control of the beating heart-muscle can be driven by chemical gradients or light as well as simple electrical impulses.

We can look forward to bio-bots creeping around with a pacemaker fitted in the base on some mission of mercy. It’s a pity that we can’t go straight to the heart of the matter and train rats for the job.


Tooth Fairy Fees

Too many teeth?

Where’s My Cloak? – He’s Looking Right Through Me

Where’s my cloak is a cry that we’re getting closer to hearing when someone wants to be invisible and move silently away unseen. We’re not quite there yet as our eyes work at the wrong wavelength. I guess we can blame the sun for that.

If its peak output that we felt down here was in the microwave region, then we might all be speaking like Cleopatra in Shakespeare’s rendition – “hand me my robe…” and we would disappear. The possibility is come close now as Landy and Smith from Duke U have built a microwave cloak for a copper cylinder which is about 3 inches in diameter and half an inch high (1, 2). It vanishes completely.

The object is considerably larger that the wavelength of the radiation and the back scattering from it would make it easily detected – imaged by the right optics. Up until now, cloaking devices have hidden the object, but scattering still occurs and the cloaked region isn’t apparently transparent but foggy.

With Landy and Smith’s new clothes for the cylinder, the radiation is guided by corrugations around the object, but the key here is that the cloak is lozenge or diamond shape and the corners are the big thing. The corners are carefully designed so that all the radiation is funneled past to illuminate objects behind the cylinder.

With no loss going and with none of the backscattered radiation lost, there I no difference between having the cloaked object there or with it and its cloak having scurried off somewhere.

Currently, it only works when the lozenge is aligned with the radiation beam so it’s not ready for radar avoidance by stealth aircraft just yet and until we can get our fabrication techniques down a few orders of magnitude, our good friend Harry Potter won’t be able to use it with visible light.


Embryonic Learning

Embryonic learning can be important (apparently) for species that are on their own once they hatch from the egg. Hatchlings of many species get help with protection, feeding and other life lessons from one or both parents, but this is not always the case.

Newly hatched turtles have to make a dash for the sea and learn on the fly. Cuttlefish hatchlings are already in the sea, but they too are on their own. Romagny et al decided to document the perception and learning of cuttlefish embryos in the latter stages of development (1,2). They have lots of stages, but stages 23, 25 and 30 were chosen for them to sit their tests.

Once they get big enough to flex their mantles, they are showing their ability to respond. They had to be taken out of their protected egg cases for their test program. They were exposed to the fishy smell of sea bass. That startled them and they flexed in consternation as sea bass like to lunch on young, succulent cuttlefish. They also weren’t very keen on being poked and prodded with a needle, blunt, of course, but nevertheless they flexed away.

Later on, they were exposed to light when their visuals were operational, and that too startled them into flexing. At stage 30, light was becoming a little boring and they would only bother flexing for a short while before quitting.

The team wondered if they were just getting tired from overwork so they decided on the willing horse solution – they spurred them on with a prod from their needle. That got them working again. They weren’t tired. They had learned that they didn’t need to respond to the light as nothing else happened. The spur, though, reminded them that they were supposed to be performing for the team of researchers and they went back to work with a will.

So it seems that it never to early to learn which side of your bread is buttered and to mind your p’s and q’s.


Anti-Phase Game Strategy

An anti-phase game strategy is often required to win in two-person sports. When we first learn any two-person sport we are usually uncoordinated at first. In a ‘sport’ like ballroom dancing we very quickly learn to get our movements in anti-phase with the other person. It matters not which role who is playing predator (moving forward) or prey (moving backwards). Alternating that phase relationship may result in severe digital consequences.

Experts will intuitively move to be coordinate phase, not just in ballroom dancing, but also in games such as tennis when long rallies develop. Not counting shot misplacements, such rallies are usually won by the player who moves to change the phase condition by moving in a different direction to place the ball in a position unexpected by the opposing player.

Kijima et al set out to study the way the dynamics and phase relationships develop in a two-person game and they present their information in yesterday’s PLoS ONE (1). They chose their university soccer team to learn a new game. (The goalie was left behind to tend his net.)

The game they had to play was called Play-Tag. It is played in a 5m square ring. (Why a square is called a ring is a subject for another day.) Each player has a chunk of nylon fabric Velcroed to each hip. The players have to rip off one of the tags of their opponent to win.  The game can be played to exhaustion. The experimental program consisted of 10 trials for each pair.

At first the players were uncoordinated as they played predator and prey and tried to work out the best strategy – should they minimize the risk of losing a tag or maximize their chance of gaining a tag?

These were all smart, able sportsmen who are used to anticipating teammates and opponents movements, but it took most of the trials before a general strategy evolved. The movement of the pairs ended up in an anti-phase coordination as the strategy to minimize their risk of loss took precedence. The result was that the anti-phase game strategy moved towards deadlock and long games.

Predator-prey alternation occurred with the players choosing a strategy in with neither have anything to gain by only changing his own strategy ­ if he does the risk is too great, hence the deadlock until a mistake through something like fatigue occurs.

These sorts of insights into game theories have applications to all sorts of other activities such as business negotiations. Even election politics when deadlock comes to the surface.