Spitting Cobra anticipates your every move

The spitting cobra – feared for its ability to blind by spraying venom into the eyes of its victims – anticipates the movements of its target, ensuring its venomous spray hits the mark every time.

It's watching you... A red spitting cobra. Image: Pogrebnoj-Alexandroff/Wikimedia

There are several species of spitting cobra, all of which live in Africa. None of them can control the direction of the stream of venom they can fire from tiny forward-facing holes in their fangs. Instead, the snakes must move their entire head to track the target. At the moment of attack, however, the snake stops tracking and instead anticipates where the targets’ eyes will be 200 milliseconds later – the length of time it takes the snake to launch the venom.

A team of German and American scientists spent six weeks goading a spitting cobra to fire streams of venom at a researcher wearing a protective mask while they filmed the snake using a high speed camera to capture 500 frames per second. They found that a sudden movement from the target triggers the spitting attack. At this point the snake can be reasonably sure where the target will be by the time the snake can release its venom, ensuring the venom lands with pinpoint accuracy.

The spitting cobra’s predictive skills are surprising as the precise planning required to do so was thought to be beyond its relatively simple reptilian brain.

So how can you ensure the snake doesn’t spray venom into your eyes should you ever encounter one? Simply don’t poke it with a stick, or disturb it in any way. Spitting cobras don’t use their venom spray aggressively; it’s purely a defensive strategy used to deter predators and other irritating large animals…

Paper Reference: Westhoff, G., Boetig, M., Bleckmann, H. and Young, B. A. (2010). Target tracking during venom ‘spitting’ by cobras. Journal of Experimental Biologists. 213, pp 1797-1802. doi: 10.1242/jeb.037135

Mind-reading machines shed light on human memory

Computers can read our minds! At least they can if we’re in an fMRI scanner and the computer just has to work out which of three videos we’re thinking about.

Can you tell what she's thinking? Image: NASA

The research, carried out by British scientists, examined brain activity in the hippocampus, an area of the brain responsible for recording ‘episodic’ memories. Episodic memories are quite complex, recording details of our everyday experiences, and this is the first time anyone has shown it is possible to ‘read’ them based on brain activity.

The scientists designed a computer algorithm to analyse fMRI images of brain activity in ten volunteers. The computer could tell which of three short videos the volunteer was thinking about more often than if it was randomly guessing, which suggests that memories are recorded in a regular pattern.

fMRI works by showing changes to blood flow in different areas of the brain. Changes in blood flow show changes in brain activity – as hard-working neurons need to be supplied with oxygen to keep them working. The pattern of blood flow in the volunteers’ brains changed as they recalled one of the video clips they had been shown earlier, each of which showed a woman performing a normal activity such as drinking coffee.

The results not only demonstrate that memories are predictable, they also show where in the hippocampus episodic memories are recorded, as three areas of the hippocampus were active in all of the volunteers tested. Unfortunately the precise roles of the three areas are still unclear, although scientists believe one of them is involved with our spatial memory.

Understanding how memories are formed, and where they are stored, could help us to understand how memories are lost as we age or through brain damage or illness. But is there a more sinister application to computer mind-reading? Very targeted advertising could be just the beginning…

Paper Reference:

Chadwick, M.J., Hassabis, D., Weiskopf, N., and Maguire, E.A., (2010). Decoding Individual Episodic Memory Traces in the Human Hippocampus. Current Biology, Published online: March 11, 2010. doi:10.1016/j.cub.2010.01.053

Regular gamers have rapid reactions

Many computer games require quick reactions: whether it’s negotiating a hair-pin bend or dodging the swing of a Minotaur’s axe, the faster a player can react, the better they’ll do. It also turns out that the quick reactions learned in action-heavy games carry over to real life, according to a recent study by American researchers.

Are all of those hours playing games good for you? Image: Hypothesisnow

By looking at many different studies published by others, the researchers compared the reaction times and accuracy of regular action game-players to those of novice gamers. Regular action game-players performed, on average, 11% faster on a range of tests designed to measure reaction times.

So gamers are fast, but do they gain their speed boost at the expense of accuracy? The data would suggest not. In fact, the accuracy of both regular gamers and novice gamers was almost identical, at 92.76% and 92.75%.

The researchers also carried out a simple experiment to test their findings: a group of novice gamers were asked to play action games (Unreal Tournament and Call of Duty 2, in this case) for fifty hours over eight or nine weeks. The gamers improved their reaction times by around 13% while maintaining the same level of accuracy when compared to novice gamers given The Sims to play in the same period of time.

So playing action games regularly can train gamers to react to what they see – known as visual processing – faster than non-gamers, or even when compared with gamers whose preferred games don’t rely on quick reactions. Speedy visual processing has been linked to better reasoning and judgement, so playing action games might help elderly people retain their mental agility for longer. It could even help people who have suffered brain injuries by boosting their mental performance. Unfortunately, the researchers point out that the content and difficulty of many modern games means they’re probably not suitable for therapeutic uses in young or elderly patients.

So we probably won’t ever see doctors prescribing a course of Modern Warfare 2 for elderly patients, or a few laps of the track on Colin McRae for people suffering head trauma.  For now, it’s just good to know all those hours of gaming are doing us all some good!

Do you have one arm longer than the other?

If you’re right-handed, you may think so. Research by an American team has shown that right-handed people think their right arm is longer than their left, despite them both being the same size!

Image credit: Hypothesis Now

The differences in perception correlate with the level of activity in the ‘arm’ regions of our brains: right-handed people show much more neural activity over a larger area in the region associated with their right arm than with their left. In contrast, left-handed people show no difference between their two arms: the area of brain activity for both tends to be equal in size.

These results are the first time anyone has shown that our perception of our body can be influenced by the body ‘maps’ our brains create.

Using a limb more often can cause the brain area related to it to increase in size. Left-handers often use both arms equally, whereas right-handers tend to favour their right arm for the vast majority of tasks. The researchers wanted to see if the uneven brain activity in right-handers matched how people actually perceive their body shape, regardless of how long their arms actually were!

To do so, they asked volunteers to estimate how long their arms were and how far they could reach to pick up an object. Volunteers were asked to hold one arm out-stretched in front of them. The researchers then held up a tape measure, with the numbers hidden, and asked the volunteers to tell them when the tape measure was the same length as their arm. They then asked volunteers to tell them when they thought a small object was within their reach as the researcher slowly slid it across a table towards them.

Left-handers thought their arms were of equal lengths, and that they could reach just as far with both hands. Right-handers, however, had a significant difference between the perceived lengths of their arms, consistently thinking their left arms were much shorter than their right and couldn’t reach as far.

The researchers are careful to point out that the unevenly-sized areas of neural activity might not actually cause the perceptual differences: someone needs to do a bit more research to establish exactly what causes this bizarre phenomenon!

Paper reference: doi:10.1111/j.1467-9280.2009.02447.x

Born to drive (badly)

Could bad driving be blamed on our genes? Volunteers with a certain gene variant did much worse on a driving task than those without the variant, according to an American study. The result is rather surprising: our brains are tremendously complicated and the researchers didn’t think a single gene could have such a dramatic effect on behaviour.

"166 mph on the wrong side of the road, Officer? Sorry, it's my genes..." Image credit: Flickr/TrickyTM

The study suggests the gene in question helps people learn new physical tasks, such as driving along a complicated route, and remember how to complete the tasks in future. It works by producing a protein called BDNF, which helps neurons in the brain communicate with one another. Concentrating on something causes your brain to produce more BDNF in the brain region doing the thinking, letting it work more efficiently. People with the gene variant produce less BDNF so they don’t get this boost to brain power.

To test the variant’s effect on learning a complicated physical task, the researchers asked volunteers in a driving simulator to drive laps around a track. Those with the gene variant made more errors than volunteers without the gene variant. They also did badly when they repeated the task four days later.

So why have we evolved a gene variant that seems to make learning harder? It turns out the variant of BDNF does have one major advantage – people with it keep their mental abilities longer if they’re affected by diseases such as Parkinson’s, which damages brain function. Our brains, it seems, can be either very resilient to damage or very flexible when faced with learning and change, but not both.

Paper reference: doi:10.1093/cercor/bhp189