Use Them Or Loose Them



Unfortunately, as we go through life, we lose some of our neurons and the number that go will depend on things like diet and not doing all those things that our family doctors keep nagging us about. However, we do have a lot of them and they normally don’t disappear very rapidly.

From this point there is good news and bad news. The good news is that we make more in our hippocampus at a steady if not rapid rate. The bad news is that a lot of these die off in a week or two, so this is something that we need to pay attention to.

So what to do? We have to use them. They like to be useful and well exercised. We exercise them by putting them to work, and to do that, we have to learn new things. To study this Nokia et al from Rutgers U employed a team of adult male lab rats and trained them to wink in response to pulses of white noise, (well blink really) (1).

They were taught to give a trace blink or a long delayed blink. The electrical activity in the brains was measured and finally their new neurons were checked out and found to be surviving. The electrical oscillations in their hippocampi at around the 10 Hz range showed that they were learning.

The important thing is that learning new things sets up new neurons for a long life. If you change the task that has just been learned, you save more new neurons from ending up on the scrapheap rather than just exercising the ones that had just been deployed on the first version.

For us non-lab rats, our best strategy is not to just do crosswords (that’s the same task over and over,) but to try taking on something more difficult. Like learning to play a musical instrument and then try to learn more and more difficult pieces.

There are other things to take up too if your family or neighbors have trouble with your new violin or trombone. They don’t have to be loud. The result of the huge memory training that London cabbies go through is an increase in the size of their hippocampi as they learn all the back streets, alleyways, one-ways, and building locations (2).


  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0031375
  2. http://james-goodwin.blogspot.com/2011/12/building-knowledge.html



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Who's The Bigger Pain In The Rear?


Zebras, as we all know, are black or brown with white stripes and each zebra has it’s own customized pattern. The old explanation is that the stripes are camouflage and, as lions are color blind, the fact that the stripes aren’t green and brown is OK. Another explanation is that looking at a herd, the stripes confuse the eye of the predator and make it difficult to pick one out. Yet another suggestion is that they help one zebra recognize another.

The most recent work suggests that the camouflage theory is correct, but it’s not the lions that are the bane of a zebra’s life. It’s a much smaller enemy that they are trying to confuse. Horseflies are a constant pain in the rear and they spread nasty disease, but they have a vulnerability that can be exploited.

They have compound eyes that pick up horizontally polarized light. They use this to pick out and locate water that they need. Black and dark brown horses also reflect horizontally polarized light so the horseflies can zero in nicely. With white horses, any reflection is apparently unpolarized. Egri et al in the Journal of Experimental Biology spotted this difference and tested the effects of a variety of black and white patterns on horseflies (1, 2).

Variously black and white patterned sticky boards were placed in a field and the fly density recorded. The least favored were boards with zebra-like stripes. To go for the clincher, they put four sticky horses out in the field, one that was black, one brown, one zebra-striped and one Dalmatian-dog spotted. Note, these were model horses, so no real horses were bitten. The zebra-striped caught the least number of flies.

Clearly, the camouflage theory is correct and the stripes reduce the chance of zebras being bitten, whether once in a lifetime by a lion or many times during each day by a tabanid (fancy name for horse fly). It is a pity mosquitos are attracted to carbon dioxide and not horizontally polarized light or we could all be more comfortable in the summer with zebra-striped make-up.

  1. http://www.bbc.co.uk/nature/16944753
  2.  http://jeb.biologists.org/content/215/5/736


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On The Move


Whenever there is a big earthquake we are reminded that the continents are on the move and at a surprisingly fast rate. What we see now is the result of the break up of Pangea, but that is not where it all started. First there was Nuna which morphed into Rodinia prior to Pangea.

As Pangea broke up, our rafts drifted apart to where we work, play and fight today. The big question is where are we going now? One possibility is that the big break in Pangea could heal. This model is known as introversion and would mean Europe and Africa snuggling up to the Americas as the Atlantic trench closed up.

The more popular model is for the drift to keep going and for the Pacific to get squeezed out into the Indian and Atlantic as America joins up with China with Amasia as the new supercontinent. This model process is known as extroversion. (I guess Walmart and their colleagues would be able to reduce prices due to lower transport costs.)

In a letter to Nature this week, Mitchell, Kilian and Evans from Yale U have been busy measuring magnetism in old rocks in order to plot out the correct old routes of our land rafts (1). This work brings them to a new model that they call orthoversion as our route is off at a right angle to the previous ones. The Canadians will end up living in close proximity to the Russians.

In the end it seems we’ll all be living around the North Pole. Any oil left up there will end up very deep. The Australians and New Zealander will be heading north too and switching the Southern Cross for the Great Bear.
  1.  http://www.nature.com/nature/journal/v482/n7384/full/nature10800.html  



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Can I Give You A Hand?


Many studies have been done that show how one member of a species reacts to another of the same species and these indicate that many species show empathy or, in some cases, altruism. Of course these are all social animals, so it doesn’t seem very surprising that a member of a group would be well aware of what its colleagues are up too.

Cooperation and awareness are key requirements of a social group that benefits from being in a group over and above being a smaller part of the general target for predators. However, aiding a colleague with no expectation other than they may be paying it forward, so to speak is indicative of a sophisticated cognitive process that is worthy of study.

Yamamoto et al studied mother chimpanzees and their offspring helping each other on request and wrote up the work for this week’s Proceedings of the National Academy of Science (1). With this experiment, mother and offspring were in different rooms with a pass through. In one room was a drink that needed a straw to get at the fruit juice. The other room had a selection of seven different ‘tools,’ one of which was a straw.

The chimps with the tools were good at finding the straw and handing it over when requested. However when the drink was hidden from the tool stockiest, they tended to hand out the wrong tool. A walking stick was a favorite, but it wouldn't help with drinking juice.

The general conclusions from the study were that chimpanzees will help when requested, but only when requested. They are quite happy to watch the other struggle if not asked to help. Maybe that’s not that surprising when we remember how closely our DNA tells us we are related.

However, like us, when asked they will often step up to the plate and hand out tools. Unfortunately, they don’t have our language skills and the helper has to see what the problem is if they are going to be of any use.

  1. http://www.pnas.org/content/early/2012/01/30/1108517109.full.pdf



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Going Dutch


Technology is moving along nicely in some areas, other areas not so nicely, but today’s post is a good news post, so we’ll concentrate on the first. 3-D printing is back in the news and we have seen previously how easy it is to fabricate plastic objects, thus making the future for bespoke items golden as they could be at least as cheap as mass produced ones, and probably with less waste.

The medical area has received attention with soft organs, complete with built in blood vessels looking possible. The printers can also print ceramics and these parts have been shown to work as a base scaffolding for bone to grow onto.  Prosthetic parts would appear to be a “no-brainer” too.

Now the BBC reports that an 83-year-old Dutch woman has had a new jaw fitted (1). It was made by Layerwise who have a print shop in Belgium, with input from Hasselt U. The lady was fitted up with this last June and is due to have a set of teeth torqued down into it shortly so that she’ll be able to nosh and gnash with the best of them.

The printer printed out titanium powder, which was fused one layer at a time with a laser and the jaw was finally finished with a layer of ceramic. The jawbone replacement weighs in a little heavier at 107 grams, but a few packs of chewing gum should build up the muscles.

This could end the professional boxer’s “glass jaw” at a stroke. Just like breast implants have become cosmetically popular, I can envision a future with many more manly square jaws in evidence along the main drags in Tinseltown and it’s wannabe lookalikes around the world.

  1. http://www.bbc.co.uk/news/technology-16907104


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Running Like Clockwork


Life has a certain regularity for most of us and this is based on a twenty-four hour cycle, more or less. We get grumpy if it’s disrupted, especially if it’s early in the morning. But our circadian clock is rather more important than effecting our grumpiness when interfered with. Many other nasty effects have been indicated, such as cancer or diabetes.

The key issue here is that our metabolism is linked to our clock. Exactly how much is the question investigated by Dallmann et al who reported their findings last week in the Proceedings of the National Academy of Science (1).

Theirs was a pretty tough study, especially for their volunteer human lab-rats who were locked away and kept on a strict 40-hour cycle. They had to eat hourly isocaloric meals, no exotic menu choices for them. In addition they were shut away in dim light in enforced positions and kept sleep deprived. This way, their body would have no clues from TV, soft beds, or bright sunshine as to what it should be doing .

This meant that their metabolism would be running on the circadian clock only with no interference from competing stimuli. The only excitement was regular blood letting and saliva sampling to check the levels of the small molecules from their metabolic workings.

The levels of 15% of these small molecules varied in line with the subjects’ circadian rhythm. The molecules in question were fatty acids and amino acids. These are involved in important metabolic pathways. Think cell membranes and fatty acids, and DNA or proteins in general for amino acids and their importance is immediately clear.

What should we do about this? Clearly the old adage of “Early to bed, early to rise…” has a lot going for it, but is eating regular meals (like you mom told you) and not burning the candle at both ends all we need to know? Perhaps we should dig a little deeper to get in tune with our inner clockwork and fit our exercise and menus so that they match up.

  1. http://www.pnas.org/content/early/2012/01/30/1114410109


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