Too Late!


Our experiences in the first few years of our lives have enduring effects on the way we behave later. At that early age we have little or no control on what is going on. Of course, now that we’re grown up, we don’t recall much of those early days and would probably assume that it is our later experiences that mostly shape our behavior. But this may not be so.

 A study by Feng et al from the Kunming Institute of Zoology report this week on a study of rhesus monkeys in which some youngsters who were separated from their mothers at birth, who were hand reared for the first month and then were reared with another youngster (1). The maternal separation was due to problems such as inexperienced moms not handling their babies properly, bad weather that is hazardous for young baby monkeys etc. and not for the purpose of studying the effects of the separation.

These peer-reared monkeys behave differently from those normally reared by their moms even three years later. They spent a lot of their time sitting around on their own and were generally less rhesus monkey-like.

When the monkeys were caught for check-ups, the control group, that is monkeys reared by their moms in the normal manner, responded with the release of cortisol. Cortisol, you’ll recall, helps us to get out there and fight for our survival. The guys who had been raised without their moms, had a much slower, and hence lower, cortisol release, so in a bad situation, they would be more likely to lose.

This effect of early life bad times is also seen in people. Published this week is a meta-data study of problems of depression in later life of children who had been maltreated and the depression treatments had poor outcomes. This work was carried out by Nanni et al from London’s King’s College (2).

Seriously scary to see how long term, permanent even, some of these effects can be on brain functionality.

  1. http://www.pnas.org/content/early/2011/08/12/1010943108.full.pdf+html
  2. http://ajp.psychiatryonline.org/cgi/content/abstract/appi.ajp.2011.11020335

Synaptic Tactics


Our old friend the Macaque, so often used for cognitive studies, has come through yet again. IBM has just announced the manufacture of a pair of “neurosynaptic computing chips”, their SyNAPSE system is to be funded by DARPA (that is the US tax payer of course) to the tune of $21M (1).

What’s DARPA got to do with Macaques I hear you ask, well, nothing, but IBM have been probing Macaques neural networks for some time. I rush to say that’s not equating their customers with Macaques, but due to the recognition that to take computing to a new level, building in the plasticity of the brain can make cognitive computing possible.

Last year, Modha and Singh of IBM have published their work on tracing a unique network of the Macaque brain using the public domain database CoCoMac (2).  This enabled them to sort out the structure of the network. They demonstrated that the brain network was not uniform like a 3D fishing net, but has increasing complexity as it went to specific functional regions, more like a group of trees growing from common roots. This means that the complex networks feed information down to simpler sub-nets.

Why is this important? Because it like a funnel concentrating the information while processing it down to the nub of the matter. This is a good model for a cognitive system to work efficiently.

Brains are nicely plastic in that the network is modified by the information it is handling, that is it is making new connections. Ultimately this also provides a route for repair of the network. Making new connections on a chip is currently not possible on the fly, but the SyNAPSE system can apparently modulate the signal so it can effectively switch connections on and off. Well almost, it’s more like turning down the signal so it lost in the background and turning the one you want up so you’re not trying to process everything with everything, as I understand it. IBM could put it much better but they aren’t saying too much at present.

This is potentially a huge step forward towards cognitive computing. The next step beyond this is for our computers to start being intuitive. I hope they don’t start showing too much initiative though.

  1. http://www.bbc.co.uk/news/technology-14574747
  2. http://www.pnas.org/content/107/30/13485.full

Retiring Mice


Flipping through the bio papers in the scientific literature, I seem to come across a very large number associated with aging – or its reversal and longevity. Of course we would all like to be long lived with the minimal amount of aging related lack of spryness. Many of the studies are associated in one way or another with our diet, and diet and exercise is what we are told to pay attention to when we visit the doctor if we can bring ourselves to do that.

Today’s post is about a helping retired mice grow older. The paper is by Matsumoto et al in the Public Library of Science (1). The retirees were all females who had spent the previous ten months raising litters. Male retirees couldn’t be considered for the study as they tend to be very, very, grumpy and fight all the time.

So, these old girls were allowed to enjoy their retirement for another eleven months with half of them fed on a probiotic diet. The good bacteria were from milk although the mice didn’t have access to live Greek yogurt, or any yogurt come to that. The good bacteria in the diet result in there being higher levels of polyamines in the colon.

The simplest polyamine is putrescine, so as you can imagine, these don’t smell too good, but they are important in body functions such as cell growth and the synthesis of our DNA and RNA. But they are also anti-inflammatory and this was at the root of the reason for the study. Is longevity increased if chronic low-grade inflammation is suppressed?

Those on the probiotic diet were longer lived and also ended up with better colons. So it’s just like your Mom told you about an apple a day, but now it’s take care of your colon and it’ll take care of you. I will be eating more live Greek yogurt and using lots more Soy sauce in my cooking and am looking forward to a long retirement (eventually).

  1. http://www.plosone.org/article/info%3Adoi%2F10.1371%2Fjournal.pone.0023652

Keep Limping Along


We all wish to stay healthy, but once in a while we catch something nasty. Severe bacterial infections can be very nasty and, with the increasing problem of antibiotic resistance build; we have to be careful as to permanent damage to our system, especially as we get older.

Now if we take a deep breath and leave humans and turn to lab rats we can study the longer-term damage of a severe bacterial infection without any likelihood of subsequent lawsuits. The current information is that healthy, but elderly rats, after they catch something nasty in the bacterial line and then get cured, show rather severe memory impairment. Younger rats don’t. The brain inflammation in the older critters that severe bacterial infections can cause is also severe and lasts a long time.

The long-term effects are that the ability to make new connections (plasticity) is much reduced and that a type of nerve growth factor (brain-derived neurotrophic factor, BDNF) has had its production severely curtailed. Now BDNF works in those crucial areas for memory and learning new and important stuff like finding your way through a maze, namely the hippocampus and the cortex. The hippocampus generates some neural stem cells so that we can continue to replace some neurons.

All is not lost for our furry friends. Barrientos et al from the U of Colorado have just published a solution, which will undoubtedly work for us too (1). They have found that regular exercise after the bout of nasty bacteria, increases the BDNF in the hippocampus and lo and behold those elderly rats that took daily voluntary exercise got back to their amazing maze solving, whilst their sedentary friends did not.

Of course, being elderly, the rats were skipping about rather gently and couldn’t manage more that half a mile a week. But that was sufficient. Even better though was the result that regularly exercising elderly rats didn’t have the severe neuro-inflammatory effect from a bacterial infection. So once again, we have the strong message to get out there and exercise. It may be good for the heart, but it’s even better for the brain!

  1. R.M. Barrientos, M.G.Frank, N.Y.Crysdale, T.R.Chapman, J.TAhrendsen, H.E.W.Dasy, S.Gampeau, L.R.Watkins, S.L Patterson & S.F.Maier, J. Neuro. Sci., 31, 11578, (2011)

Getting Small-minded


As we get older we look wrinkly on the outside, although we feel pretty much the same inside, but at some point, we start to suffer from a lack of velocity. As we gradually improve medical methodologies, our life expectancy increases, if and only if, we can still move fast enough to cross the road before the faster and faster cars catch us.

A question we could ask, but never do, of course, is how old are we supposed to get? If you are a cat or a dog 15 to 20 is pretty much all you can expect. If a macaw, maybe 70, but if a giant tortoise you could be looking at 150 to 200 years of silly politics. So where do we fit in?

Back to our closest animal relative, the chimpanzee, 50 years old is about it, and they don’t have to put up with the stress of studying stock market fluctuations. Sherwood et al in the current issue of the Proceedings of the National Academy have attacked this question of comparisons by using MRI scans of chimpanzee and our brains (1).

Looking at almost a hundred chimpanzees of a range of age from young to old, they found that their brain volumes were pretty constant. Well perhaps that’s a slight overstatement if one looks at the data, but there wasn’t a trend for loss of their little grey cells with age.

Not so with us humans though. With almost as many humans from 22 to 88, the brain scan showed that we were losing cells on the way to become small-minded with age. The authors point out that we are unusual in this rather careless habit (and another recent paper has shown that its not due to the demon drink) as other species don’t appear to do this and have their hippocampus and frontal lobes shrink.

Interestingly, their conclusion is that, maybe, we have reached our sell by date when our brain starts to shrink. Evolutionwise, we should have popped off by then and our extended lifespan is to blame. Philosophically, this seems to me to be a very scary thought to follow down its rabbit hole. Should monitoring changes in our brain volume become as routine as measuring our changes in cholesterol or blood glucose? Would that information be useful to health insurance providers?

  1. http://www.pnas.org/content/108/32/13029