Month: March 2012

The Basal Ganglia: Your internal puppet master

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Have you ever left your house in the morning and wondered whether you locked the door or remembered to close the window? Have you ever arrived at your destination and realised you had no recollection of the journey? Have you ever completed any mundane task, whilst thinking about, well… nothing? If you have, it’s not the case that your memory is leaving you or that something is wrong with the inside of your head. In fact, things are probably working better than you think.

Every one of us is perpetually bombarded with an assortment of stimuli. You are constantly seeing, hearing, smelling, tasting and touching. There are also the less recognised senses such as balance, proprioception (your sense of your “body position”) and changes in temperature. Whilst you are not consciously aware of most of these sensations, under the bonnet your brain works through this huge array of information and sorts the important stuff from the chaff. Even when you are asleep, you might awaken only to critical sounds such as a baby crying in the next room but not, say, a car driving past the window.

But your brain doesn’t just subconsciously extract the interesting stuff. It takes this information and combines it with your internal body state (Hungry? Tired? Bored?) and uses this to decide how you should act. This processing allows you to interact with your environment, seamlessly performing the most complex or the most humble of tasks.

An example: you are sitting in a chair in a room and the window is open. There is a cold draft so you get up to close the window. You probably don’t think about how to rise out of the chair. When you walk over to the window, you aren’t aware of the hundreds of muscles working in concert to move you. You aren’t considering the position of your legs, how balanced you are or the sense of touch on the soles of your feet. But your brain takes these sensations and executes movements. It all happens automatically without any need for you to be consciously aware of the process.

Below is a different example. This man is playing music on his guitar. He has to make a series of movements that are precise in both time and space. He does this in response to the sound of the notes and feeling and seeing the position of his hands. As he progresses, the subsequent sensations trigger the movements for the next section of the piece. It’s not entirely automatic but he wouldn’t be able to play this piece without having practiced and learned it first.

[youtube http://www.youtube.com/watch?v=OhaFINynWqY?rel=0&w=480&h=360]

So why is such concentration required for playing a guitar but not for walking? From your brain’s perspective, any movement that you repeat can be considered “practice”. The more you do something, the better you become and the less you actively think about it. Therefore, it’s simply the case that you spend a rather huge amount of time “practicing” walking but not playing a guitar. Even the greatest Rock God doesn’t spend as much time swinging his axe as he does putting one foot in front of the other. If you picked up a completely new instrument, how much time do you think you would need to learn how to play it? A month? Two months? And how long was it before you learned to walk properly?

Regular guitar playing is also known to result in questionable fashion choices.

Practicing, learning and then reciting these movements is part of your procedural memory. Unlike other forms of memory which are governed by the hippocampus, procedural memory is controlled mainly by the basal ganglia, with a bit of tweaking by the cerebellum. In a previous post, Sarah wrote of HM, an individual who suffered damage to his hippocampi resulting in permanent amnesia. Despite this, he could still be taught mirror writing when encouraged by the scientists working with him. When prompted, he was able to write in reverse with no effort, despite insisting he had no knowledge of ever having done it before!

Players such as Dan Carter are notorious for quick, incisive actions that are beyond that of many of their contemporaries.

Learning a new skill requires a large amount of effort and attention. However, through repetition, the effort and attention required to perform the task can be reduced. For some the practice of complex motor skills consumes their entire lives. In particular, sportsmen and women have huge demands placed upon them during matches, both physical and mental. Whilst the activity of the basal ganglia and procedural memory is certainly not the brain’s only toil, players that are quick thinking and can dictate play are thought to have greater automation of their movement skills, thus freeing up their conscious mind to analyse the game around them.

Even for everyday souls like us this system is utterly indispensable. Below is a man with Parkinson’s disease, which primarily damages the basal ganglia. He is still able to move his limbs, but coordinating himself is a huge challenge.  In the second part of the video he is given a common treatment, L-DOPA, which provides temporary respite. However, eventually even this will not restore normality.

[youtube http://www.youtube.com/watch?v=sf1N0Zf5IqA?rel=0&w=480&h=360]

Illnesses such as Parkinson’s highlight why the basal ganglia, like so many parts of the brain, are fundamental to our everyday lives. Helping to treat such disorders is the primary reason for scientific research in this area. However, if it also helps us to understand why sometimes we don’t pay attention when we pack our bags in the morning or lock our front doors, then I think that can be quite interesting too.

Post by: Chris Logie

From secret agents to drunk rats

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There’s a spy film (I can’t remember which one) with a famous scene where the secret agent and his enemy sit down for drinks. The agent secretly slips a pill into his mouth to counter the effects of the alcoholic beverages they both proceed to consume. Throughout the rest of the night, the spy retains all his mental faculties, knowing that meanwhile his enemy will succumb to impaired judgement, delayed reflexes and slurred speech. This is all caused by the alcohol slowing down the enemy’s brain by binding onto ‘depressant’ receptors, called GABAA receptors, making them more active – in turn, slowing down the brain.

Not to mention the secondary bodily actions alcohol has on the drunken enemy. Alcohol limits the production and release of the antidiuretic hormone vasopressin, meaning that important salts and fluids are excreted by the kidneys in his urine. The alcohol irritates the stomach lining so much that his brain concludes that the stomach’s contents must be harmful thus causing a feeling of nausea. The enemy’s sleep is also affected. As a compensatory reaction to the alcohol, his body produces glutamine; a stimulant which prevents deep restful sleep and can even trigger tremors, anxiety, restlessness and high blood pressure the next day. All in all, the next morning the enemy will experience the dreaded post-intoxication syndrome – also known as a hangover.

So what is the agent’s ‘magic’ pill that protected him from this dreaded sequence of events? Today the internet is full of suggestions, many herbal or vitamin-based. Not surprisingly, there is a huge market for ‘miracle’ hangover cures. Yet hardly any claim to be able to curb the primary effects of alcohol – feeling ‘drunk’. Recently, however, scientists at the University of California have tested a natural substance called DHM (taken from an Asian tree) on rats. The rats were given a dose of alcohol equivalent to a binge of 15-20 pints of beer. The rats that weren’t given the DHM lost their ‘flipping’ reflex (their ability to stand up after being pushed over) for over an hour. In contrast, the rats given DHM before the alcohol only lost their ‘flipping’ reflex for around 15 minutes. In other words, DHM made the rats extremely tolerant to alcohol.

Still, perhaps the most important finding from this study was DHM’s longer-term effects on alcohol addiction. Rats, just like humans, can become addicted to alcohol. If the alcohol was mixed with DHM, however, the rats drank much less than their untreated counterparts, possibly because it binds to the same GABA receptors that alcohol does but without the same ‘depressant’ effects. The researchers plan to test DHM on humans, with a view to hopefully using it to treat alcoholism.

Post by: Natasha Bray

Original article can be found here: (subscription required to read full article)

Can a brew help you beat type II?

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Coffee and cake – a match made in heaven. It may also be healthier than you think – well the coffee at least. A recent paper has shown that drinking coffee may help prevent obesity-linked type II diabetes. The study showed that three chemicals found in coffee can stop certain proteins from misfolding, clinging together and becoming toxic. These clusters of misfolded protein, known as amyloid bundles, are thought to lead to diabetes by damaging insulin-producing pancreatic cells. This results in the pancreas losing its ability to make insulin and regulate blood-sugar levels.

This research provides a mechanism to explain previously observed links between drinking a lot of coffee and being less likely to develop diabetes. Brilliant – I’m going to go have a large slice of sugary cake and wash it down with coffee – no diabetes for me!

Alas though, it’s not quite that simple. The authors admit that some of the links between drinking coffee and a reduced risk of diabetes may be due to the appetite suppressing properties of caffeine. If you eat less, you’re less likely to be obese and as a result less likely to develop type II diabetes. So it could be the amyloid bundle busting power of coffee or it could be a reduced likelihood of obesity. It could even be both.

Damn it! Maybe just a skinny latte and a jaffa cake for me then. So although this study doesn’t provide an all-you-can-eat cake pass, it does suggest that coffee may have some positive health effects after all.

Post by: Liz Granger

Twitter: @Bio_Fluff

Original article can be found here: (subscription required to read full article)

Scientists are People Too

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Nothing stops a conversation at a party quicker than the words “I’m a scientist.” I’ve lost count of the times I’ve had the following conversation:

“So, what do you do for a living?”

“I’m a scientist”.

“Oh, really? That’s fascinating, what are you studying?”

“Biochemistry and Cell Biology”

“Errrm …”

Unsurprisingly, no one knows how to carry on from there. This is mostly because I haven’t yet worked out how to verbalise my work into something remotely understandable (even to myself). However, I do believe that the unrealistic portrayal of scientists in the media makes it harder to explain what we really do on a day-to-day basis.

The problem I find with scientists in the media is that there seems to be only a few categories they’re allowed to fit into. Below is a list of what I believe are the main types of scientist presented to the public:

The Evil Genius: Sadly, I think the most common type of scientist in the media is the megalomaniac genius who tries to take over the world. This is an unfortunate stereotype and I can state with some confidence that none of the scientists I have come across in my career have had dreams of world domination.

 

 

The Super-Geek: Usually men but sometimes women too (see the U.S. sitcom The Big Bang Theory for examples of both). They are asthmatic, allergy-ridden neurotics with an inability to communicate with the opposite sex. Some scientists are indeed like this, but then again so are some accountants. The point is that this portrayal seems to indicate that most scientists suffer from social afflictions, which just isn’t true.

 

 

 

The Know-it-all: These seem to crop up a lot in Hollywood blockbusters. They often manage to know about an abnormally huge range of scientific theories which help to save the day. If the Know-it-all is female, there is a high chance they’ll be wearing a tank top and tiny shorts (for example Dr. Christmas Jones from the Bond film The World is Not Enough). I don’t want to say this is unrealistic, because perhaps there are nuclear physicists who go to work in tiny shorts and have an encyclopedic knowledge of everything scientific. However, most scientists are specialists in a particular field – e.g. cancer, astrophysics or biochemistry – and are unlikely to have the extremely broad range of knowledge the Know-it-all appears to have on board.

The Moral Vacuum: To me, this is the most frustrating portrayal. This scientist ignores any moral or ethical boundaries to make the next big discovery. A good example of this was in the BBC’s most recent series of Sherlock; specifically the Hounds of Baskerville episode. This is in general an entertaining show, but I was a bit dismayed by the portrayal of the scientists in this episode. They did cruel and unnecessary experiments on both animals and humans just to see what would happen. There was even a line when one scientist was asked why they were making fluorescent rabbits, she replied “because we can.” In reality, doing any sort of animal experimentation requires a licence and there are legal documents in which you have to explain exactly how your proposed experiments will be beneficial and that they have a specific purpose. “Because we can” is not an excuse and will never be accepted as one. Don’t get me wrong, I know this is just a show, but it doesn’t do our reputation any good when it appears that scientists are willing to throw out any ethics to achieve their dream of making a famous (or infamous) discovery. Admittedly some scientists, past and present, may be morally dubious but on the whole we’re an ethical lot.

Generally speaking, most scientists live a relatively normal life and don’t fit any of these stereotypes. Many of my colleagues and scientist friends are in stable relationships and are perfectly able to talk to members of the opposite sex, including non-scientists. Many go out and have a good time and regret it the day after. We too have to deal with office politics and occasionally poor boss-employee relations. Personally, when I’m not at work I like watching Pixar movies, eating at nice restaurants with my boyfriend, going to the pub and other typical sociable activities.

Of course, scientists aren’t the only career group who are pigeon-holed by popular media. I’m sure lawyers have similar gripes about Ally McBeal, and doctors with ER or House. However, I do feel that we scientists have it particularly tough as most of the stereotypes presented are negative or even downright scary.

So take it from me, if you meet a scientist at a party, don’t assume that they are like any of the characters shown in the media. Although we do know some pretty interesting technical stuff, we are just as comfortable, if not more comfortable, chatting about films or which local pubs serve the best beer!

Post by: Louise Walker

Cats on the brain

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Since their domestication in ancient Egypt, cats have carved their own niche within our society;  controlling pests and delighting owners worldwide. Whether our own, or our neighbours pets; the vast majority of western inhabitants interact either directly or indirectly with cats on a daily basis. Therefore, there is little wonder that at times we share more than just our living space with these animals.

Toxoplasma Gondii

Toxoplasma gondii is a single celled parasite whose life cycle is intimately connected with the cat. Indeed, this parasite is entirely dependent upon conditions within its feline hosts for sexual reproduction! Despite its dependence on cats for the sexual stage of its life cycle, T.gondii is  capable of infecting all mammals…including humans. The parasite can be transmitted from cats to other mammals through ingestion of T.gondii eggs. An infected cat will shed up to 20 million eggs in one leaving, with eggs surviving in the soil for over a year. Transmission occurs when the eggs are ingested by mammals feeding around the infected area. The most common form of transmission to humans is either through unwashed vegetables or undercooked meat.

When ingested by anything other than a cat the parasite reproduces asexually, forming small thin walled structures called cysts which lay dormant in many cells, most notably those of the brain. Although the dormant parasites can remain in this state for the entire life span of their accidental host, they cannot reproduce sexually until they return to their primary host (the cat). Therefore, ideally the parasite must find a way back to the cat!

T.gondii can lead to fatal feline attraction in rodents.

Scientists researching the effect T.gondii has on wild and laboratory rodents have recently uncovered the unsettling means by which this parasite ensures itself a safe return back to its primary host. The parasite has been found to manipulate the rodents behaviour patterns, making them significantly more likely to be caught and eaten by cats. Infected rats were found to be more active and less intimidated by open spaces than non-infected animals, making them easy prey for a hunting cat. However, probably the most unusual finding was that infected rats, unlike their non-infected counterparts, were not scared of the smell of cat urine; actually spending more time in the area of their enclosure treated with this odour. This is particularly unusual since all uninfected rats, even those who have never encountered a cat, show a strong innate fear of this smell.

The mind control adopted by these parasites is probably linked to the presence of cysts within the hosts brain cells. Scientists are not yet certain what aspect of T.gondii infection causes these behavioural changes, however it has been suggested that the parasitic cysts may have the ability to manipulate the hosts brain chemistry. Studies have found that levels of certain neurotransmitters linked to control of movement and behavioural responses to fearful stimuli appear to be altered in infected mice. Specifically, recent findings show that the parasite contains two genes which have the ability to increase levels of the neurotransmitter dopamine in the hosts brain; this may account for observed changes in the animal’s behaviour.

Of course the idea of behavioural manipulation makes sense in the case of prey animals like rats and mice but what happens when humans, who are unlikely to fall prey to cats, become infected? Current medical understanding of T.gondii infection in humans assumes the parasite has no notable effect on the host, with the exception of infection during pregnancy and the occasional adverse reaction to first exposure. However, in light of the recent findings in rats and mice, scientists have been taking a closer look at how T.gondii may influence our behaviour. Work by Professor Jaroslav Flegr has revealed, what he believes to be, particular personality types linked to T.gondii infection. He found that; infected men have a greater tendency to disregard the rules of their society and were generally more suspecting, jealous and dogmatic than non-infected men whilst infected women appear more ‘warm-hearted’, out and easy going but also more conscientious, persistent and moralistic. Both infected men and women also appeared more prone to feelings of guilt than their uninfected counterparts. Links have also been drawn between incidences of schizophrenia and T.gondii infection, perhaps due to altered dopamine transmission.

Since the basic components of our brains are not too dissimilar to those of the rat or mouse, it seems logical to assume that something which exerts an effect on their behaviour should also influence our own. Therefore the question is now open as to how often these parasitic passengers actually jump in the drivers seat? Indeed, T.gondii is not the only parasite carried by humans, leaving open the possibility that development of our personalities has and will continue to be influenced not only by our genes and environment but also by our own personal collection of brain dwelling parasites.

Post by: Sarah Fox