Superstitious mice

One of the nicest things about being part of a large University is that, if you can drag yourself away from your desk long enough, you get the opportunity to attend some pretty amazing guest lectures discussing cutting edge scientific findings. Last week I sat in on a particularly engaging talk given by a researcher from UCL on ‘superstitious’ mice. Although the title was a bit confusing, leaving me with images of mice refusing to leave their beds of Friday the 13th and saluting whenever they saw a magpie, the actual research gave an amazing insight into how the brain balances its own internal prejudices with its actual experiences of the world. The ‘take home message’ of the talk was that mice and men don’t always believe what they see and, on occasions, will act on what they expect rather than what is actually in front of them. The research behind this finding is both elegant and eye opening and I will attempt to do it justice here:

Research in this lab was not initially intended to test the ‘superstitious’ nature of laboratory mice. The lab was instead interested in how well mice could distinguish between two images and how similar these needed to be before the animals became confused; research such as this is important for understanding how the visual system works. The experiments relied on the notion that mice can be taught to perform specific tasks in response to different commands (similar to training a dog…just on a smaller scale). Mice were kept in special cages with two separate treat dispensers and were taught to watch a screen which flashed one of two images. Each image corresponded to a different treat dispensers, I.e. when image 1 appeared the mouse could get a treat from dispenser 1 and when image two appeared the mouse could get a treat from dispenser 2. To make the task a little bit trickier the scientists sometimes manipulated the images making them harder to tell apart, with the aim of confusing the mice.

This figure expresses the concept behind the test however the images used in this research were not coloured dots.

What was particularly impressive about this experiment was that the scientists worked with two groups of mice, one which performed the behavioural task and another which watched the same images whilst the researchers recorded activity from the visual areas of their brain. This meant that researchers could compare how well cells in the brain responded to the different images with how well the mice performed on the task. Now this is where the findings get interesting! The mice weren’t very consistent when it came to performing the task; meaning that some times they would perform well, even when the images were similar, whilst other times they seemed to be unable to recognise even the clearly separated images. However, when the researchers looked at the corresponding brain activity they found that the visual cells they recorded from were consistently good at differentiating between the images. This caused some serious head scratching as the scientists tried to work out how, when the mouses’ brain could distinguish the images, the mouse itself sometimes behaved as though it could not.

What the group found was that mice based the decision of which treat dispenser to visit, not only on the image they saw, but also on their past experiences – taking into account what choices had previously lead them to receive a reward or not. The mice tried to assign a pattern to the task making assumptions based on what they had already experienced, then combined this internal prediction with what they actually saw. Amazingly these internal predictions (which the researchers called superstitions) could be strong enough to win out over the animals own vision causing it to make the wrong choice. We can perhaps understand this behaviour better by thinking about the times in our lives when we assign patterns to things which are in fact entirely random. Take for example the national lottery. There was a time when you heard news reports speculating on lottery number, making the assumption that since a certain number had not been drawn for weeks it was ‘due’ whilst another number which appeared more regularly may be less likely to appear again. Of course the lottery draw is entirely random, meaning that the frequency of certain numbers being drawn on previous weeks has no influence on what the current draw will be. However, this did not stop us speculating and assigning our own patterns to the draws. It seems that the brain just loves to create patterns!

However, we would never be silly enough to ignore what our eyes were telling us in favor of a ‘superstitious’ belief, would we? Well… before you sit back, quietly mocking the poor mice for being slaves to their internal pattern maker, it is worth noting that they are not the only species to fall foul to the problems of over thinking a scenario. Yes you guessed it, it appears that we do this too! A follow-up experiment used a similar protocol with people and amazingly found the we also sometimes make the wrong decision even though our eyes are obviously capable of telling us we are wrong. So it seems that when it comes to both mice and men our superstitions can occasionally get the upper hand!

Post by:  Sarah Fox

For original work see here (subscription necessary to view full article)

Beware the men (and women) in white coats

There’s something incredibly authoritative about someone wearing a white lab coat. The minute I get into the lab and put mine on I feel powerful, knowledgeable, wise. This attitude changes as I realise I haven’t got a clue what my results actually mean… but for those 10 milliseconds each day I feel like I know things about science.

The problem is that a number of people involved in marketing have also cottoned on to the fact that someone wearing a lab coat and/or glasses looks clever and appears trustworthy. This has lead to a glut of adverts featuring ‘clever-looking’ people in lab coats telling you exactly why their toothpaste, pregnancy test or shampoo is the best. They often use fancy scientific-sounding words (which are sometimes entirely made up) to explain why their product is amazing then seal the deal by flashing you a trustworthy, knowledgeable smile – ‘trust me I look kinda like a doctor’.

A number of cosmetic companies use images scientists in a white coats to sell their products

Beware of these people! Just because they are wearing a lab coat, and usually glasses, doesn’t mean they are scientists or doctors. Even if someone is actually called “Dr”, this still doesn’t guarantee they know what they are talking about. I will (hopefully) be a doctor someday soon. When I finish my PhD I could put on my lab coat, fix you with a serious look, introduce myself as “Dr Walker” and give you a lecture about nutrition, shampoo or teeth; and you’d probably believe me. However, I know nothing about nutrition, shampoo or teeth for that matter and I will undoubtedly be talking absolute rubbish.

These advertisers are exploiting the fact that we are more willing to believe something if it is presented to us by someone who looks authoritative –  in this case, someone wearing a lab coat and/or glasses. Such ‘blind faith’ in authority figures was most famously studied by the psychologist Stanley Milgram in 1961. In his experiment subjects thought they were giving an electric shock to another person in a different room. They had been informed that the person being shocked had a heart condition. Someone in authority would then prompt the subject to administer an electric shock to the other person in increasing doses, often causing them to scream in pain or bang on the wall. Shockingly, many test subjects were willing to administer a potentially lethal dose of electricity as long as they were prompted to do so by the person in authority. Fortunately the test wasn’t real and the person being ‘shocked’ was just an actor, but this experiment showed how people are more likely to go against their own judgement if someone in authority tells them it’s OK.

Obviously I’m not telling you to distrust the authority of your GP or any other medical specialist. These guys have spent many years studying their field and generally know what they’re talking about. I’m referring to the people who crop up on TV self assuredly promoting their own opinions on various controversial subjects, or trying to flog you some skincare products with promises like “it’ll reverse the ageing process due to the addition of polydeageinium*” or some other equally ridiculous statement. For an excellent assessment of the ‘science’ behind cosmetics and why these names they claim to give their creams are often totally bogus, see Ben Goldacre’s website.

A good example of how people’s trust in authority has been misplaced is the PIP breast implant scandal. A French company, Poly Implant Prothèse (PIP) was using potentially dangerous non-authorised silicone for breast implants (see here for more detail on this story). This incident may have occurred because people trusted the chain of authority above them: the patient trusted their plastic surgery team, and the plastic surgery teams trusted their supplier (which was not a huge leap of faith since the PIP implants had been given the ‘CE’ mark, meaning they met European quality assurance standards). This incident has led to fears that the low-quality implants may rupture and, in some cases, have caused the patient a lot of pain. This story highlights how mistakes can be made and how blind trust in another persons authority may not always be a sensible choice.

The PIP story also highlights how divisions can appear within the medical community, with different groups claiming different things – some say the danger of rupture from the PIP-supplied implants is higher than that of medical-grade implants, others disagree. This differing of opinion has become a political issue as well as medical one (see here for more detail). Therefore, It’s also worth keeping in mind that opinions can differ even within the scientific community. This difference in opinion is not unusual since experimental findings are rarely black and white. However, understanding comes as more experiments are conducted, meaning that the consensus scientific opinion is often the closest to fact you can get. This means you should also be wary of ‘real doctors’ expressing opinions which are not held by the rest of the scientific/medical community.

Obviously, the PIP story is a rarity, but it does illustrate how sometimes people can blindly follow someone in authority, whether it’s a doctor, manufacturer or even the European Quality Assurance board! If you see someone on TV claiming to be a doctor or specialist in their subject giving their opinion on a matter which concerns you, it should be easy to search online and discover their credentials, and investigate whether what they are saying agrees with scientific opinion as a whole.

So be aware that a white coat and/or the fact that someone is a “doctor” does not automatically mean they know best. Trust me, I’m (almost) a doctor.

* “Polydeageinium” is not a real chemical. No one would ever seriously come up with a name that stupid would they? Would they??? Maybe I should copyright it, just in case…

Post by: Louise Walker

PKMZeta: a name to remember.

Will it ever be possible to delete certain painful memories from our conscious brains, as suggested in the film Eternal Sunshine of the Spotless Mind?

We all know what it feels like to remember something, like your first kiss or childhood home, but where in your brain are these memories stored, how do we gain access to them and is it possible to enhance or remove them?

These are questions neuroscientists have spent many years researching. The search for a physical manifestation of memory has taken us on a journey from the truly bizarre (for example a now disproved theory assumed that specific memory molecules existed in the brain and that these could be transfered from one individual to another by eating brain tissue), to our current view that memories are spread throughout the brain and develop when small changes occur in the structure of and connections between neurons (for more detail on synaptic remodeling and plasticity see my previous post). We hope that the more we understand about memory formation and storage, the closer we will come to being able to manipulate them and potentially offer relief to people with memory related illnesses.

PKMZeta structure.

When a memory is first formed a number of proteins become active within participating neurons. These proteins help reshape the neurons thus making the memory permanent. Once this reshaping is complete the proteins involved in the process once again become inactive. It was believed that once reshaping had taken place it would be difficult for us to further modify these neurons to remove or enhance specific memories. However, research conducted within the past 20 years is now questioning this assumption. Researchers have uncovered a protein (PKMZeta) which, unlike others involved in memory formation, remains active in cells long after the initial memory forming event…perhaps indefinitely. This discovery led scientists to question whether PKMZeta may hold the key to maintaining memory and, if so, whether this system could be experimentally manipulated.

Amazingly it seems that this is indeed the case. Scientists have found that blocking the activity of PKMZeta days or even months after learning has taken place can interfere with a rats ability to remember a location, a specific taste or an unpleasant experience. Not only does blocking its activity lead to forgetting, but boosting its activity also has the ability to enhance old faded memories.

Total brainwashing is certainly something we should avoid.

Although the discovery of PKMZeta may be a step forward in finding a treatment for memory disorders, it is important that we proceed with caution and ensure we understand the effects this protein has on the memory system before speculating over its pharmacological value. From current research, scientists believe that the memory enhancing or eradicating effects of PKMZeta are not specific to single memories, indeed they may influence multiple memories at once. Therefore, it is important we understand what memory traces are altered by this protein and how it could be made more selective before considering its wider uses. Removing or enhancing multiple memories non-selectively is certainly not desirable! However, the stage is now set for progress in this field and as our understanding grows there may come a time when we can play a more active role in memory formation and retention.

Post by: Sarah Fox