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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 13^th 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.

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)

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 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!

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

The study of the self, what makes us unique and how our brains define who we are is an intriguing and often controversial area of research. Indeed, such work may eventually shape many aspects of society from education to criminal justice.

We already know that damage to the brain can permanently alter an individual’s personality and that the type of alteration depends on the region damaged. One of the most famous examples of brain damage leading to a shift in personality was the case of Phineas Gage. Gage worked as a foreman leading a team of workers preparing the ground for a new railway line. On the 13^th September 1848 an accidental explosion blew an iron rod, over 3 feet long and 1 ¼ inches in diameter at its widest point, clean through his head. Although amazingly he survived the incident, he lost sight in his left eye and suffered significant damage to his left frontal lobe. Following the accident, although his intellect remained intact, it is reported that he changed from being a conscientious well liked man to a fitful disrespectful individual with a particularly foul mouth. Indeed, the changes in his personality were so significant that his former employers were forced to let him go.

Gage’s tragic accident was one of the first pieces of evidence linking frontal cortex damage to antisocial personality traits. The knowledge that such physical brain-damage can precipitate a change in personality raises the question of whether undesirable traits seen within the general population can be linked to subtle changes in brain function and ultimately whether these ‘defects’ may be treatable.

An area where a combination of genetics and functional brain imaging is raising just such a question is the study of psychopathology. Scientists have observed genetic and physiological differences in the brains of a number of diagnosed psychopaths. Specifically, brain scans of these individuals reveal lower than average activity and reduced communication between the orbitofrontal cortex and amygdaloid brain regions. Together these regions are important for making emotionally driven decisions, learning from the emotional content of experiences and controlling impulsive behaviour.

These brain changes are often seen in combination with a rare form of the monoamine oxidase A (MAO-A) gene known as the ‘warrior gene’. This gene codes for a protein (MAO-A) which can influence the communication of cells in a number of brain regions. Alterations in this gene lead to abnormal cellular communication, and have also been linked to behavioral abnormalities.  Indeed, individuals with the ‘warrior’ version of this gene are more susceptible to developing antisocial and often violent tendencies, especially if they also experienced maltreatment during early childhood.

Although studies of many psychopathic killers reveal the presence of both the ‘warrior gene’ and reduced orbitofrontal/amygdaloid activity, this is by no means the end of the story. Amazingly James Fallon, a neuroscientist from the university of California who had been studying the brains of psychopaths, recently uncovered some disturbing family history of his own; leading to the disquieting revelation that he himself showed both the same brain type and genetic profile as the psychopathic killers he studied. Although he admits to not always being in-tune with other’s emotions, professor Fallon is a caring husband and father who has never been in trouble with the law. These findings raise the question of how important a biological predisposition towards psychopathy is and how this may be overcome. Professor Fallon notes that he was lucky to have a very warm and loving childhood, and believes that his upbringing likely played a role in preventing any biological tendencies toward psychopathy from taking effect.

Work such as this is beginning to uncover the amazing interplay between our brains and our selves. However, as knowledge in this area increases, many of us can’t help but question where this research is leading and how these findings may be used. Although I believe we are a long way from hearing ‘my brain made me do it’ as an acceptable defence in our courts, this research is already influencing our education system. One pioneering school in the south of England accepts children with behavioural difficulties associated with low amygdaloid function. Along with their regular lessons children are taught how to recognise and respond to emotions in a socially acceptable manner. These children are considered to be at risk of developing antisocial or even psychopathic tendencies and it is hoped that this training will help them integrate into society and lead normal successful lives.

Post by: Sarah Fox

Now there’s an intriguing question…

I’m sure many of us recognize that feeling just before an important interview when your palms get sweaty and your stomach becomes home to a kaleidoscope of exceedingly acrobatic butterflies. These unfortunate effects of anxiety appear largely unavoidable and are certainly not often classed as beneficial.

However, scientists from the university of Kiel (Germany) believe that the smell of anxiety may induce feelings of empathy in others. This means that the nerves you feel may actually buy you some sympathy in that feared interview.

The study collected armpit (or to use the more fancy scientific terminology: axillary) sweat samples from a group of people both during exercise (non-anxiety condition) and during a nerve wrecking oral examination (anxiety condition). A second group were then exposed to these odors whilst undergoing an fMRI brain-scan. This allowed the scientists to monitor how these odors influenced their brain activity. Interestingly, although subjects did not consciously recognize a difference between the smells of exercise and anxiety sweat, their brains told a different story!

The smell of anxiety activated a number of brain regions believed to be important for recognizing anxiety in others and converting these observations to feelings of empathy. These regions include the insula and orbitofrontal cortex, precuneus, cingulum and fusiform gyrus, shown below. These regions were not activated to the same degree by the smell of exercise sweat.

This work suggests that our brains can detect the smell of anxiety on others and respond by making us more empathetic towards that individual. However, before you decide to ditch the deodorant, it must be noted that despite these compelling fMRI findings, none of the subjects consciously reported feelings of empathy! This could mean that, although our brains can unconsciously register the smell of anxiety and prime us to fell empathy, further physical stimuli may be required before we can consciously recognize and act on these feelings.

So to answer my question ‘could stress actually help you pass a job interview’: perhaps, but more work needs to be carried out first to find whether these unconscious brain signals will actually translate to conscious feelings of empathy in such a situation.

Post by: Sarah Fox

The full paper can be accessed free of charge here: