Saturday, March 28, 2009

Like music to my brain

According to a new study, you don’t need to be a psychic mind reader to connect with someone else through your brain. All you need is a little jazz.

In everyday life, we often have to coordinate our actions with others. Playing team sports, playing music instruments or singing in a group, dancing, even walking with someone side by side all require that we pay attention to what other people are doing and coordinate together (of course, if I’m dancing, I am generally unable to pay attention to anything but myself, so don’t bank on it). What’s more, coordinating with other people doesn’t only happen when we’re moving. Bonding socially, like when you really hit if off with your speed date and you gaze lovingly in each other’s eyes, also requires coordinated activity.

So what allows us to connect with other people’s minds to sync up with them while dancing or dating? Well, the mechanism for coordinating activities needs to meet two constraints. First, it has to be fast. If you’re trying to dance with me, you only have a split second to react before I stomp your toes mercilessly. Second, it needs to integrate sensory information (where is my foot?), motor activity (removing foot from stomping zone) and brain activity. The best candidate to meet these constraints may be brain oscillations. The cells in your brain (neurons) communicate through electrical signals, and these can be measured using a technique called electroencephalography (EEG). The oscillations are fast, and they bind information in your brain that is related, but not necessarily in the same area. On top of that, we know that these brain oscillations are involved in perception and motor activity. A team of researchers from Germany and Austria set out to examine what happens to those brain waves when we coordinate with others.

In the study, the researchers investigate if two guitarists playing jazz together will have synchronized brain waves. They measure EEG frequency and synchrony during the preparatory period (when the two guitarists are getting ready to start and are listening to a metronome giving them the beat), when they start playing the piece, later during the piece, and after the piece. And, because I’m sure you’re dying to know, the music they played was a jazz-fusion piece composed by Alexander Buck.

The results show that the brains of the guitarists exhibit synchronized brain waves during the preparatory period, at play onset, during the piece, but not at the end when the show is over. The highest level of synchronization is at the moment just when they start playing together.

There are a few limitations to this study. The sample size is small, only 8 pairs of guitarists (though all of them showed synchronization). The other limitation is that both guitarists in a given pair get the same sensory information (they hear the same metronome, are in the same room, etc) and they make the same motor movements (as they are playing the same piece), so it could just be that their brains react in a similar way. But, given the timing and the frequencies of the brain wave synchronization, the authors make a good case for this synchronization resulting from interactions between the two guitarists and not just similarities in the sensory input and motor output.

That our brain waves sync up with others is a pretty neat finding and could explain our ability to coordinate with others when we are engaging in many different activities. This may also have implications for interpersonal relations, such as mother and child bonding. To dig a bit deeper, I wish the researchers had done the same experiment on two people playing Guitar Hero. Would the brain waves synchronize if the guitarists are paying attention to a cue from the screen instead of each other? What do you think? What implications does this finding have for our increasingly virtual modes of communication and interaction?

A person wearing electrodes for EEG

Monday, March 23, 2009

Emotional forecasting: The weather man is your friend!

Some of you may recall my earlier success at understanding article titles in the journal Science. Well, I did it again! I score another 100% with a fascinating study published this week titled “The surprising power of neighborly advice”.

The researchers begin their article by insulting us, suggesting that we are terrible at guessing how we’re going to feel about future events. I personally disagree, I’m pretty sure I know just how good it’s going to feel to one day finish my PhD! I’m going to be ecstatic! I’m going to be elated! I’m going to cry with joy! You get my point. Anyway, the researchers suggest otherwise, saying we often overestimate how happy we’d be to say, win the lottery (yeah, right!), as well as overestimate how unhappy we’d be to say, not get a promotion. That’s because our strategy to estimate our reaction to future events is to imagine them, but apparently we’re bad at that too (so far, it’s not looking good). So we make mistakes. But there is hope! Their research suggests that we can get a better idea of how we’ll feel during future events, all we need to do is ask a friend.

The study revolved around speed dating (quite a sexy topic when it comes to science!). Women were told they were going on a 5 minute “speed date” with a guy, and they were given one of two types of information about the guy. The first type of information was a document with the guy’s profile: his picture, his background, activities he enjoys doing (long walks on the beach, no doubt), his favorite movie, book, etc. This is called “simulation” information because it made it possible for the woman to imagine what the date would be like. The second type of information was a document with another woman’s appreciation of a speed date with the same guy. This is called “surrogation” information because the woman going into the date can use the woman who already met the guy as a surrogate for herself. Just before meeting the guy, the woman had to tell the researchers how much she thought she’d enjoy the date based on the information she got.
After the date, she gave a report of how much she actually did enjoy the date.

The outcome of the study is two-fold. First, the women were way more accurate in their prediction of how much they’d enjoy the date if they used surrogation information (another women’s point of view). Second, opposite to what worked best in reality, most of the women believed that simulation information would allow them to make the most accurate prediction about their date. Even more surprising, over 80% of the women indicated they would chose simulation over surrogation information to make a prediction about a future date with a different guy.

How is this relevant? Well, it tells us that the best way to make a decision that’s right for us is to get advice from others. It also tells us that we tend not to take advantage of this type of information, even though it can be quite useful. A great example of surrogation information is “review” websites such as epinions and dinehere. When going to buy their next electronic gizmo or dine out at a new restaurant, more and more people will check for neighbourly advice online rather than just trusting the ‘specs’ or the menu. There’s nothing like the cover of anonymity to tell the world what you really think of it…

After reading this study it sounded like I needed to double check just how I’ll feel about finishing my PhD with my fellow labmates who’ve been there, and yes it’s confirmed: I’ll be crying with joy. And doing the happy dance.

Cartoon courtesy of Doug at

Saturday, March 21, 2009

Can your environment change your genetic code?

Before I start, allow me to apologize about today’s slightly morbid study. While this blog entry will have to do with child abuse and suicide, bear with me, it will also reveal an interesting contribution to the age-old question of nature versus nurture. What makes you who you are? Is it your genes? Is it your environment? Some will say it’s your genes: I have green eyes because of my genes, and I am unfortunately neither tall nor blonde because of my stupid genes. Others say it’s your environment: I am able to speak French and English because of my family and geographical environments, and I have an obsession with sugary cereal because when I was growing up my older siblings always go to the box before I got a chance to (also, they happen to be magically delicious!). In reality, it’s a combination of both, and to complicate things a little, sometimes the environment messes with your genes, as beautifully demonstrated in a recent article published in the journal Nature Neuroscience.

In the article, a team of researchers from Montréal studied the effects of child abuse on the brain by comparing human brains from 3 different groups. Subjects in the first group had suffered from child abuse and later committed suicide. Subjects in the second group had not suffered from child abuse and committed suicide. Finally, subjects in the third group had not suffered from child abuse and died in an accident (as the study required human brains, sadly the tragic ends were necessary).

The first thing the researchers looked at was how much a gene called NR3C1 was activated in those brains. Genes are small segments of DNA that contain a code (a recipe) for a given protein. When they are active (or “expressed”), the machinery in your cells is reading the recipe and making the proteins. In this case, the gene NR3C1 is the recipe for a protein called glucocorticoid receptor. The glucocorticoid receptor is involved in many body functions, but the researchers in this study are especially interested in the fact that this receptor is an important player in how your body handles stress.

As it turns out, the brains of the subjects who had suffered from child abuse had significantly lower expression of the NR3C1 gene, and therefore fewer glucocorticoid receptors, than subjects from the two other groups. Since all the subjects in all the groups have the same NR3C1 gene, the researchers then set out to investigate why, if you suffered childhood abuse, would your machinery not read the NR3C1 recipe and make as much of the receptor. They showed that this is due to epigenetics (where epi means in addition to). Epigenetics happen when there are changes to the activation of a gene that is not due to a change in the gene’s recipe. In this case, certain parts of the NR3C1 gene are susceptible to a change called methylation, which essentially means sticking a bunch of methyl groups (close relatives to methane) right onto the recipe. These stickers prevent the machinery from reading the recipe, and so less glucocorticoid receptors can be made. Since those receptors are involved in how your body handles stress, if you have less of them, then presumably your body won’t be able to handle stress as well.

In summary, the take-home message of this article is that the environment, in this case childhood abuse, can influence how your genes are expressed, and that can shape who you are, for example how well you handle stress. It’s no surprise that kids that experience childhood adversity are more likely to display suicidal behaviors.

Now it had already been shown in animals that how well the mother cares for the offspring can influence how the offspring handle stress, so that’s not a complete shocker, but it’s nice to see an explanation of the mechanism for this and it’s also nice to see this confirmed in humans. I recently saw a talk from Dr Sydney Brenner, a Nobel Prize recipient in physiology and medicine, and he thought we should quit bugging our little furry friends and start experimenting on ourselves. Now there’s an ethical debate for another day, but once in a while, it’s nice to see that research in animals can be relevant to humans.

Tuesday, March 17, 2009

Superbugs: Science in the household

Prior to embarking on the adventure that is the PhD in neuroscience, I completed an undergrad in microbiology and immunology in Montréal. Microbiology, with its immediate medical and environmental applications, is a science that’s very relevant to everyone in many ways. Microbiology also gives us the two everyday staples that are beer and cheese. Why I would choose to move away from a potential career of making tasty, tasty cheese to poke at mouse brains, I’m still not sure. But today, I bring microbiology back to tell you about a nice study on how our everyday actions can directly impact our health. Now that’s relevant science.

I’m sure you’ve heard about superbugs, bacteria that are resistant to all the most powerful antibiotics known to man. These strains arise from natural selection (survival of the fittest bug!), either following a random mutation or environmental pressure. Say you have a viral infection, but the doctor prescribes you antibiotics anyways (as of 2002, 53% of Canadians still believe antibiotics kill viruses, by the way). You take them, and as a result, the bacteria of your natural flora (the “good” bacteria) become resistant to the antibiotic through survival of the fittest. In addition, instead of storing this resistance in their genome, they store it in this free-floating DNA loop called a plasmid. Then, let’s say you accidentally cut yourself while chopping up raw chicken on a dirty cutting board (bad day!). You get a bacterial infection. Bacteria are quite friendly with each other, and while they’re making you miserable, your good bacteria end up passing the resistance to the bad bacteria by literally fusing together and exchanging a copy of the plasmid (this is called horizontal transfer, as opposed to vertical transfer, when they pass it on to their offspring). Now when you get antibiotics for your very real bacterial infection, they won’t work. That’s just one simple example of superbugs in the making.

The problem is, even if you’re not sick, chances are you’re using antibiotics. In your home. Everyday. Cleaning products, disinfectants, hand soaps, many of those have biocide products in them. In 2008, a group of researchers wondered if maybe that was responsible for generating antibiotic-resistant strains of bacteria. They enrolled over 200 households split into two groups: one group would use cleaning products and hand soap with antimicrobial agents in them for one year, the other would not (well, they would still clean, just not with biocides). Before and after the study, the researchers took bacterial samples from the hands of the people from each household. As it turns out, the bacterial isolates from the group who used biocides had significantly more bacteria that were resistant to one or more antibiotics. Are you surprised? Me neither.

Now that doesn’t mean those were superbugs that would definitely cause health issues, but this should be reason for concern. Continuously exposing bacteria to antibacterial-containing products is pressuring them to select their “fittest bugs”, those who have reduced susceptibility to antibiotics. As it turns out, another study published in The Lancet in 2005 (I’ll spare you the details) showed that it makes no difference whether you use antibacterial soap or regular soap to wash your hands, they end up just as clean either way. And, as an added bonus, we’re doing the environment a favor when we use biocide-free cleaning products and soaps. That’s what we call a win-win situation!

Staphylococcus aureus, a bacterium that can be responsible for antibiotic-resistant infections in humans. Image from the Agricultural Research Service, the research agency of the United States Department of Agriculture.

Sunday, March 15, 2009

Had a bad day? Erase your memories!

The reputable scientific journal Science just published an interesting article about memories called “Selective Erasure of a Fear Memory”. I especially like the fact that I understand 100% of the words in the title (unlike another article from the same issue, “Generation of Follicular B Helper T Cells from Foxp3+ T Cells in Gut Peyer's Patches”, where I score a meagre 46%).

How memories are stored in the brain has always been a mystery. It is thought that each memory is stored in the form of a group of brain cells (neurons), but it’s practically impossible to confirm that because those neurons are all over the place. We do know, however, that a brain region called the lateral amygdala (LA) is where fear memories are stored. Say you’re just a kid and your older sibling decides to make you watch Poltergeist (am I the only one who went through this?). During the really scary parts of the movie, your neurons in the LA make a ton of this protein called CREB (yet another acronym, it stands for cyclic adenosine monophosphate response element binding protein). That’s the tell-tale sign the researchers used to try to identify and then destroy the neurons responsible for fear memories.

They used an experiment called fear training (sounds like torture? Just think about all the people who willingly volunteered to be on “Fear Factor”). They put a mouse in a special cage, and then they play a tone. Right after the tone, the mouse gets a little shock on its feet. The mouse eventually catches on, and freezes when the tone is played (freezing behavior is how we know the mouse is scared). The really clever part of this experiment is that the researchers managed to engineer in the mouse a genetic switch that would selectively kill the neurons that made a lot of CREB (the ones presumably responsible for the fear memory). So after training the mouse to be scared of the tone, they flipped the switched on, the CREB-making neurons died, and voilà! The mouse forgot its fear of the tone and no longer freezes.

So, ok, researchers fried part of this mouse’s brain, and the mouse won’t freeze anymore. Sure, but will the mouse do anything anymore? I don’t know about you, but I’m picturing the mouse in a post-lobotomy state, drooling a little, unmotivated to do anything. Apparently not so. The researchers did a bunch of control experiments to show that the mouse could still run through mazes, store new memories, and even re-learn to be afraid of the tone, if properly trained. They also showed that if you just kill a bunch of random LA neurons (instead of just the ones that make lots of CREB), erasing memories doesn’t work.

So is this relevant? Well, it’s a great contribution to our knowledge of how memories are encoded and stored. A lot of people are excited about this because they see a potential therapy for post-traumatic stress disorder, but to be fair, applications in humans are very, very far down the road, regardless of what the movie “Eternal Sunshine of the Spotless Mind” suggests. If you had a choice, would you erase some bad memories of your past? How did those memories shape the person you are today?

Saturday, March 14, 2009

The jellyfish's contribution to science

I recently had the privilege to attend a lecture by Dr Roger Tsien, one of the three 2008 Nobel laureates for chemistry. His talk was fascinating, so I thought I would kick-off my brand new science blog by telling you a little bit about the reason these guys got the Nobel prize and why it’s relevant science.

The 2008 chemistry Nobel prize was awarded for the discovery of GFP, which stands for Green Fluorescent Protein. It was isolated from a jellyfish, and it fluoresces green when exposed to blue light, hence the name. You’d think they’d come up with a more exciting name, but lately it seems acronyms are all the rage. I wouldn’t blame you if you thought that a fluorescent protein would be very cool, but overall useless (kind of like those fluorescent lights some people like to “pimp up” their cars with). However, the Nobel prize committee is not known to award prizes for useless discoveries.

GFP has become one of the most widely used and studied proteins in biology research, because you can use it and manipulate it to make it work for you. For example, you can use GFP as a tag: by choosing specific proteins or genes and then labelling them with a fluorescent GFP tag, you can look at where the proteins are distributed and where the genes are expressed in a single cell all the way up to in a whole animal. Used as a tag, GFP can also change the way we use models to study specific questions. Let’s say you’re interested in studying Parkinson’s disease. This disease targets a specific kind of brain cell called dopamine neurons. Using GFP, you can engineer a mouse so that only dopamine neurons are fluorescent, making the study of those neurons much, much quicker and simpler.

In addition to tagging applications, GFP can also be used as an active indicator. Scientists have been mutating (yes, on purpose!) GFP to make it sensitive to the environment or to interactions with different proteins. For example, you can make GFP sensitive to how much calcium is in a cell, which allows you to visualize dynamic calcium changes in living cells. Who cares, right? Well, if you know someone with Alzheimer’s disease, you might care. The amount of calcium needed to keep your cells healthy is held in a very delicate balance, and in some diseases, like Alzheimer’s, this balance is tipped, which is bad news for your brain cells. Getting back to GFP, this means that being able to tell what influences the calcium balance using tools like calcium-sensitive GFP is the first step in finding good therapies for preventing and curing certain diseases.

So why is the discovery of GFP relevant science? It’s a tool that has tremendously sped up many aspects of research in health-related fields. New generations of fluorescent molecules offer even more real-life applications: some labs are working on making tumors glow for easier surgical removal. So next time you see a jellyfish laying on the beach, resist the urge to poke it with a stick (so hard, I know...). It is making a great contribution to health research. It also allows bored scientists to make really cool works of art:

A San Diego beach scene drawn with an eight color palette of bacterial colonies expressing fluorescent proteins derived from GFP and the red-fluorescent coral protein dsRed. The colors include BFP, mTFP1, Emerald, Citrine, mOrange, mApple, mCherry and mGrape. Artwork by Nathan Shaner, photography by Paul Steinbach, created in the lab of Roger Tsien in 2006.

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