Tuesday, December 28, 2010

The year in review

As the year draws to an end, it’s time to compile the exciting discoveries that marked 2010. Here is a snapshot of my top 5, in chronological order:

Study #5: Communicating with the minimally conscious

In a nutshell:
An imaging technique, functional magnetic resonance imaging (fMRI), allowed researchers to communicate with patients in a vegetative state. Researchers asked yes/no questions, and the patients answered by thinking of playing tennis for yes or thinking of a house for no. The resulting brain signals from these thoughts could be imaged, interpreted and used for communication.

The good: This technique gives great hopes for friends and relatives of patients in minimally conscious states.

The bad: The study was heavily criticized: only one patient was tested, and the technique is far from perfect.

What’s next? We will no doubt hear more about this in the near future. The first step will be to replicate these findings with a greater number of patients.

Study #4: The synthetic cell

In a nutshell: Researchers made synthetic DNA and incorporated it into an empty bacterial cell, thereby creating a fully functioning cell with a man-made genome.

The good: This study represents a technical feat and opens new doors in the fields of molecular and cellular biology.

The bad: Like transgenic organisms before this, the synthetic cell re-opens the Pandora box of ethical questions.

What’s next? Human-engineered cells will probably play a role in gene therapy and in the quest to build tissue in a dish.

Study #3: Brain training doesn’t work

In a nutshell: A study of computerized brain training using over 11,000 participants showed that people improved at the tasks they practiced, but this improvement didn’t extend to general cognition.

The good: This study urges caution when buying into the brain training craze.

The bad: The results may be misleading: it’s not because the researchers didn’t see any improvement that there weren’t any. The brain training could have been inadequate or the researchers could have been measuring the wrong parameters.

What’s next?
More controlled studies will be needed to determine the effectiveness of the games. Brain training is likely to become increasingly specialized: training for older adults, for children with autism, etc.

Study #2: Optogenetics

In a nutshell:
Researchers were able to control brain cells using light, and rescued symptoms of Parkinson’s disease in mice.

The good: I said it before and I’ll say it again: optogenetics has the potential to revolutionize medicine.

The bad: The technique is quite complex and difficult and so far only possible in small mammals.

What’s next? Researchers are already testing in larger mammals and developing new ways to deliver light into the brain.

Study #1: The slut gene

In a nutshell: Researchers found a relationship between a specific version of a gene and promiscuous sexual behaviors.

The good: The study provides new insights into the link between genes and human behavior.

The bad: It’s not that simple.

What’s next? You can expect more studies of the “this gene does that” type. However, researchers are increasingly interested in how the environment can impact the expression of genes, and the story is bound to get even more complicated.

Looking forward to more gems in 2011!

Happy New Year!

Monday, December 20, 2010

Prozac for puppies

Separation anxiety isn’t just for babies anymore: one in two dogs is thought to suffer from separation-related behaviors when their owners leave the house. These behaviors take many forms, from chewing your favorite pair of Jimmy Choo’s (Santa Baby… I want Jimmy Choo’s) to yapping uncontrollably until the neighbors call the police. Seeing as this may represent a serious problem in animal welfare, a team of researchers assessed the relationship between separation-related behaviors and the overall moods of dogs.

The researchers used 24 shelter dogs and started by measuring whether each dog suffered from separation anxiety. To do this, a researcher played with a dog for 20 minutes in a designated room. The next day, the dog was taken to the same room, played with for a few minutes, then left alone for five minutes. The dog’s behavior during those five minutes was analyzed and graded as a “separation anxiety score”.

A few days after the test, the researchers conducted another experiment to assess whether each dog had a pessimist or optimist outlook. In order to achieve this, they trained the dogs to learn that when in a given room, a food bowl placed at the very left of the room always had a treat in it, and a food bowl placed at the very right or the room never had a treat in it. Once the dogs learned this, the researchers placed a food bowl right in the middle of the room. Presumably, dogs that ran fast to see if this new bowl has a treat in it were anticipating that it had food in it and were considered to be “optimistic”, whereas dogs who either slowly made their way over or didn’t bother to check it out were considered to be “pessimistic”. It’s kind of a dog version of the glass half-full or half-empty paradigm.

The relevant finding of this article is that the researchers found that dogs who experienced separation anxiety were more likely to be of the “pessimistic” kind. Pessimism is thought to be related to negative moods, and knowing this may help in figuring out how to avoid chewed-on Jimmy Choo’s.

While I thought the study was quirky and interesting, I found it a bit of a stretch to label these dogs as optimistic or pessimistic using such a simple experiment. The researchers themselves owned up to this by saying that “the conscious experience of such a state [optimistic/pessimistic] cannot be known for sure”. When I read the article, I thought maybe the dogs who went for the food bowl in the middle were just more curious than others, and I’m not sure how curiosity relates to optimism (for example, I consider myself to be quite curious, but not necessarily optimistic: I browse the Jimmy Choo website to see what the new styles are, but I don’t envision ever owning a pair). As well, I thought the measure for separation anxiety was a bit weak. While it’s a known experiment, it’s not immediately obvious to me that the behavior of these pound dogs relates to the behaviors you would observe in dogs with a stable home.

Still, it’s a good reminder to keep our pets as happy as possible, especially during the holidays when routines are broken and moods are uneven.

Reference: Dogs showing separation-related behaviour exhibit a “pessimistic” cognitive bias (2010) Mendl M. et al. Current Biology, 20(19):R839-40.

Saturday, December 11, 2010

Food for thought on thoughts for food

Christmas party season is officially upon us. The next few weeks are pretty much going to be a long string of turkeys, stuffing, various things made with cranberries and cutesy Christmas cookies à la Martha Stewart. Faced with this, many of us who are concerned with staying trim and not slipping into food comas on a daily basis may be feeling a little apprehensive. Well, fear not! New research published in the journal Science suggests you can eat less by simply… Thinking more about food!

The study looks at the relationship between the concepts of mental imagery (imagining doing things) and habituation (getting used to things). Through mental imagery, imagining things can affect your body and your emotions just as much as the real thing: just thinking about a spider crawling on your neck can lead to the same feeling of tingling and fear as if it was actually happening. The second concept, habituation, refers to the decrease in your body and your mind’s response to a stimulus. For example, your tenth bite of stuffing is not nearly as satisfying as your first. Given these two principles, the researchers asked if you could habituate to a food just by imagining eating it.

The participants in the study were divided into two groups and each group was asked to imagine doing a task. The first group was asked to picture eating 30 M&M’s, one at a time. The second group was asked to picture putting 30 quarters into a laundry machine, one at a time. After this mental imagery task, the participants were each put in front of a bowl of M&M’s and told to eat as much as they wanted as a preparation for a “taste test” later on (obviously, the taste test is fake, it’s just an excuse to get the participants to eat). The researchers then weighed the leftover M&M’s and measured how much each participant had eaten. They found that those who pictured eating M&M’s ate significantly less candies than those who pictured feeding a laundry machine!

The researchers then compared participants who imagined eating only three M&M’s with participants who imagined eating 30. They found that participants who imagined eating more M&M’s ended up actually eating fewer of the real ones. This means that habituation (doing something repeatedly) is key to observe an effect of mental imagery.

So whether your drug of choice is M&M’s, stuffing or cheese balls, you may be able to minimize the holiday damage by doing a little mental exercise. Now if only I could just picture purchasing and wrapping a bunch of presents…
Reference: Thought for food: imagined consumption reduces actual consumption. (2010) Morewedge CL et al. Science 330:1530-1533.

Monday, December 6, 2010

"The slut gene" or "Why reporters should read science articles to the very end"

This week, I’m going to start with a quality science headline:

“Like to sleep around? Blame your genes”


The story behind this headline comes from a study of human sexual behaviour. Different people have different sex drives and different sexual behaviours, and we don’t know why, so American researchers set out to solve the mystery.

The researchers enlisted 181 male and female young adults and asked each one for a detailed history of sexual behaviour and relationships (awkward!) and a sample of spit. The spit was used to analyze the participant’s DNA and to look for a specific version of a gene called DRD4 (subsequently dubbed “the slut gene” by the media). The results of this study show that participants who have the specific version of this gene are more promiscuous (researchers actually used the words “one-night stand”) and report more instances of sexual infidelity. Well, there you have it. Free will is overridden by our genes.

How does this work? Your brain’s reward system is called the dopamine system (DRD4 stands for Dopamine Receptor D4), and among other things, it takes care of your motivation for sensation-seeking behaviours like having sex. This happens through the flow of dopamine molecules, which act as a message transmitter in your brain. For a brain cell to receive a message conveyed through dopamine, it needs a dopamine receptor like the D4. The gene that encodes this receptor (DRD4) comes in two forms: one that binds dopamine tightly and one that binds dopamine not as tightly. If you have the version of the gene that encodes the receptor which doesn’t bind dopamine tightly, you need more dopamine to achieve the same end-result in your brain (the feeling of reward), hence the string of one-night stands.

So are cheating and one-night stands excused because our genes made us do it? At the risk of becoming unpopular, I have to say the answer to that is no. The relationship between the special version of the DRD4 gene and promiscuity is not deterministic: having the gene doesn’t automatically lead to one-night stands. Many people in the study had the gene and didn’t cheat. The gene-sexual behaviour relationship is what we call probabilistic: having the gene only increases the probability that you would exhibit a given behaviour. What’s more, our environment can change how different genes are expressed, and it is possible to modify our behaviour. No excuses!

There are also two caveats to note in this study. The first is that not all the results were statistically significant. For example, 50% of people with the special version of the gene reported being unfaithful, compared with 22% for the participants with the normal version. While this may seem like a big difference, it was not significant because they are not looking at a big enough sample of people to ensure this couldn’t happen just by chance. The second problem is that the relationship between the gene and sexual behaviour could be due to a confounder, which is a variable that has not been studied that could explain the results. For example, if having the special gene makes you more honest about your sexual history, then these results would be due to a truth-telling tendency, not a sleeping around tendency.

My favorite part of the entire research article is at the very end when the researchers write:

“…we emphasize that it would be prudent to avoid premature and facile characterizations of the DRD4 VNTR polymorphism as “the promiscuity gene” or “the cheating gene.”

It’s funny, but it’s also a bit sad. They saw the “slut gene” stories coming from a mile away.

Reference: Associations between dopamine D4 receptor gene variation with both infidelity and sexual promiscuity. (2010) Garcia JR et al. PLoS ONE 5(11):e1412.

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