Big-Brained Athletes

I'm a little late posting this one here, but last month I wrote a story for Wired Playbook on how athletes, much like musicians, seem to have brains that are beefier in certain areas.

Instead of just comparing the brains of athletes to non-athletes -- a correlation that wouldn't necessarily show if sports causes the brain to gain mass or if people with a thicker cortex in these areas are more likely to excel in athletic competition in the first place -- the researchers determined how each year of practice correlated to changes in the brain:

However, in one of the brain areas studied, the researchers found that the number of years each athlete competed as a diver nearly predicted how thick the subject’s brain would be. If the results of this small study hold, there may be some biological truth to the adage, “practice makes perfect.” It’s as if each year of sports experience becomes neatly folded as a new layer of neurons atop previously mastered skills, physical knowledge, and competition know-how that have already been crammed into the brain.

I think it's interesting to think about how these findings could impact sports statistics in the future. I mused:

These findings provide a small glimpse of how biometric and neurological data may one day be used to gauge a player’s ability and performance. Granted, there’s still a lot of work to be done in understanding exactly what’s going on in an athlete’s head.

Read the entire story here.

Photo via Flickr / alandberning

Wei, G., Zhang, Y., Jiang, T., & Luo, J. (2011). Increased Cortical Thickness in Sports Experts: A Comparison of Diving Players with the Controls PLoS ONE, 6 (2) DOI: 10.1371/journal.pone.0017112

Brian Mossop is currently the Community Editor at Wired, where he works across the brand, both magazine and website, to build and maintain strong social communities. Brian received a BS in Electrical Engineering from Lafayette College, and a PhD in Biomedical Engineering from Duke University in 2006. His postdoctoral work was in neuroscience at UCSF and Genentech.

Brian has written about science for Wired, Scientific American, Slate, Scientific American MIND, and elsewhere. He primarily cover topics on neuroscience, development, behavior change, and health.

Contact Brian at brian.mossop@gmail.com, on Twitter (@bmossop), or visit his personal website.

My Scientific American Story on the Father-Child Bond

Sorry, but this post is nothing but shameless self-promotion! My first short feature article was published in Scientific American today, which discusses the neurobiology of the father-child bond.  Give it a read!

Last May, I took a trip to San Diego for my brother-in-law’s graduation from college, and to meet his 4-month old son, Landon, for the first time. Throughout the weekend, I couldn’t suppress my inner science nerd, and often found myself probing my nephew’s foot reflexes. Pressured from my wife’s disapproving looks and the blank stares I received from her family as I explained why his toes curled this way or that, I dropped the shop-talk in favor of baby-talk.

Click here to read the rest.

Sex, Stress, and Neurogenesis

There’s an article in the latest issue of Wired by Jonah Lehrer explaining just how dangerous stress can be to our health.  It’s a fascinating read -- and instead of relying on my poor attempt to paraphrase -- I suggest checking out the article in its entirety.

The part of the story that struck a particular chord with me was Lehrer’s explanation of the experiments done by Elizabeth Gould, who studies how stress hormones affect the growth of new brain cells in adult brain, a process called neurogenesis.  Gould’s previous work, as noted by Lehrer, showed that when animals get stressed out, levels of glucocorticoids -- one type of stress hormone -- skyrocket in their brains.  With brain cells wading in a constant bath of these stress hormones, neurogenesis comes to a screeching halt.

The take-home message from Lehrer’s article: glucocorticoids are bad.  And indeed, they do make bad things happen in the brain.  Aside from the fact that stressed-out animals have less neurogenesis, if you take an animal and inject glucocorticoids directly, new brain cells also stop forming.  Lehrer’s suggests that if we find ways to prevent or otherwise interfere with stress hormones (through a vaccine or otherwise), we could mitigate the effect stress has on our emotional well-being and, ultimately, its complex interaction with disease.

I’ve been putting off (for several weeks now) writing a post on the most recent experiment to come out of Gould’s lab, published in mid-July in PLoS One.  Lehrer’s story finally lit the fire under me.

The term “stress” has a very deliberate negative connotation.  We need this term to bucket somewhat-hard-to-explain feelings, like experiencing “pressure” at work.  But the term is far more encompassing than that.  Stress, by definition, is a measure of how the body responds to a challenge.  Sometimes the challenge can be a threat -- a deadline at work or a difficult family situation -- and triggers the all-too-familiar anxiety we’ve come to expect.  This is the bad type of stress Lehrer discussed.  But the challenge can also be a something, well, good, that temporarily takes our body out of balance.  Consider what happens when you exercise.  Going out for a run will create a physiological burden as the heart beats faster and faster, trying to match blood flow to the demands of the muscles and lungs.  This physical exertion is also a type of stress, a good kind of stress, if you will.

The effects of the two types of stress on the brain are completely different: While the bad stress decreases neurogenesis, the good type of stress, on the other hand,  actively stimulates extra brain cell growth.  Although the brain responds in different ways, both good and bad stress increase the levels of glucocorticoids in the body.  Knowing glucocorticoids are dangerous to the brain, researchers still scratch their heads over how exercise could battle these stress hormones, and win.

But Elizabeth Gould has a new theory.

Exercise makes us feel good about ourselves.  We like the sense of accomplishment.  We celebrate the weight we’ve lost and our increased fitness.  Gould believes that this hedonistic value of exercise could somehow trump the nasty effects seen when glucocorticoid levels rise.  But exercise is such a complex action.  Sure, there’s a hedonistic component, but there’s also a hefty physiologic one.

To give her theory some teeth, Gould would have to prove that another stressor with hedonistic value also boosts neurogenesis.  So this time around, instead of exercise, Gould’s lab used a simpler, less physically-demanding, but equally powerful positive stressor: sex.

While not typically considered a stress by popular definition, sex fits the bill, as it’s been shown to increase glucocorticoid levels in the brain.

Gould’s results show that a single sexual encounter is enough to raise glucocorticoids and increase neurogenesis in the hippocampus of male mice.  After repeated sexual experiences, the glucocorticoid levels stabilize, but the brain continues to grow new neurons and the number of synapses increases.

While this study doesn’t answer all of the questions surrounding glucocorticoids, stress, and the brain, it shows the story is far more complicated than initially thought.  Chronic good stress continually increases neurogenesis, but it also seems to level off the stress hormones themselves.  Gould’s results support the notion that the hedonistic aspect of good stress may in fact be the active ingredient that keeps the dangerous effects of glucocorticoids at bay.

Leuner, B., Glasper, E., & Gould, E. (2010). Sexual Experience Promotes Adult Neurogenesis in the Hippocampus Despite an Initial Elevation in Stress Hormones PLoS ONE, 5 (7) DOI: 10.1371/journal.pone.0011597

Exercise and Anger

CrossFit Trainer Certification (via Wikimedia)

Exercising people are happy people.

Nonsense. Ever see someone’s face at mile 20 of a marathon? Do they look happy to you?

OK, maybe people aren’t happy while exercising, but evidence shows they’re better off, in general, after the fact. Physical activity has a positive effect on mood, and is considered a valid treatment strategy to battle anxiety disorders and even depression. Although most explanations are somewhat wishy-washy, researchers believe that hedonistic value of exercise is important in mental health. Exercise simply makes us feel good about ourselves. And this is not only true in humans, but in animals, as well. Rats and mice that are given free access to a running wheel will use it, and lab rodents typically won’t do anything that doesn’t provide them some sort of pleasure.

But what about anger -- can exercise prevent us from getting angry in the first place?

Gretchen Reynolds’ new post on the ‘NYT Well’ column discuss new evidence that shows exercise -- even a single, isolated session -- can alter how we respond to challenges that angered us in the past.

In one particular study, researchers showed a group of undergraduate students a series of images while recording EEG signals from their brains. Some of the images were pleasant, while others were meant to make the participants angry. After the students watched the videos, they rated their current anger on a scale from 0 to 9. At baseline, the electrical activity in the brains of students showed they were disturbed by the nastier images, and they all rated their anger on the high-side of the 0-9 scale.

The students were then divided into two groups. And on the days between the experiment, one group did some light/moderate exercise (like 30 minutes on a stationary bike), while the other group did not exercise at all. When re-tested, the electrical activity of the brains of all the students, regardless if they exercised or not, showed that they became angry while watching the videos. But the students that had exercised the day before were able to shake-off their anger, and at the end of the session, they just weren’t as upset as those in the physically-inactive group.

The results suggest that exercise may in fact be a preventive measure against the buildup of anger.

The rest of Reynolds’ post talks about the mechanism of how exercise could make us less like to boil over in anger. She provides some hand-waiving explanations, saying changes in serotonin levels in chronic exercisers make them less angry. While this may be true, exercise is a complex activity that changes so much in the body -- neurotransmitter levels, blood flow, hormone levels, just to name a few -- so I’d caution readers that it’s hard to pinpoint which physiological catalyst could be real the anger-fighting superhero. Or maybe it’s not one particular molecule, but the sum total that makes exercise so powerful.

Time to Make a Dopamine Run

It's 6am and my alarm clock is buzzing, but I don't hear it. I don't even move. But the incessant noise wakes my wife, and her gentle nudges (read: elbows) and soft whispers (read: expletives) eventually convince me to get out of bed. It seemed like a great idea: Run in the morning before work, to free up countless evening hours. “Think of all you'll get done at night if you don't have to run after work”, I said to myself. “For once you'll actually hit your goal of blogging multiple posts per week! Maybe even finish some of those half-read books lining the shelves.” But two days into the new regime, I'm having second thoughts.

It's freaking early. I mean, I've gotten up at the crack of dawn to work on blog posts, but going out for a 6-mile run requires a bit more activation energy than typing away on the computer.

To make matters worse, I just don't feel like running today. It's cold and raining. I can hear the wind blowing from inside my apartment. My warm bed is calling to me, but I muster the will to put on my running clothes, and step outside.

I trod along, slower than usual, because my legs are still tight. A few minutes into the workout, a homeless man approaches me on a rickety bike. He rides close by, taunting me. “You keep running, boy”, he says. “Gonna run yourself right into the grave!” Living in San Francisco, I’ve grown moderately accustomed to such neighborhood friends. But today, instead of being a minor annoyance I shrug off, this guy truly sounds like the voice of reason.

We talk a lot on this blog about ways to drive healthy behavior change: Self-tracking and the Hawthorne effect. Competition and group dynamics. But no way around it, rewards are the heart of behavior change, thanks to the way our brains respond to the molecule dopamine, which differentiates what you have to do, from what you want to do. Dopamine turns a chore into a hobby.

The clearest example of the dopamine reward system in action is the now-famous experiments of Ivan Pavlov. In the early 1900’s, Pavlov noticed that when dogs saw food coming, they began to salivate. The dog's brains were moving faster than their bodies, already anticipating the sweet reward of food before a morsel even hit their mouths. So Pavlov wondered what would happen when he paired a food reward with a random stimulus, such as a bell, whistle, or electric shock. We all know how the story ends: After training, Pavlov's dogs salivated when they heard they bell, regardless if they got a food reward or not.

Pavlov's experiment unlocked our understanding of classical conditioning: Pair a random stimulus close enough to a reward, and soon the stimulus itself tells the brain to get ready for the big payout.

With brains wired for immediate reward in a world of instant gratification, it’s easy to see why we struggle when starting a new exercise routine. The stimulus (the act of running) is so far separated from the reward (the endorphin kick, the runner’s high, or even improvements in our health and fitness).

So how can we ever be expected to change a behavior unless we get an instant payout for our actions? A hand-waiving explanation would be we’ve simply trained our brains to wait longer and longer for the reward. On the other hand, consider this: If you talk to enough runners, they'll tell you they don't “feel right” when they haven’t gone for a run in a few days. They feel “off” if they don’t get their fix. I’m certainly not the first to wonder if chronic exercise somehow primes the dopamine reward system to make us crave the activity, the old “exercise addiction” theory. But the similarities between the two are striking. Could we one day use what we know about addiction to drugs to reveal new ways to get people hooked on positive behavior changes? I’m still funneling through the scientific literature regarding exercise addiction, so I’ll give you updates as the ideas surface.

For any new runners out there looking for pearls of wisdom about what to do when the going gets tough, I leave you with this: I know that even experienced runners lack motivation at times. In fact, I don't know that it ever gets easier to plunge into the first few steps of a run on days you’re dealing with bad weather, a busy schedule, or belligerent guys on bikes. But hang in there, your body and brain will thank you (hopefullly sooner than) later.

More On Intelligence

On the heels of a post I did at The Scientist (“Amazing Rats”), where I proposed a new model of intelligence based on a animal’s ability to solve problems rather than its communication skill, I read a blog post by Jonah Lehrer at The Frontal Cortex where he gives his take on what intelligence really means. Rather than smarts merely defined by how many facts someone can cram into their heads, Lehrer argues that a better measure of intelligence is to look at how well people (or animals) can shift their selective attention.  Facts are just facts, but the intelligent being can manipulate and organize the information for the task at hand, which places a high demand on the attention circuits in the brain.

Lehrer cites a study by Walter Mischel, which studied a group of children that had a marshmallow placed in front of them.  The kids were told that they could have the marshmallow now, or wait 15 minutes and get two marshmallows.  According to Lehrer, those children that were able to wait for the bigger reward payout had better SAT scores, were better behaved, and less stressed than their impulsive counterparts.

Mischel’s study is a classic test for discounting of delayed rewards, and I’m not surprised that the kids that were able to wait a short period of time for the bigger reward ultimately did better than those that couldn’t.  But are the kids that could wait more intelligent, or is there something else going on with the kids that cracked?

Numerous studies have shown that people prone to addiction continually discount delayed rewards.  They’re impulsive.  They can’t see past the immediate pleasure of the reward.

Defects in the dopamine reward system (e.g. addiction) interfere with other circuits in the brain.  Therefore, it doesn’t surprise me that very intelligent addicts make unwise decisions while seeking their next high.

I’m not saying all the kids in Mischel’s study who impulsively took the first marshmallow as a reward were all addicts.  But as Lehrer pointed out, these kids ended up more stressed out and with more behavioral problems than other children, which says there’s more to the story than simply an intelligence difference.

What Did We Really Learn From the BBC Brain-Training Software Study?

Ever since I saw the press releases yesterday telling of a new article to be released in Nature showing that brain-training software was ineffective, I knew a storm was brewing.  The paper was still under embargo at that point, so I was anxiously awaiting its release today.  Slowly, but surely, the mainstream media got wind of the paper, running headlines like “Brain Games Don’t Make You Smarter”.  Then the blogosphere lit up, with ongoing chatter throughout the day on this controversial paper. I was stuck in the lab all day, and couldn’t put a post together, so I’m a little late to the party.  But I wanted to give you a rundown of what exactly the study found, and point out a few intricacies of their findings.

When I began graduate school, there was a savvy postdoc in our lab who showed the newbies the ropes.  One of the best pieces of advice he offered was, “Don’t believe everything you read, and always check who did the study.”  I try to live by these words every time I read a study.

The group who submitted the Nature paper was led by a researcher named Adrian Owen, a professor at MRC Cognition and Brain Sciences Unit, Cambridge UK.  Owen developed this brain training program and study in collaboration with the BBC.  A quick look at Owen’s PubMed listing shows he’s primarily known for using fMRI to prove that people who are in a constant vegetative/minimally conscious state are, in fact, self-aware (a controversial field and a bold claim, which I’m not going to get into right now).  But the point is: Owen isn’t an expert in brain plasticity or behavioral training-induced cognitive changes.

Making brain-training software isn’t a task you just jump into, and experts spend years proving and refining approaches in animal models.  But it appears that Owen woke up one day and suddenly decided he had the insight to figure out whether the cognitive benefits claimed by brain training software were true.

Even if we give Owen the benefit of the doubt, and assume he knows what he’s doing, all brain-training programs are not created equal.  I try, whenever possible, to refrain from using the term “brain games”, because when training modules are created from sound preclinical and clinical research, they’re really much more than games.  Owen and the BBC only tested their program, so the results simply say that their program doesn’t work.  This finding does not generalize across the industry.

SharpBrains has the best rundown I’ve seen of what’s wrong with this report, including the nitty-gritty details showing that the participants in the Owen/BBC study used the brain training software for considerably less time than most programs.  Also, the training sessions were unsupervised, hence the participants were possibly prone to distraction.

While I’m moderately annoyed with the overreaching conclusions the authors made, I’m even more ticked at the mainstream media headlines.  We spend billions of dollars bringing drugs to market, and often things go wrong during drug trials.  Companies miss clinical endpoints, or worse, someone has an adverse event.  Yet, when this happens, I have to scour the net just to find a mention of the problem.  The brain training software industry is still in its infancy, and there will inevitably be bumps in the road.  But the truth is, these studies cost a fraction of what it takes to bring a drug to market, and despite what this rogue Nature paper says, have a huge potential to help millions of people.