Healthy Brain, Happy Life (4 page)

The word
uterus
in Latin means “hysteria.” Do you agree with this?

Do you know what the largest organ in the body is? It’s your skin! Take care of it!

Isn’t the psychology of hair and hairstyles fascinating? We could have a whole course just on that!

With every comment and through every lecture, she made anatomy personal and come to life. I remember in the middle of the semester I took gross human anatomy, I happened to go see the Alvin Ailey dance troupe perform for the very first time at Zellerbach Hall on the Berkeley campus. That was the first time I saw their famous piece
Revelations
. Not only was I mesmerized by the dancing that night but, because we had just been going over the origins and insertions of all the muscles of the leg, I could now appreciate all those movements on a whole different anatomical level. To me there was no better example of the beauty of the human body than the shapes and movements that I was seeing on stage.

Diamond was truly an inspiration. It was so clear she loved and appreciated the topics she was teaching, and she genuinely wanted us to love and appreciate this breadth of information in the same way. She didn’t only care about the subject matter but cared deeply for us students as well. She was more than available to answer questions, and just to be sure she got to know at least some of us in her class of at least 150 students, she would randomly pick names of those enrolled out of a hat and take two of them out to lunch just to chat over a meal. When I was taking her class all her students also had an open invitation to come out to the tennis courts on the north side of campus to play an early morning set of doubles with her anytime. This sounds like the perfect invitation for the tennis-playing neuroscience geek from Sunnyvale, right? Well, I have to admit that I let my shyness get the better of me, and I never gathered the courage to go play tennis with her in all the years I went to Berkeley—to this day it’s one of the biggest regrets on my list of should-haves from my college years.

Some of her teaching magic started to rub off on me, even back then. I remember an afternoon practical session where we had a whole bunch of organs spread out at different stations in the room that we were supposed to examine and learn about. I was particularly intrigued with the dense, multilobed liver and the little nub of a bile duct hanging off the bottom. I remember figuring out all the parts of the liver we had learned in class and another student coming by and asking me what we were supposed to be seeing here. I explained to him everything that I had discovered on this example liver, and he seemed to get it quickly. I ended up spending the next thirty minutes presiding over that liver and explaining to any and all students that came by all the key features of the organ. That day I became a liver anatomy expert. I think that was the day I also became a teacher. And I learned a valuable lesson that was going to serve me well for the rest of a career: The best way to learn something deeply is to teach others about it. I use that principle to this day.

The author with Dr. Marian Diamond on the day Suzuki graduated from Berkeley
.

(Courtesy of the author)

I was certainly not the only one to love Diamond’s gross human anatomy class. On the last day of class, several other students came to class with flowers and literally threw them at her feet! I was there cheering and shouting right along with them, celebrating the end of this great course, my only regret being that I hadn’t thought to bring flowers to throw.

CHECK OUT MY ROCK-STAR PROFESSOR
!

The great thing about our digital age is that you now can experience some of Diamond’s classes yourself. Just search for “Marian Diamond” on YouTube. Check her out!

WHAT WE KNOW ABOUT THE BRAINS OF CAB DRIVERS

We have come a long way in our understanding of brain plasticity since Marian Diamond’s early enriched environment studies in rodents. Now there is lots of evidence of brain plasticity, including in humans. One of my very favorite examples of adult human brain plasticity was done by my colleague Eleanor Maguire, at University College London. Maguire didn’t send her human subjects to live in Disney World for a year. Instead she studied a group of people who had meticulously learned a very specific and extensive body of knowledge about their home turf. Namely, she studied London taxicab drivers. You see, London cabbies have the daunting task of learning to navigate the more than twenty-five thousand streets in central London as well as the locations of thousands of landmarks and other places of interest. The extensive training period that is required to learn all this spatial information is called “Acquiring the Knowledge” and typically takes between three and four years of study. If you have ever been to London and seen people riding around on scooters with maps splayed out on the handle bars, those are the aspiring London taxicab drivers learning these skills!

Only a fraction of the aspiring cab drivers actually pass the stringent exams, called, very dauntingly, “Appearances,” but those who do pass demonstrate an impressive and extensive spatial and navigational knowledge of London. What an interesting group of people (and brains) to study!

In the study of these London cab drivers, Maguire’s group focused on the size of a brain structure that I will be discussing a lot in the upcoming chapters: the hippocampus. This is a long seahorse-shaped structure deep in the brain’s temporal lobe (
hippocampus
means “seahorse” in Latin) critically involved in long-term memory function, including spatial learning and memory. More specifically, because Maguire and her colleagues had localized spatial memory function to the back, or posterior, part of the hippocampus, they wondered if that part of the brain structure might be larger than the anterior (front) part in cab drivers when compared to control subjects who were matched for age and education. In fact, that’s exactly what they found.

Maguire’s research and other studies that have compared the brains of experts (such as musicians, dancers, and people of particular political affiliations) to nonexperts have all been used as examples of brain plasticity in humans. While plasticity is one possible interpretation of the data, another possibility is that people who succeed as London taxicab drivers have larger posterior hippocampi to start with. In other words, it could be that only people with naturally big posterior hippocampi have the superior spatial navigation ability required to succeed as a London cabbie. If this were true, it would not be a case of brain plasticity at all.

So, how can we differentiate between these possibilities? What would need to happen to test the idea that the experience of learning to be a London taxicab driver changes the brain would be to actually follow a group of people who started Acquiring the Knowledge and then compare the brains of those who eventually passed the test with those who did not. And that’s exactly what Maguire and her team did. This kind of study is much more powerful because you can clearly identify any brain changes as a function of taxicab training. What the researchers found is that before training started, all the wide-eyed and bushy-tailed London taxicab driver wannabes had the same size hippocampi. The scientists then reexamined the cab drivers after they had completed the training period and after they knew who passed and who failed. They found that the wannabe cabbies who passed now had significantly larger posterior hippocampi than they did before they started their training.
Ta-da!
Brain plasticity in the flesh! This group’s posterior hippocampi were also larger than those of the subjects who hadn’t passed. In other words, this experiment showed that successful training to pass the Appearances exam did indeed enlarge the hippocampus, and the trainees who had not retained enough information showed far less of an increase in size.

This is just one example of the everyday, beautiful plasticity of our brains. Everything we do and for how long and intensely we do it affects our brains. Become an expert bird watcher, and your brain’s visual system changes to be able to recognize all those tiny little birds. Dance tango all the time, and your motor system shifts to accommodate all those precise kicks and flicks you are doing with your feet. The life lesson I learned all those years ago in Diamond’s classroom was that I shape my brain every day and so do you.

MY OWN DOORMAN EXPERIMENT

London is not the only city where its municipal workers have special skills. In New York, it’s doormen. Think about all those faces they have to recognize and differentiate from strangers if they work in a thirty- or forty-story high-rise! Here is a thought experiment I would love to do with New York City doormen if the opportunity ever arose. I would examine the doormen’s brain areas known to be important for face recognition and compare the size of that area to those of other city workers who don’t have to remember lots of faces (let’s say subway conductors). Where exactly is the face recognition area in the brain? At the bottom of the temporal lobe is a unique area known as the fusiform face area, which specializes in helping us recognize faces. When this region is damaged, people cannot distinguish facial features, a condition known as prosopagnosia. The actor Brad Pitt, the famous portrait painter and photographer Chuck Close, and the Harvard professor and author of
Multiple Intelligences
Howard Gardner are a few famous people with prosopagnosia. Because they cannot recognize people by their faces, they rely on other features such as voice, hair, gait, and clothing. But in doormen, who develop and hone the skill of quickly recognizing sometimes hundreds of faces, I predict that this fusiform area will be significantly larger than that in the subway conductors. Maybe someday I’ll get to do this experiment.