Road Map of the Mind: Understanding Functional MRI

(Editor’s note: This article is from the Summer 2015 issue of Brain World magazine. If you enjoy this article, consider a print or digital subscription!)

What if I told you it was possible to read, or even hear, your thoughts? Mind reading has been the stuff of science fiction for some time — something that 50 years ago would have been thought impossible. Even today, there’s quite a bit of doubt, but what can be seen is the activity across brain regions each time we produce thoughts. While sending messages through brain waves is something that’s actively being done, right now we’re able to see how your thoughts are made — specifically, which parts of your brain are most involved in making them. This new innovation has officially paved the way for the rapidly growing, ever-intriguing field of neuroscience — functional magnetic resonance imaging, also known as fMRI.

Ever wonder why some decisions are harder to make than others? The author of “Looking Inside the Brain,” fMRI researcher, and neuroscientist Dr. Denis Le Bihan puts it this way: “We can see that inside the brain, the decision is totally unconscious. We can see that the brain is trying to solve the problem for you with the best solution, so you make up your mind and say, ‘Okay, I do this.’ We can see the timing. We can see that the response is born seconds before you realize what you do.” These might be tough choices for you, but for researchers like Le Bihan, they’re all just flickering lights.

So how does it all work? It might sound like alchemy, an actual impossibility to see inside the mind and its flickering neurons charged with thoughts and dreams, while the patient is alive and active, but the fMRI relies on a fairly simple pattern — the changes in blood flow throughout the brain. Neurons activate in the brain, signaling a rush of blood flowing to that particular region. Immediately we can tell what parts of your brain are going to work — the ones that form memories, the ones that create emotions, and then there are the parts that simply process passive listening to a conversation, or assist in the deciphering of faces and the emotions on those faces. It’s quite a sophisticated road map, navigating through all that gray matter.

The most common method for performing an fMRI is known under the acronym BOLD: the Blood Oxygen Level Dependent approach, which was first discovered by Seiji Ogawa, working at AT&T Labs, Inc., in New Jersey, who learned that differences in oxygen levels in the blood could be used to construct a three-dimensional map of the human brain. His procedure was first performed on patients in the early 1990s, and now not only dominates the fields of neuroscience and clinical psychology, but its noninvasive nature (involving no allergy-producing dyes, no under the blade surgery, no injections, and not even any shaving required, let alone exposure to any levels of radiation) has led to many biologists in other disciplines adopting the technology as well. Among other things, it may mean that dissecting frogs in science class may soon be a thing of the past.

Some of the earliest studies utilizing the new BOLD technology, conducted by Ogawa and his colleagues, analyzed the correlation between the eyes and the brain’s visual cortex — a region within the brain’s occipital lobe that takes on the arduous task of processing what we see. This might seem obvious, but the truth is, we actually see very little of what our eyes present us with from day to day. Walking to the parking lot after work late at night, you might see a slight glisten off the pavement and you know there’s ice.

Rather quickly, the dorsomedial portion of your visual cortex goes into gear and you know to immediately walk around to avoid slipping. If asked just an hour later, you probably would be hard pressed to recall the make of the car that sat right next to yours, and the same probably would go for the number of your parking spot, even though both of these details were right in front of you. Your brain is working with just enough to get you to your car and back, and the other details are processed by your visual area neurons as unimportant, although they’re still working the whole time to make your brain conscious of movement, so you’ll know to avoid any drivers who might happen to be backing up as you make your way through the lot.

You might even go so far to say that the visual cortex of the brain is almost like the brain’s own internal surveillance system, occupying portions of both hemispheres, with six different areas that you might think of as departments, processing visual acuity, one of which even monitors our own movements and responds to the visual stimuli associated with that movement — this being the reason why you’re on alert while walking outside in winter weather. At the front is the primary visual cortex, which is by far the most heavily studied area of the brain, in all different kinds of animals, for that matter, and deals with our perception of space.

Just imagining the complex highways needed for neurons to regulate the visual cortex of the brain — the bare minimum for letting us know where we’re going every time we walk around — gives one an idea of how difficult it was to study the brain until recently. Prior to Ogawa, scientists at Harvard University created a magnetic iron injection, which could be charted by MRI machines. The trouble was that even though it was largely nontoxic, it only existed in the bloodstream for a short period of time.

As far back as the end of the 19th century, researchers knew it was problematic that they could only look at the brains of people who had died, with no guides like blood flow or active motor neurons to let them know what was going on, so that resultantly the brain was a dark, mysterious place that could barely be studied, let alone mapped. That’s not to say they didn’t try — Angelo Mosso was already curious, and created the human circulation balance: a noninvasive procedure which could measure differences in the body’s circulation during emotional and intellectual activities.

Even with our modern advances, Mosso’s interest is still rather in vogue. Creativity has probably been a problem that has intrigued us from the dawn of time — even when it was mistaken for madness. How many times have you wondered where your favorite author gets their ideas? If you’re like me, who’s never played an instrument, you might just as easily wonder where the inspiration for songs comes from, particularly when it comes to artists who just make up everything on the fly.

Charles Limb, a neurobiologist as well as a musician himself, turned to fMRI technology to understand the deep science involved with improv — and perhaps, to pave the way toward understanding where gifted artists get their gifts. Are artists made, spending years of their lives in salons and conservatories, through witnessing atrocities and being pitted against the overwhelming odds of poverty? Or is it that they are simply born that way — being fortunate enough to be born as the son of Richard Wagner, or the daughter of Franz Liszt?

Sure enough, Limb noticed something interesting in the fMRIs he’s done. According to the observations, Limb says: “Musicians with perfect pitch have a structural asymmetry in the primary auditory cortex — that’s unusual.” That might lead you to thinking there isn’t much hope for your garage band, but don’t panic yet. Limb continues: “Talent doesn’t usually show up in the brain in terms of its shape, but on some level there may be differences — in cortical thickness, volume of neurons in a particular region and so on. There are trends, but it’s a chicken-and-egg-type situation. Does a person become a musician because they have that kind of brain, or is it the other way around? People may have natural aptitudes and then exercising them through music may introduce brain plasticity (the brain’s ability to restructure itself, creating new pathways with its neurons, as the individual has new experiences or learns new things).”

So, ultimately, it may be a little of both. Your grandmother may have had an eye for color and an aptitude for painting, something that you might have inherited, since our own brains are really not all that different from those of our closest relatives — but it’s ultimately up to you to pursue your interests. Think of it in terms of working out — you might not have muscles right away, but the potential is there for the longer you keep at it.

According to Le Bihan: “Genes make us able to learn, to do many things, but then what you do with your brain is your own story, and that’s why I say to teachers that they have a huge responsibility because they model the brain of the children. Whatever they teach will modify the brain.” For the brain, education really is a journey, with new roads of neural networks forming along the way.

When we’re born, we have more neurons than we’ll ever need — over 100 billion acquired well before birth. As we grow, they’ll either gradually disappear or form new connections. It’s the environment that helps with determining these connections — as the individual picks up new skills, or recognizes new colors, sounds, or patterns. Finding the right pattern has further driven Limb’s quest for answers.

He performed an fMRI experiment that consisted of several rappers as its test subjects. Before the brain scans, the individuals were asked to memorize a series of novel rhymes, or invited to freely generate rhymes that made use of a random cue word, all of which would be accompanied by a single rhythmic beat. The findings intrigued Limb even further: “During creative freestyle improvisation, rappers demonstrated functional activation in language areas, sensorimotor regions and deactivation in prefrontal cortical areas that were distinct from those changes observed during memorized rapping.”

So it would seem that creativity suggests a merging taking place between two or more regions of the brain as the artist works. Other areas become less active as Limb and his team also noticed, such as the area of the brain that tends to filter what we say while in polite company. As interesting as all of this is, you may wonder whether it has any real-world applications. Sure, it’s great figuring out how your favorite musicians improvise, but how does it help me, or anyone who can’t read music, for that matter?

Limb’s interests go beyond his own life experience as a musician too, yet another reason why he has pursued research in music. While you might think it’s pretty easy to just put on an MP3 while you drive and listen in, it’s yet another incredibly difficult task undertaken by your brain each day.

“There’s nothing more difficult to hear and process than music — it’s more complex than speech,” says Limb. “If we can understand how people hear and understand music, we could learn how to diagnose and assess the brain and improve hearing. For example, you can give a deaf person a cochlear implant and train them to achieve speech reception quite easily, but music is much more difficult.”

Listening to music not only runs you through auditory processes but also engages visual stimulation as well — forming images and invoking memory. Modern humans have been around for just over 200,000 years, and even in antiquity people were aware of the incredible emotional experience of listening to and creating music, as well as the physical intensity of performing it — which was a group activity that brought tribes together. Perhaps music’s longstanding presence is a reason why it has somehow found its way into nearly every part of the human experience — from religious services, to wars, to lovemaking. Even before modern humans, it seems reasonable to suspect that our closest evolutionary ancestors may have had their own senses of vocalization and music.

Perhaps by understanding more about these processes, not only can we solve a number of problems with hearing, but also a great number of lifelong problems as well, such as memory and even the gradual shaping of the brain — questions that have been with us for centuries, and now seem to be close within our grasp. With all we’ve managed to accomplish in just over 20 years of research — a golden age for neuroscience — who knows what we can expect from the next decade? Perhaps we should ask instead, how much longer it will take.

(Editor’s note: This article is from the Summer 2015 issue of Brain World magazine. If you enjoy this article, consider a print or digital subscription!)


Be the first to comment

Leave a Reply

Your email address will not be published.