Road Map of the Mind: Understanding Functional MRI

MRI

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: The Power of Neuroimaging,” 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, ‘OK, 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 a fMRI is known under the acronym BOLD: the Blood Oxygen Level Dependent approach, which was first discovered by Dr. 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.

Dr. 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.

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