My Brain Doing WHAT?
The brain does some wonderful things. It lets you see colors, it processes time and space, it organizes your motions and notions, and it even lets you devise cunning plans to get other humans to sleep with you. Psychologists and neuroscientists have sought to answer many questions about how the brain does these things, and in the process have advanced our knowledge and bettered many lives.
Consider Parkinson’s Disease, a complex brain disorder that can be ameliorated by the use of L-DOPA, or epilepsy, which can often be treated by drugs or surgery, or even Alzheimer’s, which has recently been demonstrated to be susceptible to drugs which may stem the progression of the disease and halt the ebb in memory function. These treatments are the end products of long and tangled skeins of basic brain research that traverse the lab bench, the rodent maze, and, when human brains are involved, the functional magnetic resonance image scanner (fMRI for short).
An fMRI scanner is a large, loud magnetic device that allows researchers to peer inside the living brain and look at what lights up inside as the brain performs its complex and vital functions. You can buy your own for a few hundred grand. Not exactly pocket change, but once you’ve laid out the initial cash, actually performing an experiment can be relatively cheap and easy. Researchers often act as their own subjects for pilot studies, and since imaging is non-invasive, it’s safe and painless.
fMRI is notorious for being able to quickly deliver results which can be expediently misinterpreted and published. At its worst, the logic of an fMRI publication follows this simple flawed logic: “area X lights up when subjects do Y, therefore the function of X is Y.” You see fewer and fewer articles these days that make this sort of egregious generalization, but the low barrier to entry and the fast path to (sometimes dubious) results means that just about any wacky idea someone has can be run in a scanner. There are some constraints of course; the scanner requires a subject to lay flat and relatively motionless during the scan so there are physical limitations to what sorts of real-life behaviors you can look at. Don’t look for “The Neural Correlates of Dodgeball” to get published anytime soon. But as long as you can do it lying down, researchers can look at your brain while you do it. Since scanners usually come equipped with headphones and a monitor screen, scientists can show you anything from Monet to pictures of butternut squash, and provide a soundtrack, no less. A number of recent studies have explored the true extent of prone behavior.
Remember how fMRI is painless? Well that’s only true if you’re not a subject in a pain study. (You didn’t volunteer for the pain study, did you?) Don’t try to tell me that pain researchers (often clad in leather chaps and bearing a cat o’ nine tails) don’t get some kind of perverse joy out of putting people in the supine position and seeing what the local IRB (independent review board) will let them get away with. In one particularly torturous study out of Japan, subjects were allowed to fall asleep in the scanner (not a difficult requirement), and then were summarily shocked with a 20 volt stimulus. The noxious stimuli were used to localize the ‘pain’ centers in the brain, which so far seem to center around the thalamus, insula, and anterior cingulate cortex. Other pain studies use phasic lasers to administer painful, yet non-debilitating, heat to the forearms or palms of willing participants. Balloon catheter studies have used fMRI look at the brain’s control of pain in response to the distention of…well, you get the idea.
Not all oddball studies in the scanner have to be so nasty. Sarah Jane Blakemore made a name for herself studying the neural correlates of tickling. A study conducted at University College London actually revealed something interesting about why you can’t tickle yourself. When subjects felt like they controlled the tickling tool, they showed more brain activity in the cerebellum than when the tool was operated by one of the researchers. The idea is that when movement is self-produced, the brain can make predictions about the incoming somatosensory information; we start feeling tingly when our brain can’t predict what’s touching the body.
Speaking of self-produced movement, how about a study of male ejaculation? Researchers at the University of Groningen in the Netherlands interested in the brain’s response during orgasm placed 11 grown men inside the scanner and prepared them for what can only be described as a unique scientific experience. Manual stimulation was performed by female partners, under controlled conditions –relaxed, perhaps even kinky, but controlled – while the men underwent the scan. Three of their eleven volunteers “did not succeed,” demonstrating with a bit less than 30% certainty that a troupe of lab-coated observers and a high magnetic field do not make for the most romantic of environments. And don’t try to accuse fMRI researchers of neglecting the female orgasm; a study by Barry Komisaruk at Rutgers investigated the question of why women with spinal cord injuries still report a perceptual awareness of what’s going on in their happy places, despite a more general loss of sensation below the site of the injury. Their fMRI data helped show that the vagus nerve serves as a bypass pathway for vaginal sensibility.
For those less inclined to participate in a sex acts within large supermagnetic scientific devices, you can still make your $25 volunteering for more passive tasks that you could describe to your grandmother - like watching a movie, for example. Uri Hasson, a professor at Tel Aviv University, had subjects watch 30 minutes of The Good, The Bad, and The Ugly while their brains activity was observed with an fMRI machine. While the experience of watching monochrome words flashing on a screen is common to psychology studies and rather uncommon to daily life, plenty of us have relaxed to watch a film in a dark room. This technique of allowing a subject to “free view” a stimulus was an effort to get away from the controlled designs of most studies and attempt a more “real-world” experience. While it may seem overly laissez faire for a scientific lab, the study actually produced interesting results; the data showed that different brains showed similar responses to some of the scenes in the movie. When Tuco assembled his new gun and carefully used his fingers to test the revolver’s cylinder, everyone in the study showed the same activity in brain regions responsible for hand movements; a comforting confirmation that perhaps we are more alike than we know.
It might seem like these experiments are more like scientific methods carelessly applied to the activities of a first date (or maybe a third date), rather than rigorous studies worthy of top-tier journals. What do these studies mean? How do we interpret them? At the most general level, these unconventional experiments show that robust and reproducible brain activity is associated with particular behaviors. But when you’re talking about something as complex as the brain and you’re using a measure that’s as indirect as fMRI (it measures blood flow, not neural activity, after all), there are long chains of inference leading from data to conclusions. It’s not always a good idea to look at a spot in an image and say that that piece of the brain is responsible for whatever the subjects are doing at the moment. This would imply that we understand how the brain works. Which we don’t.
It’s always possible to justify these studies with the gloss that “more knowledge is a good thing.” For example, some scientists have argued that knowing the individual variations in responses to movie scenes can help to aid in the proper diagnosis and treatment of visual brain disorders. The authors of the Dutch study mentioned above claimed that it had important implications for the (apologies) growing industry surrounding male sexual function. However, the most common motivation for these studies may not be what scientist tell their grant committees: that this information can be helpful to understanding the brain as a whole and that any task, no matter how weird, may give us a better picture of what’s happening inside. The appeal of doing these studies may be more basic. After all, fMRI shows us the brain in action, and even if the pictures it produces are rife with ambiguity, they are still thrillingly direct proof that even the most “unscientific” experiences and behaviors: having sex, picking our nose, admiring the scent of a rose in full bloom, involve the activity of the three pounds of spongy meat in our heads.
References
Blakemore SJ, Wolpert D, Frith CD. 2000. Why can’t you tickle yourself? Neuroreport 11(11): R11-6.
Laberrations
If you gathered everything sporting a "Hello, my name is SCIENCE" nametag in one room, there'd be plenty of shady-looking characters hanging outside the entrance and spilling into the hallway. This column is dedicated to those outliers - often the most interesting individuals in the bunch, even if it's not clear exactly how they fit in.