The Allure of Brain Scans

They sure make pretty pictures, but are we exaggerating what they can really tell us about what’s going on inside our heads?

More clues than answers?
More clues than answers? Image courtesy of the National Institute of Mental Health

Science is rarely pretty. Stunning, yes. Provocative and enlightening, of course. But pretty? Not so much.

But brain scans are a different story. Once they’ve been splashed with vibrant purples and reds and yellows, they can look downright ravishing. Makes you want you want to pat yourself on the head and say, “Stay beautiful in there.”

Alas, therein lies a problem. Not only has technology made it possible to see our brains as something they’re not–a fiesta of technicolor–but it also has made it easier to draw absurdly simple conclusions about a ridiculously complex organ.

We’re understandably desperate for a neurological Rosetta Stone, something that can help us decipher the magical call and response of electrochemical impulses inside our thick skulls. But when, with that purpose, we conjure up notions of a “love center” or “God spot” inside our brains, we insult our own intelligence.

It’s far more complex than that, particularly when it comes to such matters as spirituality. A recent study concluded that it involves not one, but many parts of the brain. But a larger issue centers on how brain scans are interpreted. As writer Vaughan Bell pointed out recently in The Guardian, false positives are a big concern, resulting in scans suggesting that parts of the brain are linked to certain activities when, in fact, other factors may be responsible. A few years ago, a Dartmouth scientist with a sense of humor made this point by reporting that scans reflected activity in the brain of a salmon shown photos of humans. He also noted that the fish was dead.

Can they predict behavior?

Most neuroscientists have become more cautious about drawing definitive conclusions about what scans show. But, as is often the case with innovative technology that captures the public’s imagination, neuroimmaging is headed in unexpected directions, spreading beyond scientific research into legal tactics and commercial ventures. In a way, it’s become the new DNA testing, science that’s seen as a nifty tool, in this case to predict or explain behavior.

Earlier this year, defense attorneys for a convicted double murderer in Mississippi submitted his brain scans in a last-minute, albeit unsuccessful, attempt to show he was mentally ill and not suitable for the death penalty. Last year the French parliament was moved to update its bioethics law so that it now reads: “Brain-imaging methods can be used only for medical or scientific research purposes or in the context of court expertise.”

Scientists were not happy about that last phrase. Many, such as Olivier Oullier, think it’s too soon to give the technology legal standing. As he wrote in the journal Nature, “Brain scientists may not be oracles, but our research, responsibly interpreted, can help policy-makers to make informed decisions. As such, it should be given the opportunity to progress. Law and science have something in common — both can be misinterpreted.”

On the flip side

That said, neuroimaging has given scientists the first real look inside the brain at work. You can’t underestimate the value of that. And it has allowed them to start making tenuous connections between blood flow to certain areas of the brain and particular behavior. But the more they learn, the more they realize that no matter what “lights up” in an image–and keep in mind, that reflects blood flow, not actual mental activity–it likely tells only part of the story.

Psychiatrists have begun using brain imaging data to try to predict who might develop neurological or psychiatric disorders. It’s a start. But as Kayt Sukel, author of Dirty Minds: How Our Brains Influence Love, Sex and Relationships, wrote recently on Big, “At best, most of these studies can only offer predictions slightly higher than chance. Better than a coin flip–but only just.”

So while they can create beautiful 3-D images of the brain in action, scientists are still working the surface, still in the realm of educated guesses. The brain, it seems, refuses to be dumbed down.

Brain puzzlers

Despite their limitations, neuroimages are helping scientists get a clearer picture of how brains function and why they malfunction. Here’s some of the latest research.

  • Think good thoughts: A study in Wales found that patients with depression could learn to control aspects of their brain activity by getting “neurofeedback” while their brains were being scanned. Scientists described to them how trying different ways of creating positive thoughts was affecting their brains, based on continuous measurements.
  • The dope on dopamine: Researchers in Germany discovered a link between low dopamine levels in the brain and aggressive behavior. It was just the opposite result from what they expected.
  • Running on empty: A University of Iowa neuroscientist says that based on MRI imaging in his research, self-control is a commodity in limited supply and that a brain can truly run out of patience.
  • Early warning system: This month doctors in southern Florida will be able to start using a new brain imaging radioactive dye that will help them detect plaques of the toxic protein that builds up in the brains of Alzheimer’s victims. It will help confirm an Alzheimer’s diagnosis and also rule it out in cases where something else might be causing memory loss. And scientists hope that these scans will help doctors spot Alzheimer’s much earlier, when there still are no symptoms and treatment can be more effective.
  • Either I need sleep or barrels of Doritos: According to a study at Columbia University using brain scans, subjects getting only four hours of sleep a night were more likely to develop cravings for junk food than those who got a full eight hours.

Video bonus: Okay, so we’ve reached the point where we’ve started to put dogs in MRI machines. Researchers at Emory University are trying to get a bead on what dogs are thinking. Good luck with that.

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