The Frontal Cortex

My latest article for the Boston Globe Ideas section looks at some recent criticisms of fMRI, at least when it's misused:

The brain scan image - a silhouette of the skull, highlighted with bright splotches of primary color - has also become a staple of popular culture, a symbol of how scientific advances are changing the way we think about ourselves. For the first time in human history, the black box of the mind has been flung wide open, allowing researchers to search for the cortical source for every flickering thought. The expensive scanners can even decode the hidden urges of the unconscious, revealing those secret feelings that we hide from ourselves. The machine, in other words, knows more about you than you do: It's like a high-tech window into the soul.

"These [fMRI] images get people excited in a way that other research just doesn't," says Kelly Joyce, a sociologist at the College of William & Mary. "The pictures have a tremendous authority, not only among scientists but among people who might just glance at a brain scan picture in a newspaper."

In recent weeks, however, several high-profile papers have ignited a fierce debate over whether brain scanners are being widely misused and their results over-interpreted. Some eminent figures in the field have taken issue with the metaphors typically used to describe brain imaging, criticizing descriptions of scanners that rely on what Joyce refers to as the "myth of transparency."

The scanners, they say, excel at measuring certain types of brain activity, but are also effectively blind when it comes to the detection of more subtle aspects of cognition. As a result, the pictures that seem so precise are often deeply skewed snapshots of mental activity. Furthermore, one of the most common uses of brain scanners - taking a complex psychological phenomenon and pinning it to a particular bit of cortex - is now being criticized as a potentially serious oversimplification of how the brain works. These critics stress the interconnectivity of the brain, noting that virtually every thought and feeling emerges from the crosstalk of different areas spread across the cortex. If fMRI is a window into the soul, these scientists say, then the glass is very, very dirty.

Here's a link to the Logothetis article in Nature that began a lot of this discussion. What do you think? What psychological states are amenable to localization experiments in brain scanners? How will we feel about most of these brain imaging experiments in ten or twenty years? Frankly, I was surprised by just how critical many scientists were.

As I point out several times in the article, however, fMRI remains an extremely valuable experimental tool, at least when used properly. It's still our best way to make sense of functional networks in the brain, such as the default system. It's also very handy when used in conjunction with other experimental techniques, such as EEG or electrophysiology. But I think only time will tell how well these localization studies hold up.