According to the Arlington, Va., based National Mental Health Association, close to one percent of the world's population suffer from schizophrenia, a terrifying condition that undermines one's ability to distinguish between what's real and what is imaginary. Millions more live with obsessive-compulsive disorder, a psychological condition that causes those affected to "suffer intensely from recurrent, unwanted thoughts or rituals which they feel they cannot control."
Both conditions can be controlled, but not cured. And both have long resisted scientists' efforts to pinpoint their causes. This is changing, thanks in part to research by John Kerns, a professor of psychology at MU. Like many of his colleagues, Kerns suspected that schizophrenia, obsessive-compulsive disorder and related psychiatric conditions might result from breakdowns in cognitive control; that is, the ability of our brain to determine appropriate responses to the sometimes contradictory information provided by our senses.
Imagine, Kerns suggests, you are crossing a busy street in London. Perhaps you're eating a chocolate. Or maybe you're chatting on your cell phone. Not only must your brain deal with these distractions, it must judge the speed and spacing of the oncoming traffic. At the same time it must take into account that, because you're in England, cars are bearing down on you from a direction opposite of what you're used to.
To those with normal cognitive control, such situations are challenging but workable. For those without such control, even less taxing levels of stimuli can be debilitating. Kerns says his research findings, published with five prominent neuroscientists in the Feb. 13 edition of the journal Science, aims to "bring to light why some of these failures in the brain take place." The key to such an understanding lies in examining the brain's neuro-biological mechanisms, he says.
To get to the bottom of these mechanisms, Kerns and his team devised an experiment that began with 23 healthy volunteers performing the Stroop Color-Naming Task. During the task, an LCD projection with words denoting colors, such as "red" or "green," are shown to research subjects, who are then asked to read the words aloud. In a diabolical twist, some of the words are printed in incongruous tints. "Red," for example, might appear in green type, or "blue" in orange.
When a word and its color didn't match, research subjects tended to get confused. As the subjects struggled to gain cognitive control of the situation, Kerns and his team recorded their brain activity using magnetic resonance imaging.
The result was groundbreaking. Word color confusion induced a pronounced increase in neurological activity in subjects' anterior cingulated cortex, or ACC, an area of neural circuitry located in the middle of the brain. This was followed shortly thereafter by a bump in activity in the brain's pre-frontal cortex, long regarded as the likely center of cognitive control. Kerns' study suggests that brain is wired in such a way that, as one of his fellow authors puts it, "When increased attention is needed, it appears that the ACC signals the prefrontal cortex to execute an increase in cognitive control."
This insight, the researchers say, may help scientists finally isolate the "precise neural mechanisms that underlie cognitive control" and thus lead to better treatments for those with mental illness. And that's not all. "It also could explain why people experience routine cognitive failures, such as forgetting why they went from one room to the next or getting easily distracted, " Kerns says. Anybody seen the car keys?