University of Pittsburgh
July 6, 2000

Pitt researchers reveal cooperation between two brain areas during attention

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PITTSBURGH, June 30 -- When 'red' is not red and 'blue' is not blue, the brain will recruit additional help to identify the color of the word. Researchers at the University of Pittsburgh believe studying this task may elucidate the brain's methods of attention.

Using a color game called the Stroop Test, Pitt neuroscience researchers Angus W. MacDonald, Jonathan D. Cohen, V. Andrew Stenger and Cameron S. Carter measured brain activity using functional magnetic resonance imaging (fMRI). They determined that two separate regions of the frontal lobe—the dorsolateral prefrontal cortex (DLPFC) and the anterior cingulate cortex (ACC)—work together in a complementary fashion to resolve the confusion when the written word and its hue do not match.

The Stroop Test uses either a congruent stimulus, in which the word 'red' is printed with red ink, or an incongruent stimulus, in which 'red' may be printed with blue ink. The test subject is presented a stimulus and asked to identify the color of the word.

"When you read the word 'red' written in blue ink, your natural reaction is to identify the word, rather than the color, and you have to pay careful attention to avoid making this error," said Carter, an associate professor of psychiatry and neuroscience at the University of Pittsburgh and associate professor at the University of Pittsburgh's Western Psychiatric Institute and Clinic.

"We used functional magnetic resonance imaging—a new brain imaging technique— to show that when subjects prepare to do this task, the DLPFC becomes very active, while the ACC is quiet, and that the subjects' DLPFC performance strongly predicted good performance on the tasks," said Carter. "In contrast, when subjects actually named an incongruent colored word, activity in the ACC shot up."

This study validates a theory on cognitive processing that says two separate processes contribute to normal attention. The two frontal lobe areas serve separate but complementary functions when paying attention.

"These two areas work together," Carter says. "The DLPFC pays attention, and the ACC lets you know when you're doing poorly."

This information may prove helpful when examining the pathology of attention disorders such as obsessive-compulsive disorder and attention-deficit hyperactivity disorder, and diseases affecting cognition such as schizophrenia.

In addition to their appointments at the University of Pittsburgh, Cohen has an appointment with Princeton University and Stenger and Carter have appointments with the University of Pittsburgh Medical Center.