For example, when learning skills such as arithmetic, the brain doesn't necessarily reach back into its basic calculating skills for each problem, suggested the researchers who made the finding. Rather, the brain builds a repertoire of rote responses to frequently encountered problems that it can use to save time and effort, they said.

Put anatomically, the new experiments suggest the human brain might rapidly circumvent deliberative processing in higher brain regions, called the cortex, as it learns to respond appropriately and automatically to stimuli such as repeated tasks.

Researchers published their findings online Feb. 29, 2004, in the journal Nature. Lead author on the paper was Ian Dobbins, assistant professor of psychological and brain sciences at Duke University. Other authors were David Schnyer and Mieke Verfaellie at the Boston University School of Medicine, and Daniel Schacter of Harvard University.

In their studies, the researchers sought to distinguish between two theories of how the cerebral cortex manages responding to stimuli such as tasks.

Both theories seek to understand the well-known phenomenon that when people are asked to perform a classification or decision on an object, they become more efficient with repetition of the task. When subject's brains are imaged during such tasks, they show reduced activity -- called "neural priming" -- as the task is learned and performance improves.

Such imaging is done using functional magnetic resonance imaging (fMRI) -- in which harmless magnetic fields and radio signals are used to detect regions of brain activity as subjects are performing tasks.

The most popular theory about neural priming holds that this reduction in cortical activity is due to "tuning" by the cortex of its information ab
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Contact: Dennis Meredith
dennis.meredith@duke.edu
919-681-8054
Duke University
8-Mar-2004