Frontal Lobes Divide to Represent Simultaneous Goals
Functional MRI findings show how human brain handles two concurrent tasks
THURSDAY, May 6 (HealthDay News) -- Though the left and right medial frontal cortex in the human brain jointly drive the performance of a single task, they divide to drive the pursuit of two concurrent goals simultaneously, according to research published in the April 16 issue of Science.
Sylvain Charron, of the Institut National de la Santé et de la Recherche Médicale in Paris, and Etienne Koechlin, of the Ecole Polytechnique in Palaiseau, France, analyzed data from 32 volunteers who underwent functional magnetic resonance imaging while performing letter-matching tasks. They were told at times to either stop the first task and switch to a second, or delay the first task in order to do the second. Participants were also cued to rewards they would receive for error-free performance.
The researchers found that the left and right medial frontal cortex (MFC) together drove single-task performance according to anticipated rewards; however, in dual-task conditions, the left MFC encoded the rewards for one task, while the right encoded the rewards for the other task. When subjects were given a triple task, their performance supported the idea that the frontal function cannot accurately handle more than two concurrent tasks at a time.
"Consistent with [a] previously suggested inability of frontopolar function to recursively compute cognitive branching, this capacity limit places a severe constraint bearing upon human higher cognition and may clarify several limitations in human decision-making and reasoning abilities," the authors conclude.