Bret Stetka in Scientific American:
Every day our brains grapple with various last-minute decisions. We adjust our gait to avoid a patch of ice; we exit to hit the rest stop; we switch to our backhand before thwacking a tennis ball.
Scientists have long accepted that our ability to abruptly stop or modify a planned behavior is controlled via a single region within the brain’s prefrontal cortex, an area involved in planning and other higher mental functions. By studying other parts of the brain in both humans and monkeys, however, a team from Johns Hopkins University has now concluded that last-minute decision-making is a lot more complicated than previously known, involving complex neural coordination among multiple brain areas. The revelations may help scientists unravel certain aspects of addictive behaviors and understand why accidents like falls grow increasingly common as we age, according to the Johns Hopkins team.
The findings, published Thursday in Neuron, reveal reneging on an intended behavior involves coordinated cross talk between several brain regions. As a result, changing our minds even mere milliseconds after making a decision is often too late to alter a movement or behavior. Using functional magnetic resonance imaging—a technique that monitors brain activity in real time—the Johns Hopkins group found reversing a decision requires ultrafast communication between two specific zones within the prefrontal cortex and another nearby structure called the frontal eye field, an area involved in controlling eye movements and visual awareness.