When Focus Steers Us Wrong: Medial Prefrontal Cortex Helps Switch Strategies Mid-Task

focus
The medial prefrontal cortex monitors what is happening outside our current focus and allows us to spontaneously turn our attention from one strategy to an even better one. Photo courtesy of Shutterstock.

Are you a person with tunnel vision — you become so focused on one thing you cannot see other, possibly better options? Or, are you someone who is alive to new possibilities even while busy performing a task? A new study has located the region of the brain that allows us to look beyond what we’re doing and shift to a new plan of action. The medial prefrontal cortex, researchers discovered, monitors what is happening outside our current focus of attention, permitting us to spontaneously turn our attention from one successful strategy to an even better one.

“Our findings suggest that the medial prefrontal cortex is ‘simulating’ in the background an alternative strategy, while the overt behavior is still shaped by the old strategy,” Dr. Carlo Reverberi, a researcher at the University of Milan-Bicocca and senior author on the study, stated in a press release.

Neuroscience, in many cases, is the study of moments. What happens in our brains during the nanosecond when we remember a forgotten phrase? What's going on when we turn suddenly violent? For the current study, the researchers, who also hail from Princeton University, Humboldt University of Berlin, and the Bernstein Center for Computational Neuroscience in Berlin, wanted to understand what happens when we swing our attention from one task to another.

For the new study, volunteers played a computer game while their brains were scanned with an MRI. The researchers instructed the players to press one of two buttons depending on the location of colored squares on the screen. The researchers, though, purposely did not mention a pattern hidden within the game — whenever the squares were green, they always appeared in one part of the screen and whenever red, they appeared in another part. If players paid attention to color, then, they could improve their performance significantly. As we might expect, not all the volunteers figured this out during the game-playing period.

Among those players who did, the MRI scans showed activity in the medial prefrontal cortex. Specific signals (corresponding to the color of the squares) arose minutes before the participants switched strategies. So reliable was this brain activity, the researchers could predict spontaneous strategy shifts before they happened. The medial prefrontal cortex, scientists say, plays a part in decision-making and retrieving and consolidating memories.

The study design — not telling players about a more effective strategy — enabled the researchers to show how the brain monitors background information while focused on a task, and then chooses to act.

“When the behavior changed, this reflected a spontaneous internal process,” said Dr. Nicolas Schuck, a postdoctoral research associate at Princeton and first author on the study. “The human brain at any moment in time has to process quite a wealth of information. The brain has evolved mechanisms that filter that information in a way that is useful for the task that you are doing. But the filter has a disadvantage: You might miss out on important information that is outside your current focus.”

While past research focused on how people switch strategies after making a mistake, the current study explored what happens when people switch to a new way of doing things based on their own interpretation of the environment. This new study, then, highlights how learning and attention interact and offers insight to those who treat disorders related to these two skills.

Source: Schuck NW, Gaschler R, Wenke D, et al. Medial Prefrontal Cortex Predicts Internally Driven Strategy Shifts. Neuron. 2015.

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