How gain and loss affect optimistic and pessimistic brains

Washington, Aug 5 (ANI): Our belief in whether we would succeed or fail at a given task-and the consequences of winning or losing-directly affects the levels of neural effort put forth in movement-planning circuits in the human cortex, said neuroscientists at the California Institute of Technology (Caltech).

Richard A. Andersen, the James G. Boswell Professor of Neuroscience at Caltech, conducted a new brain-imaging study to reach the above conclusion.

Research in Andersen's laboratory includes work to understand the neural mechanisms of action planning and decision-making.

The lab is working toward the development of implanted neural prosthetic devices that would serve as an interface between severely paralyzed individuals' brain signals and artificial limbs-allowing their planned actions to control the limbs' movements.

In particular, Andersen's group focuses on a high-level area of the brain called the posterior parietal cortex (PPC), where sensory stimuli are transformed into movement plans.

In the current study, Andersen and his colleagues used a functional magnetic resonance imaging scanner to monitor activity in the PPC and other brain areas in subjects who were asked to perform a complex task.

Using a trackball, they had to move a cursor to a number of memorized locations on a computer screen, in a predetermined order.

"The subjects were given 1 second to memorize the sequence, 15 seconds to plan their movements in advance, and then only 10 seconds to finish the task. We intentionally made the task hard-I couldn't do it myself," said Igor Kagan, a coauthor of the stduy.

The researchers found that individuals in the group who believed they had performed well were just as likely to have performed poorly, and vice versa for individuals in the group who believed they had done badly.

Furthermore, the researchers found that the pattern of brain activity in the PPC was linked to how well the subjects believed they had done on the tasks-that is, their subjective perception of their performance, rather than their actual performance-as well as by the monetary gain or loss they expected from success or failure.

How hard an individual subject's brain "worked" at the task was dependent upon their personal approach.

For example, "subjects who are 'optimists' and believe they are doing well will put out the most effort-and exhibit an increase in activity in their PPC-when they expect to earn a larger reward for being successful," said Andersen.

Conversely, those individuals who believe they are doing poorly-the pessimists-show the most brain activity when there is a higher price for failure.

"They're trying harder to avoid losses and seem to care less about potential gains," added Kagan.

"This study demonstrates that the process of planning and action is influenced by our subjective, but often incorrect, idea of how well we are doing, as well as by the potential gain or loss," said Andersen.

The results suggest that the cortical areas involved in planning actions are also likely to be involved in decision-making, and take into account higher-order cognitive as well as subjective factors when deciding among potential actions.

The study appears in the August issue of PLoS Biology. (ANI)