Monkey research pinpoints reward center, which can go awry
WEDNESDAY, Jan. 23 (HealthDay News) -- New research suggests that a specific part of the brain handles what might be called the "I've got it!" moments.
The research could lead scientists closer to more effective treatments for a variety of mental illnesses. Any new understanding of a brain region is helpful because it provides insight into "what's related to a physical problem versus a psychological issue," said Paul Sanberg, director of the University of South Florida College of Medicine's Center of Excellence for Aging and Brain Repair.
At issue is the brain's ability to learn that it's discovered the right approach to a challenge, such as picking the right answer on a multiple-choice test.
"In general, when one tries to solve a problem one has to be sure to recognize that the solution has been found and that it is no longer needed to pursue the search for an appropriate response," said study co-author Emmanuel Procyk, a researcher at the University of Lyon in France.
For example, he said, "when you face new software, you usually try menus and options with a specific goal in mind. By trying and making errors, you eliminate inappropriate selections, but once you find what you expected to produce, you detect and feel success, and consequently store this fruitful behavior for further use."
In the new study, Procyk and his colleagues placed two monkeys in front of computer touch screens and let them choose which target to press. The monkeys learned that some targets would give them a reward of juice.
As the monkeys took part in the experiment, researchers recorded electrical activity in the anterior cingulate cortex, a brain region connected to emotion, decision-making and the art of anticipating what will happen next.
The study findings are published in the Jan. 24 issue of the journal Neuron.
Judging from their analysis of the electrical patterns in the brain, the researchers suspect the region plays a role in both monitoring the situation and figuring out the best response to it.
"Neurons of that region react to the first meaningful reward, the one 'saying' that the goal has been reached and that there is no more need to explore," Procyk said.
Sanberg said: "If you have damage to that area, you're not going to react well to a reward. If you can't perceive the way the reward should be, you may [engage in] inappropriate behavior. Or you may not know you're getting the reward, or it may not be strong enough for you to adapt the behavior to the reward."
Drug addicts, for one, aren't able to properly handle their perception of rewards, Sanberg said.
The new research, which Sanberg called "elegant," could be useful in the future if scientists can figure out how to "alter" that part of the brain, perhaps through methods like deep-brain stimulation, he said.
Another study, published in the Jan. 23 online issue of PLoS ONE, also sheds light on the mechanisms behind the art of problem-solving.
Joydeep Bhattacharya, of Goldsmiths College in London, England, tracked brain rhythms while volunteers solved verbal problems. Often, the volunteers became mentally blocked when there was an excessive amount of gamma brain rhythm, which suggests that focusing too much on a particular problem might hinder the ability to arrive at a solution.
Learn more about the brain from the U.S. National Institutes of Health.
SOURCES: Paul Sanberg, Ph.D., distinguished university professor and director, Center of Excellence for Aging and Brain Repair, University of South Florida College of Medicine, Tampa; Emmanuel Procyk, researcher, University of Lyon, France; Jan. 24, 2008, Neuron; Jan. 23, 2008, PLoS ONE
All rights reserved