Aha! Eureka! Bingo! "By George, I think she's got it!" Everyone knows what it's like to finally figure out a seemingly impossible problem. But what on Earth is happening in the brain while we're driving toward mental pay dirt? Researchers eager to find out have long been on the hunt, knowing that such information could one day provide priceless clues in uncovering and fixing faulty neural systems believed to be behind some mental illnesses and learning disabilities.

Researchers at Goldsmiths, University of London report in the journal PLoS ONE that they monitored action in the brains of 21 volunteers with electroencephalography (EEG) as they tackled verbal problems in an attempt to uncover what goes through the mind—literally—in order to observe what happens in the brain during an "aha!" moment of problem solving.

"This insight is at the core of human intelligence … this is a key cognitive function that the human can boast to have," says Joydeep Bhattacharya, an assistant professor in Goldsmiths's psychology department. "We're interested [in finding out] whether—there is a sudden change that takes place or something that changes gradually [that] we're not consciously aware of," he says. The researchers believed they could pin down brain signals that would enable them to predict whether a person could solve a particular problem or not.

In many cases, the subjects hit a wall, or what researchers refer to as a "mental impasse." If the participants arrived at this point, they could press a button for a clue to help them untangle a problem. Bhattacharya says blocks correlated with strong gamma rhythms (a pattern of brain wave activity associated with selective attention) in the parietal cortex, a region in the upper rear of the brain that has been implicated in integrating information coming from the senses. The research team noticed an interesting phenomenon taking place in the brains of participants given hints: The clues were less likely to help if subjects had an especially high gamma rhythm pattern. The reason, Bhattacharya speculates, is that these participants were, in essence, locked into an inflexible way of thinking and less able to free their minds, and thereby unable to restructure the problem before them.

"If there's excessive attention, it somehow creates mental fixation," he notes. "Your brain is not in a receptive condition."

At the end of each trial, subjects reported whether or not they had a strong "Aha!" moment. Interestingly, researchers found that subjects who were aware that they had found a new way to tackle the problem (and so, had consciously restructured their thinking) were less likely to feel as if they'd had eureka moment compared to more clueless candidates.

"People experience the "Aha!" feeling when they are not consciously monitoring what they are thinking," Bhattacharya says, adding that the sentiment is more of an emotional experience he likens to relief. "If you're applying your conscious brain information processing ability, then you're alpha." (Alpha brain rhythms are associated with a relaxed and open mind; volunteers who unwittingly solved problems showed more robust alpha rhythms than those who knowingly adjusted their thinking to come up with the answer.)

He says the findings indicate that it's better to tackle problems with an open mind than by concentrating too hard on them. In the future, Bhattacharya says, his team will attempt to predict in real-time whether a stumped subject will be able to solve a vexing problem and, also, whether they can manipulate brain rhythms to aid in finding a solution.

The second probe into problem-solving focused on the anterior cingulate cortex (ACC), a region in the front of the brain tied to functions such as decision making, conflict monitoring and reward feedback. A team at the University of Lyon's Stem Cell and Brain Research Institute in Bron, France reports in Neuron that it verified that the ACC helps detect errors during problem solving (as previously discovered), but also that it does so by acting more as a general guide, monitoring and scoring the steps involved in problem solving, pointing out miscalculations as well as success.

The team discovered this by recording electrical activity in the brains of two male rhesus monkeys as they tried to determine which targets on a screen would result in a tasty drink of juice. "When you're trying to solve a problem, you need to search; when you discover the solution, you need to stop searching," says study co-author Emmanuel Procyk, coordinator of the Institute's Department of Integrative Neurobiology. "We need brain areas to do that."

He says that researchers observed increased neuronal activity in the animals' ACCs when they began searching. When the monkeys hit the jackpot, there was still heightened activity in the ACC (though only a selective population of nerve cells remained hopped up), indicating that the region is responsible for more than simply alerting the rest of the brain when errors are made. Once the monkeys got the hang of it—and routinely pressed the correct target—ACC activity slowed.

"What we think based on this experiment and other experiments," Procyk says, "is that this structure is very important in valuing things." It essentially scores each of the monkey's behaviors as successful or not successful. "It is an area," he adds, "that will help to decide when to shift from the functioning that goes on when [the brain is] learning to when the learning [is] done."

Procyk says that if this system is compromised, it could have implications for issues such as drug dependency. If the ACC is functioning abnormally, he says, it could overvalue drugs, leading to addiction. (Other studies have shown that an impaired cingulate cortex can result in maladaptive social behavior and disrupted cognitive abilities.)

Alas, the ultimate "Aha!" moment for researchers probing problem solving is likely is far off, but at least the latest research may help them avoid an impasse.