BEIJING, Aug. 24 (Xinhuanet) -- Human subject playing a game resembling Pac-Man showed fear lives in different regions of the brain depending on the proximity of a threat.

The study revealed that when humans face some sort of threat, such as a virtual munch-monster, they alter their behavior depending on whether the threat is distant or nearby.

To decipher what is happening in the brain when a threat appears, researchers at the University College London created a computer game akin to Pac-Man where participants were chased through a maze by a virtual predator. If caught by the virtual beast, they would receive a very real mild electric shock. The participants' brain responses were measured with a brain-imaging fMRI machine.

When the predator was some distance away, parts of the brain's prefrontal cortex (just behind the eyebrows) showed activity. Activity in this area, which helps control response strategies to threats, increases during anxious moments.

But when the predator came closer, brain activity moved to a region of the brain responsible for more primitive behavior, such as quick-response survival mechanisms that include flight, fight and freezing.

"The most efficient survival strategy will depend on the level of threat we perceive," said study leader Dean Mobbs of UCL. "This makes sense as sometimes being merely wary of a threat is enough, but at other times we need to react quickly."

The study is detailed in the Aug. 24 issue of the journal Science.

(Agencies)