Two key areas of the brain are involved in fear, with the more impulsive region taking over as a threat looms closer. A malfunctioning in the balance between the two could explain some anxiety disorders, researchers believe.
Scary Pac Man-like game
To find out exactly where our fear resides, British scientists scared volunteers with a Pac Man-like computer game, in which subjects were chased through a maze by an artificial predator. If caught, they received a mild electric shock.
Simultaneous brain scans measuring blood flow showed that when the predator was distant, lower parts of the prefrontal cortex area of the brain behind the eyebrows were active.
This region is associated with complex decision-making, such as planning an escape.
Fear shifts brain activity
But when the predator moved closer, activity shifted to the periaqueductal grey area, responsible for quick-response survival mechanisms such as fighting, flight or freezing.
The findings by Dean Mobbs and colleagues at the Wellcome Trust Centre for Neuroimaging at University College London were reported in the journal Science on Thursday.
"It's a bit like a see-saw - both regions play a role, but one becomes more dominant at different stages of threat," Mobbs said.
Understanding the shifts in activities between the forebrain and midbrain regions may be crucial.
In particular, it seems that the prefrontal cortex helps control more primitive systems in the brain and loss of this regulation could explain why people with panic disorders overreact to situations that pose no immediate threat. - (Ben Hirschler/Reuters)
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