A computer game in which volunteers had to move a blue triangle through a 2D maze while avoiding a red dot "predator" has shed light on how the brain reacts to imminent danger. If the predator caught the triangle, the volunteer received an electric shock. During game play, Dr Mobbs of University College London used an MRI scanner to monitor brain activity. The scanner showed which regions of the brain were receiving the highest flow of blood: as the level of threat in the game increased, and as anxiety turned to panic, activity switched from the front of the brain to the middle.
The forebrain is active during periods of anxiety, and helps coordinate escape strategies to avoid the threat while the midbrain is a primitive area of the brain, and it controls gut-level reflexes such as the decision to fight or flee. "The closer a threat gets, the more impulsive your response - in effect, the less free will you have," he noted. The prefrontal cortex in the forebrain is much larger in modern humans than it was in our ancestors, and so we may have evolved to be more adept at avoiding threatening situations, thinks Dr Mobbs.