When there is a better understanding of which brain regions do not function normally when facing fear, then it would be possible to treat phobias, declare scientists.
A large network in the brain controls human's response to fear and the source of fear in this study was a tarantula.
When a threat is farther away, a more rational functioning controls the response. When a threat gets nearer, a more primitive, panic system takes over.
The study involved a man lying in a brain scanner, with his foot in one end of a long, narrow box, which was divided into six compartments of equal size.
On a screen he watched a tarantula crawling in one of the compartments. A hand reaches in and moves the spider into another compartment, first one further away from the man's foot, then one closer.
The scanner - a functional magnetic resonance imager (fMRI) - allowed researchers to capture that fear by recording the activity in his brain as he watched the spider, illuminating the hallmarks of the human fear response in the man's brain.
In a study of 20 individuals who watched the same video, researchers reported that our brains evaluate fear in a nuanced way, drawing on several different regions depending on the proximity, trajectory and our expectations of the feared object - - in this case a Brazilian salmon pink tarantula.
By better understanding which of these brain regions fail to function normally when confronted with fear, the authors hope their findings could one day help treat people with phobias.
"I think the take home message is that what we've shown is that in tandem there are a bunch of systems that are working all at the same time," said study leader Dean Mobbs of the Medical Research Council-Cognition and Brain Sciences Unit in Cambridge, United Kingdom.
The study looked at three aspects of the fear response: the proximity of the feared object, its trajectory and the subject's expectation of how scary it's going to be.
The study new study, published in the Proceedings of the National Academy of Sciences.