I found this really cool article about how scientists are using fMRI scans and tarantulas to attempt to map out the brain’s fear circuitry. A little background: approximately 1/5 of men and 1/2 of women have arachnophobia. It is suggested by scientists that this may be an evolved predisposition, since some of the more venomous strains would have meant instant death to our ancestors.
The scientists in this study were interested in people’s reactions to both proximity and direction of movement of the threat. They had subjects lay down in an fMRI machine with one foot extending into one of 6 compartments of an “imminence box”. Subjects were then told which compartment the spider would enter and were asked to predict how frightened they would be when it did so. Then they actually watched the spider go into that compartment and reported their actual fear (the spider’s moves were prerecorded, but they didn’t know that).
Along with self-report measures of fear, researchers also looked at brain scans. If the spider was close, the amygdala was active and the prefrontal cortex was quiet. If the spider was far away, the reverse pattern was seen. One interesting finding was that irrespective of how far away the spider was, if it started moving towards the subject, a specific subsection of the fear network, thought to be the brain’s panic circuit, was activated. This indicates that our brains have a specialized mechanism for determining a threat’s direction of motion.
I found this study very interesting and I think it can have important implications; providing a more detailed circuitry of the fear network may help diagnose and treat other phobias.