In a previous entry I discussed one sort of TMS research which measured the response of the processing of happy faces in depressed subjects. Another recent study by Schutter, Hofman, & Van Honk published in "Psychophysiology," uses TMS to measure the effect of fearful faces on excitability of neurons in the corticospinal motor tract. Like the sensitivity to happy faces that resulted after increased stimulation of the cerebellum, there is a relevant biological basis for sensitivity to fearful expressions that proves useful from an evolutionary perspective. Fearful facial expressions are, in effect, a warning sign that the brain processes prior to triggering preparation for action (the fight or flight response). In the current study, TMS was used to measure the degree of excitability that resulted after a subject viewed a fearful face. Compared to faces that expressed other emotions, the response to fearful faces was very high.
This is an interesting finding. One can see why it would be useful to have a high sensitivity to fearful faces. I wonder how the rate of processing of these faces differs from subject to subject. What kinds of differences between subjects would cause processing of fearful faces to be slower or faster?
How was "excitability" measured? This sort of study would be interesting if it included an fMRI component, and I'm sure there have been similar studies conducted that do include fMRI. I'm assuming the amygdala would light up in the presence of these fearful faces.
ReplyDeleteHow can the level of fear people experience be explained? In addition to the response time of processing certain emotions, like fear, I wonder what determines the extent of our emotions. Why are some people more scared of the same thing than others?
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