Scientists used a fairly easy examination along with magnetic resonance imaging of the brain in real-time. With these pictures, scientists identified the key region in the brain called the rostral cingulate, which is capable of turning the amygdala, 'On' or 'Off'
"People are exposed to an ever-increasing amount of stimuli in our everyday lives, and so we realized that the brain must employ a processing mechanism to prioritize and refine responses -- we don't run away from every loud sound or unexpected sight," said Dr. Joy Hirsch, who led the study, published in the journal Neuron.
Researchers drew on the strengths of the stroop test, essentially to gauge the extent of mental expandability, by eliciting people's choice between a given word and its color. Subjects will be given a list of words to read, for example "blue", "orange", or "violet", in which the word "blue" might be written in red ink, "orange " in blue ink and so on.
It was observed that the responses from subjects were quicker when the color and the word matched. They improvised this test to suit this study by using fearful and happy faces, with "FEAR" or "HAPPY" visibly spread across the images. 19 healthy participants took this test and the functioning of the brain was recorded.
The scientists observed that the rostral cingulate appeared to show activity prior to the stimulation of the amygdala. Further, when subjects saw "Fear" across a smiling face, the amygdala became active; later when the rostral cingulate sparks up obviously with the realization that the face was actually not fearsome, the relief translates into the amygdala calming down. In contrast, the amygdala remained excited for a longer duration when the face appeared fearful.
Dr. Eric Kandel, a Howard Hughes Medical Institute senior investigator and professor in brain sciences who worked on the paper said this finding holds promise for patients suffering depression and anxiety disorder.