Infographic 9.4: Anatomy of Fear

There are five labeled steps along the illustration of the woman’s brain, explaining her reaction to seeing the snake. Step 1 is attached to an arrow pointing from the eyes to the thalamus, and reads “Visual information goes directly to the thalamus.” Step 2 is attached to the direct path between the Thalamus and the amygdala, and reads “Basic information about threat is conveyed directly to the amygdala, enabling rapid response.” Step 3 is attached to the indirect path between the thalamus and the visual cortex, and reads “It takes longer for neural information to go to the visual cortex for processing.” Step 4 is attached to a pathway leading from the visual cortex to the amygdala, and reads “If it’s been determined that the threat is a false alarm, this message will instruct the amygdala to inhibit the fear reaction.” Step 5 is attached to the amygdala, and reads “After receiving information about the threat the amygdala: Instructs the hypothalamus and medulla to alert the sympathetic nervous system; and prompts the pituitary gland to secrete stress hormones.” Next to the photograph of the woman seeing the snake is a photograph of a brain scan, taken from the back of the head, with the amygdala highlighted. The amygdala is shown as two walnut-shaped structures, mirrored around the horizontal center of the brain. Text under the photograph reads “The amygdala, shown here in red, plays a pivotal role in experiencing fear. Information about threats prompts the amygdala to activate the physiological responses that characterize fear.” The photograph of the cat and mouse is underneath this photo. Text attached to the photograph of the cat and mouse reads “What happens when the amygdala doesn’t work? Animals with amygdala damage may not exhibit any response to a threat, like this rat, which is uncharacteristically comfortable with a predator. Similarly, one study found that people with amygdala damage demonstrated an absence of expected fear behaviors (Feinstein, Adolphs, Damasio, & Tranel, 2011).”