Why Zebras Don't Get Ulcers: The Acclaimed Guide to Stress, Stress-Related Diseases, and Coping

by Robert M. Sapolsky

anxiety and fear conditioning are the province of a related structure, the amygdala.* To begin to make sense of its function, you have to look at brain areas that project to the amygdala, and where the amygdala projects to, in turn. One route to the amygdala is from pain pathways. Which brings us back to chapter 9 and how there’s pain and then there’s subjective pain interpretation. The amygdala is about the latter. The structure also gets sensory information. Remarkably, the amygdala gets sensory information before that information reaches the cortex and causes conscious awareness of the sensation—the woman’s heart races before she is even aware of the accent of the man. The amygdala gets information from the autonomic nervous system. What’s the significance of this? Suppose some ambiguous information is filtering in, and your amygdala is “deciding” whether this is a time to get anxious. If your heart is pounding and your stomach is in your throat, that input will bias the amygdala to vote for anxiety.* And, to complete the picture, the amygdala is immensely sensitive to glucocorticoid signals.