Mapping the neural circuitry of predator fear in the nonhuman primate.

In rodents, innate and learned fear of predators depends on the medial hypothalamic defensive system, a conserved brain network that lies downstream of the amygdala and promotes avoidance via projections to the periaqueductal gray. Whether this network is involved in primate fear remains unknown. To address this, we provoked flight responses to a predator (moving snake) in the marmoset monkey under laboratory conditions. We combined c-Fos immunolabeling and anterograde/retrograde tracing to map the functional connectivity of the ventromedial hypothalamus, a core node in the medial hypothalamic defensive system. Our findings demonstrate that the ventromedial hypothalamus is recruited by predator exposure in primates and that anatomical connectivity of the rodent and primate medial hypothalamic defensive system are highly conserved.