Imaging fear stress responses in monkeys.
Harder J, King J, Garelick T, Chen W
UMass Medical School, University of Bradford
There are fundamental similarities in responses to threat across mammalian species. These fearful responses to unlearned stimuli (such as predator odor) are relevant to unlearned fear states in humans, including phobias and other psychiatric conditions. In humans, it is known that fearfulness increases with aging. Functional MRI of conscious marmoset monkeys reveals that the amygdala (associated with emotional states including fear) and frontal cortices (which modulate the amygdala) show significantly increased positive BOLD in response to predator scent exposure. Furthermore, we have shown that in aged marmosets this fear response is significantly greater than in adolescents.