Wired for Fear
It’s not enough to know the various structures that participate in brain function. It’s also important to know how those structures relate to one another and coordinate different processes.
New York University professor Dr. Joseph LeDoux, has spent decades studying fear in the brain. He describes two pathways of differing lengths that fear signals follow within the brain. His experiments suggest that our sensory organs pass information to the thalamus, where signals split and trace two separate paths on their way to the amygdala, the brain’s threat center.
Following the shorter path, one signal manages to sound the fear alarm before we’re even aware of the situation. The other reaches the sensory cortex a fraction of a second later, providing a much clearer picture of the potential threat. The second signal can reinforce the fear response or declare a false alarm.
LeDoux believes the concept of two separate pathways helps explain not only how we respond to danger so quickly, but also why patients with certain forms of amnesia can react with fear to immediate threats despite their lack of memory, as we normally think of it.