The conventional view held by neuroscientists about how the brain processes information is that the sensory information is first passed to a mammalian part of the brain called thalamus.  From there the information is sent to the visual cortex which processes the information, compares it with your world model and eventually you identify the objects you see or are experiencing. From there the signals are sent to the limbic brain and commands are then sent to the rest of the body to generate the appropriate behaviour.

This is the way our brain works most of the time, as we perceive the world, evaluate and respond to it. LeDoux found something remarkable. He found that there is a smaller bundle of neurons connecting the thalamus to amygdala. This small pathway, allows amygdala to receive a selection of sensory information coming in before it has been sent to the visual cortex for further processing.

In other words, amygdala can receive information and formulate a quick response well before the rest of the brain has process the situation and has delivered its appropriate response.

This discovery comes to explain a lot about our fight-or-flight behaviour, quick emotional reactions to novel situations and our built-in hardwired system that is capable of short circuiting our logical mind. No wonder we can sometimes be so vulnerable to this short-circuiting of our illogical mind.