Most of our immediate emotional responses to stimuli are not under our control. For the first half second after your brain begins processing any new information, you have an automatic, or autopilot type response. The amygdala is implicated in this automatic processing and response of information as we encounter changes in our environment.
This makes sense because we are under a continuous barrage of sensory information from our outside world which needs to be filtered and prioritized for response. It has been known for a long time that the amygdala is critical for learning predictive environmental signals of threat (J. LeDoux, 1996). Whether you decide that you should not walk down that dark alley because of a noise you heard, or because you realize that someone is walking up behind you (because the person in front of you just widened their eyes), it is the amygdala that monitors your environment for those types of signals.
While you might have been told that it is the ‘fight or flight’ center of your brain, some researchers believe that it is better to think of the amygdala as one of the brain areas critical for learning and then detecting predictive environmental signals (P. Whalen et al., 1998). That said, the amygdala does control some very initial and automatic responses such as facial expression, heart rate and respiration changes as well as somatomotor (movement-related) related responses (K. Roelofs et al., 2010.).
Independent researchers all over the world are studying how the brain responds to stimuli and directs these autopilot-type responses. Deciphering the brain chemistry underlying these responses will lead to new strategies for treating and predicting psychopathology and predictive insights to behavioral patterns.