The key player in the generation of panic attacks is an almond-shaped, one-inch long grouping of nuclei in the brain called the amygdala. The amygdala is located in the temporal lobe (lower side) of the brain just a few inches from each ear, inward and in a direction toward the forehead. And it's situated equally in the left and right hemispheres. The amygdala is a member of the brain's limbic system, which is all about the memory and motivation components of emotion. Its star players, for our immediate purposes, are, indeed, the amygdala, the hippocampus (long-term memory), and the hypothalamus (metabolism, hunger, thirst, fatigue, 24-hour life rhythm).
It's commonly accepted that what we perceive as fear is produced by a very sophisticated two-way input system. Sensory input passes through a gateway in the brain, a messenger hub if you will, called the thalamus. The main function of the thalamus is to transmit its received sensory data to the higher-centers of the brain for reasoned response. The primary recipient of these messages is the thought and logic centers of the cerebral cortex (the approximately .10 inch outer layer - grey matter - of the brain involved with functions such as awareness, thought, language, and consciousness). However, as you're about to learn, the thalamus has other chat buddies.
When environmental input from our senses of sight, sound, taste, and touch reaches the thalamus, and very specific cues are analyzed, there looms a fork in the road. One bit of pavement leads directly to the amygdala, while the other takes its sweet time and heads toward the cerebral cortex. And each of these destinations generates very different and very unique responses. By the way you may have noticed I left out our sense of smell from the first sentence of the paragraph. And that's because input from our sense of smell forgoes all the thalamus formality and shoots straight into the amygdala, though the amygdala doesn't facilitate perception.
Now, when the amygdala receives a message it's engineered to react by launching an intense physical response, the charge led by the secretion of a flood of stress and action hormones, such as cortisol and norepinephrine (a.k.a. noradrenaline). So this is the actual physical manifestation of fear that panic sufferers know all to well. See - the amygdala doesn't care if it's right or wrong, justified or not; it receives input and fires. By the way the amygdala also sends messages to the brainstem to facilitate required adjustments in heart rate and respiration in response to fear and stress.
Well, after the initial onslaught of environmental kaboom hits home the slower sensory messages from the thalamus finally hit the cerebral cortex, specifically the prefrontal cortex, the area at the very front of the brain responsible for executive functioning. As this occurs, conscious and rational thought regarding the events at hand is generated. Yes - it's in the prefrontal cortex that the fear stimuli are logically analyzed in great detail, the final assessment being sent to the amygdala. Now, the prefrontal cortex must remain on high-alert and do its best to ensure assessment accuracy because of its communication with the areas of the brain associated with pain, pleasure, anger, aggression, and panic. Indeed, there's a lot at stake. And when it's all said and done the amygdala ultimately takes its version of appropriate action, which, by the way - if sufficiently convinced - can include restoration of calm. Ah all of this is the panic sufferer's dilemma, isn't it?
Nonetheless, think about what a great system this is. I mean, the amygdala has its fear message and is prepping the body for immediate action. It's taking no chances, as it elects to err on the side of caution. And as you consider these dynamics always keep in mind that evolution presented us with a genetic make-up that leans toward the anxious. After the amygdala sends its message the prefrontal cortex takes the time to calculate the exact nature of the threat. If sufficient evidence exists that there is no threat, the amygdala is told to chill-out. Again, what an incredible mechanism this truly is. However, as it applies to us there's a major drawback. In the face of fear, the amygdala is the dominant of the two structures. And once the amygdala starts beating the drums it's really tough for the prefrontal cortex to convince it to knock it off. And without practiced intervention it really doesn't stand much of a chance.
And that's the very foundation of panic!