The metaphor goes like this: the older a brain system is on the evolutionary scale (and the closer to the brain stem), the more power it has to suspend the actions of the younger systems. And the lizard brain within the limbic system is the loudest example of this metaphor. You rarely have a heart attack (I hope) and you probably won’t get so dizzy that you fall down, but your amygdala regularly suspends all civilized activity within your brain and takes over, putting you into lockdown.
