reptilian brain awoke for a split-second and triggered an involuntary shudder when the shadow of a "space alien" was projected on our neighbor's wall. Of course, it turned out to be just the satellite dish, and the heartbeat immediately returned to normal.
According to neuroscience the baser emotions like fear and anger are the product of the brain's oldest structures, aka the reptilian brain. Higher functions, such as language and consciousness, come from newer sections such as the hippocampus and the neocortex.
Fortunately, your observer is in total control of his animal instincts, which is why only sweet reason and enlightenment may be found on these humble pages.