Neurologists and biological psychologists have witnessed a sharp increase in the knowledge and understanding of particular structures of the brain over the past two decades. As technology becomes ever more advanced, scientists are able to isolate the functions of even small regions of the human brain.
One noteworthy discovery is the role of the amygdala in human fear and aggression. The amygdala, a small, almond-shaped conglomerate, is just one part of the limbic system. Located at the very center of the brain, the limbic system is the core of our 'emotional brain;' each individual structure in the limbic system is somehow connected to an aspect of human emotion. Scientists have found that electrode stimulation of the amygdala can elicit extreme and aggressive acts. Patients or experimental subjects who experience this utter rage and fearlessness have no rational foundation for their reaction. In other words, this aggression is wholly attributable to electrode stimulation.
On the other hand, patients with trauma or damage to this structure exhibit a complete absence of aggression. Researchers find that no amount of poking, prodding, or harassment will evoke even remotely aggressive responses from these subjects
The author suggests that persistent passivity and imperturbability may be a direct result of which of the following?
