Answer:
Amygdala
Explanation:
Amygdala is the part of the brain. It plays a vital role in brain functioning. Amygdala is specifically known for emotions. Amygdala is the part of the limbic system in the brain. This part of the brain has two different roles. It functions both in pleasure and fear emotions. It works the same in both animals and human beings.
It is related o the aggressive behavior in animals. When castration has done in males it shrinks around 30%. When stress, anxiety, depression, post-traumatic stress disorder, and other disorder occur, it has been considering that it happened because of the dysfunction in the amygdala.
So that Collin was not a mannered man. but suddenly his behavior has been changed. He starts to abuse people. This problem does because dysfunction occurs in the amygdala.