When you think of the amygdala, you should think of one word. Fear. The amygdala is the reason we are afraid of things outside our control. It also controls the way we react to certain stimuli, or an event that causes an emotion, that we see as potentially threatening or dangerous.
A rat climbs over a cat without fear.
Numerous studies have been performed where researches have used deep lesioning (procedure where a thin wire is inserted into the brain to remove or terminate a part of the brain) to remove the amygdala of rats. After this procedure, the rats were said to have no fear of anything, even cats. The removal of the amygdala had taken away the rats' memory of fear, therefore the rats did not fear anything!