Amygdala belongs to the limbic system which is an old part of the brain. It belongs to the Mammalian Brain which we share with mammals. This part of the brain takes care of more sophisticated functions than the basic reptilian functions  e.g. sexuality, instincts, emotions, immune system as well as blood pressure, blood sugar and so on.

Discovery of the role of the amygdala in our behaviour is relatively recent. Daniel Goleman, explained the significant breakthroughs in the field of neuroscience and the role of amygdala in his best seller books, Emotional Intelligence and Working with Emotional Intelligence. A lot of this research goes back to the great work carried out by Joseph LeDoux, a neuroscientist at NYU which fundamentally changed our view of how emotions impact behaviour.