The theory that claims that emotions are organized in the brain is called The Cannon-Bard Theory. The cannon-Bard theory is also referred to as the thalamic theory of emotion. It is more like a description of emotions that is given by Philip Bard and Walter Cannon.
According to this theory, human emotions and physical reactions to those emotions including trembling, muscle tension, and headaches, all go simultaneously hand in hand. Going deeper into this theory, it is set upon the premise that emotions are a result of nerve impulses send to the brain through the thalamus, as a response to any stimulus.