Emotion is defined as having cognitive, physiological, and behavioral components. The limbic system, specifically the amygdala, plays an important role in emotions like fear and rage. The right hemisphere of the brain is also active during emotional displays and damage can leave one emotionally indifferent. Emotions produce sympathetic nervous system responses like increased heart rate and respiration. Plutchik's theory proposes eight primary emotions that combine to form secondary emotions. James-Lange and Cannon-Bard theories differ on the temporal order of physiological and emotional awareness during emotional experiences. Culture influences the expression and meaning of emotions through display rules.