<P> The main concepts of the Cannon--Bard theory are that emotional expression results from the function of hypothalamic structures, and emotional feeling results from stimulations of the dorsal thalamus . The physiological changes and subjective feeling of an emotion in response to a stimulus are separate and independent; arousal does not have to occur before the emotion . Thus, the thalamic region is attributed a major role in this theory of emotion . The theory is therefore also referred to as the thalamic theory of emotion . </P> <P> Walter Bradford Cannon (1871--1945) was a physiologist at Harvard University, who is perhaps best known for his classic treatise on homeostasis . Philip Bard (1898--1977) was a doctoral student of Cannon's, and together they developed a model of emotion called the Cannon--Bard Theory . Cannon was an experimenter who relied on studies of animal physiology . Through these studies, Cannon and Bard highlighted the role of the brain in generating physiological responses and feelings; a role that is important in their explanation of emotion experience and production . </P>

What is the main idea of the cannon-bard theory