Cannon–Bard theory
[4] To do so, Cannon experimented with severing afferent nerves of the sympathetic branch of the autonomic nervous system in cats.
Cannon identified and outlined five issues with the James–Lange theory's notion of the vasomotor center as the explanation of emotional experience.
To further support the assertion that emotional expression results from action of subcortical centers, Cannon and Britton[11] performed further experimental research with cats.
[7][12] However, once the lower posterior portion of the thalamic region was removed, the display of sham rage by the cats subsided.
Based on this finding, it was concluded that the thalamus was a region from which, in the absence of cortical control, impulses are discharged which evoke an extreme degree of "emotional" activity, both muscular and visceral.
Based on these findings and observations, Cannon asserts that the optic thalamus is a region in the brain responsible for the neural organization for the different emotional expressions.
[6] There are numerous reported and cited cases of patients with unilateral lesions in the thalamus region who have a tendency to react excessively to affective stimuli.
Cannon wrote that within and near the thalamus, the neurons responsible for an emotional expression lie close to the relay in the sensory path from the periphery to the cortex, and when these neurons fire in a particular combination they innervate muscles and viscera and excite afferent paths to the cortex by direct connection or irradiation.
[15] Secondly, a tumor on one side of the thalamus can result in unilateral laughter or grimace under the appropriate conditions, although cortical and voluntary control of the same muscles is bilateral.
James Papez[16] initially suggested that the interconnections among structures of the limbic system were ideally constituted to handle the long-lasting, intense aspects of experience that are typically associated with emotion.
[17] MacLean elaborated on Papez's earlier work, adding the prefrontal cortex, the septum, and the amygdala, and named this group of structures the limbic system.
