Final answer:
According to the Cannon-Bard theory of emotion, the thalamus is the part of the brain that plays the most crucial role in the process of emotional response, sending signals to the cortex and the autonomic system simultaneously.
Step-by-step explanation:
In the Cannon-Bard theory of emotion, the thalamus is thought to play the most important role. This theory suggests that when an emotion-provoking event occurs, the thalamus sends simultaneous signals to the cerebral cortex and the autonomic system. The cortex is responsible for the conscious experience of the emotion, while the autonomic system triggers the physiological arousal associated with the emotion.