The experience of emotion is accompanied by activation of two major areas of the nervous system: the brain and the autonomic nervous system.
The area of the brain known as the limbic system is highly involved in emotion. One structure in the limbic system, called the amygdala, plays a particularly important role in regulating emotion.
Researchers believe that sensory information about emotion-evoking events moves along two pathways in the brain. The information goes first to the thalamus and from there moves simultaneously to the amygdala and the cortex of the brain. The amygdala processes the information quickly and sends signals to the hypothalamus, which in turn activates the autonomic nervous system. The cortex, on the other hand, processes the information more slowly, allowing people to appraise or evaluate the event.
Example: When information travels from the sense organs to the thalamus to the amygdala, people respond instantaneously, without thinking, to events in their environment. A parent may snatch her child away from a curb without thinking if she hears the sound of squealing tires coming toward them.