Emotions
The thing about emotions is that it’s impossible to name an emotion and point to a single part of the brain that controls it. Instead, different aspects of different structures contribute, and the network of neurons that enables communication throughout the entire brain leads to what we call feelings. The other thing about emotions is that the physical changes can be named, the feeling can be subjectively described, and beliefs and understandings can contribute to how a situation is perceived and the reaction, but, in the end, there is no objective definition of happiness, sadness, or any other emotion.
Stimulus
Physical response
Emotionalresponse
Emotional Theories
Three theories make up current understandings of emotions: the James-Lange theory, the Cannon-Bard theory, and the Schachter-Singer two-factor theory. None have been disproven, although the Cannon-Bard theory is most widely supported by scientists. The Cannon-Bard theory suggests that emotional feelings and physical reactions are two separate entities that come from different areas of the brain as the result of one stimulus. Since the feeling and the physical reaction are simultaneous, they are perceived as being together. The James-Lange theory says that actions are the cause of emotions. For example, when someone sees a spider, their heart rate increases, their pupils dilate, and their palms start to sweat. As a result of these physical changes, fear is the labeled emotion. The Schachter-Singer two-factor theory requires the viewing of the situation as a whole in which the combination of the physical response and the idea that a feeling should come as a result, called an emotion label, trigger the emotion.
Emotions in the Brain
Although no one part of the brain can be linked directly to a particular emotion, it is known that the amygdala is the receiving unit of sensory stimuli that trigger emotions, and the orbitofrontal cortex helps to distinguish them. Stimuli can take two paths to the amygdala: either they can go straight through the thalamus to the amygdala for almost instantaneous, surface-level associations, or they can go through the sensory cortex and then to the amygdala. This path allows for the stimulus to be better processed and evaluated. This way, the feeling has more meaning and can contribute to the making of memories by altering how the hippocampus receives it. Being part of the limbic system, the amygdala has a major role in the processing of stimuli, especially those that lead to fear. Emotions, depending on the stimulus, vary based on their level of intensity and the valence, or if they are labeled as pleasant or unpleasant. The amygdala specializes in identifying the intensity whereas the orbitofrontal cortex identifies the valence. Stimuli that present a danger are more likely to be more intense, meaning that the amygdala will have a stronger and faster reaction and emotion attached to it. These fears are often remembered because of the way it is presented to the hippocampus and the survival advantage in remembering situations that cause fear. Emotions with a high intensity are put into long-term storage by the hippocampus whereas those with lower intensity go to short term storage. From here, people can be conditioned to feel fear in response to a particular situation or stimulus by repeatedly presenting an image seemingly harmless and connecting a strong emotion, such as fear, with it. Because of the brain’s high capacity of storing emotions, the image will eventually be associated with fear, leading to the immediate triggering of the emotion in response to the image.
