By, Arin Levenstein And its Emotional and Psychological Significance

 The amygdala is closely related to the emotional state in people.  This can include fear, social interaction, and stores memories tied to intense emotions related to fear.  Has been tied to depression and autism.

 The amygdala is located in the medial temporal lobe, near the hippocampus.  It is almond shaped and is also about 1 inch long in fully grown humans.  Is connected to the visual cortex, temporal lobe, and is closely tied to the limbic system (which deals with emotional expression).

 The amygdala is generally split into four different nuclei.  These are the Basolateral, Basomedial, Central, and Lateral.  The lateral and central nucleus control fear levels in humans and animals.

 Extensive testing on animals has proven that changes in the health of the amygdala can greatly influence a subjects fear levels.  In one such study, a group of monkeys with damaged amygdalas were observed against normal, healthy monkeys of the same species.  The monkeys with the damaged amygdalas had less fear towards meeting others and was more social and outgoing.

 The amygdala can be linked to depression  One study indicated that people with depression symptoms had an abnormally small left side amygdala.  This is caused by over activity that kills healthy cells.

 There has been debate as to whether or not there is a connection between the amygdala and autism.  Lab animals with lesioned amygdalas had hesitant social behaviors which were observed to draw certain similarities with autism.  This is inconclusive evidence though because the monkeys that were tested still had minimal interactions with each other.  This means that the social behavior is abnormal but not necessarily a sign of autism.

 As previously mentioned, there can be multiple effects when the amygdala is damaged.  One will have an underactive sense of fear.  This can lead to lead to not being cautious enough when placed in a new environment or confronted with a new activity.  Hyperactivity of the amygdala can cause panic.  This can also lead to anxiety.

 More Research -  More studies have been conducted with the amygdala.  Fear tests were conducted on rats in the lab.  These rats were given a slight shock and an auditory signal.  The rats became fearful of both the shock and the simple signal.  This showed that not only is the amygdala associated with fear but also with the remembering of fear if provoked. Another Image -

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