Final answer:
The amygdala is integral to emotional processing, particularly fear and anxiety, and changes in its structure and function are associated with mood and anxiety disorders.
Step-by-step explanation:
The question involves matching certain brain regions with their associated functions and emotions. The amygdala is a part of the limbic system and plays a key role in the processing of emotions such as fear and anxiety. Research has shown that the amygdala has a complex structure with various subnuclei, like the basolateral complex, which is involved in classical conditioning and attaching emotional significance to memories. The central nucleus of the amygdala has been linked with regulating attention, and its connections to the hypothalamus and brainstem influence the autonomic nervous and endocrine systems.
Moreover, functional and structural changes in the amygdala have been associated with mood and anxiety disorders, and its activity patterns may help differentiate between major depressive disorder and bipolar disorder. Given the information provided, fear and disgust could be attributed to the amygdala, while sad mood and depression might be linked to alterations in amygdala function.