Final answer:
Individuals with mood disorders generally exhibit increased activity in the limbic system, particularly in areas like the amygdala and hippocampus which are key in emotional processing.
Step-by-step explanation:
Those with mood disorders often show an increased activity in the limbic brain areas. The limbic system includes the amygdala and the hippocampus, which are vital in processing emotions. Increased amygdala activity is significant as it is associated with the learning of fear and can be observed in individuals who are at risk for, or are suffering from, mood disorders. Moreover, the hippocampus is crucial for emotional processing, and changes in its function and structure have been associated with mood and anxiety disorders. Dysfunctional hippocampal activity can impact emotion and cognition, making it highly relevant in the study of these disorders.