Discuss the theories of brain abnormalities associated with depression.

Key terms and concepts that may be included in student responses:
▪ Prefrontal cortex-involved in attention, short-term memory, planning, and problem solving; reduced metabolic activity and volume of gray matter; lower brain-wave activity; left prefrontal cortex is involved in motivation and goal-orientation-inactivity in this region may be associated with motivational difficulties as seen in depression.
▪ Anterior cingulate-a subregion of the prefrontal cortex; plays an important role in body's response to stress, emotional expression, and social behavior; different levels of activity in the anterior cingulate; problems in attention, planning of appropriate responses, coping with anhedonia.
▪ Hippocampus-critical in memory and fear-related learning; smaller volume and lower metabolic activity in the hippocampus; chronic arousal of the body's stress response, role of cortisol.
▪ Amygdala-attention to stimuli that are emotionally salient; enlargement and increased activity; overactivity may bias people toward aversive or emotionally arousing information and lead to rumination over negative memories and negative aspects of the environment.