Final answer:
PTSD is associated with an enlargement of the amygdala when individuals view trauma-related stimuli. Research links amygdala changes with mood disorders, but a causal relationship between hippocampal volume and PTSD cannot be determined. Treatments can increase hippocampal volume and improve behavior in PTSD patients.
Step-by-step explanation:
When individuals with PTSD view trauma-related stimuli, their amygdala grew larger compared to other study participants. Research has shown that changes in the amygdala structure and function can be seen in those at risk for or suffering from mood disorders. The limbic system, which includes the amygdala, is involved in fear responses and emotions.
The hippocampus is also part of the emotional processing in the brain, and diminished hippocampal volume has been observed in individuals with PTSD. While there's a correlation between hippocampal volume and PTSD, we cannot make causal claims due to the nature of the research. However, improvements in behavior and increases in hippocampal volume have been seen following treatments such as pharmacological or cognitive-behavioral therapy.