Week 12

The last section in this semester of Behavioral Neuroscience covered “Special Topics in Mental Disorders.” For this topic Eric separated the class into four groups. Three of the groups presented their topics to the class during lecture times this week (Monday, Wednesday, and Thursday during an hour of lab) with that material being covered in this week’s exam. The fourth group, which was my group, presented the following Monday as it was the last week of classes and Wednesday was the last class meeting day of the semester. The exam covering our topic was on that Wednesday.

The topic my group presented on was posttraumatic stress disorder. It is caused by some type of traumatic event or stress such as rape or war. It involves reliving the event in some way such as flashbacks or nightmares that prevent a patient with posttraumatic stress disorder from dealing with the problem effectively and moving on with their life. The disorder was broken down into components like behavioral changes, treatments, and brain changes. My section was brain changes.

Learning about the brain changes was rather interesting because it is so complex. Much research investigated the involvement of the hippocampus, which makes sense because the hippocampus is involved in memory processing. A link was found between hippocampal volume (the size of the hippocampus) and developing posttraumatic stress disorder. However, the link was not super clearly defined. One study looked at the brains of police officers, all of which had gone through the traumatic events of serving their community, and found that officers with posttraumatic stress disorder had smaller hippocampal formations. This establishes a connection between the hippocampus and posttraumatic stress disorder but the connection gets more complicated. There was a different study looking at Vietnam War veterans who developed posttraumatic stress disorder and who also had a monozygotic (identical) twin who did not serve in the war. The results showed that the veterans with posttraumatic stress disorder had smaller hippocampal volumes, which was to be expected. However, the interesting part is that the twin who did not serve in the war also had a smaller than average hippocampal volume. This implies that having a smaller hippocampal volume is a predisposition for developing posttraumatic stress disorder.  I read about a third study looking at a different group of veterans and their brains. This study found more evidence supporting the connection between decreased hippocapmpal volume and the development of posttraumatic stress disorder. However, the results showed that the decrease in hippocampal volume was proportional to the amount of time the soldier had served in armed combat. This suggests that trauma has a causal role in the shrinking of the hippocampus. Clearly we have a lot more to learn about the disease and there are many more important factors than just the hippocampus but I found all of that rather interesting.