USMLE® Step 1 style questions USMLE
USMLE® Step 2 style questions USMLE
A 44-year-old woman is brought by her husband to her primary care physician's office because of chronic personality changes. The husband complains that the patient has gradually become very hypersexual, making inappropriate remarks in public and sexual advances toward strangers. He states that sometimes she does not recognize him and has trouble communicating. She seems to always have something in her mouth, whether it is her fingers, clothes, food, or inedible things. Her past medical history is significant for oral cold sores that seems to come up in times of stress, and are usually controlled with acyclovir. Which of the following areas of the brain is most likely affected?
Klüver-Bucy syndrome is neurobehavioral condition first observed in the 1930s by Heinrich Klüver and neurosurgeon Paul Bucy.
They discovered that monkeys that had bilateral temporal lobe lobectomies developed dramatic behavior changes in their memory, as well as their social and sexual behaviors.
In retrospect, it’s not surprising that having a significant portion of the brain removed caused behavior changes in monkeys - the biggest one was probably anger at Klüver and Bucy for putting them through that!
The temporal lobe is one of the four major lobes of the brain.
It has a variety of functions which are involved in sensory processing.
The ventral, or anterior, part of the temporal lobe helps process visual information, such as the recognition of objects and faces.
Whereas, the medial, or middle portion, of the temporal lobe, along with the hippocampus, is responsible for the formation of new memories.
The temporal lobe also houses the primary auditory cortex, which is needed for speech comprehension.
Other important structures found within the temporal lobe include the olfactory cortex, which processes the sensation of smell, and the amygdala, which processes emotions.
The amygdala also plays a role in the reward center of the brain which motivates and reinforces behaviors that elicit positive feelings.
In Klüver-Bucy syndrome there’s a bilateral lesion of the temporal lobe.
The most common cause of such a brain lesion is herpes simplex encephalitis - a viral infection that particularly affects the temporal lobes.
Other causes of Klüver-Bucy syndrome include trauma, stroke, Alzheimer's disease, and Niemann Pick disease, which is a rare metabolic condition that affects various organs of the body, including the brain.
The damage affects the amygdala which is a part of the brain that regulates emotions and reinforces behaviors related to food and sex.