The Limbic System

The limbic system is a neural system located below the cerebral hemispheres of the brain. Three structures that are part of the limbic system are the hypothalamus, hippocampus, and the amygdala. These three structures work together as a whole making it feasible for the body to function properly. The hypothalamus is a small, but busiest part of the brain located just below the thalamus and is mainly concerned with homeostasis. It is an important link in the command chain governing bodily maintenance and helps keep the body’s internal environment in a steady state. In addition, the hypothalamus is responsible for regulating your hunger, thirst, response to pain, levels of pleasure, sexual satisfaction, anger, aggressive behavior, and more. The pituitary gland is under the influence of the hypothalamus, which in turn pumps hormones into the bloodstream that are vitally important in regulating growth, metabolism, and controls other endocrine glands.

The hippocampus is situated in the left and right temporal lobes in close proximity to the amygdala and is in charge of processing conscious memories. When animals or humans lose their hippocampus to surgery or injury, their ability to form new memories of facts and events is also lost. Instead, a person lives in a strange world where everything they experience just fades away, even while older memories from the time before the damage are untouched. The amygdala is two almond sized neural clusters in the limbic system, located deep within the temporal lobe of the brain. It is involved in many of our emotions and motivations, particularly those that are related to survival. The amygdala is involved in the processing of emotions such as fear, anger and pleasure and receives emotionally rich memory from the hippocampus. Lesions of the amygdala reduce responses to stress, particularly conditioned emotional responses.

Thinking back to elementary school, I can recall a memory that is still vivid in my mind and how the limbic system played a major role. After getting off the school bus and walking down the street towards my house I saw a big husky. It started to run towards me and in that moment I was in fear, thinking that the dog will bite me. I immediately began to run down the street with a heavy backpack on my shoulders. Breathing got harder and I dropped the backpack to gain speed to reach my house for shelter. However, the dog caught up to me and pushed me and I fell to the ground scraping my knees.

The dogs’ intention was not to harm me, but only to play. In this scenario, my amygdala began to process fear as soon as I saw the dog running towards me. The hypothalamus was concerned with the internal environment to be in a steady state. Therefore it tried to regulate the fear and the pain after falling to my knees. The hippocampus stored this memory in my brain. Now when I see a large dog the memory of the dog that was just trying to play with me will turn off the stress response and I wont run away. Structures of the limbic system are vital to what sets us apart from other organisms in the animal kingdom.