The Limbic System

The Limbic System

The Limbic System is a complex group of interconnected structures deep within the brain that is primarily involved in emotion, motivation, memory, and certain survival behaviors (like feeding, reproduction, and fight-or-flight responses).2

It is often referred to as the emotional nervous system because of its profound influence on how we feel and react to the world.³

---

🧠 Major Components and Functions

While the exact components can vary slightly depending on the source, the core structures of the limbic system and their primary functions are:

Structure	Shape/Location	Primary Role
Amygdala	Almond-shaped, near the hippocampus	Processes emotions, especially fear and anger. Essential for forming memories tied to strong emotions (emotional valence).
Hippocampus	Seahorse-shaped structure	Crucial for forming new long-term memories (memory consolidation) and spatial memory (navigation).
Hypothalamus	Sits below the thalamus	Regulates the Autonomic Nervous System (heart rate, blood pressure, body temperature) and the endocrine system (hormone release). Involved in hunger, thirst, sex drive, and the body's response to stress.
Cingulate Gyrus	Arch-shaped structure above the corpus callosum	Involved in emotion formation, pain processing, learning, and linking behavioral outcomes to motivation.

---

📍 Location and Context

The limbic system structures are located on the border ("limbus" is Latin for border) between the older, subcortical areas (like the brainstem) and the newer, sophisticated cerebral cortex.⁴

It is considered an evolutionarily ancient part of the brain, involved in the basic instincts necessary for survival.⁵ It works in conjunction with other parts of the brain, particularly the prefrontal cortex, which provides the executive control necessary to regulate and modulate the emotional impulses generated by the limbic system.

OTHER SOURCES

The brain parts that you do not often see in drawings is found deep within the brain. This brain part is called the limbic system and is involved in emotions and basic drives. Some refer to the limbic system as the lower brain, not only because of where it is located, but because it handles the things about us that are a bit less civilized.

 For example, the amygdala and nucleus accumbens are important for processing fear and reward. They are also involved in drug, alcohol and other addictions. The cingulate gyrus runs the day to day activities of the body that we do not directly control, like heart rate and blood pressure.

One interesting part of the limbic system that actually resides in the parietal cortex is called the hippocampus. The hippocampus is the brain part that forms memories. You have one of these on each side of the brain. 

If one hippocampus is injured, say by a stroke, the other one will still allow your brain to make memories. However, if both hippocampi are removed, as was once done through surgery, then you cannot form new memories! 

This horrible thing happened to a person that underwent surgery to prevent almost continuous, life-ruining seizures. 

After the surgery, it was found that the person could only remember things that happened prior to the surgery and could not make new memories. 

Each day, in fact each new moment was a confusing, perpetual question of How did I get here?

 Needless to say this surgery never happens anymore but this terribly unfortunate occurrence demonstrates the importance of the hippocampus in memory.

Diagram of Brain...

Diagram-of-brain-frontal-lobe